12 hp from GMPP Performance exhaust!

I ran my car stock and ran it again after the GMPP Performance catback install.
Huge thanks to Tom at http://crateenginedepot.com for the awesome deals and service. Keep an eye for the next group buy on these.

Best Stock Dyno Run:
211.1 hp 180.3 tq

Best Run with GMPP catback ONLY
223.1 hp 190.3 tq


On The Dyno
http://cobaltss.net/gallery/files/1/s_cobalt_gmpp_001.jpg

2 Best Stock Dyno Runs
1.
http://cobaltss.net/images/jonyyb/s_dyno001.jpg
2.
http://cobaltss.net/images/jonyyb/s_dyno002.jpg

2 Best runs with only GMPP catback
1.
http://cobaltss.net/images/jonyyb/s_dyno003.jpg
2.
http://cobaltss.net/images/jonyyb/s_dyno004.jpg



Install pics
http://cobaltss.net/gallery/files/1/s_cobalt_gmpp_004.jpg
http://cobaltss.net/gallery/files/1/s_cobalt_gmpp_005.jpg
Got to cut the stock pipe to take it off. This is where we cut it.
http://cobaltss.net/gallery/files/1/s_cobalt_gmpp_006.jpg
http://cobaltss.net/gallery/files/1/s_cobalt_gmpp_007.jpg
http://cobaltss.net/gallery/files/1/s_cobalt_gmpp_008.jpg
http://cobaltss.net/gallery/files/1/s_cobalt_gmpp_010.jpg
http://cobaltss.net/gallery/files/1/s_cobalt_gmpp_011.jpg
http://cobaltss.net/gallery/files/1/s_cobalt_gmpp_009.jpg





If you want to hear the difference in the sound….

Right Click and Save As to Play Vidoes.

Stock Exhaust Video (http://cobaltss.net/video/vid_stock_ex.avi)

GMPP Exhaust Video (http://cobaltss.net/video/vid_gmpp_ex.avi)

I apologies for the crappy camera ;)

finally someone has the intelligence to do the install right after original dyno to show real world gains

i knew i felt a nice kick in the ass when i installed mine;)

^ for sure :D

12hp is a nice gain jonel! makes me wanna get one as well ;P

Thats nice to hear,I did'nt think that exhaust would put down that kind of power because of
it's 2 1/4 size.What was the temp. difference between your stock run and your gmpp exhaust.

sounds good man what did that run you by chance

stupid question but i was just wonderingif that is the touring or the sport version GMPP Exhaust and BTW Your Car SPITS NOW U SHOULD PUNISH IT!!!:lol:

Nice gains, I can't wait to get mine on.

Nice gains, and I like the sound.

I was so happy to get rid of that exhaust when I had it on my car, I went from a fat bitch a skinny bitch and got performance and weight reduction at the same time :)

Great! somebody finally went and did it, probly 9hp for the 2.4 though?

was this done the same day?
if not was the out side tempeture the same

thanks

Carlos A

would you expect to see the same gains from a touring system and a sport system?

Very nice write up, dynos and vids included. Doesn't get much better than that. These results make me very happy. I can't wait to bolt mine up. :twothumbs

would you expect to see the same gains from a touring system and a sport system?
They are the exact same gains,just different tones is all

They are the exact same gains,just different tones is all

Exactly^^^ 12hp is a great gain. I can't believe it! :twothumbs

Exactly^^^ 12hp is a great gain. I can't believe it! :twothumbs

12 hp is alot for the smallest aftermarket exhaust out there. Somethings weird but whatever it is it good for jony

12 hp is alot for the smallest aftermarket exhaust out there. Somethings weird


I agree.

The 2 dyno's are a week apart and at different times of the day.

Was it hot during the first session?

But like you said, good gains.

dam those are some nice gains on a catback shit

12 hps 10tq very nice

very nice gains dude

im sure you'll see even more with that gmpp manifold ;)

so im still wondering if thats the turing or sport :confused:

You got my vote! I think im getting 1 this week- anybody know where i could get the best pricing? Thanks

paceperformance.com

354.95

If you want to hear the difference in the sound….

Right Click and Save As to Play Vidoes.

Stock Exhaust Video (http://cobaltss.net/video/vid_stock_ex.avi)

GMPP Exhaust Video (http://cobaltss.net/video/vid_gmpp_ex.avi)

I apologies for the crappy camera ;)

Holy uncompressed video, Batman!

Nice gains, though! Exhaust will likely be one of my last mods, if not the last, but this will help me have my decision made when the time comes! :cssNET:

so im still wondering if thats the turing or sport :confused:
I got the Performance one, not the touring.
Was it hot during the first session?
Outside temps were identical. Low 70’s.
anybody know where i could get the best pricing? Thanks
Tom has a special on these. Hit him up, he'll take care of you:
http://www.cobaltss.net/forums/showthread.php?p=506548#post506548

Can the exhaust tip from the stock fit the new performance exhaust? It would save $50

hey johnyyB... is that the 60 dollar exhaust tip from gmpp? or is that one froma local autozone or murrys? thanks man

nice nice NICE!!!!!!!!!!!

hey johnyyB... is that the 60 dollar exhaust tip from gmpp? or is that one froma local autozone or murrys? thanks man

Yes, It is the tip from GMPP.

does anyone know where i can get an avi player so i can hear how it sounds? my windows media player cant play it and quicktime is givin me an error when i go to play it and yes i saved it..darn i wanna hear it lol

congrats nice gain!

Nice numbers..I can't wait till they get the kits set up for the 07's ...just got my silver one on fri with the g85 package...Loving it sooo far...

i really like your tag, great gains too

I got the Performance one, not the touring.

Outside temps were identical. Low 70’s.

Tom has a special on these. Hit him up, he'll take care of you:
http://www.cobaltss.net/forums/showthread.php?p=506548#post506548

Hi there,
Nice HP gains, I was wondering if you could be more specific at to which exhaust you are refering to:
A. Cobalt Cat-Back Exhaust System Performance 17802111 $357
B. Cobalt Corsa SS 2.0L Sport System 14128 $679

I want to get one....just want to make sure I get the right one

thanks

Hi there,
Nice HP gains, I was wondering if you could be more specific at to which exhaust you are refering to:
A. Cobalt Cat-Back Exhaust System Performance 17802111 $357
B. Cobalt Corsa SS 2.0L Sport System 14128 $679

I want to get one....just want to make sure I get the right one

thanks

He's talking about this one. :twothumbs

A. Cobalt Cat-Back Exhaust System Performance 17802111 $357

He's talking about this one. :twothumbs

A. Cobalt Cat-Back Exhaust System Performance 17802111 $357


wow, thats a big gain for a small amount of $$$$

does anyone know the HP gain difference between the Performance exhaust vs. the Corsa SS?

I don't think I want to spend the $$$$ for the corsa SS unless the HP gain differnce is substantial, I'd go stage 2 instead for those $$$$

thanks

I just passed 1000 miles on my car. Haven't even looked under it yet. What is the black box over the axle ?

