johnnloki said:
You'll see higher numbers in third than fourth. You're putting down a multiplied torque number in first, second and third, almost even in fourth, and a division of your torque in fifth.
If the HP# comes from your torque #, then a lower gear will give you an overly optimistic view of both.
HP comes as a product (multiplication) of torque
and rpm.
Double the torque at the wheel by a lower gear and the wheel rotation speed is cut in half. 1 x 1 is equal to 2 x .5, so power doesn't change. Go up a gear, reducing torque, but the wheel rpm increases by a compensating amount. 1 x 1 is equal to .75 x 1.33, so power still doesn't change.
The difference between a lower gear pull and a higher gear pull is the amount of time needed to run from low rpm to red-line. A higher gear will take more time and reduce the effect of the turbo lag. If it takes .5 seconds for the turbo to spool up and your engine rpm rises too fast, you'll be past the natural peak before the full boost has built.
But... take too long, as might happen in a higher gear ratio, and heat soak becomes an issue.
I've done back to back 3rd, 4th, 3rd pulls and the power (wheel torque factored with wheel speed) is within fractions of a percent regardless.