Converting RW torque to gross engine torque
Thread Starter
Burning Brakes
Joined: Mar 2001
Posts: 1,171
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From: Thornton Co
Converting RW torque to gross engine torque
Went to the dyno last month and got figures for RWHP and RWTQ. Do the conversion factors used for driveline loss (16%) and accessory loss (20%) giving you gross HP work for torque, or do you need completely different conversion factors.
Safety Car
Joined: Feb 1999
Posts: 3,631
Likes: 14
From: Fountain Hills AZ
HP, rw or otherwise, is calculated from the torque measurement so, yes, the same factors can be used. Keep in mind that those factors are only "ballpark" figures and the actual difference between fw net/gross and rw can vary from car to car.
Race Director
Joined: Apr 2000
Posts: 17,671
Likes: 199
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Drivetrain 16-18 % loss and depending on your accessories, exhaust and mufflers being the worst drain you can add another 15-20 %. If you are running open headers for example the loss is minimal. Ballpark figure for a Vette running a waterpump, alternator, power sterering and full exhaust might be 35% loss from Gross to RWHP I have seen higher. 
