Subaru Crew - Modifications II

lucien2 · January 2002

Thanks! Hey colin, while we're at it, I'd like your opinion. I have some money to spend on the car, but can't decide between exhaust or AGX struts. Mike Shields seems pretty down on the whole exhaust thing, but other swear they get 20hp over 5K rpm with a 2.25" catback. Problem is MD dumps all the salt of the atlantic at the 1st sign of a flake, so I am thinking about the Brullen SS (NOT the headers!) there is also an SS Stromung (muffler only) for sale on i-club. Since you've been down this road already, I'd like to hear what you think.

Cheers,
Lucien

hondafriek · January 2002

There is no way on Gods earth you are going to get 20 HP with a catback exhaust, and I do not care who told you that.

Cheers Pat.

kens · January 2002

20HP doesn't sound right. Maybe 2HP?

Between the two, I think the money is better spent on suspension components on our NA vehicles.

Ken

mdisaacs · January 2002

Kept the stock wheels but swapped out the Bridgestones for Yokos, 235/R55-16 and have no rubbing even while the suspension is compressed and wheels are turned. The 235's are as wide as the 6.5 wheels can fit. The tire does bulge out from the rim about 1.25/1.5 inches.
-Mike

ateixeira · January 2002

Urethane bushings are more prone to squeeking.

I like to go with chassis bracing, suspension, brakes, and engine, in that order. Better to have an over engineered suspension than a chassis that cannot handle its power.

-juice

locke2c · January 2002

Loosh,

Pat's right, you might gain 20HP by replacing the muffler on a 750HP car but not on one making 165.

There's probably a small gain though and it sounds neat.

The AGX struts are proven, relatively inexpensive and ride about like stock when at/near the lowest adjustments. I have a set sitting around, but sorry can't sell 'em because I plan to go back to them (with H&R springs) very soon. 400lb/in springs are too much for my use of the car.

-Colin

paisan · January 2002

I might be interested in those 2.5RS springs... Very tempting to put in the XT6, but that would knock me out of stock

-mike

PS: 20hp? Ithe guy on crack?

lucien2 · January 2002

Well, see, that's my thinking, so that's why I came here to get backed up on it. It's a "quote" from SCC's test of several systems for the RS, I done heard tell. there is also the MRT mild steel system available....MRT claims a gain of 12-14hp, and 17.5 at peak with their header-back system. That sounds a little more reasonable, but still a wee bit fantastical.........

locke2c · February 2002

The header results are much more believable because of the inherent flaws in the stock exhaust manifold design.

-Colin

ateixeira · February 2002

Look at all the kinks and turns in the exhaust, and I believe the header-back can make a difference.

Also, Jake Moran took Mike's exhaust apart, and said the cat was by far the most restrictive part. So a cat-back doesn't remove that weakest link, and may not make much different at all (besides noise).

-juice

locke2c · February 2002

click me

I am unconvinced about the turbo performance-- doubting mainly that the tests were completely equal. But what I am sure of is that the Borla header is better than stock for naturally aspirated cars.

-Colin

hazdaz · February 2002

I think that the WRX shouldn't have ANY muffler at all - this weekend I probably plan on getting a straight pipe installed from the last cat back. Since the exhaust is ALREADY restricted as it is, the muffler does next to nothing (atleast thats what I am HOPING). I am not expecting any power gains with THIS mod, just a nicer sound. And it has to be lots cheaper than any aftermarket muffler.

ateixeira · February 2002

I bet you'll get some kickback. A turbo will certainly sounds more mellow than a N/A engine with a straight pipe, though.

-juice

c_hunter · February 2002

The one thing to remember about exhaust tweaks is that all engines have been tuned for a certain level of back pressure. If you do alter the exhaust, the effect on the engine could be positive or negative. And getting good performance may involve more than just exhaust mods. If you think about it, the engine is a big pump with an intake and an exhaust. You really have to work both ends effectively to get things right.

Steve - along those lines, I don't think removing the muffler will be a good thing. I am sure it will be loud as heck without the muffler. It's the only component in the exhaust system with baffles and compartments. Everything else provides a straight through duct to propagate noise.

Craig

locke2c · February 2002

Craig--

Not true at all on a turbocharged engine. The backpressure is provided by the turbocharger, what's going on with the rest of the exhaust plumbing is somewhere between irrelevant and only detrimental.

