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sleepy04
10-11-2009, 01:20 AM
For most people, the first true “performance” upgrade they do is to replace the exhaust. The idea behind the exhaust is that it allows your engine to breathe easily by allowing the exhaust to escape from the engine faster. Now there are many, many different types of exhausts out there to choose from. Which one is best?

The exhaust can be broken down to three basic sections, the axle back, the cat-back and the turbo back.(see fig. #1. Thanks to Mach V and Matt Randolph for the picture.) What’s the difference between them?

Axleback:

This is basically just the muffler. In the figure, it’s the farthest section from the engine. This gives minimal power gains, if any at all

Cat-back:

This is the exhaust from the Catalytic Converter back, in the figure it’s the farthest two sections from the motor. This gives small power gains.

Turbo-Back:

This is the exhaust is just as it sounds, from the turbo back. It replaces the down-pipe, mid-pipe and muffler. In the figure, it is all four sections. This will give the highest power gains.




So now I’ve decided which exhaust setup is best, but there are so many different manufacturers, which do I choose?

Again, choice is up to you. Some people like the way a certain exhaust sounds, others like the way it looks. This is up to you. But for the most part, you get what you paid for. The cheaper the exhaust, the shorter it will last.

But before you buy an exhaust, RESEARCH the exhaust. Find out how loud it is. Besides the power gains, it also will bring out that great Boxer engine sound. It won’t sound like a Killer Bumblebee. But if it’s too loud, it WILL get you hassled by the MAN. If you've been on any Honda website, i.e honda-tech, you would not believe all the whining that goes on about exhaust tickets. So go to meets, cruise around and stop random Subaru owners with exhausts and ask them, listen to YouTube clips if you have to, just figure out how loud your exhaust will be before you buy it and if you want to put up with the noise.


When replacing your exhaust ALWAYS check the legality of the exhaust and the type of exhaust you are getting. Catless exhaust (exhaust with out catalytic converters) are great, but can cause your car to fail smog tests and safety inspection.


Also just bolting on the exhaust will give you power gains. But to truly benefit from the exhaust, you need to get it tuned. For 04+ WRX’s & STI's this is a MUST. Your car will not run correctly because of an OPEN/CLOSE loop that is used by your ECU.


This was a just basic writeup on exhausts. It will give you enough to get started in looking for an exhausts. If you would like learn more, this link will really help. http://forums.nasioc.com/forums/showthread.php?t=447182(Unabombers the MAN, and from the VA!)

xxthat girlxx
10-11-2009, 04:04 PM
Don't forget your exhaust may fail inspection due to volume!

RCKSTR
10-11-2009, 09:04 PM
how bad is it for you ladies in mass? when I drive to work down in Greenfield I allways get the hairy eyeball from the mass state troopers on the highway :rolleyes: but have yet to be pulled over by them :p

love the wright up with the break down of the different setups!

xxthat girlxx
10-11-2009, 11:20 PM
I had a 3" catless Megan Racing turbo back that I had for quite some time. Then I was pulled over twice. Played dumb girl twice. And had two written warnings. I had to get rid of it.

Then I through on an STi catback and was sad every time I turned on my car.

Now I have a Maddad dp, Maddad intermediate pipe and Prodrive axle back and I LOOOOOOVE it. Loud enough but it can be toned down quickly.

sleepy04
10-12-2009, 07:52 PM
I had a 3" catless Megan Racing turbo back that I had for quite some time. Then I was pulled over twice. Played dumb girl twice. And had two written warnings. I had to get rid of it.

Then I through on an STi catback and was sad every time I turned on my car.

Now I have a Maddad dp, Maddad intermediate pipe and Prodrive axle back and I LOOOOOOVE it. Loud enough but it can be toned down quickly.

That sounds like what happened to me. I had a custom built exhaust on my turbo accord, no cats whatsoever and some cheap 3 inch outlet muffler from ebay. That car was loud as crap. I got pulled over a few times, but paid the tickets for it.

When i went in for inspection, the dude just about hit the roof. Failed it immediately, and told me that i was lucky he was in a good mood. Apparently in VA it's a $10,000 fine for running a street car with out catalytic converter.:eek:

BoostinChick
01-08-2010, 03:52 PM
Hrm, I want to do a Turbo-back but then I read this:
06-07 WRX OWNERS READ: On the 06-07 WRX there are boost spike or creep issues in all cases with the use of an aftermarket downpipe or turboback. This is because the 2.5L engine pushes so much air. Even with the internal wastegate fully open not enough air can exit to stop spinning the turbo, the result is boost creep or boost spike. With the 06-07 WRX, unlike the STi, you cannot fix the problem by just porting the stock turbo wastegate, since the problem has to do with the actual size of the turbo. We suggest porting the stock turbo wastegate AND getting an engine management system to help fix the issue like a UTEC or AccessPORT. With the added costs this will entail, 06-07 WRX owners may want to consider waiting to get an aftermarket downpipe or turboback after they have upgraded there turbochargers or they may want to consider getting a cat-back exhaust only.
http://www.jscspeed.com/wrx/experiment/exhaust_101.htm

Thoughts? (other than upgrading my turbo lol)

08vtwrx
01-08-2010, 05:53 PM
I have an spt for sale!!! 08+ WRX

SassySTi284
01-10-2010, 03:43 PM
Hrm, I want to do a Turbo-back but then I read this:

http://www.jscspeed.com/wrx/experiment/exhaust_101.htm

Thoughts? (other than upgrading my turbo lol)


Yes the 06-07 have boost creep issues when a TBE is put on but you will be fine IF you get a tune right away. Best option would probably be Cobb AP. Can monitor many diff engine parameters and clear check engine lights. Plus with the AP you can have different maps and flash over at anytime compared to an open source tune. But that's just my opinion.:cool: