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Oldsmobile Aurora: Modifications
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If you stay on these Aurora boards long enough, the topics do repeat themselves. The last time we had this discussion the issue was that more than a few of these performance chips either do nothing or hurt the performance of the car. By hurting the performance, I recall the timing advance issue. Specifically, the timing advance made the car not function properly under all weather and atmospheric (sic) conditions.
I remember commenting at the time that I would only chip the car wih a GM chip. And since I have already done that, I dont think I would risk the domestic perfromance chip.
My 2 1/2 cents.
Henri
Disabled
1. Torque management
2. Traction control
3. Speed limiter (if desired)
Enabled.
1. Better spark curve
2. Firmer trans shifts
3. Less EGR flow (inhibits performance)
4. Earlier converter lock
5. Earlier fan on/off
I know less egr flow will give a little bit better off the line, and help keep the car cleaner. earlier fan on/off would be nice since we all run hot in the summer, thing im not sure about is earlier convertor lock. i would think we would want a latter convertor lock (like a higher stall?) not sure what that ones about. he can leave the traction control alone if you want. its not going to be a huge improvement, but...he claims to have brought a stock 3.48 geared one from 16.79 to 16.1 (at 2600 feet) while spinning a little off the line. i plan on getting one, not sure when, money's kinda tight now. but if you buy it, and a week later think its completly junk, just send it back and all your out is shipping charges. ive seen the chip come and go on gmforums for the last year and a half, but i really do believe in this chip, but its only for 95's
http://www.modulardepot.com/density.php
a 16.79 at 2600 feet corrected to sea level is about a 15.71 dependeing on temperature, maybe a 16.0. with the chip, 15.02 - 15.35....according to him. i asked for dyno results and he said 23hp, 32 tq at 5200rpm, must have been the biggest difference, but i never saw a dyno graph. if he's making these kinda claims....the chips gotta do some good, or everyone would just send it back, he claims "almost 7/10's off the 1/4" so i guess it ran somewere in the 16.1x range
http://westers_garage.eidnet.org/
I had an aftermarket MAF that changed A/F ratios and all and supposedly added power. The dyno proved otherwise. I was losing power. But before that, my subjective seat of the pants was convinced it was better.
Maybe shifting and all could be improved - fine. But that much power?
As for the high flow cat, please explain how this will add power. You have to pass the exhaust through the same amount of media. You have to. I've seen these things. They use the same media as well. The exhaust shop that installed my Corsa system even sells them and says they don't do anything. You might say, "well it's bigger so it's less resistance". That's possible, but you have to expand the "drop pipe" or "down pipe" from the manifold. Otherwise you are just shooting a very fast moving "jet" of exhaust through the same amount of substrate/media. The exhaust gas flow will not magically expand its flow path to the bigger converter over an inch or two of flow path. The sudden increase in diameter could actually create some turbulence and hurt the exhaust flow.
If you came into a bigger converter with bigger plumbing from the manifold and the new converter truly had some smoother/better flow characteristics at the inlet and outlet, then yeah, you could probably pick up a couple HP, maybe a little more. Just a guess.
Bottom line, if it isn't at least dyno'd back to back, same day, with reasonably repeatable results, then anybody can claim anything they want.
RJS - where's that "chips ahoy" link from Car & Driver. That was one eye opening article about what the chips actually "delivered" vs. the claims.
But really, show me some first hand respectable testing of the converter or a chip or whatever (not a g-tech HP measurement) that shows it adds significant power and I'd be one very happily wrong Aurora owner.
mrdubya, if there was that much power available without affecting anything else, why wouldn't GM unleash it? Most of the chips make the shifts firmer, which doesn't feel all that nice most of the time. And they advance the timing which makes the engine much more suceptible to knock, and much less tolerant of hot days, fuel-quality variations, and so on. All of which really doesn't make the car much faster.
as for the highflow cat, i don't understand why you would waste all the $$ on a MAF and not even try a highflow cat!
Dyno results?!?!? ive seen dyno results PROVING that the 80mm tb from RSM racing does nothing! it actually hurt the performance, maybe the diff between a dirty one and a clean on is were you saw a gain? just kinda shows that dyno's are off too, i think it was pat that had his dyno's posted, same day and everything, lost power with the bigger tb. your willing to drop the money on a tb but not a cheap cat? just try it, trust me.
highflow cats do help, i used one, the peak power comes much sooner and quicker. off the line torque was better too. someone else on gmforums said the same thing....i think it was pat...EVERY other board about all other cars say the same thing. i know for sure the inside case is much smother than stocks, stocks have edges that hang over like fins. i know thats not a big dif, but add the fact that its now 2.5" instead of 2.125, stock one is probably partially plugged. I do remember seeing flow charts too
here's some testimoinies from magazines about random techs highflow cat over stock
Corvette Fever Magazine
Switching to a Random Super High Flow converter (in place of original equipment type) improved the quarter-mile performance of a 1987 Corvette from 13.79 at 98.72 mph to 13.65 at 100.15 mph.
Chevy Truck Magazine
Installation of a Random Technology Super High Flow converter (in place of the original equipment type) improved quarter-mile times from 15.97-second ET at 82.88 to 15.83 at 83.73 miles per hour
ill try to find the independant flow charts i saw a long time ago comparing all the different brands to the stock oem, its like K&N is to your intake, they do flow better.
