View Full Version : gears and dyno

09-17-2002, 11:13 PM
Got a question I am confused with.

Do gears increse the horse power to the rear wheels?

I mean they make it easier for the vehicle to move. So I would think it would make it seem like the engine has more power. So on a dyno would make the engine seem to have more horsepower.

I might be wrong so what's you thoughts.


09-17-2002, 11:23 PM
I have heard that gears do NOT change the HP. ;)

09-17-2002, 11:58 PM
Gears don't change power output, only it's application. Acceleration vs. top speed in most cases.

Some vehicles will "run out of gear" if not geared properly and will lose top speed but have quick take off. You see this a lot in 4 wheeling too (where I'm more used to discussing it). Too large (numerically smaller) a gear and you have higher top speed but may not be able to apply power for take off if you need that, which you would get from a smaller (numerically larger) gear. I think that's why some people say that certain gear swaps are better for track cars, some are better for daily drivers that want a little more oomph. The trick is to find the middle ground. This is also part of the reason that some of the worlds fastest cars (Ferrari, Lambo etc) may have a top speed of over 200 mph, but may get their butts kicked at the dragstrip.

I'd like to hear more about results of regearing a '91. ;)

09-18-2002, 01:43 AM
Changing rear gears will change your TQ, but not your hp. If you go from a 2.73 to a 3.27 gear, your TQ will increase.


09-19-2002, 05:45 PM
I am not saying the gears will give the engine more horse power. I am saying it does manipulate it. Unless they have a program and put in the gears and it adjust to the car.

Think about it putting gears in the car will make the power going to the rear wheels different. Hence turning the drum faster making the computer think there is more power than is really there.

Ok torque is how much twisting force

Horse power is how fast it turns.

Putting in higher gears will change the force on the spinning drum that is reading how fast it is turning.

This is my thought. Untill I get proof like the computer changes to the gears or something. I mean tell me why and not just it doesn't do that. Not trying to be rude but I am here to learn and these are just thoughts that come to me.


09-19-2002, 10:13 PM
Well, in all fairness, your question was:
"Do gears increase the horse power to the rear wheels" which was addressed, but I guess that's neither here nor there.

My impression is that gears won't really change the max torque, but will change where that max torque/HP manifests itself (at what RPM). It's possible to gear a car to where max power is outside of the engine's physical ability to rev, or make it come so fast at low RPM's that it's useless and the car has to shift ridiculously fast and at low speeds. Maybe someone with dyno experience will give us a better answer.