Transmission Losses - Calculation

Does anyone know what the transmission losses are on an Exige from flywheel to the wheels?

I was looking at some of the Emerald maps and they suggested about 30% - is this about right or to high?


Dave Walker of Emerald is VERY highly respected throughout the Lotus/Caterham tuning industry, & there is no reason to doubt his figures. Obviously, the loss will vary to some degree from car to car, but 30% is generally accepted to be accurate.

He is in the process of building a dyno, so exact figures for individual installations should be available (at a price!) shortly.

30% sounds way too high to me…that’s probably how Lotus managed to quote 190hp for their 190 kits I would say 15%.

30% does sound a bit high…

Quoting a percentage doesnt make sense, a 500BHP car at 100MPH will have similar losses to 100BHP car, according to any percentage calculation the losses will be 5 times higher. You cannot estimate losses in terms of percentages, the loss at the rollers will vary depending on roller speed, tyre size and pressure, weight over the driven axle etc.etc.

The only accurate way to assess the losses is to measure them using a coastdwon test. The least I have ever seen is 25BHP, the most 57BHP.