gear ratios and effects on rwhp

[mrr23]

it has to do with load on the engine with the gearing. my wonderful 10 speed bike comparison:

from a stop, take off in 1st gear on the bike. it's real easy to get going, but you pedal your ass off to keep up top speed.

from a stop, take off in 10th gear. really hard to get moving, but easy to pedal at top speed.

so, you make more torque from a lower numerical gear because the motor has to work harder, producing more torque. and horsepower is a calculation of torque. and the opposite happens when you have a higher numerical gear. less load means less energy needed to move an object.

now, you are actually wasting the energy produced in the low rpms with the lower numerical gear (2.73) because it takes more effort to get moving. then the opposite happens with higher numerical gears (4.10). you waste energy in the upper rpms. if you could do a dyno run in third gear from 0 - top speed with both gears for comparison, you'd see the trade off. as with most dynos, you only get to see from the middle of the rpm to the top rpms.

this is why you get better 60ft and lower ETs with lower numerical gears, but you get a lower mph.
3.23 to 4.10
http://www.stealthram.com/familypics/formula00/dynosheet/410gearunprocessed.jpg

4.10 to 3.73
http://www.stealthram.com/familypics/formula00/dynosheet/373gearprocessed.jpg

[MadSeason]

This should get a stickie

[tt69camaro]

Have you track tested this theory? I noticed that there was a 23 degree difference between your runs with the gears.

[mrr23]

track times won't show much as they are almost a year apart. the dynos are SAE corrected. while dynojet isn't totally accurate on their weather corrections, it's close enough for me.

[tt69camaro]

Seeing how you have tried different gears, which are your favorite? Why? Im trying to decide on 3.73 or 4.10 for a stock 98 TA with a 3400 stall. What brands have you used?

[mrr23]

i liked the 4.10s for driving and accelerating. made 4th gear with converter locked feel like 3rd. pulled like a mofo. unfortunately, for drag racing with the n2o, it put me way out of the rpm band. i had to shift into 4th about 60ft before the traps. with the 3.73s, i go through the traps at about 5700 rpms in 3rd.

brand was AAM for the 3.73 gears and motive for the 4.10 gears. the 4.10 gears howled badly. and that was both sets. the stock set and the mikronite treated set. the mikronite set was quieter though.