ATW % to add

[Chilliman]

Know this has been up hill down dale and everywhere else in between and I've done a search (again) but just a quickie question as some one might have this off the top of their head.... What percentage are the RR people typically adding to the ATW figures. I can see it varies alot, seemingly between about 15% and 25%.

I think some of the better known RR's are adding 25%. Should the percentage for any given motor not be the same (or almost) regardless of RR ??? We've basically all got the same transmission etc ???

Also keen to know what kind of ATW figures people are getting with various mods etc (interested in all and particularly 500's)

[Graham]

all this percentage figure to calculate flywheel power is a load of old bo**ocks, the better rolling roads should be doing coast down tests so theelectronics can try andwork out the amount of power needed to turn the transmission over at any given speed, which is then added to the graph of the power read at the wheels.

any rolling road that gives ou a peak measured power then adds a percentage to give you a peak number is about as useful as you or I guessing a number...

but back to your question, in my experience the tranmission setup in a chimaera takes around 50bhp to turn over at peak rpm. this will be the same for a stock 4 ltr or a heavily modified 5.4 so kind of proves the point that a percentage is fairly meaningless.

[Chilliman]

Er, thanks for that

[haircutmike]

That's about right I guess.

When I had a session a couple of years ago, it was 275 at the wheels and about 328 at the fly from memory!

[Chilliman]

Hmm ties in spot on, last RR was 307 at the wheels and 355 fly, so the approximately 50 bhp looks to be a good guestimate for flywheel power....