Wow, ok I think I got it :thumb:! So, Eric, does that mean when we ask how many RWHP/TQ a car is making, we are really referring to the amount of power being transferred to the wheels from the crank, rather then the actual amount of power at the wheels?SeriousEric said:Good question. The # that the dyno reports should actually be called flywheel torque as measured at the rear wheels. You are correct in that a stock viper making 500 lb.ft torque (at the flywheel) is actually putting down 1500 lb.ft. at the rear wheels (minus losses).Clint Sever said:By the way - what does the dyno measure then? I know Vipers dyno in fourth cause the ratio is 1:1 - does that cancel the torque multiplication factor? In what gear would the RWTQ be 2456?
In my mind, if the ratio is 1:1 and the rear is a 3.07 then the dyno is measuring power at the 3.07 ratio - why then is the RWTQ 1000 ft/lbs less when measured on a dyno?
So how does the dyno *know* how to factor out such things as gearing (trans & diff) and wheel/tire size? It does that by a ratio of drum speed to known engine speed. They're measuring your rpm, right? And the dyno knows at any instant how fast the drum is turning and that allows them to factor out the mechanical advantage (torque multiplier) due to gearing etc.
And if torque is a quantifiable, tangible 'thing', then is horsepower simply a function of torque relative to engine speed?
Sorry I missed your call last night, I didn't hear my damn phone! I will definitely get it tonight.