My original intent was to re-orient the top of the dipstick so that the "ENGINE OIL" label on the top of the dipstick would read left-to-right from the front of the car. The cable dipstick on the 3.5 is not quite as flexible as I expected. The top portion of the dip tube as a slight bow and the cable has a permanent, conforming curve to match the bow in the dip tube. When I tried to twist the top of the dipstick so that it would read left-to-right, the cable would spring back to its factory position as it rotated back to the at-rest position with the curve of the cable matching the curve of the dip tube. The technician added a minor crimp in the cable about 4" down from the top to re-orient the top of the dipstick. Now, standing at the front of the car, the dipstick reads left-to-right. This required no modification to the dip tube, and produced no measurable change in the length of the cable dipstick that might affect the oil level reading.
I see on Edmund's main Aurora board that rhale2 posted the minor mod of wrapping the turn signal can with foam tape to make the sound more pleasing to him. In my mind that qualifies as a very minor modification. I like it!
Having had two power antennas fail (1980 Delta 88 and 1986 Toro), I wanted to extend the life of my Classic's power antenna. Since I do not often need the antenna to retract (I park in my garage when at home and in a secure parking garage at work), plus the fact that the antenna makes several cycles when unlocking the car with the remote (starts to extend up), opening the door (down), turning on the ignition (up), starting (down), releasing the starter (up). I figured all those gyrations would wear it out in short order. I bought a small rocker switch at Radio Shack for about $2 and wired it into the power lead to the antenna motor. I mounted the switch in the trim panel that hides the antenna mechanism. With the switch on, the antenna operates as normal. With the switch off, the antenna will not move. The way I use it is to turn the switch off with the antenna extended and leave it that way most of the time. When I park in a public area, I turn the switch on, then turn the ignition off and the antenna retracts as stock.
I haven't posted to the aurora board in about a year, and I didn't know we had all these new discussion areas. Acceleration and modification sections, sounds good!
I bought my 2001 aurora (v8, white/neutral w/sunroof) in early 2001 after a long process of looking at all the cars that would fit my (arbitrary) limit of $40K (plus tax etc). 28000 miles later, all I can say is that I couldn't be happier (well maybe a 2002 with navigation...). I did add one major thing to it, a hitch. It's really the only proper way to add a bike rack to the car. It's also great for long trips with a platform for extra cargo space. Or to haul a popup. Of course this added weight to the car, so it's sort of an anti-performance mod...
I also added a K&N (33-2063-1), and switched to Mobil 1 synthetic oil. I figured this would offset the additional weight
I also got microfiche, manual etc so that I could get a better idea of what could be done if anything to improve the performance of the car.
Now, the 4L northstar is a very efficient engine to begin with. At sea level, normal barometric pressure, 20 celcius, normal humidity, it has a volumetric efficiency of 95.5% at peak HP (which happens at 5600 rpm). Typical detroit iron is 80-85% efficiency. At 100% efficiency, the engine would put out 261hp. Now, this is a 4v/cyl quad cam engine, so efficiency of greater than 100% is achievable, so not to worry, 261 is not the absolute maximum. To achieve greater than 100% efficiency tough will require an exhaust tuned for the application and a very efficient intake.
That's where I get into the second part of my post: the airbox. At 5000 rpm, the engine breathes 337 cfm. That's a good bit of air. At peak HP (5600 rpm) it's 378 cfm! The K&N mentionned above is able to flow 410 cfm according to some litterature. I do not have a confirmation of this. However, this is assuming 100% utilisation of the surface. As anybody noticed changing the paper air filter, only 1/3 of the filter gets really dirty. Obviously most of the flow is going through that area. I think this can be improved significantly. The fact that the same filter is used on the 300hp Cadillac STS means that this filter is not maxxing out on the 4L aurora (and overkill on the 3.5L aurora), if we can believe the caddy info on the web and dyno runs.
If more air can get from section 1 to section 2 of the airbox we probably can approach 100% efficiency with everything else staying the same. At true 100% efficiency (261hp), there is 424 CFM going through and this would be 14 cfm above the figure I've found for the 33-2063-1. Any additional gain would be on the exhaust side only. If we want to improve the intake further, it would require a conical filter within the current airbox with the center divider removed, or with a new airbox.
What K&N are people using on the classic and what is it's CFM? I'm sure it's larger than the one for the 2001+ and in that regard the TB and MAF grill removal would do nothing for the 2K1 as the filter is already maxxed at 258hp.
Now assuming a better filter scheme, the next step on the intake side past 265 hp or so will more than likely require new cams. Caddy STS cams would work great and would get the VE another 10% I would think. Anybody has looked into swapping heads yet?
Also, another area full of promise is the ODB2 interface. The timing at lower RPM is just darn too conservative. And with new cams you'd want a better fuel map too. I'd be interested in comparing the dumps from the 1999, 2001 and 2002 and see what has been tweaked. Well this is getting a bit long, so I'll stop for now.
We got a lot to talk about, right now I dont have time for a lengthy response, but check out a little bit back in the modification section, I put an intake kit and bored out thorttle body on my 96 Aurora for a Dyno gain of 16.7HP at the wheels. Read more about my car on my site I just started, http://www.cardomain.com/id/800wattaurora I'll get some pics up wensday night, check out www.caddyinfo.com to.
Saw your chrome wheels on your site. I've got the alloys and wish I had the chrome as I think they look sweet. What did the swap to chrome cost you and how did you go about it?
Wow... You've really done the math. I think (and I believe Garnes does too) that a cone inside the existing airbox would be a great upgrade for the 2001+ Aurora. The existing airbox would act as a great heatshield and it draws air from behind the headlight which is as good a place as any. I'm not sure where you could get an extra one, short of the dealer. I doubt too many have ended up in junkyards yet.
It's funny you think the current filter is overkill because it's the same filter as for the 4.6L Northstar. I figure it's a constriction for the Aurora V8 and the Northstar because it's the same filter that is used on cars with the 3800, 3.5, 3400, and 3100 V6. To me, that's not a good sign...
Maybe we can bug RSM and get them to develop a new airbox or at least a new lid on the airbox so it can hold a cone filter. It seems it would apply to the Northstars too because the newer ones have a very similar airbox.
The cam swap does sound interesting, however the STS has a fairly weak torque curve in order to make that high-rpm power. I imagine it would have a similar effect on the Aurora V8. I wonder, though, if the STS cams aren't good for a lot more power than they make, and that's why the compromise on the low end is so big. Garnes pointed out to me that the pre-2000 STS has areas where it's torque curve is within 10 lb-ft of the pre-2001 Aurora's curve (I think that's right).
800Watt, go for the 100 octane gas next time. I think it would be worth it just to see if it helps. If nothing else, it will let the car run its max timing. I'd certainly try it if I could get it somewhere other than the track.
RJS: I mentionned it was overkill for the 3.5L aurora. I also wrote "if we can believe the caddy info on the web and dyno runs". There are some dyno runs with the 33-2063 on the STS and while it doesn't seem to show much gain, it actually doesn't reduce the peak hp. This is puzzling to me. Either the K&N is more than 410 cfm or the dyno runs are not very accurate.
So if it truly does the job on the STS, it should be adequate on a stock aurora 4.0 and much more than adequate (overkill as I put it) for the 3.5L.
At any rate, cone filters are the way to go. I've had one on my Peugeot 505 turbo (205hp, 2.1L) and also on my 505 V6 (2.8L with a measly 145hp california or 150hp stock in US form, 170hp in euro form, but currently at 165 hp and I've not put the 10:1 euro pistons or cams yet). I have the k&n catalog and will be taking some measurements to see which filter would be best suited.
aurora5000: from the k&n website faq: "20. How do I know when to clean the filter?
The general rule of thumb is that the filter needs to be cleaned when the dirt build up gets as thick as the wire mesh. The usual interval is 30,000 - 50,000 miles depending on driving conditions. We recommend that you check your filter about once a year in normal usage.
