I'm interested in all results so thanks for posting. You don't by chance have the torque value, do you?

Most all dyno runs will be in a second or third gear, this way the engine is under a strong load while the power band is traveled.

 

Sure, Max torque is 129.38.

 

A dyno pull should be done in a the direct drive 1:1 ratio. Anything lower and your getting a false reading due to torque multiplication through the trans.

 

I dissagree, and this is why:

The purpose of a dyno is to baseline performance which is useful for discovering gains/losses when tuning. It is not a good tool for comparing another same vehicle or comparing data, across days, because of environmental issues.

As long as you profile the powertrain using the same gearing on each pull, your results are fairly accurate with respect to the engine's environment (e.g.: engine temp., air temp., humidity, etc).

When doing a dyno run, you capture the engine's abilities (ability to apply torque with respect to time (HP)) begining in a mid gear all the way through to the end of the gear's range (max RPM).

If you ever get a change to watch a dyno pull, you will see what I'm talking about. Check out some of the car shows on the speed channel or spike TV.

When my tuner does a dyno pull on my GTO, they get the car 's speed up to the low end of 3rd gear and then go wide open throttle to red line. Then they make adjustments to the timing or fueling or what ever they are tweeking this day, give the engine a 20 min. cool down, and start over.

 

Is your GTO an auto?? Third gear is the 1:1 ratio in a 4 speed auto.

 

This is interesting, when I got to work this morning I looked up both the auto and manual trannys for both the GTO and the HHR, here is what I found:

On both vehicles, a 1 to 1 ratio was in third gear for the automatics as you indicated. For the manuals, the GTO had a 1:1 in fourth gear and the HHR's manual had a 0.98 ratio in forth gear.

My GTO is a manual and third gear has a ratio of 1.43. Should my tuner be doing my dyno pulls in forth gear?

I think you are trying to teach me something here but I'm missing it....

 

Doing a pull in a lower gear will skew your final numbers, they will inflate the number as the wheels are turning faster than the motor is, making it seem as if you are putting down more than your are. I guess if all your doing is just tuning and not going for a true number it doesn't matter. I could be completely off base on this, but this is just how I always understood it, and if you think about it, it makes sense. Each gear in the trans should get lower as you go up in gear, with anything above 1:1 being overdrive, 4th gear in an auto and 5th and 6th in the GM manual tranmissions. Usually you won't get a perfect direct 1:1 ratio, it is usually off just a little bit like the HHR having a 0.98:1, but it should be within a tenth or 2.