Our results on the Redline were nearly identical, I believe it was 11/11 when it was tested, so sounds pretty legit...

I just passed 1000 miles on my car. Haven't even looked under it yet. What is the black box over the axle ?

the black box looks like fuel pump/ fuel recirculation..... correct>?

the black box looks like fuel pump/ fuel recirculation..... correct>?

I believe that's the BCM...

12 HP gain! Sounds like that's what I will get for $357! Hopefully, it will be even cheaper in March-April time frame.

damn those are good #'s

great stuff yo ... question though ... my exhaust having been installed a few weeks seems to be resting on the left side (drivers side) of the exhaust position and I don't know why ... when I installed mine it seemed correct but for some reason it it resting nearly on the car ... anyone know what I can do to correct it? from your pics it would seem that you wont have this issue though I didnt have it either at first ... should I get another paid of rubber mounts?

I went from 220whp and 186wtq, on my stock dyno, to 231.7whp and 198.xxwtq by adding the Typhoon CAI and the GMPP Perf. Exhaust to my car. So I believe this guy. Love the exhaust too, nice and deep tone.

looks nice and congrats car looks clean

the black box looks like fuel pump/ fuel recirculation..... correct>?
yep, don't think it's the pump but something with for recirculation
He's talking about this one. :twothumbs

A. Cobalt Cat-Back Exhaust System Performance 17802111 $357
CTCOBALTSSS is correct. If you ask me, Corsa is a bit overpriced. Buy GMPP and use the rest of the money for other mods :thumb: But that's just me. Your car, your $

i really like your tag
Thank you, :cssNET:

yep, don't think it's the pump but something with for recirculation

CTCOBALTSSS is correct. If you ask me, Corsa is a bit overpriced. Buy GMPP and use the rest of the money for other mods :thumb: But that's just me. Your car, your $


Thank you, :cssNET:
Price and gains pretty much says it, GM catback for all:twothumbs I love mine

I really worry about limiting myself with a 2.25" exhaust... but the price is so damn attractive and I can just go pick it up from the place...

I really worry about limiting myself with a 2.25" exhaust... but the price is so damn attractive and I can just go pick it up from the place...
it's about flow rate man. plain and simple the gmpp flows a helluva lot better than people give it credit for.

it's about flow rate man. plain and simple the gmpp flows a helluva lot better than people give it credit for.

Oh I do understand, but there's only so good it can flow for it's size. Even a straight pipe with no cats or resonators reaches a limit. It's made by Borla, IIRC, if it's not it's IDENTICAL to the one they sell for the SS/SC. They are a great company, but there's only so much you can do to bend physics before it brings you back to earth.

it's about flow rate man. plain and simple the gmpp flows a helluva lot better than people give it credit for.
Big exausts might br everated for our cars,a friend tells me you should not have a 3inch exaust unless you are putting out big numbers, the GM catback, corsa et.. are great for our cars

Big exausts might br everated for our cars,a friend tells me you should not have a 3inch exaust unless you are putting out big numbers, the GM catback, corsa et.. are great for our cars

There's quite a few choices in between though, I dunno about you guys, but for the Redline we have 2.25, 2.5, 2.75 & 3".

Sounds like i just found my next mod!

Its got a good price, good gains, and keeps your warranty. Only thing im wondering is how long it takes the dealership to install it. My dealership charges 78$ dollars an hour.

sounds like waaaay too much for a 2.25 system

Anyone who says bigger is better with these cars will always be stuck wondering why they just lost a race.

2.25" is more than enough for a SS/SC, a 300WHP SS/SC might need 2.50" but most likely not.

Although it is restrictive a 1998-2002 LS1 (Non SS or WS6) can still put down 280WHP + with a single 2.75" pipe.

Even with 30psi of boost our cars a re still just a 2.0 liter.



I was debating the GMPP exhaust and now seeing true gains I think it's on my need to buy list.

Anyone who says bigger is better with these cars will always be stuck wondering why they just lost a race.

2.25" is more than enough for a SS/SC, a 300WHP SS/SC might need 2.50" but most likely not.

Although it is restrictive a 1998-2002 LS1 (Non SS or WS6) can still put down 280WHP + with a single 2.75" pipe.

Even with 30psi of boost our cars a re still just a 2.0 liter.



I was debating the GMPP exhaust and now seeing true gains I think it's on my need to buy list.

It's not as simple as HP... keep in mind the time attack balt was using a Corsa 3" setup, and how did that do at the races?

High RPMS require a larger pipe, forced induction requires a larger pipe. While your 2.75" on an Fbody was plenty, the EGT's of the LS1 are MUCH cooler than a 2.0 running mad timing, 20psi and supercharged, I haven't seen many LS1's pusing 7500 rpms either. In addition, N/A cars thrive on exhaust tuning, just like intake runner tuning along with pressure wave tuning, these are also not applicable on a 2.0 Supercharged car either.

As far as 300whp... what are your goals? Hell, my redline is pushing 260 whp now... 300 is a minimum...

It's not as simple as HP... keep in mind the time attack balt was using a Corsa 3" setup, and how did that do at the races?

High RPMS require a larger pipe, forced induction requires a larger pipe. While your 2.75" on an Fbody was plenty, the EGT's of the LS1 are MUCH cooler than a 2.0 running mad timing, 20psi and supercharged, I haven't seen many LS1's pusing 7500 rpms either. In addition, N/A cars thrive on exhaust tuning, just like intake runner tuning along with pressure wave tuning, these are also not applicable on a 2.0 Supercharged car either.

As far as 300whp... what are your goals? Hell, my redline is pushing 260 whp now... 300 is a minimum...
the time attack cobalt was running over 300 hp on a big shot of squeeze so it is logical for that specific car to need it.

Yea i think spraying a supercharged car makes for an entirely different situation.

But let me re-ask my question. How long is the install on the GMPP Performance cat back exhaust?

Yea i think spraying a supercharged car makes for an entirely different situation.

But let me re-ask my question. How long is the install on the GMPP Performance cat back exhaust?
on racks it can take 1-2 hours depending on if there are 1 or 2 people doing it. on a lift it should take about an hour

on racks it can take 1-2 hours depending on if there are 1 or 2 people doing it. on a lift it should take about an hour

Thanks dude. Thats EXACTLY what i needed to know. So installation shouldn't run more than 160 plus tax. Now all i need is the exhaust system and 160 bucks.......

I believe that's the BCM...


Its an evap canister

How long is the install on the GMPP Performance cat back exhaust?
It should not take over 30 minutes. Especially for a professional.
1 hour MAX if you are doing an exhaust for the first time….

