We all know that gears do not add horsepower, but this has been bothering me.

Shouldn't gears increase torque? Since torque = force x lever arm, and gears = lever arm. Bigger gears should = more torque. I would think that although power at the crank would not change, rwtq should.

Also, at the very least a dyno should reveal a shifted powerband, with max torque occuring at lower rpm.

Opinions? Facts?

 

this is true, but when you are dynoed you input your final drive ratio so the software compensates for this change, if you input the stock 4.10 final drive and you have 4.57 gears, your dyno will read high

 

See where it says ratio. That can be obtained from http://www.turnzero.com/technical_resource...gear_calculator

See where it says total gearing in 4th gear. When input correctly you will get the ratio.
Dyno should be run in 4th gear otherwise you must recalculate the ratio for the gear you are in.

 

ok. so i'm not crazy. when i get my dyno with gears i'm gonna want to set it at 4.10. i want to see the simulated power difference over stock gearing. would this give me the desired result?

thanks for your input

 

I'm not sure what you are trying to accomplish. The ratio is not 4.10. It's the calculated final drive.

The power is calculated by the dyno from the torque knowing the correct gearing.

For gearing changes you can convert the torque to thrust and look at the difference that way. Same thing with larger wheels/tires.

 

i've never dynoed before, so thanks for the correction, but i was reffering to this post. i want to find out the equivalent horsepower of my gears.

for example: how much whp would a non-geared S need to have to stay even with a geared one (neglecting top end losses). i know the cars would have to produce equal power at equal rpm. so the real question is, how much power does an S2k need to produce 158rwtq at (let's say...) 5000rpm.