I saw where the TB from a 4.6L Cadillac was 80MM and would fit our Classics. Does anyone know if that would at least be comparable to RSM's bored out one? It would seem that the 80MM stock model may work as well if not better than a bored out one or does RSM do something else to ours when we send them I'm not aware of? Kayaman, how's your stock airbox doing vs. the other? I'm thinking an 80MM Tb and the other exhaust mods (Dynamax, 2.5" pipes) should add enough punch to start with.
this weekend i plan on cutting out the airbox to match the holes in the sheetmetal (below and to the side of the airbox) then get some black duct tape and make a type of seal to connect the two, so there's no "gap", should make sure no hot air from the engine gets in there. also gonna take off the tb to clean it out all the way. ill post on the results...if there noticible!
How are you? Don't those STS's have the 4.6 L engine? How much hp/torque do they put out before mods? Hey Garnes, Kayaman, et al - how much difference is there in output between the Corsa setup and the others - all other mods being equal?And is it noticeable across the whole curve, or mainly at the top end?
http://members.cardomain.com/kayaman420
I believe Greg said he would love to see you produce a dyno for the chip that showed a measurable gain. He has produced one for the bored TB, so what point are you trying to make about some other person with a Caddy who dyno'd their TB?
The OEM 80mm Caddy TB is for the RWD Northstar. This also has an electronic throttle instead of a cabled one. It looks very different from the Aurora's TB (either of them) and I seriously doubt it will fit your car.
As far as the convertors, did either of these magazines measure the difference in emissions? Was that 1987 Corvette swap to a single convertor? The '87 had three cats initially (were you aware of that?), so I'm sure replacing them with only one would help. No doubt you can get power at the expense of emissions, but I don't personally want to do that. And a wider cat won't necessarily do this. If you really don't care about emissions, just punch a hole straight through the substrate in your stock cat. That costs zero dollars (maybe the cost of a long screwdriver), and will improve flow at the expense of emissions.
In addition, you are citing roughly 15/100ths of a second gains in the 1/4 mile. How many passes did they make? Was it on the same day? Same time of day? What was the weather like each time? I could improve my 1/4 mile times by a lot more than that by just going to the track in October. I'm not saying those mods didn't make more power, but your citing of 1/4 mile times is hardly concrete evidence.
Regarding the power curve, I sincerely hope the high-flow cat didn't move your power peak to sooner in the curve. That would tell me it hurts upper end power. It's fairly counter-intuitive as well. Wouldn't the cat be a bigger restriction at higher rpm, and not really make much difference at lower ones, when there is less exhaust to move?
Lastly, didn't you suggest buying a Carsounds cat? Yet, you are posting articles about Random Technology. Do you think they are the same because they both make the same claims? Or because they are both "high-flow"? I would have a lot more confidence in the Random Technology to be generally designed well, than I would in the Carsounds.
It's funny how you both like and dislike dyno results. They are good for some people's results - not credible for others. BTW - another former Aurora owner also dyno'd the TB and got similar results. My experience is that once the car is up to temperature, it has been repeatable. Now, if it's close but not full temp, you will get less power. Hence your "before" run could be lower - assuming it was the first run.
Anyway, about the 80mm throttle body - you better let the engineers at Cadillac know they are so foolish because one of the IMPROVEMENTS to the new Northstar is that the TB was increased to 80mm. Imagine that! Truth is that the engineers can calculate things all they want, but quite often there are just too many variables to account for in modeling. In the end they do a very good job at designing these things, but some old fashioned trial and error testing can uncover an improvement to be made that will squeeze a little more out.
Oh - and my stock TB was not very dirty at all for my testing. No real build up at all.
What's up? Thanks for the advice. I'm cleaning my TB this week (broken hand must come out of cast first), and I'm going to my local performance guys to discuss intake mods. From your experiences I agree the box mod seems best. My guys have offered me a great deal on the Super Turbo II's (they did a ton of work on my old Mark VII). I figure the money saved by going for the Dynamax I could use on the tips and 2.5" tubes. Before I plunge, what have you heard pro or con about Ravin? Like I said, I'll see my guy today and maybe he'll have some info. From their website it seems like they would be a bit quieter, assuming one is seeking quiet. If they perform, I don't mind them being a little less throaty. I want performance and sound, not just noise for noise sake. I prefer to ambush not announce. Just leave 'em wondering what the heck just happened?!
I doubt the differences in those magazine track times you cite could be felt either. If you can "feel" .1 to .15 seconds over the 1/4 mile, your seat of the pants meter is an incredible medical mystery.
1) NO WERE in my post did i say that deleting torque management will improve hp. lets take a extreme, drop a 5 speed into a aurora (JUST FOR ARGUMENTS SAKE!) you'll have the same amount of power but it will be faster!. the point im trying to make is you don't necesarily have to improve power to make a car faster. Like i said, some people would like torque management gone, some wouldn't. it will retard the timing at shifts to add to the life expectancy of a transmission on WOT, it gives you SLOWER 1/4 mile times, plain and simple, no argument about it. i don't think that it would put to much stress on the transmission anyways, since its rated for more hp and torque than we have, and rated for higher rpm shifts. ive seen LOTS of forums ranging from Corvettes to W-body's to H-body's, all of them reported lower 1/4's without the torque management.