Now seriously, 12whp for going from a 2.5inch catback to a 2.25inch. I mean maybe the air flows better, but dont you think that magnaflow being 2.5 inch and true mandrel bent. I mean download a pictures of the GMPP and the bends arent nearly as nice as vibrants and magnaflow ect.. so really your 2.25 inch could be in reality like 2.15... Now that is small. We need backpressure for our supercharge to work well, but i still think abything smaller than 2.5 inch is a waste of money. I saw at a couple of places a gmpp catback and highflow gmpp manifold giving 6whp on the dyno. Seems low, but this seems high:ca:

Now seriously, 12whp for going from a 2.5inch catback to a 2.25inch. I mean maybe the air flows better, but dont you think that magnaflow being 2.5 inch and true mandrel bent. I mean download a pictures of the GMPP and the bends arent nearly as nice as vibrants and magnaflow ect.. so really your 2.25 inch could be in reality like 2.15... Now that is small. We need backpressure for our supercharge to work well, but i still think abything smaller than 2.5 inch is a waste of money. I saw at a couple of places a gmpp catback and highflow gmpp manifold giving 6whp on the dyno. Seems low, but this seems high:ca:

Sorry bro but there is no difference in the bends of these exhausts. They are both mandrel bent. Backpressure is more important than most people think.
The 2.25" gives good backpressure for low end power and the free flowing bends and muffler give you your mid and top end. I think it's a good exhaust, just my opinion. :twothumbs

GMPP

http://www.crateenginedepot.com/store/images/17802111_large.jpg

Magnflow

http://www.gravanatuning.com/prod_images/large/MFL-16619.jpg

yeah yeah i understand where you are comming from bud. But if you want to put headers and downpipe, well they dont make 2.25inch, you have to got at least 2.5 inch and 2.25 inch catback isnt perfectly ideal, although it would still work good. Guess thats where iam comming from when i talk about this... i want to put headers and downpipe this spring

I remeber seeing somewhere that someone here with gm performance sais that if you are not pushing over 300hp you dont want to go over2.5 cause the car runs better with 2.25-2.50

I am most impressed with the underbody of the Cobalt. GM did a great job getting the suspension nice and deep into the chasis as well as making the underbody as smooth as possible for a car in this price range. Flatter the belly the better high-speed stability we will get, and I don't know about you guys but 100 mph feels like 100 km/h in most other cars.

I told my girlfriend to close her eyes while I slowly accelerated and I asked her to guess what speeds we were at. She consistently said 100 - 110 km/h while I was really going 170 km/h. She's the biggest critic, cause' she's a real wuss about speed.

Exhaust looks great, it's on my list too!
RYan

the exhaust tucks away nicely and is otherwise out of sight on a level plain.

It will be my next mod, I am almost done spending money on this car. CAI, and exhaust then, I move into the interior.

Here's a good question..............You are running with LSD. Would a 2005 Cobalt SS/SC without LSD make similar gains? Just a question???????

Here's a good question..............You are running with LSD. Would a 2005 Cobalt SS/SC without LSD make similar gains? Just a question???????
of course your engine itself has nothing to do with whether or not there is an lsd installed or not. that is a different argument for a different day and running a search will show the results of that as well so the gains will be the same to make a long story short

why is the sport more than the touring? anyone know?

why is the sport more than the touring? anyone know?
the two are supposed to have the same gains

oops, sorry. i meant why does the touring cost more than the performance? has anyone heard the touring next to the performance?

touring costs more b/c the muffler and resonator are different... and more expensive...

oh ok. i wish someone had a clip up of how a touring sounds because the ggmp exhaust is what i definitly want (naturally since i've seen the hp gains) but i dont know which to get b/c i dont know how it sounds

nvm about the sound clip *hits himself on the head*

I haven't found a "sound clip" that will do any exhaust justice in my book... something about recording/digitizing that makes these things sound ricey...

they're loud... but not ricey at all... I think you'll like the sound of the Sport exhaust... especially if you have the SS/SC

I haven't found a "sound clip" that will do any exhaust justice in my book... something about recording/digitizing that makes these things sound ricey...

they're loud... but not ricey at all... I think you'll like the sound of the Sport exhaust... especially if you have the SS/SC


Agreed, i just had mine installed four days ago. Of course they forgot the exhaust tip, but it still sounded great. I had to go to advance auto and buy a cheap 20$ exhaust tip to keep from melting my rear bumper, but even with that tiny little tip, the exhaust still sounds AMAZING, especially in the car.

Granted, its not the loudest exhaust, especially in lower RPM's, but thats what sold it to me, because i can still have a casual conversation at 80mph.

Its definately a good purchase, i cant imagine a 2.0 liter sounding any better.

Granted, its not the loudest exhaust, especially in lower RPM's, but thats what sold it to me, because i can still have a casual conversation at 80mph.

Its definately a good purchase, i cant imagine a 2.0 liter sounding any better.

I can't agree more :)

Nice thread here.

Please correct me if I am wrong here on my impressions as I have debated in mind over Corsa and GMPP for months now.

I have GMPP Stage 2 and maybe,maybe someday I will go with 2.8 pulley colder plug, and some GMPP parts out of the LSJ buildup on gmtunersource and gmperformancedivision.com. I don't plan on running more than 300 wheel HP if I plan on spending 4K for all the GM parts, Pistions, camshaft, camgears head ect..

So will the GMPP catback be enough if I go up that high?

The gains for the touring vs. the sport are identical on GMPP exhaust? I want to go touring as I don't want any drone.

Gains for GMPP vs. Corsa for GM stage 2 cars should be about the same?

How does Magnaflow compare to the other two for drone vs. performance? I see dyno charts for the Magnaflow to have 13 lb tq gain and only 7 wheel HP.

Lastly how productive is a CAI and GMPP Exhaust manifold if you already have the exhaust? IE some folks get say 10 HP out of a CAI, but if you already have a catback will you really get another 10 HP. My gut says no. Same thing with the GMPP header will you get another 10 HP or more like 3 HP for the GMPP header?

Kind of long I know but I just want to make the right choice.

sounds good Jonel

Nice thread here.

Please correct me if I am wrong here on my impressions as I have debated in mind over Corsa and GMPP for months now.

I have GMPP Stage 2 and maybe,maybe someday I will go with 2.8 pulley colder plug, and some GMPP parts out of the LSJ buildup on gmtunersource and gmperformancedivision.com. I don't plan on running more than 300 wheel HP if I plan on spending 4K for all the GM parts, Pistions, camshaft, camgears head ect..

So will the GMPP catback be enough if I go up that high?

The gains for the touring vs. the sport are identical on GMPP exhaust? I want to go touring as I don't want any drone.

Gains for GMPP vs. Corsa for GM stage 2 cars should be about the same?

How does Magnaflow compare to the other two for drone vs. performance? I see dyno charts for the Magnaflow to have 13 lb tq gain and only 7 wheel HP.

Lastly how productive is a CAI and GMPP Exhaust manifold if you already have the exhaust? IE some folks get say 10 HP out of a CAI, but if you already have a catback will you really get another 10 HP. My gut says no. Same thing with the GMPP header will you get another 10 HP or more like 3 HP for the GMPP header?

Kind of long I know but I just want to make the right choice.

I'd like to bump this......GMPP exhaust enough for GM stage 3, or do we need the 2.5" Corsa?