21. Can I use anything other than K&N cleaner and oil?
We recommend that you only use K&N oil and cleaner. K&N air filter oil is a compound of mineral oil blended with special polymers to form a very efficient tack barrier. We have performed tests on numerous oil combinations and our blend has the required properties for maximum flow and filtration. Petroleum products such as transmission fluid and motor oil will soften and destroy the rubber sealing edges. Our cleaner is a non-detergent degreaser. Solvents and gasoline will harden the rubber seals causing the filter to distort (shrink). A mild detergent can be used in a pinch, but care should be taken to fully rinse it out. Rinsing detergent out of a filter is similar to getting soap out of a sponge; it’s not that easy to do. Always make sure the filter is completely dry before re-oiling.
22. Can I use compressed air to dry the filter faster?
No, this can blow the filter material right out of the wire mesh and ruin the filter. Pick a nice day to clean the filter and let it dry naturally.
23. Should I brush the wire screen with a toothbrush to get all the “crud” off?
No, this could tear up the cotton gauze. A soft bristle paintbrush is a better idea and is recommended on the cleaning instructions."
That E-Ram seems like a scam to me. For one thing, it takes about 50 amps? That's more than half of most alternators peak output. And at lower rpm's most alternators are nowhere near their peak. And, it sounds like crap. Did you hear it buzzing in that movie clip? Also, on some forum that was discussing it, someone had purchased it. They said it was much cheaper than it appeared. It was all plastic, not the metal housing as it appears in the picture. They said the housing collapsed in on the fan when he put it in his intake ducting. The company never refunded his money or offered a fix.
fdion, you're awesome! You really seem to have done the research (responding to your Acceleration posts too). I wonder how big a cone would fit in the second chamber of the airbox (I'm not sure I want to hack mine up). The way the opening at the top is, it could probably be fairly sized. I guess some plastic tubing would have to be glued to the lid to hold the cone. Definitely interesting.
Steve, I have checked the filter a few times, and I'll probably clean it after about 30,000 miles. I use the K&N cleaning kit. It has some cleaning solution and some oil spray. They are only about $10. Just follow the directions that come with it. As noted before, though, I let my filter dry at least overnight. It's soaking wet after you clean it. I'd have a hard time just oiling it down and slapping it in the car, although apparently it's ok to do that.
What the heck is up with this board? The "Accessories & Modifications" board suddenly doesn't get shown as "new" anymore for me, but the other boards do.
Did RSM say how much the stock vs bored increased flow? Any cfm ratings or at least velocity? I'm also looking at the accordion style hose between the MAF and the airbox. I know this is great to quiet the noise, but for performance this is not exactly the ultimate. As far as ducting and hoses and the like there are a lot of sources for that, in particular:
Here is an idea. Connect the MAF to an aluminium pipe that would go into the airbox top lid (needs expanding a little) with a coupler like this:
And using an alloy (flexible) pipe like this:
And then putting the cone air filter on that pipe inside the airbox. That's $40 in parts from BMC, $15 in clamps and whatever the K&N will cost. Possibly an airbox top lid from the dealer.
Garnes: How much did you pay for a used TB? How much did the mod with shipping cost on top of that? Also, I remember when I was on the board last year you were about or had bought a Granatelli MAF. What is your opinion of it a year later?
Cleaning K&N - I would be careful about going 30k miles with some cars as they use such a small area of the filter they block off really fast. This is my experience with our 2001 Impala and I think it is true for the millions of GM 3.8's out there with the really crappy air box. Also, when the filter looks a little dirty on the classic - just look at where the dirt builds up. It's on one side of the pleats! Just rotate it 180. I think the car sees an almost new filter again. The new Aurora may be the same.
fdion - I got my TB for $175. $14 shipping. RSM will charge me about $270 or so including shipping for their work.
I don't agree about the TB or other intake mods not helping in relation to the filter capacity. Air is compressible (or stretchable). As the air makes it's way through the intake, any restriction (everything it contacts really) causes a pressure drop and with air, it probably lowers the density as well. I deal a lot with pumping water and have to calculate losses all the time. I know there is a big difference between compressible air and incompressible water, but I think that the fundamental principles still apply to some degree. On a suction or discharge line, the losses along a line are all added up for any given flow. There is no such thing as "well this restriction is so great at this end, that this lesser one in the middle doesn't matter". Sorry if I misunderstood your post - I feel as though I may have. But I'll bet a bigger TB will help the new 4.0 just the same as 800wattaurora has shown it helped the classic.
One possible interesting test. Just dyno it with no filter (if you really wanted to). I'm not sure it would really hurt anything, although I don't want to try this. That would tell a lot as to what the filter is doing to you.
MAF - THE GRANATELLI MAF DID NOT WORK FOR ME! It was a lot of money, and LOST me power on my dyno runs. It leaned out the car's A/F a lot. Granatelli doesn't have any testing of the MAF for the Aurora that I'm aware of and the same may be true for the caddy 4.6. It was recalibrated to fake out the computer. I think the stock A/F's are pretty good. They recalibrated it back to stock A/F but it's in the box for now. Maybe I'll test it sometime.
CAM - I really thing the 275 4.6 would beat the 300 version if it were mated to the 3.71. It has a lot more HP up to 5000 rpm and a ton more torque all over. I think the 300 HP thing is more for marketing. I don't think adjusting the 4.0 performance to behave more like a 300 HP version of the 4.6 would benefit acceleration at all. You might have more peak HP bragging rights though.
fdion - I posted somewhere not to long ago about the TB velocity. I've just used 350 cfm for an easy approximate number. I think at that flow rate, the velocity through a stock 75mm ?? TB is something like 83 or 84 mph. The 80mm TB brings it down to the 73 mph range. I'm going from memory here.
If the losses for air are a function of velocity squared (like for water) then you have a difference of 29% for the example above. I admit, I don't know what that relationship for air is, and I'm sure it varies with density/pressure too. But for getting a general idea, this stuff might help.
Hey - have you looked into the Corsa exhaust for your 2001? I think they are working on a system tuned for the new Aurora. Apparently the classic sounds good with their STS system, but they want to tune the sound better for the new 4.0. Apparently the difference in exhaust valves and perhaps some other differences make a difference in sound on the classic vs the new 4.0 when using Corsa's cat-back system for the STS.
Garnes, it does get mainly on one side of the pleats. I've already rotated mine just to keep it even. Plus, the spot it pulls from is off-center so when it's rotated it is seeing a very clean part. However, I think as that spot gets dirtier, air will pull across the rest of the filter. It's going to take the path of least resistance. Part of the filter may get dirtier quicker, but the filter should still be able to go the distance. It isn't like no air passes through the rest of the filter. If part gets blocked up, it will certainly travel over the clean parts.
I've never seen any info about the actual flow rate of the throttle-bodies. I'm sure it isn't quite (80mm/2)^2*Pi because there is a big butterfly sitting in the middle of it. However, I would think the larger size would definitely help.
Man... I want to mod the airbox, get the TB, and get the Corsa. But I also want to try some new paint protectant products. And that OBD-II thing sounds cool. However, I'm not sure I want to dump that much money all at once. I'm pretty cheap by nature. Plus, I want to try the track again with a basically stock car once the temps have dropped. Well, I'll own the car a long time, so I guess I have plenty of time to accumulate mods.
Give me a break man. At WOT the throttle plate and the center support are pretty skinny. Yeah, it's basically a simple difference of area. I'm sure I'm well over 90% accurate on the area and velocity comparisons. If you're going to make a point like that in the future, please qualify it a little like "you could be off 5% or so". If you really think it's way off because of the throttle plate well... that's goofy.
Heck - if you want to get picky, then you should also consider that as the area is increased, the diameter becomes a smaller percentage of the area. In other words, the larger throttle body is "more efficient" in it's use of the total area.
Dirty filter - path of least resistance. Nope. At least the path of least resistance is not what it looks like. I can show you a dirty filter from the Impala and the dirt is entirely caked in one area. The rest of the filter is right out of the box clean. The air is almost never going there. That's because the filter is practically in-line. Both sides of the box come very close to the filter face.
When the air is shooting through the intake for the box at 30 to 60 mph, it's pretty tough for the flow path to do a 90 in a fraction of an inch and then another 90 to go through the filter - and then two more 90's (again within a fraction of an inch) on the clean side to continue toward the engine.