And actually, on a naturally aspirated engine backpressure isn't what you're after it's flow. Too large of exhaust piping allows the gasses to cool too much, so there absolutely is an efficient size.

-Colin

c_hunter · February 2002

My point was that most engines are tuned to work with the effective back pressure of the exhaust system. That back pressure comes from a pressure drop due to losses in the exhaust system, which translates into greater than ambient pressure upstream at the engine. If you removed all exhaust plumbing, the engine would be exhausting to ambient pressure and would run very differently than the same engine with an exhaust. Whether it's better or worse depends on how the rest of the engine (like the intake and pumping action of the cylinders) can adjust to the different back pressure. It could be a positive or negative impact. Reducing back pressure will do no good if the resulting increased flow rate of the engine exceeded the capabilities of the fuel/air intake system, for example.

When it comes down to it, the turbo is not causing back pressure -- it is extracting work/energy from the exhaust flow which decreases the pressure of the exhaust gas (that work is then transferred through a shaft to increase the intake pressure by the reverse procedure, minus some losses). If you start at the tailpipe (where the flow must be at ambient pressure) and work backwards, that means the pressure drop across a turbo results in higher pressure upstream of the turbo than you would get without it. So yes, the turbo engine sees higher pressure in the exhaust manifold downstream of the engine, but that pressure is different from the back pressure I discussed above.

It's important to discriminate whether or not pressure rises are coming from losses in the exhaust system (back pressure, bad) or from extracting energy from the flow (windmill effect, good). Lumping it all under the nomer of "back pressure" is misleading.

Craig

originalbitman · February 2002

Griots garage sells clear protective film by the foot: http://www.griotsgarage.com/catalog.jsp?L1=L1_1000&L2=L2_1007&L3=L3_1090&SKU=77892

I would be happy to set up a site of Crew links and host it at my site along with posting pictures there if anyone is interested. I have my old mods there and still have some of the OE install instructions posted too. Would be glad to add more.

http://www.bitman.com/SoobMods/

http://www.bitman.com/soobinstall/

Now that I am semi-retired I need something to do and so this sort of fits the bill.

bit

1subydown1togo · February 2002

You're back!..it's been a while since I've seen you here...

hondafriek · February 2002

Welcome back. I had given up hope of ever hearing from you again.

Now that you are back in circulation could I pester you once again for your directions for the the Map pockets,and where I would loofor the supplys.

Cheers Pat.

miksmi · February 2002

Mike, Glad to see you here again. Since you're here, I presume the move is complete?

I'm sure juice will take you up on the offer to host his numerous instructions and photos.

..Mike

lakepop · February 2002

lakepop · February 2002

Amen to the comments re a normally asperated engine. It can be considered a pump and I subscribe to the "AIR IN/AIR OUT" when modifying the system. Most mods respond when done as a system as opposed to only one change.

Caveat is that you can't exceed capabilities...something like fuel capability. Too much air flow without enough fuel=lean condition=BAD. By in large our NA subes can keep up with things like a CAI/cat back exhaust

mrluther · February 2002

My 2002 forester l has 9k on it and I was thinking about installing a K&N filter or modifying the air intake in some way.Can anyone share their advice about doing this and expected results. Thanks, Mike

declansdad · February 2002

Just installed my subaru hood deflector yesterday, sure does look nice. The directions were horrible, kind of backwards if you ask me. Installing the brackets to the hood should be the first step (after cleaning the car of course). Took about 10 minutes to install (another 10 minutes laughing at the directions).

mrluther: I've heard good things about the K&N air filter system. I don't have any experience either, but I'm considering one myself.

Michael

maverick1017 · February 2002

Well, the K&N filter alone wouldn't make that much of a different, just prolonging the time between filter cleanings. If you remove the snorkus, and keep the factory filter box, and run a pipe or something down to the front of the car, i.e. in the wheel well, behind the fog lights, then you would notice a drop in engine rpm at any given speed. For example, instead of running at 3k at 60mph, you would be running at 2.5k at the same speed. The reason being the car would then be sucking in colder air, but the draw back being you can't really do any significant trail driving or water crossings. Just don't expect any seriouse performance gain. I did it on my 98 and to be honest I have mixed feelings about the end result, just remember not to throw away any of the factory parts you might take off, so in case you are not happy with the end result you can always put the factory system back in. Oh well, I guess I'll have to see what happens after a new high-flow cat and a new and bigger cat back system.