I'd like to bump this......GMPP exhaust enough for GM stage 3, or do we need the 2.5" Corsa?


my logic says its enough.

update for christmas i got a gmpp exhaust. definetly looking forward to installing it later on in january. i got the performance exhaust system so i will definetly be looking forward to this. merry christmas :twothumbs

o and are the gains for a 2.2 ecotec the same for the exhaust than the 2.0 ss/sc?? thanks

I'd like to bump this......GMPP exhaust enough for GM stage 3, or do we need the 2.5" Corsa?
if u are planning on doing more in the future u will definitely want the corsa. gmpp is fine for a stage II tho

I got, well getting prob tomorrow (ordered) a GMPP touring catback and manifold!! sssoo looking forward to getting that installed!! WWhhoohoo!! bring on the Greddy turbo SI's

I actually like what it did for his torque curve. Filled in the bottom end a little and actually give him enough flow that the top end was restricted, so his overall curve went even flatter than stock.

I actually like what it did for his torque curve. Filled in the bottom end a little and actually give him enough flow that the top end was restricted, so his overall curve went even flatter than stock.

You say it restricts you on top and gives you a flatter torque curve?? If its restrciting you on top it would give you oposite than flat torque curve wouldnt it??

It sounds good

wow an actual cat back that makes 12hp!

my gmpp touring system has been on back order fro two weeks now.

You say it restricts you on top and gives you a flatter torque curve?? If its restrciting you on top it would give you oposite than flat torque curve wouldnt it??
his reasoning is that if you add more to the bottom, take some away from the top, that the line is flatter (more horizontal). if you do the opposite (for example), the bottom-end is reallllly low, but the top is reallllly high. this is approaching a more verticle curve. :)

although i would not venture to say that this exhaust restricts you on top. it is smaller diameter, but i would believe the performance muffler flows much better.

is the 12 hp for all ecotecs or just the ss/sc?????

ARG, was suppose to be unrestricted, not restricted. From everything I've seen, the GMPP Exhaust gives you more backpressure at the low end (picks up low end torque) but flows better than stock once the pressure builds up (picking up the top end).

Doh, sorry about that. I think I said restricted because that is what you often see from the GMPP Exhaust when you start putting smaller pulleys on. But with what he has right now, no restrictions.

And yea ReMz, thats what happens when you put one of those big azz 3" straight pipe exhaust on. :D

Nice thread here.

Please correct me if I am wrong here on my impressions as I have debated in mind over Corsa and GMPP for months now.

I have GMPP Stage 2 and maybe,maybe someday I will go with 2.8 pulley colder plug, and some GMPP parts out of the LSJ buildup on gmtunersource and gmperformancedivision.com. I don't plan on running more than 300 wheel HP if I plan on spending 4K for all the GM parts, Pistions, camshaft, camgears head ect..

So will the GMPP catback be enough if I go up that high?

The gains for the touring vs. the sport are identical on GMPP exhaust? I want to go touring as I don't want any drone.

Gains for GMPP vs. Corsa for GM stage 2 cars should be about the same?

How does Magnaflow compare to the other two for drone vs. performance? I see dyno charts for the Magnaflow to have 13 lb tq gain and only 7 wheel HP.

Lastly how productive is a CAI and GMPP Exhaust manifold if you already have the exhaust? IE some folks get say 10 HP out of a CAI, but if you already have a catback will you really get another 10 HP. My gut says no. Same thing with the GMPP header will you get another 10 HP or more like 3 HP for the GMPP header?

Kind of long I know but I just want to make the right choice.

Any answers to this because its either the GM Performance exhaust or Magnaflow for me. I plan on doing stage 2 and some more mods in the future wil the GM exhuast be able to handle 275hp or even 260hp at that. IMO i think it will be much more restrictive than a magnaflow with 2.5 piping. I have heard from many people not to go 2.25 because it will become restrictive so if anyone can answer? Also is Magnaflow emissions legal?

Any answers to this because its either the GM Performance exhaust or Magnaflow for me. I plan on doing stage 2 and some more mods in the future wil the GM exhuast be able to handle 275hp or even 260hp at that. IMO i think it will be much more restrictive than a magnaflow with 2.5 piping. I have heard from many people not to go 2.25 because it will become restrictive so if anyone can answer? Also is Magnaflow emissions legal?
I am still not convinced by people saying larger is the way to go to reach 300hp. everything I read says flowrate dictates all so from what I can tell the gm performance exhaust has plenty in terms of flow rate since so far it hasn't shown signs of being restrictive at all. lots of people say oh but it will eventually become restrictive and that kind of comment is kinda like uh DUH of course it will ... but WHEN. some quote 250-280 others say at most 300 but noone has proof. someone will get there and hopefully that ends this argument. there are a couple that are close like ct but so far it is just slightly beyond reach

good point onimirage but i did hear from a good friend in the family who has his own shop if you plan on running higher hp numbers you will need a bigger exhaust to keep detonation down. also i heard if you want to run a 2.8 pulley or smaller it will become restricted as well. he told me go magnaflow 2.5 your safe either way.

good point onimirage but i did hear from a good friend in the family who has his own shop if you plan on running higher hp numbers you will need a bigger exhaust to keep detonation down. also i heard if you want to run a 2.8 pulley or smaller it will become restricted as well. he told me go magnaflow 2.5 your safe either way.

i think most would be better off trying to get as high as possible and keep fine tuning the car as much as possible as well. if it becomes an issue ... sell it. SOMEONE will take it im sure of it

I get the feeling we either don't know or there are just lots of opionions (sp?) out there.

Basically I will be running the 2.9 pulley from the GM stage 3, then at best the GM head, peformance cams, cam gears and some titanium valve springs. When the warranty is up I will go with a 50-100 HP shot of nitrous *of course upgrade to the tires clutch and flywheel along the way. Hopefully be around 300-310 wheel HP.

So will GMPP touring be ok for this or do I need to go Corsa touring? I am keeping this car as street friendly and reliable as possible, so I'm trying to go all GM, along with going no higher than 310 or so to the wheels.

I get the feeling we either don't know or there are just lots of opionions (sp?) out there.

Basically I will be running the 2.9 pulley from the GM stage 3, then at best the GM head, peformance cams, cam gears and some titanium valve springs. When the warranty is up I will go with a 50-100 HP shot of nitrous *of course upgrade to the tires clutch and flywheel along the way. Hopefully be around 300-310 wheel HP.

So will GMPP touring be ok for this or do I need to go Corsa touring? I am keeping this car as street friendly and reliable as possible, so I'm trying to go all GM, along with going no higher than 310 or so to the wheels.

I am in the same exact boat actually. But I just got my tourin catback and GMPP manifold yesterday. I mean I still have at least 3 years of warranty left on the car. So when the warranty is done and I put a GMPP S3, I'll owrr about that then. Someone will buy your touring catback for sure. The touring seems a little more looked for as being sold used.

Calgary dude, your catback (touring) has been on back order for 3 months?? I ordered mine and got it a week and a half after and they didnt have it at the regional dispatch thing. They had to order it from the canadian distribution center in woodstock, ont. So I dont know whats the hold up for you??

I get the feeling we either don't know or there are just lots of opionions (sp?) out there.