If you want to argue it further, I'll just have to send you the dirty filter. Its like someone drew the dirty spot on there with a marker and shaded it in - and was real good about not going outside the lines.
that if you never changed it, and that spot caked up to where air wouldn't flow through it at all anymore, that your car would just stall out and die? I seriously doubt that. Hell, just cut out a little cardboard circle and put it over the spot. See if you can start your car. I guarantee air will flow through the rest of the filter. You can twist a vacuum hose completely around and the air will amazingly travel a complete 360 degrees just to fill in the pressure differential. In fact, you can do this two or three times and the air will still make it even though it has to turn way more than 90 degrees! :O
"Give me a break man. At WOT the throttle plate and the center support are pretty skinny. Yeah, it's basically a simple difference of area. I'm sure I'm well over 90% accurate on the area and velocity comparisons. If you're going to make a point like that in the future, please qualify it a little like "you could be off 5% or so". If you really think it's way off because of the throttle plate well... that's goofy."
Here's all I said: "I've never seen any info about the actual flow rate of the throttle-bodies. I'm sure it isn't quite (80mm/2)^2*Pi because there is a big butterfly sitting in the middle of it. However, I would think the larger size would definitely help." So you don't think it would be interesting to see actual flow rates of the two throttle-bodies?
Garnes-So what do you say I contact Corsa this week? Give Jim Browning Jr. a call, see if things are slowing down yet. I hope so. When did RSM say they'd have your TB done? I plan on calling some junk yards soon, see if I can find a TB core to send back to them. Also look for a some heads and an intake manifold for a future port & polish job. At least price it out.
Stall out - of course not. Sure it will flow around, but I'll bet the car will run really bad. If you saw the filter, you'd realize things would have to get extremely bad for air to pass through a different part of the filter.
I'm just saying that even really really dirty, it's still easier to keep going straight through the dirt, than to wind around it in an almost in-line situation. What seems to be the path of least resistance (as measured by what your eye tells you about the dirt on the filter) may not really be so.
TB - sure, give me the info if you have it. I never said I wouldn't be interested. But hey, I can calculate area and velocity to get an idea of what's happening. If you want to worry about the "big" throttle plate, go for it.
It's sad that I can't post a general observation or calculation without often having some small detail brought up as if I hadn't thought of it and as if it significantly compromised the point being made. Sorry, but I don't have a TB sitting on the table to measure the thickness of, but it sure looks thin and small compared to the circular opening.
If that seems to you to make a big enough difference so as to mention it, then please tells us how much of a difference you think it makes. Really. Please do. I still say the basic area calculations will get you extremely close to the % difference in TB area.
Also, did you consider that much of the throttle plate takes the same area on either TB? All but 5mm I guess. That would kind of cancel out when just making a general comparison of area.
"It's sad that I can't post a general observation or calculation without often having some small detail brought up as if I hadn't thought of it and as if it significantly compromised the point being made. Sorry, but I don't have a TB sitting on the table to measure the thickness of, but it sure looks thin and small compared to the circular opening."
Actually, I was responding to Fdion, not to you. He asked: "Did RSM say how much the stock vs bored increased flow? Any cfm ratings or at least velocity?". And as far as I know, nobody has seen these actual numbers, so that is what I said. So don't get all pissy. I'm sure the butterfly doesn't make much difference. And obviously there is a butterfly in the stock TB too, so the gains are still there. The butterfly probably makes less difference in the larger TB since it only grows in one direction (I don't think it gets thicker).
I wasn't implying either that you were off. In fact, 800wattaurora ET is definitely proof of the gain of the TB. I was just asking for some numbers so I could quantify and see how much of an impact it would have on the engine Ve assuming a less restrictive intake on a 2K1 and trying to gauge how much of a difference with the current stock intake.
If you think the classic is bottled up, you should see the 2k1+! Beside the smaller area on the filter, it gets air solely from the front of the airbox, behind the headlamp and the only way the air gets there is through a little round hole in the underbody plastic pan and through a foam "filter" at the driver's side intake grille. And sideways at that, since half the grille is blanked out.
The reason for this less than ideal air path is to not have a "straight from the front" air intake in case of rain. And that is why the foam is there too. The problem with this foam is that it blocks the airflow significantly and also since it's sort of just put there, it gets sucked in and blocks the little round hole too!
I appreciate your posts and the fact that you've been looking at performance for the aurora for a longer time than anybody else and put a lot of research into it says that you are serious about performance. Please dont take posts as criticism. Take them as additional info.
I wouldn't worry about it if I were you. I think Garnes was just annoyed at me, not you (although I don't want to speak for him, but I'm pretty sure that's the case). We go back and forth like that sometimes. Your description of the airflow to the 2001+ is interesting. I was under the impression that the foam was just there to direct air into the radiator. I guess it does keep air from the airbox, though. When I was really looking at it, I figures air came up from the bottom. I forgot that I'd taken the tray off the bottom, though. With it in place, it would keep air from coming up off the ground. I doubt much sneaks in by the headlight because it's got a sort of rubber gasket around it. Did you see what I tried to do with that driver's-side grill inlet? I thought I could pipe air in from the blocked-off part, and that way it wouldn't interfere with the radiator airflow. Perhaps you can come up with a better scheme. Maybe narrower ducting would be better than nothing. If the ducting might be a restriction, I could always not connect it to the airbox (which I considered before but thought it wouldn't really help that way) so it would just pipe more air up around the box, but if it couldn't keep up, the box could still pull from it's normal supply. Or perhaps you can think of a better type of hose that might be more flexible/compressible that would work.
Is the intake manifold made from thermoplastic on the classic like on the 2K1+? That does limit the things one can do to it. I suspect it's already pretty slick inside anyway to begin with.
Is the SLS and STS using the same manifold? I think I need to get me microfiches and shop manual from the classic and the cadillacs. Also the part exchange tsb would be good to have.
That is pretty interesting. I've ran without the intake grille and it seems to help, but haven't truely measured anything. I wouldn't do that in the rain... Would be nice to install a electromechanical vane at that grille...
I'll look into a better hose (or if there is a better hose).
fdion - none of my posts of late were directed at you.
RJS - is it pissy or annoyed??? Make up your mind. Just go for it and say I'm outraged - that will just cover all the bases for you. :>
I think my responses are quite appropriate and factual. I make a general comparison of TB before and after area and velocity % change, and you have to point out that I left out something - something pretty darn inconsequential for the sake of making a general comparison. In addition, I later explained that the throttle plate mostly cancels out as it's there for both (remember I was getting at % change in area/velocity/losses), and that the plate becomes a smaller part of the total area for a larger TB.
I've been basically looking at it from a little different angle I guess - trying to get an idea of pressure drop or a loss at the same flow rate through each. Just a different angle as opposed to what is the flow at a given pressure.
As for my "it's sad" comment - well your post # 215 comment about it not exactly being Pi r^2 sure seems to be to me. Thanks for finally admitting in 221 that it probably doesn't make much difference. My point all along - especially when comparing the two. I'd actually care to estimate it if I was interested in knowing exactly the area and velocity at a given flow for a specific unit. So, what is the point of making a comment like that if it doesn't make much of a difference? That's sad. :<
Perhaps this info won't be available. But, if anybody knows what the relationship between the pressure drop across an obstruction for air flow as it relates to air velocity, that would be interesting.
For example, with water, it's basically a function of V^2/2g, g being the gravitational constant of 32.2 ft/sec^2. Some obstructions are worse than others so the V^2/2g gets multiplied by different constants depending on what you are looking at. If you are just comparing different sizes of the same obstruction (orifice, bend...) then the constant is basically the same.
So - with air flow, is it V^2?? V^1.5??? I don't know. Maybe a look in the physics book would yield a clue pretty quick, but I don't have mine any more. I deal with water all the time and have plenty of info on that - but nothing for air.
I'm sure there are similar relationships for density too.
Anyway, this might prove interesting when trying to get an idea of how much a mod might help air flow compared to stock - assuming it's a significant restriction in the first place.
The TB orifice is pretty small compared to the rest of the intake.
