Depending on the drive train losses, we might have passed the 600
BHP mark on a 4.0 XKR (same can be done for a XJR) with our twin-screw conversion.

We actually where able to pull 470 rear wheel horsepower, and using
a 22% drive train loss figure (for some a common loss for automatic
cars), you come to 603 BHP.

We have learned from this dyno day and taking the conditions of
that day into account, we are confident that the next miles stone
of 500 rwhp (641 bhp) might be very feasible without major engine
modifications...

Very exciting stuff (at least for me and a small crowd ;-).

Regardless of drive train loss, the rwhp is imho already immense,
not to forget the torque (with 22% drive train loss at 4300 rpm 626
lbf/fft or 849 nm).

Here the dyno graph and some more info can be found:
http://www.maxperformancecars.com/index.php?option=com_fireboard&Itemid=53&f unc=view&id=2707&catid=3

Andre.

 

wow!
now i want a twin Screw Supercharger! and the rest of your build!