Basically I will be running the 2.9 pulley from the GM stage 3, then at best the GM head, peformance cams, cam gears and some titanium valve springs. When the warranty is up I will go with a 50-100 HP shot of nitrous *of course upgrade to the tires clutch and flywheel along the way. Hopefully be around 300-310 wheel HP.

So will GMPP touring be ok for this or do I need to go Corsa touring? I am keeping this car as street friendly and reliable as possible, so I'm trying to go all GM, along with going no higher than 310 or so to the wheels.
seems to be the case but I think the gmpp should be fine. first one to 300 can prove all the bigger is better freaks wrong

is the 12 hp for all ecotecs or just the ss/sc?????

Common sense should tell you that an engine putting out 130whp isnt going to gain 12whp.

if that were true, the 2.2 would be gaining almost 10% horsepower from a catback....
and the 2.0 SC engine would only gain 5%.

boy... 12 hp in 3rd gear..... not really anything to write home about.... neither is 208 stock in third..... hmm, i guess it gives a relative idea of what to expect.

boy... 12 hp in 3rd gear..... not really anything to write home about.... neither is 208 stock in third..... hmm, i guess it gives a relative idea of what to expect.
each dyno in each city of each state is different. there are a huge amount of variables that come into play. what someone does in one area will never be exactly the same in another. the purpose of writing about it or even doing pulls is to establish a baseline to see where you are and how far you have come. comparisons are never an exact science but give you a general idea of what your car did at this time at this place in this condition.

Well just installed the (sport )GMPPcat back exhaust for $50 at Tuffy's and they welded the exhaust tip on for me. It is definatly louder that stock and kinda resembled the sound of my buddies SRT 4 Borla that he has on his. Highway speeds in fifth are quiet inside which I like but when yuo down shift into third it is really loud. I got mine from Crate engine for 448 with exhaust tip and tax and shipping. As far as hp I could not really feel the 12 hp that it claims that it puts out but maybe it just needs to break in. Next stop Ingalls TB .

Well just installed the (sport )GMPPcat back exhaust for $50 at Tuffy's and they welded the exhaust tip on for me. It is definatly louder that stock and kinda resembled the sound of my buddies SRT 4 Borla that he has on his. Highway speeds in fifth are quiet inside which I like but when yuo down shift into third it is really loud. I got mine from Crate engine for 448 with exhaust tip and tax and shipping. As far as hp I could not really feel the 12 hp that it claims that it puts out but maybe it just needs to break in. Next stop Ingalls TB .

How loud is it in the cab when in 3rd on the highway. How 'loud' is it as a daily driver, normal shifting and throttle on the street ect... any drone, does the sound beat you up? I know touring is my cup of tea, but if the sport is not abrasive it is cheaper :twothumbs

I got touring, deeper tone sounds awesome. I find the performance sounds almost stock (louder) where touring sounds deeper and meaner. For 100$, I thought of the attention it will bring a little less and how thats good when it comes to cops and driving around town!j
Just my 0.02 cents

I got touring, deeper tone sounds awesome. I find the performance sounds almost stock (louder) where touring sounds deeper and meaner. For 100$, I thought of the attention it will bring a little less and how thats good when it comes to cops and driving around town!j
Just my 0.02 cents

Good point. Did you notice a 'seat of the pants' difference on your stage 2 after installing the GMPP Touring?

I got touring, deeper tone sounds awesome. I find the performance sounds almost stock (louder) where touring sounds deeper and meaner. For 100$, I thought of the attention it will bring a little less and how thats good when it comes to cops and driving around town!j
Just my 0.02 cents

Also with the plugs in your siggy those are iridiums correct? With the gap and the 2.9 pulley did you use the GM hub, and GM stage kit tuning *Not trying to hijack the thread just asking a question while I clean out my PM box since it is full....sorry guys and gals*

I third gear on the highy way is real loud definatly louder than stock in the cab. Cruising around town you can definatly tell that you have something other than stock. I really have not gotten on it yet but it seemed to me that the seat of the pant feel is the same as stock. Just my thoughts.

what company makes the exhaust again? borla or corsa? sorry im braindead.

bump question above

borla

Well if ure talking the 12whp its GMPP that is made by borla. But the dyno #'s seem high IMO. But hey, the dyno on that car if its true talk for itself

I'm very curious myself if I'm going to see the 7-12 Wheel HP that folks are getting out of the GMPP Touring. We shall see.

cobaltSSilver do a before and after dyno pulls with the GMPP. Let us know how it works out!! Hope you see gains in the 7-12HP range. But i think they are inflated at those #'s

From what i have in my signature plus a 2.9, GMPP manifold, possibly a highflow cat, will i be alright with my GMPP performance exhaust?

If not i want to try and get rid of it now so there less miles on it!:twothumbs

From what i have in my signature plus a 2.9, GMPP manifold, possibly a highflow cat, will i be alright with my GMPP performance exhaust?

If not i want to try and get rid of it now so there less miles on it!:twothumbs

i seriously believe you will be fine. ct has more mods than you or I and he has the gmpp too so if he hasn't had an issue I doubt anyone will have an issue. I say this can get you to 300whp with no issues

cobaltSSilver do a before and after dyno pulls with the GMPP. Let us know how it works out!! Hope you see gains in the 7-12HP range. But i think they are inflated at those #'s

That's the idea....did you do any dyno pulls with your ride....before and after with the Stage 2, the smaller pulley, plugs ect....

i seriously believe you will be fine. ct has more mods than you or I and he has the gmpp too so if he hasn't had an issue I doubt anyone will have an issue. I say this can get you to 300whp with no issues

NGK plugs....in your siggy, those are iridium correct.....any issues with it and the stage 2 with the exhaust?

i dont know, I think they arent iriduim? Wahts the difference?? I havent done a dyno pull with it, but I am poutting it stock GM S2 this spring and then going one by one witht he modd to see the HP diff with my Gtech pro. I know its not accurate, but it gives an ideal. But you with the real dyno would be more detailed

NGK plugs....in your siggy, those are iridium correct.....any issues with it and the stage 2 with the exhaust?

they are not irridium ... i will not buy irridium. they are pure copper plugs and since putting these in I have not had a single issue

i dont know, I think they arent iriduim? Wahts the difference?? I havent done a dyno pull with it, but I am poutting it stock GM S2 this spring and then going one by one witht he modd to see the HP diff with my Gtech pro. I know its not accurate, but it gives an ideal. But you with the real dyno would be more detailed

irridium has a really large heat resistance ability but have a low heat disipation rating so while it can keep the plug from getting hot quickly it cant cool down very quick which means with a lot of hard passes or long rides of spirited driving or road racing the plugs' benefit becomes its weakness and the plug gets hotter and hotter

The car does come stock with irridium plugs though, and irridium is better than platnum. Irridium should be fine for most street apps, but if you like to drive fast and push it hard, or you changed your setup so your creating more heat (higher boost!), then copper would be a safer bet. You just have to change them out about 10 to 20 times as often.

Where's the best deal on copper spark plugs pricewise?

Also we agree .40 gap is ideal.