2) as for the 80mm tb on the new northstars, forget about the displacement difference? a 4.6 will need more air than a 4.0. if cadillac decided that 80mm was perfect for there 320hp 4.6, wouldn't a 4.0 only need 87% of that flow to be "perfect"? a 75mm TB has 88% of the total area....TB size seems to go hand in hand with displacement in general. i would agree that 75 is slightly undersized for early 4.6's. and i didn't just say that it was worthless, the point i was trying to make is that dyno tests do not always show consistancy, even when both tests were at full temp, same day, 20 minutes apart. I think it was taylor, on gmforums (not 100% sure) that said when he took off his old TB it was super dirty and mucky, thats were some of his gain came from for sure. its like comparing a partially plugged air filter to a new K&N. besides, a 80mm tb costs....$350, my carsounds cat cost me $60 + $40 to get it welded on. before i bought one i found a independant test done comparing a OEM 2" vs carsounds 2" vs catco 2" vs random tech 2", and one other one, carsounds had the 2nd highest flow, then random tech(really close), then catco then way back there oem. they also flow tested some 2.5's that were better yet. go to any forum in the world about any car, you won't ever find someone saying "i replaced my cat with a highflow one and didn't notice anything" ive seen alot of " i took off my race pipe for a highflow cat so it was legal, its not as loud but no loss in performance". i only used the random techs website because carsounds is gone now...not only that but a oem one weighs 13.5lbs, randoms is like 6.5lbs there the same outside size, but the material inside is made of different stuff, they do flow better, go to any other forum and ask people that use them.
the torque is better and the high end is better with a highflow cat, not only that but garnes, your cat is about 6 years old, you know its partially plugged robbing power, why not get one thats rated to flow a little more than oem. not by much, but not only that there ALOT cheaper than oem. ive never dyno'd my car, so i don't know if/how much torque it added, but i do know that it revved alot faster off the line and up high. so maybe it didn't add any peak power, maybe it only revs faster, but the car takes off faster than it did before.
Thanks
weafrog
Just think about it for a minute. How can a larger throttle body cause a loss in power?? How can that happen? I could understand no power increase, but a loss??? Something is likely wrong with the test or something was inadvertently affected while swapping the TB's - who knows, but this is illogical.
Yep, that was Taylor. He coached me through. His TB was dirty and he did get bigger gains than I did. I think his bigger gain was perhaps due to the stock unit being dirty. But our results were basically consistent. In fact, if he had a mm or so or build-up, I would expect a couple more HP over what I got. Also interesting about both out tests is that at the time, neither of us had the plenum (mounting plate) bored to 80mm yet. So we had an 80mm TB, a 78mm plenum, and then the opening to the manifold is 80mm. That's certainly not ideal. I've since had the plenum bored too so everything is smooth and matches at 80mm. I'm sure this helps a bit more as well.
"as for the 80mm tb on the new northstars, forget about the displacement difference? a 4.6 will need more air than a 4.0. if Cadillac decided that 80mm was perfect for there 320hp 4.6, wouldn't a 4.0 only need 87% of that flow to be "perfect"? a 75mm TB has 88% of the total area....TB size seems to go hand in hand with displacement in general. i would agree that 75 is slightly undersized for early 4.6's."
So you just "know" that the 75 mm TB was undersized for the 4.6 but must have been perfect for the 4.0? You did the calcs or whatever? No possibility that it was small for both by differing degrees? OK. Whatever. I still say that because the Northstar engineers increased the size - even for the 4.6, it's something I'd try to duplicate on my 4.0. You may be right - 75 is all that is needed for the 4.0, but I'll trust the dyno and the engineers at GM.
About those "independent tests" on the converter. How was it tested???? On a car's exhaust system??? On your model of car?? Or was the unit "bench tested" where they attached a port to the inlet and outlet that matched the unit? Was the flow difference measured against a pressure drop that is truly representative of what occurs in a car? In your car? My MAF was "tested" and flowed some huge % more air too - supposedly. Yeah right.
I still say that on the car, I doubt it'll make a difference unless perhaps all the plumbing also matches. There is no way in hell the exhaust will utilize the bigger size of a converter with the stock "down pipe". You are basically shooting a jet of gas through it. Conversely, with a TB, it's much smaller than the upstream ductwork. Increasing it's size to reduce the restriction and match the intake manifold port is clearly better.
So, you still won't address these points. And please share more information about these tests. Again - I'd love to see that it worked when they actually bolted this thing to an actual car's exhaust system (everything else stock) and did the flow measurements for actual operating conditions. Some dyno numbers would be cool too. Really, I'll consider this if this information exists.
As for plugging. Was yours blocked at all when you changed it? If so, how many miles? The exhaust shop that installed my Corsa system (pretty good place - works with 304 ss and all and does sell these things too) said that the stock converters are fine even after many many miles as long as the car is running properly. Too rich, or maybe a trace of coolant is getting through - yeah they will plug. But he says that they look fine after a lot of miles as long as the car runs right.
If they plugged at a steady (significant) rate over time, you'd have them generally failing to meet emissions requirements certainly well before 100k and you'd be getting a SES light. Perhaps the added backpressure of a fouled cat could trigger something too - who knows.
