Did some searching around, but really did not find any particulars.

Anyone know the specifics about the factory down pipe and catback on the 2007 SS/SC?

Diameters?

HP gains with aftermarket catback?

Worth it to gut the cat at first?

Is the catback good enough to support 250whp?

Any info greatly appreciated.

 

I am very interested in this as well. I would like to go to a 3 inch catback exhaust?
I do not want to loose any power?

 

2.25 catback supports 250+ whp itself. Im also using vibrant shorty+hiflow dp.

3--->2.25

If your going bigger than the m62 get 3, otherwise no larger than 2.5 or you will lose hp...and you will lose torque already.

 

Size exhaust depends on your plans for the car.

stock can support ~250-270 hp

2.5" catback~250-300 hp

3.0" catback~300+ hp.

Also, I would strongly recommend a header/dp combo.

 

hmm i dont know if "stock" can support it. Well it "could" its the EGTs id be worried about.

The stock DP + muffler need to be ditched. They just trap too much heat. I used the regular gmp 2.25 sport exhaust.

 

Depending on mods it could do 250 and maybe more. I agree that it is not the best route. I said that I strongly/highly recommend a header/dp combo. It all depends on what the goals for the car are.

 

Appreciate the input. I will look into a header and downpipe and leave the stock catback for now. That is the easiest thing to upgrade, so it can be done any time.

So the stock diameter system is 2.25?

 

as are the gmp sport and touring exhausts.

 

gmpp is proven to add +12whp and its a 2.25 so... dont believe anything you read really.

 

You think it is due to just a differing muffler on the GMPP catback?

 

i have vibrant header back and injen intake and thats it for engine mods and i picked up probally 15hp you can tell a diffrence with the exhaust and i didnt loose hp i know

 

Thanks brutha!

 

Ive done alot of research as right now I have the Pacesetter header w/GMPP catback and stock cat and downpipe which was a huge mistake. I am very paticular about the performance gains and the sound so I have researched almost every available option and what I finally ordered was the Hahn's shorty header, Hahn's downpipe w/highflow cat and the Hahn's catback so everything will be replaced. This system is a 3" catback and it sounds sick and the dyno shows a gain of 17+HP at the wheels. I personally dont think any other system for my 07' SS SC can stand up to this one.

 

Bad move...

3" Should only be used for applications running approx 300hp..

Youve just lost power...

Actually, that pacesetter header is one of the best headers on the market..

Considering you went to a shorty header, you lost gain on the lower rpm band (although it has been placed more up top)

 

probably sounds like a honda after 3,000 rpm and loud as hell.

delete the GM resonator and replace it with 2 glasspacks. Makes it just a little louder than stock, yet no fartcan sound.

 

MODS listed in sig, I am running the stock cat back exhaust and I made 261 and 228 with a SLP Header and 3" dp w/hf cat

 

Hope that helps

 

Awesome Wannabe... thats why you gotta love OTT

 

Thanks wannabe! I have already bought the 2.8" pulley, will add 60# injectors and tune myself using HP Tuners. This will be on stock exhaust from the manifold back and stock intake. Then I will add other components and re-dyno. I am fortunate to have free dyno time and access to HP Tuners, so I will do my best to provide good feedback when I do mods with actual dyno numbers.

 

Nice, let me know how it goes and when your ready for 60's let me know

 

Will do....sent you a PM.....used to live in Macomb County

 

the stock lsj downpipe is 2.75" o.d. .... There is a 2" transition that is only about 1.5" long inside the flex coupler, and then it opens up to 2.75". After the cat right before the flange that connects to the resonator, it necks down to 2.50" for about 2". I know these dimensions to be true, because I just measured my downpipe last night when I was uninstalling my shitty ass CTI 3" downpipe.