Mike

c_hunter · February 2002

For fixed gearing, the engine will always turn at the same RPM for a given speed, no matter what you do to the engine. Unless parts slip or break, the engine RPM and wheel speed have to obey a fixed ratio. The only way to lower the engine RPM for a given speed would be to change the gearing.

Snorkus removal may be a bad thing from the standpoint of performance -- it depends on the purpose of the snorkus, and whether it is just a noise suppressor or a tuned intake system. It is my understanding that the snorkus on the Phase II 2.5 engine is tuned for a standing wave pattern, which increases the pressure in the intake system. Removing it may sound cool, but my bet is that you lose some torque down low. This may be partially offset by pulling in colder air. The best bet would be to route colder air in through the snorkus without changing its configuration too much.

Craig

kens · February 2002

Since the topic of intake mods came up, take a look at this article:

http://www.cobbtuning.com/tech/airflow/index.html

I think it reflects what Craig was trying to say.

Ken

locke2c · February 2002

I can't speak for a 00+ MAP-equipped SOHC, but my '99 MAF sensor equipped 2.5L SOHC did not loose any part- or wide-open throttle when removing the snorkus from the fender. It functioned as a watertrap and silencer only. The anti-reversion honker is right behind the MAF sensor, and there are also plastic ridges inside the torque chamber to cut reversion under closed throttle and standing waves.

Although, no other Subaru except a 99-01 2.5RS has a convenient hole in the front fascia to feed cold air into the fenderwell (and thus airbox) so your results may vary.

-Colin

-Colin

locke2c · February 2002

not on my scoob though, those days are gone.

helped a friend install a set of Tein RA coilovers on his '98 RS. They have 8kg/mm springs in front (about 447lb/in) and 6kg/mm springs rear (335lb/in). the tein HAs on my RS use 7/6, but after riding in and driving his car the slightly stiffer front springs does not seem to have affected ride quality any.

of course that means it's pretty abusive over bumps just like mine. but I actually think it's more forgiving (on the lowest damping settings) than my HAs probably due to a more expensive and thus more sophisticated strut. aluminum bodies, inverted dampers, large pistons. (42mm I believe.) I think these coilovers go for about $2300 shipped. (whew!)

this guy is a serious autocrosser though and hopes to compete for a national championship in Street Touring.

also put goodridge braided brake lines on the car and boy that's not fun when they get corroded and the 10mm threaded ferrule holding the stock line in place starts to round. had to heat two of them up with a propane torch, even then one took the vice grips to get it off. I warned him that in 4-5 years when it's time to replace the goodridge lines that he better either not own the car anymore or he should replace the solid lines and thus those two (mostly) stripped ferrules.

I had the same problem on my car but not quite as bad, probably the difference between 17k miles of use (at my time of installation) and 55k, eh?

in the other corner of the garage, my dad was helping another friend port his cylinder for a 125cc kawasaki dirtbike engine. he recently sold his '98 RS and bought a '94 talon TSi AWD, but the engine is for a shifter kart. fun stuff!

-Colin
dirty fingernails

kens · February 2002

Ah, so are you now doing vicarious mods, eh? :-)

Cool report. Glad to know that you're still into tinkering with Soobs even if they're not yours.

Ken

fibber2 · February 2002

Michael,

You may need take two of the leftover clear tapes and wrap the leading painted edge of the hood where the deflector folds around going to the screw attachment points. Mine was chafing the paint.

Steve

bluesubie · February 2002

Good advice Steve. Mine is also chafing the paint (installed by me) and so is my wife's car (installed by the dealer).

-Dennis

maverick1017 · February 2002

The reduction in engine rpm is what I experienced after I removed the snorkus from my 98 and running a hose to the front of the car right below the radiator. Again this is only what I experienced, didn't loose any low end torque. Individual results may varie.

Mike

locke2c · February 2002

mike,

I agree with what was said earlier... regardless of what you feel you might have observed, it's physically impossible for the RPM at a given speed, in a given gear, to be any different unless the clutch or tires are slipping, or you've altered the gearing in some way. (like taller/shorter tires, changing something inside the gearbox, etc.)