I don't think Greg or I claimed the high-flow doesn't work. Just that you haven't shown it to work. You are just offering up ramblings as evidence.
Greg has a point about the larger diameter of the cat likely helping very little. I agree, and I think this is unlikely to increase the flow, as the airflow will not fan out that fast, and probably won't contract that well either, possibly introducing turbulence.
The only way I could see a "high-flow" cat actually flowing noticeably more would be if the substrate were spread apart more. I.e. if all the little holes through it were wider. However, this would decrease the cats ability to do its job. And it would likely cause a lot more noise to pass through the cat. So I really don't see that as an improvement. Plus, as I said, I could achieve that same thing by just punching a hole through the substrate. This would be free, and wouldn't require cutting and patching my exhaust all up.
Your comments about 1/4 mile times and seat of the pants just aren't that convincing to me. Seat of the pants impressions could be swayed simply by the increase in noise. Same thing with the installation in other cars. There can be factors that the article doesn't mention, and which you aren't aware of. Like the Corvette having three cats from the factory. I've removed the front two cats on my Corvette (which was 12+ years old at the time) when a small piece of substrate broke off the front of the cat and was rattling around endlessly. They were not crudded up or blocked at all. I suspect the piece chipped due to the constant expanding and contracting of everything.
If you are happy with your cat mod, then that's great. But don't be surprised that some of us aren't in a rush to do it. I have no interest in ruining the quiet, smooth sound or increasing the emissions on my car just for a little gain. Keep in mind that this is an Aurora, not a Camaro or something. Most of us bought the car for its blend of luxury, comfort, sport, and power. Not just for the power alone. Trading off other areas for more power really isn't what many of us want to do. I feel this applies even more to a chip.
"No. Our Dyno doesn't plot graphs as it's a load bearing dyno only. Yes--it's
possible to change your shift points.
Lyndon
www.ecmprogrammer.com"
btw, he CLAIMED 23hp & 32 tq at 5200, and "nearly 7/10's off the ET" a while ago - don't shoot the messenger!
so it is possible to change my shiftpoints. right now it shifts at 5950/6k, id have him change it too 6300 most likely, what would you guys do?. what would be really sweet, is if you could tie in the disabling of torque management with the power shift button.
if i do order it won't be for a little while though
and garnes, the test flow charts i saw were bench testing. i mean, how wouldn't a free flowing cat help power? using your reasoning, how would changing any of the exhaust help power. as far as backpressure, wouldn't a cat be just another muffler? i know it helped the power, so im happy. im sure the TB helped power too, but i just don't think its worth $350
i emailed the chip company again, to see if tq management could be tied in with the power shift button. i know you guys couldn't ever use this, but there are some 95 guys here.
Bench test:
I'll try this again. Look, you can pass X cfm through a converter (numbers are arbitrary here) that's 2.5 inches in diameter. You can then pass the same cfm through a 2.0 inch converter. Yes, the 2.5 inch converter will produce a smaller pressure drop thus more power goes to the crank which is good. However, if your car has a 2 inch converter and you replace it with the 2.5 inch converter it's likely not flowing the same as in the bench test. I'm sure the bench test had a 2.5 inch and a 2.0 inch duct or whatever for the respective units. I highly doubt they flowed a 2 inch pipe up to the 2.5 inch unit for the bench test. On your car, the plumbing is still the same size as the original smaller converter and your likely not utilizing the additional media. The sudden increase in diameter may even introduce some turbulence.
And what flow rate was the test done at? What pressure? The exhaust gas is compressible. A cfm is not the same mass of exhaust for different pressures. In short, was the test truly representative of your car's operation?
If you increased the plumbing upstream of the converter - sure, it may help some.
Now about the comment about the exhaust vs. converter. The stock exhaust is very different than the Corsa system. The stock plumbing in much smaller, the resonator has a lousy irregular perforated metal sleeve shoved in there and the mufflers are baffled. The Corsa system is all straight through - like straight pipe. No baffles - all smooth. Now, the stock converter and the "high-flow" converter still have to pass the exhaust through the SAME media. You have to. And as I described above, you are probably still passing the same amount of exhaust through the same area of substrate/media - therefore not much change.
Smoother inlet and outlet. Yes, should help. But there is no way it's going to be something you can "feel". A couple HP's?? for a much better inlet and outlet? Maybe at most - assuming the stock unit is really rough or requires the air to make sudden changes in direction.
As far as the TB vs. converter comment, I do believe the TB is an improvement that works as logically explained above and is also supported by my tests, other's tests, and apparently even Northstar engineers. Yes, it was sort of expensive, but not that bad. So the converter is less money - I don't care if it doesn't do much anyway. But again, I'd like to see some sort of evidence as tested on a car under actual running conditions.
for everyone else, just go to different forums, and ready what everyone thats actually tried one has to say, proof enough for me.
here is your PROOF!
http://www.randomtechnology.com/new_products_gp.html
green line is stock, blue line IS JUST a random tech cat. 8.2hp, 9tq at the wheels.
ive got to go to work, when i get home ill look more, not many people dyno there cars with just a new cat.
I asked:
"No possibility that it was small for both by differing degrees?"
