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Discussion Starter #1
So today I got the local shop to run my 3" exhaust (also got them to install my ZZPerformance 3" catless downpipe).

For some reason (maybe it's jsut in my head) I feel like I lost a good bit of power. But I don't get it. Everyone else LOVED their 3" exhaust. Is it in my head? Do I just need to get tuned for it? It's 3" exhaust with no mufflers or resonators - just 3" pipe. And I know someone is going to say "not enough back pressure" But I know that's BS. You don't want any back pressure for a turbo vehicle.

Anyone???
 

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Downsize sir. I suggest a 2.5" exhaust thats why yer losing power and yes a tune is involved in a sense. but to have an exhaust doesnt really require a tune. Some say you do but from a mechanical standpoint you dont need one.
 

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Discussion Starter #3
I really, really don't see any reason in down sizing.
3" exhaust is recommended by just about everyone I know that knows a LOT about cars - especially turbo'd. Almost every single exhaust available for ANY turbo car under the sun is a 3" system...no one would offer it if it was a bad idea/would hurt the vehicle in a horsepower sense. ANY place online worth mentioning would tell you The more flow the better fr a turbo application. It's not like a naturally aspirated engine where back pressure is required.

With that said, I'm not trying to argue with you or anything like that in any way. I jsut don't agree. And I've done my share of reading...and asking.
 

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Discussion Starter #5
I don't know what that is. Reduce three exhaust outlets?
 

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If the only thing you change is put a bigger pipe on the exhaust it will totally change your low end torque curve and make it FEEL slower but on a dyno you could very well make more torque beyond 4500 RPM and lose some down low. It's a good sacrifice for 1/4 mile times, not so good for butt dynos. It almost always helps people get more traction in lower RPMs so you can grip and rip up top. IT'S ALL IN YOUR HEAD FOOO! :)

No doubt, you are making more power in the top end now regardless how it feels. Just don't expect it to add more than 15whp. The stock setup breathes pretty good so you can't take something that's efficient and expect it to gain crazy power when all you really did was make it breathe a tad better on one side of the motor. I don't know your mods but that's my .02.
 

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It also depends on how the exhaust is routed. Does it look like its straighter then stock or more curves? if you add size to the exhaust it doesnt make up for poor bends and bad welds that can cause restrictions. On the other hand it might just be in your head. and Im assuming you have a turbo cobalt? stock? no tune I mean?
 

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I really, really don't see any reason in down sizing.
3" exhaust is recommended by just about everyone I know that knows a LOT about cars - especially turbo'd. Almost every single exhaust available for ANY turbo car under the sun is a 3" system...no one would offer it if it was a bad idea/would hurt the vehicle in a horsepower sense. ANY place online worth mentioning would tell you The more flow the better fr a turbo application. It's not like a naturally aspirated engine where back pressure is required.

With that said, I'm not trying to argue with you or anything like that in any way. I jsut don't agree. And I've done my share of reading...and asking.
You are completely correct sir.... A turbo car with a 3" exhaust is the way to go. Like another member said, it may just be that the low end torque is not sufficient because you sacrificed but once you kick into boost, it should be a lot faster. Plus, your turbo would run cooler, and increase gas mileage :rolleyes:
 

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Discussion Starter #9
Yeah, after having the exhaust for a few days, I may have lost a LITTLE power b***om end, but 3500+ RPM's it's definitely there plus some!

Mods so far: Dejon intake, Dejon intercooler piping, ZZP 3" catless donwpipe, 3" exhaust, and ZZP tune is on order....as soon as they get a freakin core in!!
 

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How does the GM Performance exhaust compare to anything else out there? I have the GM performance exhaust on my car(came with the car when i bought it) and im just wondering if i should change it out?
 

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Discussion Starter #11
How does the GM Performance exhaust compare to anything else out there? I have the GM performance exhaust on my car(came with the car when i bought it) and im just wondering if i should change it out?
Really depends on what size the piping is and what kind of mufflers and or resonators are on it.
 

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I believe GMP exhaust is 2.5" which would be just fine for a ss/sc. I wouldn't change it out atleast.
 

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Discussion Starter #14
Like Austin said, it's probably good as long as you don't push over 12 psi or or turbo'd.
 

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Discussion Starter #16 (Edited)
People are going to say go with Hahn (super expensive for nothing special) or some other name brand systems, but do yourself a favor and get you local (TRUSTWORTHY) exhaust place to run you a nice 3" system for half the price of any of the name brand ones out there that yield the exact same perormance gains.
 

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Its what I'm doing. I've got a place putting on 3" from the dp back for $120 (very good shop) on Friday.
 

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Discussion Starter #19
One of the best things to do is just ask around...if you see people with exhaust (that you know they didn't buy online) ask who did it for em...then go look at the welds and how they ran the exhaust....if the welds look like a 2 year old did it or the exhaust is ran in figure eights you obviously don't wanna go wherever he or she went. lol
 
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