GMPP touring or GMPP Performance or Corsa Touring or Corsao Performance....yeah I'm still trying to make the right decision for me and my car's application....driving me batty :cussing:

But eventually I'll decide! :)

Where's the best deal on copper spark plugs pricewise?

Also we agree .40 gap is ideal.

GMPP touring or GMPP Performance or Corsa Touring or Corsao Performance....yeah I'm still trying to make the right decision for me and my car's application....driving me batty :cussing:

But eventually I'll decide! :)

copper plugs are so cheap it doesn't really matter where you get em from if you pay less than 15 bucks your good

I paid 5$ canadian dollars a piece. 15$ USD would be CRAZY expensive IMO

I got the GMPP touring and love it. I would DEFF go touring. Corsa or GMPP is preferance and big difference in $$$ Both are really good quality....

12 hp...nice jonnyB!!!!

i only paid 10 bucks us personally so if you pay over 15 your nuts thats why i said under 15

I paid 5$ canadian dollars a piece. 15$ USD would be CRAZY expensive IMO

I got the GMPP touring and love it. I would DEFF go touring. Corsa or GMPP is preferance and big difference in $$$ Both are really good quality....

Yeah I'm tring to decide if the money is worth it for the Corsa. Some folks say hey if you're going to try and get 310 WHP *That is my goal* then you may want to use the Corsa for the 2.5" others say the GMPP will get me there or be really close to that mark.....

How often would copper plugs need to be changed around? 25K or 35K or 50K miles?

[QUOTE=CobaltSSilver;794877]Yeah I'm tring to decide if the money is worth it for the Corsa. Some folks say hey if you're going to try and get 310 WHP *That is my goal* then you may want to use the Corsa for the 2.5" others say the GMPP will get me there or be really close to that mark.....

If you want yo get #'s like 310 WHP, get a 2.5. I heard the magnaflow and it sounds awesome and cheaper than corsa!... but if you want 300+, dont bother with GMPP. IMO. And I got the GMPP, and I love it, but I want to keep it warrantied. Then when the warranty is over, I will be trading it for something else. (new model balt maybe, if it has enough HP.)

[QUOTE=CobaltSSilver;794877]Yeah I'm tring to decide if the money is worth it for the Corsa. Some folks say hey if you're going to try and get 310 WHP *That is my goal* then you may want to use the Corsa for the 2.5" others say the GMPP will get me there or be really close to that mark.....

If you want yo get #'s like 310 WHP, get a 2.5. I heard the magnaflow and it sounds awesome and cheaper than corsa!... but if you want 300+, dont bother with GMPP. IMO. And I got the GMPP, and I love it, but I want to keep it warrantied. Then when the warranty is over, I will be trading it for something else. (new model balt maybe, if it has enough HP.)

An exhaust won't void your warranty unless it causes a problem.....only problem that I can think of off hand is a CEL based on 02 sensor maybe.......I hear the magnaflow is great, a little loud *I wonder if drone is a problem with it in the cab, I want something easy on the ears cruising* but has issues with the elements....not rust mind you but she doesn't stay looking clean....is that b.s?

Also I'm tired of all this hear say....I wish we could get some hard facts on what the GMPP will support, if it restricts with certain mods ect...and when to go with 2.5, and which is better for flow Corsa, Magnaflow, Borla.

I finally got this piece of shit dezod 2.75 exhaust off of my car! i had it on since like august and its been raspy and loud as hell for me. replaced with a gmpp touring today and it feels like a brand new car. runs 100% smoother. feels much much quicker too!

damn those are impressive numbers i raced a guy that had gmpp exhaust stage 2 and intake , i have stage 2 , header downpipe and airbox and we were dead even kinda weird

you have stage 2 in you 2.4 (Red2.4ss/sc)

i smell something here.....

you have stage 2 in you 2.4 (Red2.4ss/sc)

i smell something here.....

:lol:

:lol:

Yeah smells like the stock yards in Colorado!

Hey guys just so you know, 3" exhaust is way too big unless you are putting out massive numbers. 2.5" is also too big for most of us.

My dad's bud at work, has an 06 'balt SS/sc and is running 7.7-7.9' in the quarter and has a 3" exhaust. He had a 2.5" until he reached 10's, still street legal.

He is running a twin turbo setup and virtually everything is custom. He has never put his car on a dyno but he guesses he has about 1200hp at the wheels. He said he is gonna try and qualify for pro stock this coming season. And if any of you watched the PIR Pinks all out he was on there for a second or two, but he was running too fast for the group they chose.

He told my dad that for our lowly cobalts 2.25 should be fine to about 300whp, 2.5 to about 450whp, and anything above that 3". These engines love backpressure.

Just some info coming from a hardcore cobalt enthusiast.:cssNET:

Hey guys just so you know, 3" exhaust is way too big unless you are putting out massive numbers. 2.5" is also too big for most of us.

My dad's bud at work, has an 06 'balt SS/sc and is running 7.7-7.9' in the quarter and has a 3" exhaust. He had a 2.5" until he reached 10's, still street legal.

He is running a twin turbo setup and virtually everything is custom. He has never put his car on a dyno but he guesses he has about 1200hp at the wheels. He said he is gonna try and qualify for pro stock this coming season. And if any of you watched the PIR Pinks all out he was on there for a second or two, but he was running too fast for the group they chose.

He told my dad that for our lowly cobalts 2.25 should be fine to about 300whp, 2.5 to about 450whp, and anything above that 3". These engines love backpressure.

Just some info coming from a hardcore cobalt enthusiast.:cssNET:

any pics or vids of this beast?

Actually I've never seen his car or talked to him in person, but like I said he is on Pinks all out. He also has a low 8 sec Nova. He's one of those guys that does real estate to make his millions, but works at a car dealership for fun. Kinda confusing huh.

He is in close contact with GMPP a lot. He actually had some GMPP reps looking at his engine because they couldn't figure out how he was able to build such a fast car in less than a year without sponsorship. My dad told me that GMPP took extra interest in his custom header. He doesn't know if they might make a mass production header or not, but they took a lot of pictures and measurements. Not to start putting out rumors or nothin.;)

twin turbo set-up, 10 sec 1/4 and running a 2.5 exhaust...................... interesting how ppl on this forum have different opinoins than seemlying everyone else.

the HP is BHP
http://cobaltss.net/gallery/files/4/6/0/exhaustsize.gif

Wow, I never saw this thread before somehow. I dynoes at 217/188 stock, and 221/190 after the GMPP performace exhaust, but it was on different days. Maybe I have been underestimating the gains I got from the exhaust.

twin turbo set-up, 10 sec 1/4 and running a 2.5 exhaust...................... interesting how ppl on this forum have different opinoins than seemlying everyone else.

I love how it starts at 2.5 liters:thumbsdow Where'd you get that chart, cause I'm pretty sure it's talking about V6's and V8's, maybe a couple of i4's but obviously his 2.0 falls outside of your chart.

When he was running 10's it was a single turbo by the way.

I love how it starts at 2.5 liters:thumbsdow Where'd you get that chart, cause I'm pretty sure it's talking about V6's and V8's, maybe a couple of i4's but obviously his 2.0 falls outside of your chart.