I wish I could respond to the bulk of your post, but it's kind of incoherent. Anyway, It's easier to push exhaust through 2.5 inch pipe than 2 inch pipe. Self explanatory. It's easier to push exhaust through a muffler that is straight through than one that has baffles. Again, self explanatory. I'm not sure if you are debating this or what. Kind of sounds like it though.
The link you provided is pretty cool. The converter shown includes the expanded "plumbing" included as well - which is exactly what I said needs to be done. Thank you for proving my point. It shows +9 HP. This is from a 240 HP SC 3.8, so maybe it's comparable to what an Aurora does.
However, they don't make one with all the plumbing for an Aurora. So your just not going to utilize the large diameter.
As for the different media material - I'll have to read more on that. I'm skeptical. I called them an they said the media "looks" a lot different than stock, but didn't have any pictures on the web site. If it's that much different, they're pretty stupid for not showing the difference on the web site. Maybe you could help us here and tell us what the difference was. If the substrate has a bigger pattern, then it could help - even with the stock plumbing. But even based on Random's dyno (which conveniently omitted the run date and time - ahem)(by the way, I thought dyno runs were so goofy) then maybe you could pick up 2 to 5 HP.
That would be cool, but you are not going to "feel" that. It's going to be top end only too. Still, that's not bad.
"Anyway, It's easier to push exhaust through 2.5 inch pipe than 2 inch pipe. Self explanatory. It's easier to push exhaust through a muffler that is straight through than one that has baffles. Again, self explanatory. I'm not sure if you are debating this or what. Kind of sounds like it though."
and its easier to push exhaust through a hi flow cat than a oem, self explanatory.
i noticed after i posted that it included the downpipe. the point i guess i was trying to make is if the downpipe is only 2", and putting on a bigger cat won't help flow, how could bigger pipes after the cat help? i know the material is diffent because they weigh half as much, this page explains how there different. if they flow better on a bench test, how wouldn't they flow better on a car, at least on a bench test there are no real variables
http://www.randomtechnology.com/technical.html
i dunno, im kinda burned out on argueing (god i can't spell..) about highflow cats, if i ever order that chip ill let you guys no on the results. im not to worried, cause if it does nothing ill send it back for a refund.
Is this self-explanatory because it says "High Flow" on the packaging?
For the moment, just picture this: Your exhaust is 2" in diameter. There is a stretch of it you decide to replace to make it flow better. If you splice in some 5" diameter pipe for a few inches, it should increase the flow, right? Because a 5" pipe flows more than the 2" it replaced.
However, in reality, the flowing air will not expand that much. It will essentially jet through about a 2" wide center of it. Plus, the bit that does expand out will just slam into the other side and cause turbulence, thus probably hurting the flow.
So now, picture that this is the catalyst. If you expand it arbitrarily, you won't just get better and better flow through it because the piping in front and behind isn't very wide. The exhaust flow will only expand out so much, and taper down so much. So any media wider than that isn't doing anything, and may be causing turbulence.
If the media is less dense or something, thus allowing more exhaust to flow through the same diameter of media, then fine, this is probably an improvement, and will also probably increase the sound that passes through.
The comparison to the Corsa isn't really the same. The Corsa isn't 5" wide in order to flow better. The stock mufflers consist of a series of chambers and non-contiguous pipes. The flow has to push through several chambers, and make several 180 degree turns. Needless to say there is a ton of turbulence and a terrible flow path. The Corsa simply straightens this out.
I believe this is essentially what Greg is getting at too. I can understand the points he is making about both the TB and the cat, but yours come across as more random statements with no real focus or point. Maybe try to address one issue at a time when you reply. I hope you aren't offended, but it is hard to glean a point from some of your posts.
I would like to address a few other issues you mentioned as well.
You mentioned if the new Caddy TB was 85mm+, then Greg's argument would hold water, but not for 80mm. What's the reasoning behind this? How did you conclude 85mm = relevant, 80mm = not relevant? Also, as Greg mentioned, the intake plenum entrance is 80mm, so having the TB match up will make for smoother airflow into the manifold. 80mm seems more ideal than 85+mm, which would have the air hitting a ridge in its path. Not to mention Greg dyno'd this mod, and isn't just saying it felt better.
As far as that chip, 23hp and 32 lb-ft, but the dyno can't produce graphs? So, how do you know these weren't just abberations on the run? Dynos will usually have some spiking. This can be filtered out of the graphing by averaging and such. However, this requires adjustment and attention by the dyno operator. However, it can easily be spotted on a graph, and you can easily look at what is generally the peak output by optically filtering out the spikes. You can even see this in that Random Tech dyno chart you put up. Notice how it isn't perfectly smooth. That doesn't compromise a dyno's ability to be a good tool, but it is something you need to pay attention to, and that's something that is impossible to do without a graph...
In addition, a torque gain at 5200rpm of 32lb-ft should result in a horsepower gain of almost exactly 32 hp. Yet the chip claims 23 hp. Why is that? Not to mention that 23 hp and 32 lb-ft from advanced timing is just incredible. It is very difficult to swallow that figure.
If you like the cat, and like the feel, then again, that's great. What you need to realize is that some of us aren't going to rush out and buy something that we are skeptical of just because someone posts up "it felt awesome". While there may be a great argument or explanation of how it can boost power, you just haven't made that argument yet, at least not well enough that I'm gonna go try it.