"As for my "it's sad" comment - well your post # 215 comment about it not exactly being Pi r^2 sure seems to be to me. Thanks for finally admitting in 221 that it probably doesn't make much difference. My point all along - especially when comparing the two. I'd actually care to estimate it if I was interested in knowing exactly the area and velocity at a given flow for a specific unit. So, what is the point of making a comment like that if it doesn't make much of a difference? That's sad. :<"</i>
I don't know what I can say differently than the last post. Garnes, I wasn't responding to you at all. Fdion asked if anyone had actual numbers, and I responded that I'd never seen any. While your numbers are interesting, they aren't actual measurements.
RJS - I never asserted that anything was an actual measurement. Perhaps I should have tried to make the point without using any numbers. Nice straw-man attempt though.
OK - assume i drive in snow (i will) assume i will take the car to the track (i will)both 1/4 and solo (cone racing) BUT - want a decent life out of the tire
whats my top two or three choices for the above and still wanting a decent ride quality ?
there are just way too many posts on this forum to research on my own, so thought id test you guys and your tire sense - thanks
Does anybody have any info on the relationship between air velocity and the resultant pressure drop or loss through some sort of obstruction?
I realize air is compressible and such a relationship may vary depending on density and maybe even some other factors, but assuming the rest are constant, it would be interesting for comparing any sort of modification that improves air flow to the stock condition.
FJK - you are a physics guy. Any help? fdion seems to have been into the physics stuff too. Anything?
Otherwise I may just have to look this up myself. That would be a shame.
I was thinking about that air intake thing again and how the air gets into the airbox. Anyway, it made me remember my 1/4 mile runs. With the headlight in place, and the car breathing regularly, I ran a 16.098. With the headlight removed, I ran a 16.056. Removing the headlight probably doesn't cause much "ram" effect because the intake is angled away from the front a bit. However, the air wouldn't have to travel up from the center inlet to the airbox. This is a pretty small difference (both are 16.1 basically). I wonder if lower temp would increase the difference, or if turbulence affected the breathing somehow. I just thought it was worth pointing out.
Garnes, I'm not sure exactly what formula to look for, but I remember you mentioning resistance varying at the square of velocity for water. I found this website which seems to show it as velocity to 1.6 instead of squared for air. But I don't really know what I'm looking for, so maybe this is worthless.
Or whatever they are called. The classic Auroras have those black painted exhaust extensions, they are unattractive. Does anyone have a solution to a chrome-plated replacement, for instance. - and what has to be done? It appears that the 'extension' is welded to the system. I have a 99, midnight blue, just bought it at 25,000 miles. Sold my '96 silver teal at 120,000 mi.
OK, I finally installed the RSM throttle body at the dyno and got some before and after results. It's pretty interesting.
First, I'd like to point out that the RSM TB seemed to measure 79.5 mm. Not quite 80. Whatever. What's really weird is that my stock TB measures 76 mm. Not 75 mm! What's going on????!!! Can anybody check this officially? I thought I was getting something 5 mm over stock, but it seems to have been only 3.5 mm. I will be calling RSM as well.
I did not get peak HP and torque increases as great as Taylor, but I'm pretty happy just the same. I was really happy that the gains were ALL OVER the curve and actually bigger down lower in the 4000's.
It was 86 degrees for the baseline runs, 87 after I was done installing the throttle body. All my previous dyno runs were done on 70 degree days. Here are the numbers:
The first baseline was not as strong, and I think it's because the engine was not up to full temp. I guess I should have run one more. Oh well. After installing the TB my first run was with the engine not quite up to operating temp and the first run was about 2 HP less than the next 3 runs. These next 3 runs were dead nuts on the same as each other throughout the curve, so I'm confident of the TB results. For some reason, my experience at the dyno is that the car runs best when up to temp and is just fine even a little over the 200 line as well - just my experience. I'm comparing the results to the better base line. If I use the lower base line I get some big gains more like Taylor's.
New TB runs: 198.6 HP, (+5.4 peak HP - at wheels) 214.2 torque (+5.1 peak torque)
Now, here is the good part, the gains were all over the curve which is really most important. Look as these numbers:
Please, I hope nobody feels compelled to point out the discrepancy in the peak numbers/gains with the gains shown for the various rpms. The peak numbers are literally from the slightest bump in the curve just before or after one the rpm values listed.
I'm still pretty happy with the results. I'm totally confused by the stock unit being 76 mm. Taylor, can you please check the diameter on your stock TB? If it's somehow 75 mm, then that may explain something. Also, I swear my RSM was a shade under 80 mm.
In addition, it's possible that Taylor's stock TB was dirty enough (I remember him saying it was really bad) to rob a HP or two for the baseline. I think it's possible to have 1/2 mm build-up (that's rough too). Maybe more. Mine was pretty clean as I had cleaned it recently.
Taylor - thank you very much for walking through this with me first. It was kind of a pain in the rear job, but certainly not too bad. It would have been bad if I had not seen how the throttle cable simply snaps in (on the junk yard unit). I also knew in advance that the cruise control cable assembly just snaps on as well. Those two little hoses were the BIGGEST PAIN IN THE BUTT! They got me swearing. Also, thanks for the manual info and the TB position relearn thing.
The car seems to run just the same for regular driving. No problems. I'd recommend this modification - especially for any 4.6 caddy guys. They HAVE to do this. It will probably really help.
With the air box mods, K&N filter, and the RSM throttle body, I'd estimate (somewhat conservatively) the engine HP to now be about 266 HP, and 275 torque.
The Corsa exhaust should get it to 280 HP, and torque should be well over 280, maybe close to 290.
BTW - I did check tire pressure before and after runs. No difference.
Also - I got to see the difference 16 or 17 degrees made to the power. It was much more humid too. It certainly is big. The computer correction factor was 3% different than on the cooler days. Roughly .03 x 200 = 6 HP, and I was still getting results at least 5 HP lower. So perhaps the total was at least 11 HP. I know that it has been posted that such a temp difference should make even more of a change, but again - I hope nobody goes into this. The dynojet computer tries to adjust but it is nowhere near exact. I've seen it use the same correction factor for similar days, but the temp and other conditions were certainly different. It also has a major disclaimer about trying to compare results from different days with different conditions. Bottom line, you have to do test the same day -back to back. I really question the value of dyno testing the exhaust now.
So, based on the above, my "after" HP and torque runs should be another .3 higher (?? just a WAG) since it got 1+ degrees warmer. :>
That's great that it's been tested twice and passed both times. How strange about the sizes, though. I think when Taylor measured his stock TB he said it was about 74mm. I wonder if it depends on where you measure it or something. I haven't actually looked at the TB on my Aurora, but on my Corvette it sort of tapered down to the butterflies (it had two). That would definitely make it interesting to see some flowbench numbers. I wonder how expensive that is. Maybe RSM could do it, or maybe the next person to buy one can if it's cheap.
Garnes, I wonder if you got less of a gain than Taylor because of his cone? Maybe the cone flows more so the extra TB size can be put to work more? Did the intake manifold opening seem substantially smaller than the TB opening with the new TB? Taylor mentioned that. I was wondering what your opinion of it was. I wonder if sanding it out would be a bad idea? If RSM answers my questions about the TB (they seemed a bit surprised that the MAF doesn't mount to it like on the classic) and I get one, I can't see myself dremeling out the intake manifold even if it would help...
Thanks for checking the tires. That's interesting they didn't change. I would have thought that accelerating up to 80+mph a few times would have put some heat in them. Especially since the Aurora has so much weight on the front tires.
If you were really interested, maybe Corsa could arrange a dyno test for you. Do they have one? Or maybe you could have the exhaust system clamped so you could swap it at the dyno. That might be a bit of a pain (plus you'd have to drive a whole exhaust system over to the dyno place), but it might not be much more work than swapping the TB since it's just a few clamps and hangers.
Garnes, you mentioned "The car seems to run just the same for regular driving. No problems." Do you just mean that it didn't exhibit any poor behavior, or do you mean that you don't feel much power gain?
Thanks for taking the time to test it and to let us all know how it went. You and Taylor have provided us with some great info.
Runs just the same - yes, I meant that there are no problems. Everything seems normal. This mod doesn't seem to have any negative affects. I have not had a chance to jump on the thing yet on the road.
