Do you lose rwhp with 3.73 gears?

[Mighty Thor]

Some guy told me that you do. But you gain a snappy acceleration. I don't see how you could lose rwhp. Maybe because it's parasitic since the engine would work harder to spin it.

What do you guys think?

[merlinsrealm]

Depending on what you had for stock in the first place will dictate aprox. what you will lose. I had 3.08's and went to a 3.73 gear and lost about 10 RWHP.

[WickEdSix9838]

3.73's would make it easier for the motor to get the car moving, and i dont think you'll lose or gain any RWHP w/them in actuality but on a dyno maybe, but dyno numbers mean jack $hit...

[SkAchilles]

Parasitic loss goes up with a higher ratio gear. Car will feel stronger and be faster in the 1/4th, but will lose a few on the dyno.

Track queen or dyno queen? Its your choice.

[HAZ-Matt]

<blockquote>quote:</font><hr>Originally posted by SkAchilles:
Parasitic loss goes up with a higher ratio gear. Car will feel stronger and be faster in the 1/4th, but will lose a few on the dyno.

Track queen or dyno queen? Its your choice.<hr></blockquote>

Exactly.

[Bliggida]

On the dyno, since it takes the gearing into account as a factor, you won't see any gain or loss at all.

Street, ET, and MPH wise racing from a stop you will be faster because you have gained multiplied horsepower to the rear wheels...but not actual RWHP.

Anytime you multiply the amount of power going to the rear wheels you will have the same effect as if you left the gearing alone, and added horsepower to the engine. Same difference.

200 horsepower times 1:1 gear is 200 multiplied horsepower.
200 horsepower times 2:1 gear is 400 multiplied horsepower.

The only way you would lose "RWHP" in the sense of a loss in power or acceleration from 3.73's is if you swapped them in from previously having lower (numerically higher gears) such as 4.11's.

3.08's, 3.23's, 3.42's will all see nothing but gains across the board stepping up to 3.73's.

[Mighty Thor]

<blockquote>quote:</font><hr>Originally posted by Bliggida:
On the dyno, since it takes the gearing into account as a factor, you won't see any gain or loss at all.

Street, ET, and MPH wise racing from a stop you will be faster because you have gained multiplied horsepower to the rear wheels...but not actual RWHP.

Anytime you multiply the amount of power going to the rear wheels you will have the same effect as if you left the gearing alone, and added horsepower to the engine. Same difference.

200 horsepower times 1:1 gear is 200 multiplied horsepower.
200 horsepower times 2:1 gear is 400 multiplied horsepower.

The only way you would lose "RWHP" in the sense of a loss in power or acceleration from 3.73's is if you swapped them in from previously having lower (numerically higher gears) such as 4.11's.

3.08's, 3.23's, 3.42's will all see nothing but gains across the board stepping up to 3.73's.<hr></blockquote>

Very interesting. So you don't lose rwhp at all and you don't gain any either. I think I could use that for an argument next time.

[Dominic]

I agree, changing gearing (in the simplest of terms) only changes the rate at which you apply power and what rpm, the power is actually the same.

The multiplied power goes up, but in less time and speed, so its actually the same net horsepower. You will accelerate quicker but you won't dyno higher.

[merlinsrealm]

<blockquote>quote:</font><hr>Originally posted by Bliggida:
On the dyno, since it takes the gearing into account as a factor, you won't see any gain or loss at all.

Street, ET, and MPH wise racing from a stop you will be faster because you have gained multiplied horsepower to the rear wheels...but not actual RWHP.

Anytime you multiply the amount of power going to the rear wheels you will have the same effect as if you left the gearing alone, and added horsepower to the engine. Same difference.

200 horsepower times 1:1 gear is 200 multiplied horsepower.
200 horsepower times 2:1 gear is 400 multiplied horsepower.

The only way you would lose "RWHP" in the sense of a loss in power or acceleration from 3.73's is if you swapped them in from previously having lower (numerically higher gears) such as 4.11's.

3.08's, 3.23's, 3.42's will all see nothing but gains across the board stepping up to 3.73's.<hr></blockquote>

I am wondering why you even post here...As usual, you give out wrong information....

It is a fact you lose RWHP going from stock to numerically higher gearing IE 3.73, 4.11 and so on because the dyno sees a different engine rpm's vs rw rpms and calculates it differently

I guess if you were to go with a 12 bolt rear you would not lose RWHP either huh?

He asked do you lose RWHP not FLYWHEEL.

Dyno numbers are what at the rear. Nobody cares about whats at the flywheel. Thats why one of the reasons for example why people put lighter driveshafts in their cars.

[ September 23, 2003: Message edited by: merlinsrealm ]</p>

[MustangEater8251]

MY understadnign is you do no lose actual HP but it is applied differently to the car.

But with higher gear ratio you feel more of a grunt down low but at the top end you feel like the gear is to high.

Dynos are calibratied to your gearing to be accurate.

[V6Bob]

Let me give it a shot.

Horsepower is energy. Torque is force.

The energy (horsepower) put out by an engine does not change much as it goes through the transmission and rear end. Some energy is lost heating up the transmission and rear end gears (maybe 5-15%, it's hard to measure). That may be a little more with 3.73 gears (maybe one of those percent?), but it's not a very important deal.

On the other hand, the force applied by the engine (torque) goes up just as much as the gear ratio (overall, including both transmission and rear gears) increases numerically.

So, it's incorrect to say that gears increase horsepower, and it's nit picking to say you'll lose horsepower with 3.73 gears.

In any given transmission gear, you'll increase the torque available at the rear wheels. So, driving properly, you'll come off the line better in first, and you'll be quicker overall because you can use the transmission more effectively, by shifting more.

The big drawbacks are that you lose miles per gallon, particularly on the highway when you're in fifth gear, and the car will be noisier. That's why the car comes with lower numerical gears. There also is some increase in engine wear. You'll likely wind up shifting more. Any horsepower change is trivial by comparison.