Same with the chip. If you want to remove the limiter and change the shift behavior, then have fun. That's probably the best reason to buy it anyway, because those are believable claims. I can believe the chip can change your shift point or firm up the shift or (no idea why this is desirable) remove the traction control. But if you are buying it because you think you are paying for 23 hp and 32 lb-ft, then I personally think you are going to get scammed.
The same is true of the horsepower curve. It appears to peak at around 5600-5800 rpm, yet the engine's peak is rated at 5200 rpm.
Lastly, the 3800 S/C has a fuel cutoff at 6000 rpm, and I am quite positive the stock tranny would force a shift before this point. On the same note, I belive the speed limiter on these cars is in the 112-118 range. What speed is the car going in 3rd gear, with the very low axle ratio of the 4T-65HD, at almost 6000 rpm? The dyno claims it is a stock car...
And the peak of 273 lb-ft at the wheels is within 7 lb-ft of the rated max... Though, this could be because GM underrated it. That thing is torquey as hell in the low rpms...
What gives?
A aftermarket convertor doesn't have to meet the same specs as a oem one, thats how they get away with a free-er flowing less effective convertor. the actaual bricks inside the convertors (2 of them) have the same size holes, but are shorter in length in "highflow models". this is why they typically set off codes on a OBDII car, they arn't as "effective" as the computer thinks they should be (a simple 02 simulator will fix this). they still have rules on how much they filter, and will easily pass emissions, but by using shorter bricks of materials they flow about 75 more cfm.
my car did get louder by adding the new cat.
for the TB i was saying this. you guys made it a big point that cadillac engineers thought that the new northstar needed to have a 80mm tb. i said that isn't relevant because a 4.6L will need a bigger TB than a 4.0L. If cadillac thought that a 4.6 needed 80, then a 4.0 would need 75. but if cadillac thought the 4.6 needed 85, then a 4.0 would need 80. Im sure the 80mm tb would help, but i don't think it will help $350 worth.
The chip...like i said, don't shoot the messenger! lol. but by deleting TQ management, the car won't lag so much on shifts, since it won't retard the timming. He can also change my shift point from 6k to 6.3k, the classics won't shift as high as your newer one. for firming up the shifts, i asked him if he could make it so tq management was off only when the power button is pressed. Not sure if he can do this yet, but im pretty sure that tq management only retards the timing at WOT, so regular driving the shifts wouldn't be harsh. neither of these mods will add actuall hp, but will help 1/4 and ET's. lessing the egr flow and a earlier tq lock will help the off the line tq from what ive heard from the people at clubgp that have the "fast" cars (sub 13's and lower). earlier fan on/off is good to. they claim 'better spark curve" or somthing too. i agree, i don't think ill get those #'s either, never thought i would, but i do think it will add some actuall hp/tq, and make the car make better use of that power.
GTP's transmission has a 18% loss, verses our....24% ouch, i hate it. in typicall GM fashion the L67 (sc 3800) actuall makes more than 280tq, ive heard 310 stock, but the transmission is only rated at 280, so the car gets rated at 280. the 04's actually make 340-350ft lbs.....but the computer limits it to 300, still rated at 280 though. this shows because they did ALOT of improvements to the supercharger, ALOT all the stuff they did should have increased the tq and hp, but only the hp #'s went up, the computer took care of the tq gains.
the tq numbers in that graph still sound a little high for at the wheels, but the numbers they list don't go with the graph, the graph shows about 255 stock tq. the 04 guys are dying for a chip...GM limited the power to there transmission, maybe they did to ours too.
Granted, I may not like everything on my 2002 Aurora or how the factory set up is to conservative standards, but I feel if you jack with it too much, you stand a chance of destroying it. All of the factory set ups were done for a reason.
If I wanted to do modifications, I would just buy another car to tinker with.
INVHO
Steve
I'm looking to see if someone did not want the extra 2 pieces left over that were not used, since a wooddash kit comes with the heated seats and non-heated pieces, I'm looking for the non-heated seat pieces.
Anyone out there, let me know at javs55@hotmail.com.
I have looked everywhere, but they seem to only have the whole kit.
thanks.
Http://www.cardomain.com/id/javidogg
To make it flow more without cleaning as well isn't really that hard. Instead of springing for a new convertor, I'll just take a screwdriver to mine. Same result, but a lot cheaper.
If the Random Technology convertor does a crappy job of converting, then what's so special about it? It's high-flow because it sucks as a convertor, not because it is some superior product.
You have basically just made the point we were getting at. The only real way it can improve the flow is by some breakthrough in convertor technology, or by doing a poor job converting. Sounds like the "high-flow" cats do the latter.
sure you can do what alot of people do and just ram a pipe through there, not sure if you have to pass emissions were you live, i don't. wouldn't it also smell bad? somthing a cop might notice if he pulled you over? not sure.
looking at the results, there was no gain, somtimes actually a loss in power switching from a highflow cat to no cat.
the highflow cats don't do a crappy job of converting, im sure it would do a better job then the used on in garnes car for sure, they are still 50 state carb legal, and will still pass any emissions test there is.
im not a salesman, so i personally don't care if you guys want it or not. and rjs, you can't even legally change your cat until 5years/50,000. i just thought maybe some other people were looking for a cheap easy way to free up another 5-10hp/tq. want proof? ask anyone thats switched it. dyno results arn't always consistant, thats why i figured you guys would better realize the gains when thousands of people switch them out and see the same gains in the "seat o pants" meter, and just watching the rpms climb faster.
