Is there a problem with 3rd gear pulls on a dyno...

[jonnyg]

....rather than doing 4th gear pulls?

[habbie]

what do you mean by problem?

[jonnyg]

Well, not really a problem, I mean would there be a difference between the #'s put down?

[habbie]

i had a 4th gear and 3rd gear pull and both were almost identical.

[SG_M3]

you want the grear that is 1:1. If you are on stock software you can't do a true 5th gear run. So most use 4th as it is the closest to 5th(1:1)

[timsev]

you want the grear that is 1:1. If you are on stock software you can't do a true 5th gear run. So most use 4th as it is the closest to 5th(1:1)
so what do you do if you have different software? such as JimC?

[SG_M3]

if the dyno guy doesn't care, run it in 5th

[CosmosMpower]

if the dyno guy doesn't care, run it in 5th

Why would stock software not let you dyno in 5th? Is it a matter of topping out the speed gov before you get to redline or something?

[SG_M3]

yup, the speed limiter is 137, so you would not reach redline.

[GG///M3]

i dynoed both of my m3's in 3rd before nothing special, and i made 234rwhp on 1 car, 245 rwhp on the other. :D

[Bernanke]

my 3rd/4th gear runs also identical ,i don't think it really matters. supposedly the lower the gear the more "sensitive" the runs are but i didn't see much of a difference

[Serious]

if its corrected it doesnt really matter

[POPS M3]

The poor engine does not know what gear you are in. But, from a theory stand point, you should produce the highest rear wheel HP numbers in the highest gear - lowest inertial losses. This is because the rate of acceleration of the engine (RPM), drivetrain, wheels etc. is the slowest and thus the power to accelerate the entire drivetrain is lowest. Lowest inertial losses produce the highest net output power.

I usually do 5th gear which is 1:1 and this also produces the lowest transmission loss -- straight through vs through gears. Most good dyno shops can do 5th gear provided the DME software does not limit based on speed.

Ken