Intake manifold - I'm so glad you asked. I did take a good look at this as I was interested too. Basically, it appeared to me that the TB outside diameter was nearly flush with the manifold (or whatever the segment is that it bolts to) in some places and most places it seemed to protrude maybe 1 mm - not much at all. Looking at it, I remember thinking that the larger TB must be taking advantage of a little extra size immediately downstream. BTW, that piece that the TB bolts to looks like it can be removed as well. It seems to bolt to something too - the actual manifold I guess.
Tire pressure - well the car basically come into the place with the tires warm. They never get a chance to cool down that much I guess. Plus the dyno run goes by so fast, I don't think there is a lot of heat generating time with the tires - maybe enough to keep them warm. That's my guess as to why I did not see a difference.
With the crud build-up on the TB, I really think 1/2 mm accumulated (total 1 mm from the diameter - plus there is stuff on one side of the plate - plus it's rough) could amount to a considerable loss in TB area and flow compared to the small diameter increases we are trying to realize with the boring. That may be why Taylor got a little more punch. Then there is this stock size thing. That is really weird.
About the intake cone thing - I don't think it's that much of a difference. I basically got the same peak number gains as Taylor by using the K&N panel filter, but it was admittedly mostly top end gain. The air box mod fattened the gains out throughout the curve and added as much if not more power in the 4000's as the K&N. So, with the box mod & K&N I think I should be pretty close to the cone set-up.
My personal opinion is that the cone set-up should be a little better because you get rid of the hard 90 in the box, but I think it may not be a whole lot better than what I have now. Also, with the box mod, I know for sure I'm pulling fresh air and I don't have to worry. I totally agree with Taylor's work to build a heat shield as I think it will help a lot. For some reason, RSM just doesn't think it is necessary (but the K&N FIPK cold air kits have heat shields).
Taylor - I may be interested in your heat shield and try the RSM induction some time. Could you make additional pieces? How much $$?
The guy at the dyno told me a couple of Mustang guys were debating if removing the screen from the MAF helped. He said - let's just test it. End result - no gain from removing the screen on the Mustang MAF. He did say that the A/F was still the same, so apparently it was still able to read correctly.
I got a reply from Zsolt at RSM that shines a lot of light on my throttle body tests. Here's what he said.
"Thanks for the feedback, the overall size of the TB is between 79-80 mm depending on the casting of the TB core we have. To realize the full potential of the TB you can match port the piece that the TB attaches to(that piece can only be done by hand) or you can send it to us so we can do it ($US100.00 for the labour). The limiting factor in boring a TB is usually the throttle plate bushing housing (and this is only obvious if you have the plate removed) and the size of the intake port where the TB is mounted. The stock TB should be 75 mm but we have seen anywhere from 74 to 76, you would be surprised sometimes how bad the OEM castings are."
So, my stock throttle body was on the big side at 76 mm which certainly nipped a little off the gains. I guess I was already experiencing some of the gains with an extra 1 to 2 mm over some other stock cars. This explains a lot. Of course I'll be comparing my actual stock area vs. if it had been 75 mm and trying to extrapolate a little. I'd guess I might have seen at least another 1 HP and torque "gain" with the baseline down a little if it was 75.
Now, I'm tempted to port out that intermediate block. I wish I knew about it in the first place. I would have got it along with the TB and sent that in too. I may be able to do this myself though.
That is interesting. I guess it's no surprise about the casting variances. If you hand-port the mounting piece, do you take it off first or would you have to do it in the engine bay? I guess you could mark through the TB while it's attached to give you a guideline of where the TB opening is so you can easily port it out properly. I'm going to give some junkyards a call.
Hey Greg, did you have to remove all the sensors (like the TP sensor and probably some idle control) from your stock (not the junkyard one, but the one that came with your car) TB and attach them to the new one, or did it come with them already on there? Also, if they were on there, are they just whatever was on it before the porting, or does RSM put new sensors on it as part of the price?
The idle control and TB position sensor were on the junk yard piece. RSM broke the sensor plastic housing but it did not matter because I just attached my stock sensor and idle control to the new TB. The stock ones are all wired up already.
More on that 75 vs 76 mm thing. That 1 mm represents about 22% of the extra area I would have got from the 79.5 mm unit if the stock unit was indeed 75. Interesting. If Taylors was only 74 (and really dirty) that explains everything I think.
I'm calling the bone yard to try to get that intermediate piece. If I get it, I'll do it, but won't dyno it as it will probably only add another 1 to 2 I think.
The bone yard said they could get one for me (off the same car I think) and it's FREE. Very cool. RSM said it had to be done by hand. I don't know why. I guess I'll just pick this up and give it a try. I'll have to get a gasket too. This should help a little more for sure.
While your at or calling the boneyard would you mind seeing if they have the door to the front center ashtray. I've been looking for one of these for close to a year now. If they have one let me know their phone #. I'd really appreciate it. Thanks.
Sure, I'll call, but the wood may not match - it's a gamble. Is that a concern?
Hey - you gotta do the TB now too, and when you do, make sure you get the mounting plate too. It just has to add even more to have that bored to 80 mm as well.
If I can do it, anybody can. Taylor guided me through and I'd be happy to return the favor for anybody else.
Comments
I see on Edmund's main Aurora board that rhale2 posted the minor mod of wrapping the turn signal can with foam tape to make the sound more pleasing to him. In my mind that qualifies as a very minor modification. I like it!
Ken
I haven't posted to the aurora board in about a year, and I didn't know we had all these new discussion areas. Acceleration and modification sections, sounds good!
I bought my 2001 aurora (v8, white/neutral w/sunroof) in early 2001 after a long process of looking at all the cars that would fit my (arbitrary) limit of $40K (plus tax etc). 28000 miles later, all I can say is that I couldn't be happier (well maybe a 2002 with navigation...). I did add one major thing to it, a hitch. It's really the only proper way to add a bike rack to the car. It's also great for long trips with a platform for extra cargo space. Or to haul a popup. Of course this added weight to the car, so it's sort of an anti-performance mod...
I also added a K&N (33-2063-1), and switched to Mobil 1 synthetic oil. I figured this would offset the additional weight
I also got microfiche, manual etc so that I could get a better idea of what could be done if anything to improve the performance of the car.
Now, the 4L northstar is a very efficient engine to begin with. At sea level, normal barometric pressure, 20 celcius, normal humidity, it has a volumetric efficiency of 95.5% at peak HP (which happens at 5600 rpm). Typical detroit iron is 80-85% efficiency. At 100% efficiency, the engine would put out 261hp. Now, this is a 4v/cyl quad cam engine, so efficiency of greater than 100% is achievable, so not to worry, 261 is not the absolute maximum. To achieve greater than 100% efficiency tough will require an exhaust tuned for the application and a very efficient intake.
That's where I get into the second part of my post: the airbox. At 5000 rpm, the engine breathes 337 cfm. That's a good bit of air. At peak HP (5600 rpm) it's 378 cfm! The K&N mentionned above is able to flow 410 cfm according to some litterature. I do not have a confirmation of this. However, this is assuming 100% utilisation of the surface. As anybody noticed changing the paper air filter, only 1/3 of the filter gets really dirty. Obviously most of the flow is going through that area. I think this can be improved significantly. The fact that the same filter is used on the 300hp Cadillac STS means that this filter is not maxxing out on the 4L aurora (and overkill on the 3.5L aurora), if we can believe the caddy info on the web and dyno runs.
If more air can get from section 1 to section 2 of the airbox we probably can approach 100% efficiency with everything else staying the same. At true 100% efficiency (261hp), there is 424 CFM going through and this would be 14 cfm above the figure I've found for the 33-2063-1. Any additional gain would be on the exhaust side only. If we want to improve the intake further, it would require a conical filter within the current airbox with the center divider removed, or with a new airbox.
What K&N are people using on the classic and what is it's CFM? I'm sure it's larger than the one for the 2001+ and in that regard the TB and MAF grill removal would do nothing for the 2K1 as the filter is already maxxed at 258hp.
Now assuming a better filter scheme, the next step on the intake side past 265 hp or so will more than likely require new cams. Caddy STS cams would work great and would get the VE another 10% I would think. Anybody has looked into swapping heads yet?
