They make it up as they go along, IMO almost all RR tranny loss figures are greatly exadurated to make the owner feel like they got their moneys worth, skylines included.
Some very interesting (and old) quotes for you...
Heres a quote from a PM i kept from 2003 from Guy who used to own the mad ProjectX R32 (ie that thing that was doing 155mph terminal speeds
).
It was after i said on the GTR board that the huge tranny losses people claim are bullshit, and he was backing me up.
GTRs on the rollers do not get the huge transmission losses that many suggest occur. G-Force do not like stating 4wd losses and have indicated a 27% on the fixed 4wd transmission of an Evo 6 and this has been taken by some (Dirk) to mean that a GTR has 27% losses.
This is rubbish for several reasons.
Firstly losses are not a straight proportion of power.
Secondly there is no way his transmission is losing 250bhp, this kinetic energy can only be lost to heat and there's no way his transmission is absorbing 250bhp of heat.
Thirdly, running high cars such as Project X on the Dynapack (hub dyno) proved that only about 25% max torque was passed to the front wheels and this percentage reduced as the revs increase, once past the torque peak.
My guess is that a truer transmission loss would be about 20% or less. Of course that doesn't produce the same claimed flywheel figures......
This is also validated by running the car in rwd only on the dyno, the power figures do not jump massively, thus proving the car was nearly rwd to start with, in which case a loss of 15%-20% is more reasonable.
Heres another VERY interesting quote, Guy again, just after the first TOTB...
Two 3 door rear wheel drive RS's:
Andy Wornell 126mph at 500m
Rob Wiles 123mph at 500m
Both with claimed 500+bhp on the website.
Pick a few of our GTRs at 500m:
Andy Barnes 130mph (550bhp est)
Glen H 127mph (540+bhp)
Mike Smith 126mph (515bhp)
The GTRs also pulled higher 1.25mile times, so in conclusion:
The GTRs were better off the line.
The GTRs were travelling faster at 500m (ie were not being caught)
The GTRs were travelling much faster at 1.25miles.
So if the 500+bhp Cossies are slower than the GTRs, how is a 420bhp Cossie ever going to keep up?
I use the speed at 500m, since that is a determinant of rate of acceleration from meaningful speeds ie 30mph+. The traction really only has an effect on the ET (elapsed time), hence why I ignored the times
So bearing in mind a Skyline is FAR heavier and has potentially more transmission loss due to it being 4wd, whys the terminal speeds at 500m higher even vs cars with the same (claimed by the cossies) power?