PowerShift408

iTrader: (44)

Can't believe the headers and exhaust didn't pick up ****, that makes zero sense.

Gary Wells

Whether zero sense or not, this is not the first time that I have seen this reported, and Jesse Bubb, owner of Wait4Me Performance, who is a very big player in making RWHP & RWTQ with these cars just reported on another that he doesn't recommend headers on these cars due to the $ spent per RWHP returned. Another thread on this forum reported the same thing just a few months back on another CTS-V2. Strange and / or unusual, yes, but untrue, no.

disc0monkey

iTrader: (10)

9 mpg love it

WSsick

iTrader: (13)

Don't the 03/04 Cobra's have the same issue with adding headers? Something adbout losing cylinder pressure I heard...

Wesmanw02

iTrader: (4)

If anything, headers typically help on supercharger applications. The more air you can move through the engine, the more power you can make. Typically, when you add headers to an S/C engine, boost pressure actually drops as a result of the increased airflow. To counter this, you install a smaller pully, up the boost back to it original number, and you get a nice power gain.

My bet is that the stock manifolds flow so well that the power gain is negligeable. This is also the case with the LS7, which uses similar manifolds to the LS9. GM designed the stock manifolds to be highly efficient and optimized for the engine's powerband. Obviously the work quite well, because nobody has had great luck with aftermarket headers on the LS7 or the LSA.

odarabla

iTrader: (1)

Sorry brother but the comment was for 94guy. He doesn't have a CTS-V

Gary Wells

No problem Oops, my bad.

Buff

What heat exchanger did you guys go with that install..

The things with the CTS-V is to replace the piping from the front cats back and get rid of the secondary cats in the back. I picked up around 25-30rwhp with that modification using 3 in. plumbing

Gary Wells

Car bone stock, no mods before modding the exhaust?

Did you dyno before and after that mod, and were you running any other mods at that time?

Did the car have a tune prior to the mod, and did the after include a tune?

Buff

I didn't baseline the car stock. This was with no tuning at all.

Gary Wells

Thanks.

zippy

The LS9 cam was used because even if you spent the time to really go over everything and spec out a custom grind it would be very close to the specs of the LS9 cam. To get the stock like driveability and idle of the LS9 cam out of a custom grind it would also have to be small and wouldn't be worth more than a few hp and torque over a stock LS9 cam. That cam was worth about 30RWHP or so over the stock cam and yet still idles and drives like the stocker with roughly the same amount of vacuum.

On a side note I can't seem to post up the other sheets. Send me your e-mail address and I'll send you the entire dyno info from stock and this sheet. The car is now back and getting a compression bump in search for more power. A 416 was the desired choice, but with the piston oilers that isn't going to happen. The 4" stroke doesn't look like it's going to work in this block.