Also, another area full of promise is the ODB2 interface. The timing at lower RPM is just darn too conservative. And with new cams you'd want a better fuel map too. I'd be interested in comparing the dumps from the 1999, 2001 and 2002 and see what has been tweaked. Well this is getting a bit long, so I'll stop for now.
Ciao,
Francois
More later
800wattAURORA
It's funny you think the current filter is overkill because it's the same filter as for the 4.6L Northstar. I figure it's a constriction for the Aurora V8 and the Northstar because it's the same filter that is used on cars with the 3800, 3.5, 3400, and 3100 V6. To me, that's not a good sign...
Maybe we can bug RSM and get them to develop a new airbox or at least a new lid on the airbox so it can hold a cone filter. It seems it would apply to the Northstars too because the newer ones have a very similar airbox.
The cam swap does sound interesting, however the STS has a fairly weak torque curve in order to make that high-rpm power. I imagine it would have a similar effect on the Aurora V8. I wonder, though, if the STS cams aren't good for a lot more power than they make, and that's why the compromise on the low end is so big. Garnes pointed out to me that the pre-2000 STS has areas where it's torque curve is within 10 lb-ft of the pre-2001 Aurora's curve (I think that's right).
800Watt, go for the 100 octane gas next time. I think it would be worth it just to see if it helps. If nothing else, it will let the car run its max timing. I'd certainly try it if I could get it somewhere other than the track.
Thanks,
Steve
So if it truly does the job on the STS, it should be adequate on a stock aurora 4.0 and much more than adequate (overkill as I put it) for the 3.5L.
At any rate, cone filters are the way to go. I've had one on my Peugeot 505 turbo (205hp, 2.1L) and also on my 505 V6 (2.8L with a measly 145hp california or 150hp stock in US form, 170hp in euro form, but currently at 165 hp and I've not put the 10:1 euro pistons or cams yet). I have the k&n catalog and will be taking some measurements to see which filter would be best suited.
aurora5000: from the k&n website faq:
"20. How do I know when to clean the filter?
The general rule of thumb is that the filter needs to be cleaned when the dirt build up gets as thick as the wire mesh. The usual interval is 30,000 - 50,000 miles depending on driving conditions. We recommend that you check your filter about once a year in normal usage.
21. Can I use anything other than K&N cleaner and oil?
We recommend that you only use K&N oil and cleaner. K&N air filter oil is a compound of mineral oil blended with special polymers to form a very efficient tack barrier. We have performed tests on numerous oil combinations and our blend has the required properties for maximum flow and filtration. Petroleum products such as transmission fluid and motor oil will soften and destroy the rubber sealing edges. Our cleaner is a non-detergent degreaser. Solvents and gasoline will harden the rubber seals causing the filter to distort (shrink). A mild detergent can be used in a pinch, but care should be taken to fully rinse it out. Rinsing detergent out of a filter is similar to getting soap out of a sponge; it’s not that easy to do. Always make sure the filter is completely dry before re-oiling.
22. Can I use compressed air to dry the filter faster?
No, this can blow the filter material right out of the wire mesh and ruin the filter. Pick a nice day to clean the filter and let it dry naturally.
23. Should I brush the wire screen with a toothbrush to get all the “crud” off?
No, this could tear up the cotton gauze. A soft bristle paintbrush is a better idea and is recommended on the cleaning instructions."
Francois
This is like the xstream top type cone filters but with even more surface. Here is the xstream type:
I suspect both are much more expensive than the regular type cone filters.
Francois
fdion, you're awesome! You really seem to have done the research (responding to your Acceleration posts too). I wonder how big a cone would fit in the second chamber of the airbox (I'm not sure I want to hack mine up). The way the opening at the top is, it could probably be fairly sized. I guess some plastic tubing would have to be glued to the lid to hold the cone. Definitely interesting.
Steve, I have checked the filter a few times, and I'll probably clean it after about 30,000 miles. I use the K&N cleaning kit. It has some cleaning solution and some oil spray. They are only about $10. Just follow the directions that come with it. As noted before, though, I let my filter dry at least overnight. It's soaking wet after you clean it. I'd have a hard time just oiling it down and slapping it in the car, although apparently it's ok to do that.
What the heck is up with this board? The "Accessories & Modifications" board suddenly doesn't get shown as "new" anymore for me, but the other boards do.
Flexfab
And the better place to buy that is at:
Hosenow in detroit.
Less expensive than this space age stuff:
Baker Precision
Hose techniques
Here is an idea. Connect the MAF to an aluminium pipe that would go into the airbox top lid (needs expanding a little) with a coupler like this:
And using an alloy (flexible) pipe like this:
And then putting the cone air filter on that pipe inside the airbox. That's $40 in parts from BMC, $15 in clamps and whatever the K&N will cost. Possibly an airbox top lid from the dealer.
Garnes: How much did you pay for a used TB? How much did the mod with shipping cost on top of that? Also, I remember when I was on the board last year you were about or had bought a Granatelli MAF. What is your opinion of it a year later?
Francois
fdion - I got my TB for $175. $14 shipping. RSM will charge me about $270 or so including shipping for their work.
I don't agree about the TB or other intake mods not helping in relation to the filter capacity. Air is compressible (or stretchable). As the air makes it's way through the intake, any restriction (everything it contacts really) causes a pressure drop and with air, it probably lowers the density as well. I deal a lot with pumping water and have to calculate losses all the time. I know there is a big difference between compressible air and incompressible water, but I think that the fundamental principles still apply to some degree. On a suction or discharge line, the losses along a line are all added up for any given flow. There is no such thing as "well this restriction is so great at this end, that this lesser one in the middle doesn't matter". Sorry if I misunderstood your post - I feel as though I may have. But I'll bet a bigger TB will help the new 4.0 just the same as 800wattaurora has shown it helped the classic.
One possible interesting test. Just dyno it with no filter (if you really wanted to). I'm not sure it would really hurt anything, although I don't want to try this. That would tell a lot as to what the filter is doing to you.
MAF - THE GRANATELLI MAF DID NOT WORK FOR ME! It was a lot of money, and LOST me power on my dyno runs. It leaned out the car's A/F a lot. Granatelli doesn't have any testing of the MAF for the Aurora that I'm aware of and the same may be true for the caddy 4.6. It was recalibrated to fake out the computer. I think the stock A/F's are pretty good. They recalibrated it back to stock A/F but it's in the box for now. Maybe I'll test it sometime.
CAM - I really thing the 275 4.6 would beat the 300 version if it were mated to the 3.71. It has a lot more HP up to 5000 rpm and a ton more torque all over. I think the 300 HP thing is more for marketing. I don't think adjusting the 4.0 performance to behave more like a 300 HP version of the 4.6 would benefit acceleration at all. You might have more peak HP bragging rights though.
If the losses for air are a function of velocity squared (like for water) then you have a difference of 29% for the example above. I admit, I don't know what that relationship for air is, and I'm sure it varies with density/pressure too. But for getting a general idea, this stuff might help.
Hey - have you looked into the Corsa exhaust for your 2001? I think they are working on a system tuned for the new Aurora. Apparently the classic sounds good with their STS system, but they want to tune the sound better for the new 4.0. Apparently the difference in exhaust valves and perhaps some other differences make a difference in sound on the classic vs the new 4.0 when using Corsa's cat-back system for the STS.
I've never seen any info about the actual flow rate of the throttle-bodies. I'm sure it isn't quite (80mm/2)^2*Pi because there is a big butterfly sitting in the middle of it. However, I would think the larger size would definitely help.
Man... I want to mod the airbox, get the TB, and get the Corsa. But I also want to try some new paint protectant products. And that OBD-II thing sounds cool. However, I'm not sure I want to dump that much money all at once. I'm pretty cheap by nature. Plus, I want to try the track again with a basically stock car once the temps have dropped. Well, I'll own the car a long time, so I guess I have plenty of time to accumulate mods.
Heck - if you want to get picky, then you should also consider that as the area is increased, the diameter becomes a smaller percentage of the area. In other words, the larger throttle body is "more efficient" in it's use of the total area.
