dnbguy86

I got the gmpp exhaust and well, i used to have 2.5in exhaust with just a resonator, much better than stock, but it was loud. So i figured the gmpp would be the best of both worlds, but unfortunately im noticiting the gmpp seems to restrict some flow up top. So i was thinking of removing the resonator on the system just leaving the muffler it came with and the rest of it would just be the mandrel bent tubing. What do you think...Picture of what im thinking of removing, yay or nay ???

g5mike

Im curious about this also, will it make the car louder and what about emmission standards ( we have an aircare system inB.C.

dnbguy86

Well, i would have already done it, but im gonna have to order some quality pipe to replace the resonator with cause i still want it to look good, i dont want it to look shity afterwards, but im definitely debating this hard.

IonNinja

well I doubt it will do much performance wise...its just going to make your car loud again and I thought that was the reason for getting rid of the previous exhaust in the first place.

the reason the gmpp exhaust doesn't appear to come on as strong on the top end is because the 2.25" exhaust delivers the power a little sooner. The 2.5" piping is so large that you don't feel anything until you get in the upper rpm's and really get the gases moving.

J_Rod

I have a custom build 3 inch magnaflow system on my car. We cut out the resonator. Sounds Sick!! I love it. Its still pretty deep and is only raspy right when you first start the car. DO IT!!

dnbguy86

Thats what i originally thought, i kinda find it hard to cut up my 400+ gmpp system but obviously im just in search of better flow. I think before i make any rash decisions im going to order the zzperformance header and possibly downpipe with cat and complete the exhuast system, and then see if ther is still a flow restriction.

Cobalt_Supercharged

The down side to going to freer flowing, is that you could loose lowend torque. They designed the GMPP as a full 2.25" catback for all 3 Ecotecs. I think It should be great on your 2.2 unless you intend on pushing some serious power or go FI.

I would leave it the way it is.

dnbguy86

Well, i finally got around to getting my nitrous kit. So i want something a lil better flowing for when i put the squeeze on, ya know ?

NJHK

Took the words right out my mouth...

And DNBGuy, if your 2 1/2" exhaust was too loud, you should have put an resonator on it and you would have saved yourself $300 or so.

dnbguy86

I tried a number of things first, i tried 2.5in exhuast straight thru no muffler or resonator, ungodfully loud, then i put a small resonator on it, still kinda loud, then i put a 30in resonator on it and it brought it down to bearable levels, but i lost a lot of low end, but the gmpp offers lots of that, i guess im just used to or liked the top end gains the 2.5in exhaust gave, or at least thats the way it felt driving it.

glockglade

I have custom 3" catback w/ultraflow muffler and it sounds badass like he said only raspy at startup plus I gained 12whp on the dyno while others are having no gain w/2.5's. I don't know why people want the 2.5 for other than emmisions a car that is supercharged needs the least restriction it can have.

NJHK

What type of resonator did you use?

dnbguy86

Some basic no name brand the muffler shop had. Nothing special...

NJHK

That might be your problem. Resonators aren't supposed to be restrictive airflow wise.

dnbguy86

Well, im sure the gmpp exhaust has quality components but in my mind, anything other than straight pipe is a restriction. I think maybe that all the resonator does on my particular system is muffle sound, but im just curious to look inside this thing and see whats goin on. Im curious to see if a new header and high flow cat with a bigger dp will help anything, maybe its not the cat back thats the problem. I know the dp on the 2.2L is kinda mediocre, looks like 2in after the cat...

Cobalt_Supercharged

If the SS S/C guys are showing decent gains with it, I think your 2.2 with spray should be fine.

zomghax

A quality resonator is just a perforated core wrapped in sound absorbing packing material. Is that an actual picture of your catback in the first post? Does the GMPP system use Borla components? If so, rest assured that your exhaust flow is not compromised. Borla is straight through performance all the way. Cutting out that resonator is just going to make your exhaust sound worse, and defeat the purpose of buying a beautiful catback. But eh, your car dude.

dnbguy86

Yeah, the gmpp exhaust is pretty much the same thing as the borla, but with gm performance parts badged on it. Im thinking im wrong about the exhaust and that its actually the header and downpipe that now seem restrictive, hopefully once those are changed out, itll help out a lil more...or maybe its just cause i got a 2.2

Cobalt_Supercharged

Yeah I think those are collector is 2" for the 2.2. You should see if a 2.4 or 2.0 manifold and down pipe would bolt on. Then you should be good.

07lsdh

Also could have used a glasspack as a resonator, get both the resonating qualities along with high flow characteristics

FryLoch

iTrader: (5)

Cutting up the gmpp is a waste. So what? u might get 2hp with it cut up...