[Sodemo]

Hello,

I am taking part in a project which is aiming to bring at least 3 supertouring cars to modern PC race sims. We are trying to be as faithful as possible to the real thing and wherever possible we have begged borrowed and stole (not really) data from anyone that will give us it.

Our Nissan has already been published and is available for free download.

However we are currently working on the BMW and Audi so RWD and AWD, and we are discussing transmission losses and the power to give the relevant cars.

I have been reading a lot of into on such things on the web. Road cars it looks like anything between 10-15% of torque is lost through the transmission. However I read a figure that a motorsport gearbox + diff might only cost 7%. So thats the figure we have ran with. I was given some engine info from Judd, so we have used that as a basis and have essentially ended up with a figure of 252nm of torque @7000 rpm at the front wheels.

Logically speaking, the RWD and AWD cars should suffer greater losses given their drivetrain type, however when I initially did the maths, I put RWD at -8.5% and AWD at -10%, however given the low powered nature of the Audi lump, this only gave it 234nm at 7000 rpm. In a car which weighs 70kilos heavier than FWD, that doesn't really add up as they are then so slow on the straights. I have read many articles and watched dozens of historic videos and they used a lot of tech to minimise the AWD transmission losses.

So, to my original point, what are realistic transmission losses for FWD, RWD and AWD for touring cars?