When he was running 10's it was a single turbo by the way.

dude im not knockin ur dad's friends set-up but every person i have ever talked to and every bit of info I've ever read about turbos talks about big ass exhaust systems or none at all.

BTW the chart wasnt in response to that TT balt rather a reference for ppl trying to decide the size of exhaust they want. 2.0L + m62 = 3.1L but that doesnt matter as much as how much HP ur making, so the liters in the left hand coloum can be excluded

BTW the chart wasnt in response to that TT balt rather a reference for ppl trying to decide the size of exhaust they want. 2.0L + m62 = 3.1L but that doesnt matter as much as how much HP ur making, so the liters in the left hand coloum can be excluded

Okay lets talk HP. My 450hp 550tq GTO had the purple hornies that narrow to 2.5". Explain that one, eh.

Okay lets talk HP. My 450hp 550tq GTO had the purple hornies that narrow to 2.5". Explain that one, eh.

dual, notice how theres a column for that.... and N/A im guessin

Yeah dual says for 450 hp, 3" not 2.5" c'mon man know what your chart says or don't post it.

All I'm saying is that paper can say one thing, real world is totally different.

dude im not knockin ur dad's friends set-up but every person i have ever talked to and every bit of info I've ever read about turbos talks about big ass exhaust systems or none at all.
Isn't that cause turbos use exhaust pressure to create boost? (therefore, eliminating back-pressure after the turbo allows for more efficient compression) Since the SC doesn't use exhaust pressure to create boost, I don't think bigger is always better......

Yeah dual says for 450 hp, 3" not 2.5" c'mon man know what your chart says or don't post it.

All I'm saying is that paper can say one thing, real world is totally different.

i agree with you on that, Im not saying that you HAVE to go by that but I would rather go by actual information that ppl have researched than a bunch of teenagers that list decals and painted calipers as mods. it's not my chart supercool it's just a reference.

Isn't that cause turbos use exhaust pressure to create boost? (therefore, eliminating back-pressure after the turbo allows for more efficient compression) Since the SC doesn't use exhaust pressure to create boost, I don't think bigger is always better......

that was in the context of a turbo car..... 2.5 is best for S/C but 3" while hurtin low end will help high end and espically if you making more than 300hp

Okay so bigger for turbos huh? Then why at over 1000 hp he can still run just a little 3 incher. According to your chart a 700+hp car would need at least 4".

Since he's at 1200hp might as well bolt on one of those diesel turbo exhausts right. You know the ones I'm talking about the 5" or 6" pipes.

Sorry but that reference is flawed. Where'd you get that chart from anyways?

And this guy I'm talking about is actually in his 40's. Hence the money to build an 8 sec car and a 7 sec car. And I really don't talk to guys who think they have fast cars, like your friend with the stealth and talon. I listen to the older guys who have been racing cars for decades not a 24 year old.

Okay so bigger for turbos huh? Then why at over 1000 hp he can still run just a little 3 incher. According to your chart a 700+hp car would need at least 4".

Since he's at 1200hp might as well bolt on one of those diesel turbo exhausts right. You know the ones I'm talking about the 5" or 6" pipes.

Sorry but that reference is flawed. Where'd you get that chart from anyways?

And this guy I'm talking about is actually in his 40's. Hence the money to build an 8 sec car and a 7 sec car. And I really don't talk to guys who think they have fast cars, like your friend with the stealth and talon. I listen to the older guys who have been racing cars for decades not a 24 year old.

once again it was a reference dumbass, ur dad's bum buddy and you can run whatever you want I couldn't care less. HERE I found the latest and greatest exhaust reccomended by all ppl with 400 years of racing experience.

http://www.mommyneedscoffee.com/images/uploads/straws-l.jpg

hi/flow cat included.

That's funny, but seriously where is the reference from I would like to complain to the person who made it, if you insist it isn't you.

I think its off a stang forum, I saved it a while back just a reference for what other cars use for exhaust at whatever HP, it's difficult to find exhaust info for supercharged cars but anyways...I didnt make it

Okay thanks. No offense meant. :beer:

that chart doesn't say much but predict using numbers that seem to match.

what about exhaust velocity/flow for the pipe and overall pipe design. if a 2.25" can flow just as well as a 3" due to flow characteristics and design then the only difference in either would be size and sound

that chart basically says anyone that reaches over 200 hp on a 2.25" exhaust is lying but there are plenty of people reaching over 250 with the 2.25" exhaust from gm. plus we also need to have a 4.1 liter engine to even think about it according to the chart. it seemed like a nice try but appears to have been made by someone that thinks that is how it works.

:twothumbs

HI
IT hard to see what is better.
Me I am looking to reach 300hp when I have all the money for all my mod.
I have stage 2 right now runing at 18psi and intake and exhaust is on my list for this summer, but first what is the stock size exhause, it not the same 2.25?
Me I was thinking to get the 3'' corsa exhause but I am not sure any more.
what is the best exause type and size for 280 to 310hp?

I love charts - Corky Bell.

Archie - looks like ur 2.5 dual is to big, you should be running a 1.5-2.0 :lol: And I need around 500 more hp to match that 3" of mine :lol:

http://cobaltss.net/gallery/files/3/6/5/0/ExhaustGraph.jpg

I love charts - Corky Bell.

Archie - looks like ur 2.5 dual is to big, you should be running a 1.5-2.0 :lol:

http://cobaltss.net/gallery/files/3/6/5/0/ExhaustGraph.jpg

and this is a perfect example that shows why most of the road race cobalt teams have went back to a 2.5" exhaust, from a 3" even at 300whp a 2.25 isn't going to be that restrictive

I love charts too!

I would say that one is much closer to reality. It says bhp which would be crank hp, I guess? My 458 whp would be somewhere like 500-525 crank so 2.5" is about right.

Cool, thanks for finding a nice chart. That one looks more professional with an explanation too.

With a 2.8 I was making 18.5 PSI, which is more than I should be making. I felt the stock exhaust was restrictive so I started replacing it. Switched to a 3" DP w/cat and the boost went up to 19.1 when I was expecting to go down. Was confused at the time. Thinking about it I realized that with the 3" DP I was creating more back pressure then even before. All that air rushing through the 3" and then get really slowed down with 2.25 stock exhaust. So I bought a 3" exhaust, havent put it on yet but Im betting that my boost will drop to 17PSI right where I want it. If this turns out to be a bad choice I'll swap to TAG 2.5 header back and buy you guys a E-beer :twothumbs or keep it because ill be turbo next summer :)

I love charts too!

I would say that one is much closer to reality. It says bhp which would be crank hp, I guess? My 458 whp would be somewhere like 500-525 crank so 2.5" is about right.

