herk01SS

My brother in law just sent me a copy of dyno results on an TA that went from 3.42 to 4.10 gears in an M6. The horsepower and torque curves showed a drop of 15hp and 17TQ at the wheels. I put 4.10's in my 95 Z28 and dropped 0.4 in the 1/4. This does not make any sense to me. Does anybody have an explanation for this?

Ouija

iTrader: (3)

You will see a HP drop. It is normal, someone explained it to me, but I've forgotten. Has somethign to do with taller versus shorter gears gives you more torque but less HP.

I lost 5HP going from 2.73 to 3.42's.

jay_99z

iTrader: (5)

Your gains from the gear ratio change will far outweigh any HP loss. Unless you are really big into dyno numbers......not something to worry too much about. It's all about the ET...

Vortec5300

Ya I lost 18hp and 15lbs tq going from 3.42s to 4.10s. Car feels much stronger though.

mrr23

iTrader: (3)

i lost 13/24 when i went from 3.23 to 4.10 in my 00 formula auto. it's about the ability to accelerate faster because of the gear ratio change. the loss of hp is because it takes less torque to turn the higher numerical gears. less tq = less hp on the dyno. think of a ten speed bike. it's easier to pedal from a dead stop in 1st gear vs 10th gear. it takes more energy (torque) to pedal in 10th gear from a dead stop. and you have to pedal your *** off to do any speed (hp) in first gear. here's my dyno:

transam1998

iTrader: (5)

Don't have any horsepower loss figures, but when I changed to 411s in my 10 bolt, I went from running 12.4s at 110 mph to 12.6s at 111 mph, mph could have been due to better air, traction probs caused the lower ets. Essentially, I didn't seem to gain a thing.