Dirty filter - path of least resistance. Nope. At least the path of least resistance is not what it looks like. I can show you a dirty filter from the Impala and the dirt is entirely caked in one area. The rest of the filter is right out of the box clean. The air is almost never going there. That's because the filter is practically in-line. Both sides of the box come very close to the filter face.
When the air is shooting through the intake for the box at 30 to 60 mph, it's pretty tough for the flow path to do a 90 in a fraction of an inch and then another 90 to go through the filter - and then two more 90's (again within a fraction of an inch) on the clean side to continue toward the engine.
If you want to argue it further, I'll just have to send you the dirty filter. Its like someone drew the dirty spot on there with a marker and shaded it in - and was real good about not going outside the lines.
"Give me a break man. At WOT the throttle plate and the center support are pretty skinny. Yeah, it's basically a simple difference of area. I'm sure I'm well over 90% accurate on the area and velocity comparisons. If you're going to make a point like that in the future, please qualify it a little like "you could be off 5% or so". If you really think it's way off because of the throttle plate well... that's goofy."
Here's all I said: "I've never seen any info about the actual flow rate of the throttle-bodies. I'm sure it isn't quite (80mm/2)^2*Pi because there is a big butterfly sitting in the middle of it. However, I would think the larger size would definitely help." So you don't think it would be interesting to see actual flow rates of the two throttle-bodies?
I finally got some pictures up too, http://www.cardomain.com/id/800wattaurora
What you guys think?
800wattAURORA
The TB is done. UPS will have it to me Monday.
I'm just saying that even really really dirty, it's still easier to keep going straight through the dirt, than to wind around it in an almost in-line situation. What seems to be the path of least resistance (as measured by what your eye tells you about the dirt on the filter) may not really be so.
TB - sure, give me the info if you have it. I never said I wouldn't be interested. But hey, I can calculate area and velocity to get an idea of what's happening. If you want to worry about the "big" throttle plate, go for it.
It's sad that I can't post a general observation or calculation without often having some small detail brought up as if I hadn't thought of it and as if it significantly compromised the point being made. Sorry, but I don't have a TB sitting on the table to measure the thickness of, but it sure looks thin and small compared to the circular opening.
If that seems to you to make a big enough difference so as to mention it, then please tells us how much of a difference you think it makes. Really. Please do. I still say the basic area calculations will get you extremely close to the % difference in TB area.
Also, did you consider that much of the throttle plate takes the same area on either TB? All but 5mm I guess. That would kind of cancel out when just making a general comparison of area.
How about it?
Actually, I was responding to Fdion, not to you. He asked: "Did RSM say how much the stock vs bored increased flow? Any cfm ratings or at least velocity?". And as far as I know, nobody has seen these actual numbers, so that is what I said. So don't get all pissy. I'm sure the butterfly doesn't make much difference. And obviously there is a butterfly in the stock TB too, so the gains are still there. The butterfly probably makes less difference in the larger TB since it only grows in one direction (I don't think it gets thicker).
If you think the classic is bottled up, you should see the 2k1+! Beside the smaller area on the filter, it gets air solely from the front of the airbox, behind the headlamp and the only way the air gets there is through a little round hole in the underbody plastic pan and through a foam "filter" at the driver's side intake grille. And sideways at that, since half the grille is blanked out.
The reason for this less than ideal air path is to not have a "straight from the front" air intake in case of rain. And that is why the foam is there too. The problem with this foam is that it blocks the airflow significantly and also since it's sort of just put there, it gets sucked in and blocks the little round hole too!
I appreciate your posts and the fact that you've been looking at performance for the aurora for a longer time than anybody else and put a lot of research into it says that you are serious about performance. Please dont take posts as criticism. Take them as additional info.
Francois
Is the SLS and STS using the same manifold? I think I need to get me microfiches and shop manual from the classic and the cadillacs. Also the part exchange tsb would be good to have.
Francois
That is pretty interesting. I've ran without the intake grille and it seems to help, but haven't truely measured anything. I wouldn't do that in the rain... Would be nice to install a electromechanical vane at that grille...
I'll look into a better hose (or if there is a better hose).
Francois
RJS - is it pissy or annoyed??? Make up your mind. Just go for it and say I'm outraged - that will just cover all the bases for you. :>
I think my responses are quite appropriate and factual. I make a general comparison of TB before and after area and velocity % change, and you have to point out that I left out something - something pretty darn inconsequential for the sake of making a general comparison. In addition, I later explained that the throttle plate mostly cancels out as it's there for both (remember I was getting at % change in area/velocity/losses), and that the plate becomes a smaller part of the total area for a larger TB.
I've been basically looking at it from a little different angle I guess - trying to get an idea of pressure drop or a loss at the same flow rate through each. Just a different angle as opposed to what is the flow at a given pressure.
As for my "it's sad" comment - well your post # 215 comment about it not exactly being Pi r^2 sure seems to be to me. Thanks for finally admitting in 221 that it probably doesn't make much difference. My point all along - especially when comparing the two. I'd actually care to estimate it if I was interested in knowing exactly the area and velocity at a given flow for a specific unit. So, what is the point of making a comment like that if it doesn't make much of a difference? That's sad. :<
For example, with water, it's basically a function of V^2/2g, g being the gravitational constant of 32.2 ft/sec^2. Some obstructions are worse than others so the V^2/2g gets multiplied by different constants depending on what you are looking at. If you are just comparing different sizes of the same obstruction (orifice, bend...) then the constant is basically the same.
So - with air flow, is it V^2?? V^1.5??? I don't know. Maybe a look in the physics book would yield a clue pretty quick, but I don't have mine any more. I deal with water all the time and have plenty of info on that - but nothing for air.
I'm sure there are similar relationships for density too.
Anyway, this might prove interesting when trying to get an idea of how much a mod might help air flow compared to stock - assuming it's a significant restriction in the first place.
The TB orifice is pretty small compared to the rest of the intake.
I don't know what I can say differently than the last post. Garnes, I wasn't responding to you at all. Fdion asked if anyone had actual numbers, and I responded that I'd never seen any. While your numbers are interesting, they aren't actual measurements.
and on a cheerier note . . .
I am heavily leaning towards the Yokohamas Z rated tires.
Any information on how these perform in the snow and rain.
RJS - I never asserted that anything was an actual measurement. Perhaps I should have tried to make the point without using any numbers. Nice straw-man attempt though.
assume i will take the car to the track (i will)both 1/4 and solo (cone racing) BUT - want a decent life out of the tire
whats my top two or three choices for the above and still wanting a decent ride quality ?
there are just way too many posts on this forum to research on my own, so thought id test you guys and your tire sense - thanks
dennis
I realize air is compressible and such a relationship may vary depending on density and maybe even some other factors, but assuming the rest are constant, it would be interesting for comparing any sort of modification that improves air flow to the stock condition.
FJK - you are a physics guy. Any help? fdion seems to have been into the physics stuff too. Anything?
Otherwise I may just have to look this up myself. That would be a shame.
what movie? what movie?
Garnes, I'm not sure exactly what formula to look for, but I remember you mentioning resistance varying at the square of velocity for water. I found this website which seems to show it as velocity to 1.6 instead of squared for air. But I don't really know what I'm looking for, so maybe this is worthless.
First, I'd like to point out that the RSM TB seemed to measure 79.5 mm. Not quite 80. Whatever. What's really weird is that my stock TB measures 76 mm. Not 75 mm! What's going on????!!! Can anybody check this officially? I thought I was getting something 5 mm over stock, but it seems to have been only 3.5 mm. I will be calling RSM as well.
I did not get peak HP and torque increases as great as Taylor, but I'm pretty happy just the same. I was really happy that the gains were ALL OVER the curve and actually bigger down lower in the 4000's.
It was 86 degrees for the baseline runs, 87 after I was done installing the throttle body. All my previous dyno runs were done on 70 degree days. Here are the numbers:
Baseline runs: 191.1 HP, 205 torque
193.2 HP, 209.1 torque
The first baseline was not as strong, and I think it's because the engine was not up to full temp. I guess I should have run one more. Oh well. After installing the TB my first run was with the engine not quite up to operating temp and the first run was about 2 HP less than the next 3 runs. These next 3 runs were dead nuts on the same as each other throughout the curve, so I'm confident of the TB results. For some reason, my experience at the dyno is that the car runs best when up to temp and is just fine even a little over the 200 line as well - just my experience. I'm comparing the results to the better base line. If I use the lower base line I get some big gains more like Taylor's.