You're not the first person to be pretty sure something changed with respect to rpm versus speed, but you're mistaken just the same. Sorry.

-Colin

declansdad · February 2002

fibber2: Thanks for the tip. I'll have to try this out before I go visit my family this weekend. I'm so looking forward to a nice 3 hour drive in my sub (sure beats the wife's integra)!

Michael

paisan · February 2002

Unless it's an AT, and even then most lockup in 3rd and 4th gears.

-mike

ateixeira · February 2002

Bit: check your inbox. :-)

Mike: I removed my silencer, AKA "snorkus", from the intake. It's a bit louder at wide open throttle, but the same the rest of the time. It's free, too. Your intake is less restrictive than mine was, though.

Colin: so that's what Empty Nesters do on weekends? Still, our toddler was so fun at the beach that I admit for once I am not envious.

-juice

locke2c · February 2002

juice, the nest has never been full... that makes me a DINK I believe.

-Colin
dual income no kids, before someone asks

ateixeira · February 2002

We have a jumbo mortgage, so when our 2nd is born we officially become SITCOMs (single income, two children, oppressive mortgage).

Back when we were DINKs I guess I had much less free time. Bummer.

-juice

kens · February 2002

I'm a DINK too and I have no idea where we're supposed to get all this free time.

Oh wait, I just went all-day snowboarding last Saturday! ;-)

Ken

lakepop · February 2002

Juice..I'd bet the barn that you would not give up what you now have to go back to being a DINK.
Kids make it all worthwhile albeit a frequent challenge.
The struggle has to have a purpose...to me its family and being a SITCOM is a noble position.
Just my feelings.............

lucien2 · February 2002

anyone notice the new Focus print ads? They're done up like movie ads, with critics' quotes. But one of the critics is someplace called Edmund.com!! Well Pat, is there an "S" in the puzzle??

ateixeira · February 2002

On weekends you probably have free time. When we were DINKs, I had much less leave from work than I do now. Too bad, they didn't have Alternate Work Schedule back then, so I didn't have every other Friday off.

Now that I have the time, I spend it with my daughter. No regrets, I just wish I had the time earlier in my life, too.

If I even begin to wonder what it would be like to be a DINK again, I here our toddler get into one of her giggle-fits and forget all about it.

I like the Focus ads. They make the car seem really trendy. If Ford had work on the big Q issue, they'd have a real winner. People seem to like the car, dynamically, a lot. The SVT just won a C&D comparo against the new Civic Si and the GTI, and by a wide margin, too.

Also, Focus is bringing in younger buyers, and without the incentives the Escort needed. From a marketing perspective, it's a huge success, no question.

-juice

paisan · February 2002

It's kind of our mantra that everyone drives home from an offroad event or installfest under their own power if at all possible. Only 1x did we have to get someone towed home from an offroad event and that was because he didn't listen to us when he sucked in water. Installfest we've turned down some people to do stuff cause we didn't feel that the collective knowledge could accomplish the task with the tools or time allotted. Hopefully it won't turn you off to future installfests.

-mike

ateixeira · February 2002

OK, thanks to Bit and his new pass time, I posted some photos on his site:

http://www.bitman.com/juice/

Check out the glove box and dash-top bin liner. The flash went off, so the green appears lighter than it really is. The stuff was $5 for 4 sheets (Con-tact shelf liner, velour, green) from Michael's, a local craft store. That was enough to do all 3 cars! :-)

-juice

hypov · February 2002

http://www.ravensblade-impreza.com/parts/partsimpreza.html

if it interest anyone, I thought I pass it along.

-Dave

lucien2 · February 2002

I was just sayin' there was a spelling error is all. ;')

kens · February 2002

Dave,
Thanks for the great site!
Ken

hypov · February 2002

You're welcome :-)

Like I'd said, I stumbled on it looking for MY '00 RS wheel.

Here's the home page.

http://www.ravensblade-impreza.com/index1.html

Again, for anyone interested.

-Dave

ateixeira · February 2002

No comments on my glovebox and dash top bin liner? I did the ash tray and the coin tray, too.

-juice

Subaru Crew - Modifications II

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