My cat-back exhaust is 2.5 inches. It actually fits nicely to the outlet of the stock converter as it is tapered. But even if the outlet on the converter was much smaller, the length of piping in the cat-back is quite long and there is a benefit to having the larger diameter.
If a converter (for sake of argument) was 6 feet long - then yeah - even approaching a 2.5 inch converter with a 2 inch pipe at the inlet may have some benefit. But with the stock down pipe, you are likely going to jet the exhaust flow through a larger converter and not realize the gain from a larger flow area. That's WHY they offer systems with the larger down pipe. It matters.
Hey - you stated the dyno graphs were "PROOF". The missing run times and dates are very telling, but the stuff RJS pointed out is pretty good. If I remember the torque curve never showed a peak. It was a downhill slide from the left side of the graph. I though - Hmmm maybe those SC 3.8 have peak torque at some low rpm that's off the graph. I think the tranny on a 3.8 is about 80% efficient. Anyway. isn't 80% of 280 = 224? But the graph does show a huge 270+ torque. The engines aren't THAT underrated. In short, when you start to see stuff like this on the web site, you really have to wonder - what else are the (dare I say) fibbing about?
Just for the heck of it, do you understand what I'm saying regarding the TB issue when I ask "No possibility that it (75mm)was small for both by differing degrees?"
You simply won't address this logical question. For you it's "75mm was too small for the 4.6, but must have been right for a 4.0, so the improvement to 80mm for the new 4.6 has no implications for the 4.0.
Besides there are other issues other than flow area like RJS pointed out. Expanding it like I did makes everything match ported for a smoother flow pattern.
and i believe you that a 80mm tb, on a 4.0, will help performance. if i had a extra $650 laying around id get one, granted you get $300 of it back. but im a broke college student.
personally, ill spend the money on the chip, take off my tb and clean it good. maybe im a sucker, but ive talked to the guy and i believe him, and if i get it and relieze ive been had...ill send it back and get my $289 back, hopefully ill have some money next week, lol
never really looked at that graph, but now that i look at it, it does look like it was altered or the scales on the sides are off.
I thought the MAF added power. I debated that it it should help a lot on this board. But two separate trips to the dyno showed that it lost power. But I "thought" it was better. I wanted it to be better.
If the chip is an easy thing to activate or switch back and forth, you really should go to a dyno. First, it's a TON of fun - especially first time. I admit though it's not that fun when you see that something doesn't work. Second, you can monitor A/F ratios so you can see if that chip is actually changing some operational parameters. Running the car too rich or lean can hurt things - especially lean. It's about $100, but it is just too cool to change something, and actually measure what happens. Going 120+ on the dyno is a rush.
I'm sorry to hear about the converter on the OBD II codes. I guess that might be some evidence that it really is less restrictive due to a bit less media, but I can't imagine it's helping a lot. You know, given that reality, you might as well just run with a gutted converter and use the fake-out O2 (like RJS said) and then switch it back if you had to. It's illegal to do though. I'm a bit surprised the high-flow converter would pass emissions too.
Mr. Dub, I dyno'ed my car w/ the Hi Flow cat and exhaust and K&N, 282HP. I added the $650.00 80mm TB and plate and redyno'ed less than an hr later and got 282HP.
I think most of the intake gains I've seen posted come from the cone filter and according to my butt dyno) not the TB. A trip back to the dyno will confirm when I get my 2 new cone filtter intakes done.
I did the Garnes mod +1, actually cutting out metal and adding a cold air "scoop" below.
Greg, did you have your MAF cold cal'ed? Granatelli supposedly doesn't make a 4.0 calibrated Aurora MAF, so unless yours was custom, I wouldn't expect it to work very well.
Chips work great on turbos, but it's tough to get much on a normally aspirated engine, maybe some timing things, etc. Plus there's only so much you can do by upgrading the octane rating (i.e; a 91 octane chip vs. a 93 octane chip). I've seen them run on a dyno (Audi S4 w/ several APR programs) and there's very little gains between those octane levels, almost indiscernible.
The bored out TB also set off my codes. Adding a cone filter made them go away. So did resetting the computer by disconnecting the battery for a while. The computer then "relearned" how to live with the new TB.
Yes, I spent $650.00 on the bored out TB & plate, yes, I dyno'ed it, and yes, I saw 0 HP gain, as the guy that owns the dyno shop said I would. He, consequently, runs a smaller TB on his 450 HP Mustang.
This was the first dyno test. I'll have to scan the ones from the TB in. I wasn't too happy about wasting $650 plus the dyno test and install cost.
By the way, if I was going to get the cat again, I'd get the 3" like RSM recommends, I think it will flow just a little more air due to its geometry. This will require a little more work from your exhaust guy, maybe another $30?
saw the biggest gain with the highflow cat, probably becuase it complimented all the other work, just a highflow cat wouldn't have seen such a big gain. your the one that convinced me to do it. only $60 for the cat, i think $35 for the install, huge difference.
id really like to take my car to Rock Falls wisconsin next rear, just to see what it does in the 1/4, im hoping low 15's. if i have the funds id be a good comparision to do 2 runs then pop that chip in and do 2+ runs, there is a 35day money back warranty if im not happy.
took the 18's off for the winter, man can i tell a difference in performance, really flies from a role.