New TB runs: 198.6 HP, (+5.4 peak HP - at wheels)
214.2 torque (+5.1 peak torque)
Now, here is the good part, the gains were all over the curve which is really most important. Look as these numbers:
4200 rpm + 7.8 HP, + 9.6 torque
4400 + 5.8 HP, + 7.0 torque
4600 + 5.2 HP, + 5.9 torque
4800 + 6.5 HP, + 6.8 torque
5000 + 5.3 HP, + 5.7 torque
5200 + 5.4 HP, + 5.5 torque
5400 + 4.8 HP, + 4.7 torque
5600 + 4.7 HP, + 4.4 torque
5800 + 3.8 HP, + 3.5 torque
6000 + 4.7 HP, + 4.0 torque
Please, I hope nobody feels compelled to point out the discrepancy in the peak numbers/gains with the gains shown for the various rpms. The peak numbers are literally from the slightest bump in the curve just before or after one the rpm values listed.
I'm still pretty happy with the results. I'm totally confused by the stock unit being 76 mm. Taylor, can you please check the diameter on your stock TB? If it's somehow 75 mm, then that may explain something. Also, I swear my RSM was a shade under 80 mm.
In addition, it's possible that Taylor's stock TB was dirty enough (I remember him saying it was really bad) to rob a HP or two for the baseline. I think it's possible to have 1/2 mm build-up (that's rough too). Maybe more. Mine was pretty clean as I had cleaned it recently.
Taylor - thank you very much for walking through this with me first. It was kind of a pain in the rear job, but certainly not too bad. It would have been bad if I had not seen how the throttle cable simply snaps in (on the junk yard unit). I also knew in advance that the cruise control cable assembly just snaps on as well. Those two little hoses were the BIGGEST PAIN IN THE BUTT! They got me swearing. Also, thanks for the manual info and the TB position relearn thing.
The car seems to run just the same for regular driving. No problems. I'd recommend this modification - especially for any 4.6 caddy guys. They HAVE to do this. It will probably really help.
With the air box mods, K&N filter, and the RSM throttle body, I'd estimate (somewhat conservatively) the engine HP to now be about 266 HP, and 275 torque.
The Corsa exhaust should get it to 280 HP, and torque should be well over 280, maybe close to 290.
Also - I got to see the difference 16 or 17 degrees made to the power. It was much more humid too. It certainly is big. The computer correction factor was 3% different than on the cooler days. Roughly .03 x 200 = 6 HP, and I was still getting results at least 5 HP lower. So perhaps the total was at least 11 HP. I know that it has been posted that such a temp difference should make even more of a change, but again - I hope nobody goes into this. The dynojet computer tries to adjust but it is nowhere near exact. I've seen it use the same correction factor for similar days, but the temp and other conditions were certainly different. It also has a major disclaimer about trying to compare results from different days with different conditions. Bottom line, you have to do test the same day -back to back. I really question the value of dyno testing the exhaust now.
So, based on the above, my "after" HP and torque runs should be another .3 higher (?? just a WAG) since it got 1+ degrees warmer. :>
Garnes, I wonder if you got less of a gain than Taylor because of his cone? Maybe the cone flows more so the extra TB size can be put to work more? Did the intake manifold opening seem substantially smaller than the TB opening with the new TB? Taylor mentioned that. I was wondering what your opinion of it was. I wonder if sanding it out would be a bad idea? If RSM answers my questions about the TB (they seemed a bit surprised that the MAF doesn't mount to it like on the classic) and I get one, I can't see myself dremeling out the intake manifold even if it would help...
Thanks for checking the tires. That's interesting they didn't change. I would have thought that accelerating up to 80+mph a few times would have put some heat in them. Especially since the Aurora has so much weight on the front tires.
If you were really interested, maybe Corsa could arrange a dyno test for you. Do they have one? Or maybe you could have the exhaust system clamped so you could swap it at the dyno. That might be a bit of a pain (plus you'd have to drive a whole exhaust system over to the dyno place), but it might not be much more work than swapping the TB since it's just a few clamps and hangers.
Garnes, you mentioned "The car seems to run just the same for regular driving. No problems." Do you just mean that it didn't exhibit any poor behavior, or do you mean that you don't feel much power gain?
Thanks for taking the time to test it and to let us all know how it went. You and Taylor have provided us with some great info.
Intake manifold - I'm so glad you asked. I did take a good look at this as I was interested too. Basically, it appeared to me that the TB outside diameter was nearly flush with the manifold (or whatever the segment is that it bolts to) in some places and most places it seemed to protrude maybe 1 mm - not much at all. Looking at it, I remember thinking that the larger TB must be taking advantage of a little extra size immediately downstream. BTW, that piece that the TB bolts to looks like it can be removed as well. It seems to bolt to something too - the actual manifold I guess.
Tire pressure - well the car basically come into the place with the tires warm. They never get a chance to cool down that much I guess. Plus the dyno run goes by so fast, I don't think there is a lot of heat generating time with the tires - maybe enough to keep them warm. That's my guess as to why I did not see a difference.
With the crud build-up on the TB, I really think 1/2 mm accumulated (total 1 mm from the diameter - plus there is stuff on one side of the plate - plus it's rough) could amount to a considerable loss in TB area and flow compared to the small diameter increases we are trying to realize with the boring. That may be why Taylor got a little more punch. Then there is this stock size thing. That is really weird.
My personal opinion is that the cone set-up should be a little better because you get rid of the hard 90 in the box, but I think it may not be a whole lot better than what I have now. Also, with the box mod, I know for sure I'm pulling fresh air and I don't have to worry. I totally agree with Taylor's work to build a heat shield as I think it will help a lot. For some reason, RSM just doesn't think it is necessary (but the K&N FIPK cold air kits have heat shields).
Taylor - I may be interested in your heat shield and try the RSM induction some time. Could you make additional pieces? How much $$?
You asked about the TB port - it's basically just a bored cylinder. It's as simple as can be and easy to measure.
"Thanks for the feedback, the overall size of the TB is between 79-80 mm depending on the casting of the TB core we have. To realize the full potential of the TB you can match port the piece that the TB attaches to(that piece can only be done by hand) or you can send it to us so we can do it ($US100.00 for the labour). The limiting factor in boring a TB is usually the throttle plate bushing housing (and this is only obvious if you have the plate removed) and the size of the intake port where the TB is mounted. The stock TB should be 75 mm but we have seen anywhere from 74 to 76, you would be surprised sometimes how bad the OEM castings are."
So, my stock throttle body was on the big side at 76 mm which certainly nipped a little off the gains. I guess I was already experiencing some of the gains with an extra 1 to 2 mm over some other stock cars. This explains a lot. Of course I'll be comparing my actual stock area vs. if it had been 75 mm and trying to extrapolate a little. I'd guess I might have seen at least another 1 HP and torque "gain" with the baseline down a little if it was 75.
Now, I'm tempted to port out that intermediate block. I wish I knew about it in the first place. I would have got it along with the TB and sent that in too. I may be able to do this myself though.
Hey Greg, did you have to remove all the sensors (like the TP sensor and probably some idle control) from your stock (not the junkyard one, but the one that came with your car) TB and attach them to the new one, or did it come with them already on there? Also, if they were on there, are they just whatever was on it before the porting, or does RSM put new sensors on it as part of the price?
More on that 75 vs 76 mm thing. That 1 mm represents about 22% of the extra area I would have got from the 79.5 mm unit if the stock unit was indeed 75. Interesting. If Taylors was only 74 (and really dirty) that explains everything I think.
I'm calling the bone yard to try to get that intermediate piece. If I get it, I'll do it, but won't dyno it as it will probably only add another 1 to 2 I think.
Hey - you gotta do the TB now too, and when you do, make sure you get the mounting plate too. It just has to add even more to have that bored to 80 mm as well.
If I can do it, anybody can. Taylor guided me through and I'd be happy to return the favor for anybody else.