I was taking a look at the GM Performance Cat Back comparing it to the Hahn and noticed that it looks like the GM exhaust comes with a new catalytic converter. Is this a high flow cat? Would it offer significant improvement in flow compared to the stock cat?

I'm wanting to keep the cat converter to stay legal, but was wondering if the cat that is on the GM exhaust would result in a better setup than a Hahn with the stock cat.

Any thoughts on the stock cat and the GM performance cat would be appreciated!

 

I'd guess that it's not a cat, but a resonator.

 

Alright...well after showing my lack of exhaust knowledge...would there be any advantage to go with the GM exhaust instead of the Hahn bolted up to the stock cat?

 

GM exhaust is 2.5" diameter, hahn is 3" diameter

 

ya you get to keep your 5 year 100,000 mile warranty

 

Aside from potential warranty issues, I can't see any advantage. GM exhaust is either 2.25 or 2.5 inches, can't remember for sure, but not as free-flowing as the Hahn unit. I'd love to hear some sound clips on both the tc, though...the track videos of HRC are too hard to hear. They need to get some fly-bys up on the site like they do with their ss/sc cat-back.

 

getting a new catback isn't going to void the rest of the powertrain warranty

 

Really? Call GM or better yet call your dealer. Wow I wish my dealer was as cool as yours

 

Try 2.25

Way too small for an LNF Balt

 

Since I obviously am not familiar with the parts of the exhaust...

What are the physical differences?

I understand the issues with size...but what about the resonator that is on the GM one...any other physical differences besides the tubing diameter?

 

really? stock LNF exhaust is 2.5 so GMPP would be a downgrade

sucks for people that don't realize that

 

Also the downpipe is already three inches and catted...so the only upgrade would be catless...

 

the stock exhaust system is a mandrel bent 2.5" system.

 

So basically, the only upgrade while keeping the cat would be to go for the Hahn 3" in order to increase the diameter? Any use of the GM exhaust would be pointless based on the exhaust that they put on the SS/TC?

 

Yep.

And a catless pipe will still be kinda quiet.

Turbo muffles quite a bit of noise.

 

If you are not messing with the cat (removing it to replace with a downpipe) or header, an aftermarket exhaust should not void any warranties...

If you mess with anything that will throw a code, you are running a risk of voiding your warranty...just bolting on a larger exhaust will not void anything....

 

2.5" is good for around 400hp why not spend the money on something better like TUNING and then worry about the exhaust when you need to change it out... if there is even a need. I wont be changing mine untill it proves to be restrictive and without a good bit of work I dont see that happening. Get a tune or maybe intake when it comes out.

 

although its possible to make 400whp on a 2.5" exhaust thats a lot of restriction you have to overcome. there are definate gains to be had in the 300-400whp area with a 3" exhaust. at the 300whp level on other cars we have tested showed gains of 15-20whp without any other changes.

 

oh absolutely, I will not argue that point at all. but I do think it would be better to get there first and then worry about it later... Maybe until a company by the name of Synapse comes out with a cat back?

 

i was just reading on that GM performance exaust and it is NOT compatible with the 2.0LNF, so we will have to wait.

 

you don't know this 100%.....call YOUR dealer. And I believe you can have your vehicle serviced at any dealership (GM).... duh.....so just check around... dunnno when it comes to warranty work..

 

They can't void your warranty because of a catback no matter what dealer . Before the cat they can give you crap , but catback isn't going to affect anything .

GMPP is too small for a LNF and besides doesn't the LNF downpipe have a 3 bolt flange? GMPP CB has only a 2 bolt.

 

Confirmed, GMPP does NOT have an exhaust out for the cobalt ss/tc, YET..........