Great results from PCM for Less tuning . . .

[ChevyHighPerformance]

Originally Posted by HummBebe

Meaning a graph with all those little squiggly lines on it..., that was done for an H3. Recently.

I can understand if you don't want to share proprietary information with the whole whirrled.

What about changing the shift points for hauling around a set of 35's, a roof rack, front winch bumper, winch, rock rail-side steps, 2 roof ladders and a rear bumper?

Can it do that? I'm really curious, I'm a girl, you know.....kinda dumb when it comes to all this techie stuff.

I just looked at the stock PCM program for the 04, 05, 06 colorado I5 and the 06 H3. The high octane timing table is essentially the same (there are very small differences at low RPMs and low cylinder airmass) for all these vehicles/years. The WOT timing is identical. The commanded air/fuel ratio is identical. The timing and the A/F ratio are the major items that control engine performance. I would look at this 04 Canyon dyno curve and ratio the performance gain.

http://www.pcmforless.com/images/dyn...s/04Canyon.jpg

Stock 166 HP, tuned 182 HP -> ~10% increase in peak power

Stock 174 TQ, tuned 188 TQ -> ~8% increase in peak torque

It's reasonable to assume that the H3 would gain 10% HP and 8% torque with the same tune and octane fuel. This would make the 06's 220 HP -> ~ 242 HP about same as the 3.7L 2007.

The percenatage gain at the wheels would be the same, but the actual gain (delta HP gain) would be less since we have more drivetrain loss than the colorado/canyon. So, the 04 Canyon's HP gain of 16 HP at the wheels might be ~13 HP at the wheels for the H3.

A region that doesn't show up on the dyno plots is the off-idle power/torque. The custom tune really helps in this low RPM range but the range is rarely dyno'd (only felt by the seat-of-the-pants).

The other benefits of the custom tune are better idle quality, better auto tranny shifting RPM/speed and firmness, and many people see an improvement in MPG.

I think PCMforLess has a dynojet (front or rear wheels only) but not a 4-wheel dyno. 4-wheel dynos are expensive and pretty rare to come by and expensive. The problem is that not all wheelbases are the same so it becomes a business return-on-investment issue to buy a 4-wheel dyno. When I was publishing truck articles, I think I was the only person that could dyno an all-wheel drive/4-wheel drive vehicle within my state and all the nearby states.

I wouldn't take the lack of a dyno as something bad.