Lost power with Tune Non-SHO

[jedhead]

I did a before and after dyno run on my STS-V. I lost some power with a tune. Same peak torque, but the torque dropped off slightly quicker with the tuned ECU.



The engine is a stock supercharged Northstar DOHC V8 267ci 4.4L Much smaller engine than the 6.2L push rod engines in the newer CTS-V


Bob

 

[Sho Amo]

take it back lol

 

[sho_sc]

1st I would suspect that the knock sensor is pulling timing. (or the engine was hot).
2nd I wouldn't tune one that "lean" in the 3K -4K range.
3rd I assume it was a cool day, nice and sunny, when this was done?

 

[jedhead]

1. I was suspecting that timing may be getting pulled. We have only 91 Octane in Cali.
2. I thought the tune was a little lean so I reinstalled the stock PCM
3. 64F on the first run 67F on the second. Normal for March in SoCal.

I am thinking about buying a tuning program like EFI live, copy the stock tune. Remove the speed limiters, allow 100% throttle in 1st, 2nd and 3rd gear, accelerate the speed in which the throttle opens, close the boost bypass sooner, and quicken the shifting. Leave the fuel trim stock. I may not gain any more power, but the car should feel faster.

Bob