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Old 05-26-2009, 11:43 AM   #15
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Member#: 175453
Join Date: Mar 2008
Chapter/Region: MWSOC
Location: wilCO, IL
AE86 GT-S coupe
i <3 alqonquin homosauce


Originally Posted by MFactory View Post
Dyno numbers are good to give you a rough idea of what sort of power your engine is making and, of course, as a tuning tool.

What really matters though is what power (torque) your car is putting to the ground, as a dyno is not calibrated to measure that (dynos are calibrated to show a 1:1 ratio). You actually make 22% more torque in 3rd gear and 27% more torque in 4th gear (throughout the full rev range, not just peak), than if you were using your stock transmission.

To put this into perspective, the 279lbft peak you are making on your car just now is equal to a car that is making 354lbft peak that is running on a stock transmission.

Just some food for thought, as not everyone understands the torque multiplication aspect of changing your gears
That's what I miss about my MFactory setup.

I could definitely feel it too. The car felt way crazier with the 5-speed.

Originally Posted by MFactory View Post
Engine torque doesn't change. It is the torque that is put to the ground that changes. Your transmission is basically a torque converter.

You're engine is making 279lbft peak just now. On assumption that you are running a 3.9 Final Drive, you would actually be putting down 1347lbft peak to the ground.

i.e 1.238 (4th) x 3.9 (FD) x 279lbft = 1347lbft to the ground.

0.972 (stock 4th) x 3.9 (FD) x 354lbft = 1341lbft to the ground.

Put it this way, a stock WRX only has 217lbft engine torque. If the engine to ground ratio was only 1:1 (as a dyno will show), you could have several friends push your car faster than the car could accelerate.

Nice graph too.
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