Got to dyno a bone stock Pontiac G8 today. Nice car. Boy does GM cover their back-sides with all the timing reduction for temperature in coolant and IAT. Also very rich mixture.

Spent lots of time working on the tune since this customer would only run 87 octane. The results were very positive.

Baseline numbers were 279 rwhp, 299 rwtq

Tuned numbers were 313 rwhp, 328 rwtq



Because this tune was done on a Mustang dyno, we were also able to run the G8 on a 1/4 simulation.

Stock 1/4 mile dyno run: 13.44 @ 104 mph

Tuned 1/4 mile dyno run: 12.81 @ 109 mph

Tuned 1/4 mile dyno run with torque management removed: 12.49 @ 111 mph

Don't know how accurate the 1/4 mile dyno runs will be compared to the track, but a 13.44 @ 104 mph is not too far off of what stock G8s seem to be running. The owner plans on taking the car to the track soon so we'll have some real world results to back these up. Gotta love technology. We dropped nearly a second ET and we didn't have to turn a wrench.

I also made the AFM much more aggressive so the motor will cruise in 4 cylinder mode all the time cruising down the highway. I know this was good for a 2-3 mpg gain on my Suburban. I would expect similar gains on the G8. In this day of nearly $4 per gallon fuel, it's nice to gain over 30 rwhp and increase fuel economy at the same time.

 

Interesting!

..thanks for posting

 

man it responded well, be nice to see him get it to the track now and run it into the 12's.

G8 will be my next car fo sho.
J

 

Way to go PAT G !! That is awesome especially considering the 87 octane. How much do you think is left on the table had he went with a 93 octane tune ??

 

great results!

 

Very nice Patrick.

 

Probably not a lot. The motor is only 10.4:1 and would probably make best power with around 26 degrees of timing. On 87 octane, we were logging an actual 23 degrees from 3000-3800 rpm, then pulling down to 20-21 degrees from 4000-5200, then ramping up to 23 degrees from 5400 rpm up. Not sure if that extra few degrees of timing with 93 octane would make much more power or not. I spent considerable timing tweaking the knock sensors to make sure they pulled timing for real knock, but desensitised them enough to keep them from jumping every time you moved the throttle (exageration). There is lots of power to be gained by carefully tuning the knock tables when trying to perfect an 87 octane tune.

 

Wow, impressive results. I'd love to see this car hit a 12 at the track, as well, especially on 87 (but even on 93 it would be impressive).

 

Why would someone buy a G8 and run 87octain?They shouldn't own the car.

 

The G8s come from the factory as 87 octane motors. The engine is basically the same as the 6.0L Vortech Max truck motor. That too runs on 87 octane only. The main spark tables allow for some headroom to run 93 octane, but the temperature timing retard protocol and oversensitivity of the knock sensors spoil most of the gains without a really good tune.

 

nice, are you using hptuners or efilive for the tuning?

 

EFI Live version 7.5.

 

Damn, I'm liking those G8's more and more every day! I wonder how far my 2 camaros would get me toward owning one...

 

Grat work Patrick and awesome numbers.

 

It's strange seeing a car with more torque then hp. Is it a tiny cam or the intake/heads don't flow well up top? Seems like a ton of potential.

 

Totally bone stock. Needs cold air intake, headers, UD pulley and better intake manifold for some good gains. The stock cam is pretty tiny though. They cylinder heads are killer though. Love the 4 cylinder mode too.

 

Nice gains Pat!!! That kind of of power and mpg increase on 87 octane is outstanding!

 

Good gains Patrick!

 

Very nice! Hopefully GM will offer a M6 in the GT model.

 

Hey could u "lock" it in 4cly mode and dyno it like that??