Originally Posted by Kev.H
im sure i read the
McLaren f1 lm which had ground effect floor had enough downforce to in theory hang its self upside down

hence why it never had the top speed of the normal f1 cos with downforce comes a cost

I love that quote. Its normally used for F1 race cars. "oooh it could drive on the roof of a tunnel it generates so much downforce"
Actually it couldnt. Yes at 150mph+ the front (10% ~) and rear (10%~) and more importantly FLOOR (80%~) aero is producing more than 700KG of downforce.
Just a shame the engine systems use gravity to work, so the engine wouldnt run
EDIT:
Oh and your nearly right about the McLaren F1 LM. It had a more powerful engine, was lighter but was still slower than the non HDK cars because it had a shorter ratio gearbox as well as the increased drag.