Cool, thanks for finding a nice chart. That one looks more professional with an explanation too.

np, but I think ur looking at the single tube numbers the dual numbers are to the right of the other numbers and says that a 1.5-2.0 would be good for ur 500+ rank hp

A Guinness e-beer and I'm in.:beer:

np, but I think ur looking at the single tube numbers the dual numbers are to the right of the other numbers and says that a 1.5-2.0 would be good for ur 500+ rank hp

Oh, you're right. :eek: Damn now I hate all charts!!:cussing: :guns:

Oh, you're right. :eek: Damn now I hate all charts!!:cussing: :guns:

@ the moment im not liking them either, anyways Im done, good arguing with ya, peace

see that chart makes much more sense. so it looks like the 2.25 would be good for over 300 hp before it starts to become a restrictive component looks like roughly 310 hp with no restriction. since I am not making big power right now the 2.25 is perfect until I get ready to jump into a sc'er swap at which time a 2.5" would be a good idea yay!

at the dealer do you know is that where they place the lift arm just b4 the back wheels right at the edge. i have neons right close to there and dont know if theres clearance for that. and dont want them to cruse them so i have to ask them about it.

ryan.

i just ordered the cat back exhaust (preformace) for my cobalt which is on order too...... any advice if i should get the flat or the cut piece

IMO either one looks good. I went with the straight tip because I didn't know how radical the angle cut would look. When I saw the angled tip on another member's car, I liked that as well.

i just ordered the cat back exhaust (preformace) for my cobalt which is on order too...... any advice if i should get the flat or the cut piece

Both tips are winners in my opionion. I like the angled a little better though....all personal preference. Congrats and Enjoy!

Okay so bigger for turbos huh? Then why at over 1000 hp he can still run just a little 3 incher. According to your chart a 700+hp car would need at least 4".

Since he's at 1200hp might as well bolt on one of those diesel turbo exhausts right. You know the ones I'm talking about the 5" or 6" pipes.

Sorry but that reference is flawed. Where'd you get that chart from anyways?

And this guy I'm talking about is actually in his 40's. Hence the money to build an 8 sec car and a 7 sec car. And I really don't talk to guys who think they have fast cars, like your friend with the stealth and talon. I listen to the older guys who have been racing cars for decades not a 24 year old.
Each cars power curves and exhaust requirements are different and what size pipe they require, but 11-12 hp gain from just a cat back changeover on a 4 cyl is pretty damn good.. Our 600 hp Pontiac dyno charts showed it choking with 3" dual exhaust yet our 850 hp Z06 is fine with 3" dual exhaust and actually dropped hp with larger. Our Datsun race car picked up hp with 3" single and choked with 2.5" and 3.5" hp dropped off even with retuning. Dyno results vary alot depending on different sizes of pipe and whether its mandrel bent or crushed pipe turns, sizes of cats whether single or dual, muffler types and sizes/restriction, header tube sizes and collector sizes and so on.... Ive been racing for 35 years and have seen so many different variations of what works and what doesnt on exhausts its mind boggling. Gotta have those dyno numbers to compare with no other changes to car other than exhaust each time to compare. If you change pipe sizes/muffler types or cats you gotta tune for the size/flow differences otherwise its not a fair comparison other than a baseline difference.

wow i just read 10 pages of exhaust banter... i know a thing or two from owning many cars and playing with the exhaust on most of them. here goes. too much exhaust no matter what N/A sc turbo nitrous whatever is no good. too little exhaust is no good either. flow is very important. what you want to do compared to what youll actually do is the most important. if you want 900 hp sure the smaller exhaust wont be good. if youll actually only make 260 and then be done the smaller exhaust is fine. honestly just think for a minute how far your gonna take the vehicle and then get what works for that situation. my trans am it was a big decision to go with 1 5/8 primarys or 1 3/4 primaries one gave better low end the other gave better top end. i drove my car at 1k rpm more than i drove it at 5k rpms so it was a no brainer. hopefully you all can figure out what your gonna do compared to what you wanna do and get what you need.

fantastic sound, nice work posting not only the dyno results but some vids to go along with it

wow i just read 10 pages of exhaust banter... i know a thing or two from owning many cars and playing with the exhaust on most of them. here goes. too much exhaust no matter what N/A sc turbo nitrous whatever is no good. too little exhaust is no good either. flow is very important. what you want to do compared to what youll actually do is the most important. if you want 900 hp sure the smaller exhaust wont be good. if youll actually only make 260 and then be done the smaller exhaust is fine. honestly just think for a minute how far your gonna take the vehicle and then get what works for that situation. my trans am it was a big decision to go with 1 5/8 primarys or 1 3/4 primaries one gave better low end the other gave better top end. i drove my car at 1k rpm more than i drove it at 5k rpms so it was a no brainer. hopefully you all can figure out what your gonna do compared to what you wanna do and get what you need.

Very well said! :cool:

Pretty sweet

I got the Exhaust from GM installed, also an AEM intake. I have the stage two being put on tomorrow at 9. i'm too excited man. good luck with your car!

This is a terrific post you made, very helpful. I am thinking about getting this exact exhaust and also the GMPP Extruded Honed Exhaust Manifold as well.

Part of the rationalization of putting this $ in a car I know I will never get back out is better gas millage. Did you notice any Gas Millage improvement after install of the low restriction exaust?

Also, you do a great job on these forms!

i have also been thinking about the same system.

With a 2.8 I was making 18.5 PSI, which is more than I should be making. I felt the stock exhaust was restrictive so I started replacing it. Switched to a 3" DP w/cat and the boost went up to 19.1 when I was expecting to go down. Was confused at the time. Thinking about it I realized that with the 3" DP I was creating more back pressure then even before. All that air rushing through the 3" and then get really slowed down with 2.25 stock exhaust. So I bought a 3" exhaust, havent put it on yet but Im betting that my boost will drop to 17PSI right where I want it. If this turns out to be a bad choice I'll swap to TAG 2.5 header back and buy you guys a E-beer :twothumbs or keep it because ill be turbo next summer :)



np, but I think ur looking at the single tube numbers the dual numbers are to the right of the other numbers and says that a 1.5-2.0 would be good for ur 500+ rank hp

Were supercharged no back pressure hear my friend...thats turboes

Holy old post batman!

Were supercharged no back pressure hear my friend...thats turboes

:wtf::wtf::wtf::wtf:

ummm we certainly DO have back pressure.

Were supercharged no back pressure hear my friend...thats turboes

Yes, please enlighten us as to how any exhaust system, even N/A, has no backpressure...

Jesus!! That's the second time this thread has been resurrected!!

Man that's two nono's in the same post. Thread revival and posting something that is obviously wrong.:lol:

I love it, I hope to get one by April.

i got my gmpp performance exhaust installed today.. man, that thing sounds sweet.. i really cant tell if i got any performance gains from it though.. ive heard that you should disconnect the battery for a half hour when you add an intake so the computer can learn the increased airflow or whatever but is that the same with an exhaust?

i got my gmpp performance exhaust installed today.. man, that thing sounds sweet.. i really cant tell if i got any performance gains from it though.. ive heard that you should disconnect the battery for a half hour when you add an intake so the computer can learn the increased airflow or whatever but is that the same with an exhaust?

...I installed my intake with the battery connected, and my car "learned" itself just fine. I don't think you need to worry about it.