Hi everyone!

Just bought a pretty clean 2008 SS 5-speed with 117k miles. Service history was complete and it looks like the oil was changed every 2000-5000 miles. For $4k, I couldn't say no! Runs good, but I'm always looking for more power, so I got my hands on the GMPP tune and revised it for the stock 2-bar MAP sensors that came with the car (3-bar are on the way from ZZP!). Anyway, in doing some data logging on the original factory tune, I was seeing lots of knock retard in regular, everyday driving...and this is with a full tank of 92 octane Tier 1 gas from Costco. After swapping out to the GMPP tune, the KR is completely eliminated and the car definitely feels 30 HP stronger, with far better throttle response and a 2 MPG increase in fuel economy across the board. I know this is probably old news to most of you, but I was stunned to see just how poor the factory tune is on these cars. Once I get the 3-bar the MAP's installed and I replace the timing chain guide (precautionary), I know I'll be able to find more through customizing that GMPP tune.

Looking forward to learning more from this community!

 

6 speed ?
The HHR SS was only available with a 5 speed.

 

You’re right…I’m used to saying 6-speed because my other two cars are 6-speeds, so yes, 5-speed!

 

Perhaps this SS is the one a member talked about converting to a 6 speed with the kit from ZZP

 

Good a confirmed typo!!
We like photos, feel free to post some!

 

And. The 5 speed in the HHR SS is a Saab transmission.

I had the GMTU kit in my 2010 SS. Nice tune back then when my car was still under warranty.

 

to the forums!