You better submit your dyno results showing that the TB does nothing to caddyinfo.com to balance my graphs showing that it does something. Taylor has some positive results regarding the TB there as well. It's a shame if I've misled people all this time. While you are at it, you should perhaps submit these results to Cadillac to let them know the larger 80mm TB they use on the new Northstar is a waste. If it's applicable to the new Northstar, it probably has some applicability to the older one as well. I doubt it's 100% effective at adding a little power for the one engine and 0% effective on the other. It's possible, but matching the TB assembly to the intake manifold was an improvement for smoother flow that the new Northstar included and is also an improvement resulting from the RSM TB work. It's basic stuff (but admittedly not hugely consequential) that for some reason seems to have been overlooked on the first Northstar. Enlarging what is clearly the smallest passage in the intake just makes sense too.
I'm not so sure the 230 degree run is all that bad. When the engine is warmer, the fluids in the tranny and the engine oil have less resistance to flow and basically create less drag on the engine and tranny. Yes, at some high temp, there may be other adverse effects, but I'm not sure 230 is all that terrible. Colder runs (less than normal operating temp) clearly have a drag on how much power makes it to the wheels for the reasons explained above (in reverse). I think the computer is in some sort of "close loop" default mode until it warms up too. I had some pretty warm/hot runs like yours and did not notice a negative effect on power. Colder runs were not so good.
As for the MAF from Granatelli - yes it was custom. It was an actual Aurora MAF that they modified. I talked to "JR" himself about it several times. "JR" even did the work himself - so he said. I followed all the battery disconnect instructions. The thing is a POS. I even sent my dyno A/F curves to JR and he admitted it was running too lean as a result of their adjustments. I had them put the A/F back to stock for WOT, but I just put the stock MAF back on. But hey, if you think they are so great, I'll happily sell you my customized Aurora MAF from Granatelli for a great price. Let me know. Oh, and what's hilarious was that they said it flowed 30+% better than stock. What, from just removing the screen??? I love that "flowed X% better" crap. At what pressure? Under what kind of installation set-up? Was the pressure differential commensurate with actual operating conditions?
BTW - earlier before when discussing the high flow cat, a link to their web site was included that showed dyno graphs for a SC 3.8 I believe. That dyno they posted is so hokey and full of problems it's pathetic. It doesn't look legitimate. What a confidence booster in their product. In addition, they sell systems with the drop pipe matched to the new cat. Why? Because you have to gradually expand that flow path to realize the advantage of a bigger cat. If you don't have the better drop pipe - well you are probably shooting the exhaust through the same amount of catalytic converter media.
of course you and taylor got results, i mean...i got good results from spending a half hour with a toothbrush just cleaning it out! you would have gotten about 90% of those results by cleaning yours. its like comparing a dirty air filter to a K&N, gotta have a balanced test!
cars go into closed loop way before 210. if the car was 230 then that air comming in would be alot hotter than 210. plus the only way to get up to 230 is to let it sit in park while it idles, raising the temp of the air under the hood.
its funny that everyone who's done it is saying, YEAH IT HELPS!!! the only people saying it doesn't are the people who have never tried it. i even tried to prove that they use less media inside there, which they do......which is why there called highflow.....which is why they don't filter as much.....which is why they throw codes......which is why so many people try them and say they help.....which is why the sell so many.....
yeah a downpipe would help more, but the fact remains that the cat is a bigger bottle neck than the stock downpipe. so reduceing that bottle neck, while still keeping the bigger bottle neck, will help.
and seriously, get off the whole thing about cadillac using a 80mm tb on the new caddies. its a bigger engine!!!!!!!!!!!!! i think i should say this one more time, ITS A BIGGER ENGINE!!!!!!!!! not only that, its got alot of different stuff, doesn't it have vvt??? alot of other variables, but the biggest, ITS A BIGGER ENGINE!!!!!!LOL
i could come to your house tonight, while your sleeping and put a highflow cat on your car. then when you woke up and went to work and noticed your car felt faster, i could tell you what i did and you would still say....no, must be weather changes or somthing.
personally i don't care if you get one.....i like haveing a faster car than you
Garnes has nothing to show for his $650? I think he had about 9 hp at the wheels to show for it. Greg's car didn't really gain power because Spike says it didn't?
I'm guessing you then moved on to talk about the catalyst saying everyone who tried it says it helps? You were talking about how the TB is worthless, but then say everyone who tried it says it helps. I can only assume you had changed your train of thought to cayalysts... But you mention filtering, which a cat doesn't do. Also, you mention they are called high-flow because they have a poor catalysing ability? I think high-flow means it flows more, not pollutes more. At least, that's what those words mean to me... You say it like that is implicit in flowing more, which it is not. An Aurora has a catalyst that flows more than an Alero's cat, but it doesn't mean it is less effective.
I also think Greg would notice if you replaced his cat with a high-flow. He'd notice the second he turned the key and the "Service Engine Soon" light came on...
Please don't turn Edmunds into the frantic, hyped, exclamation-point-instead-of-logic, pointless forum that GMForums was. The forum here actually has useful info and rational explanations of things. Don't come here and stomp all over that.