Practical to reduce engine/ compression braking?

[Flieger]

I think he is using the Cup gearbox with the Cup motor. I doubt that a 901,911,915, or normal G50 could stand up to that engine. The clutch would probably be larger than 225mm and might be a racing puck style.

[Grady Clay]

I suspect you can cram a huge clutch in the G64 bell housing.
That is the point I was trying to make.

With a large clutch of the type like the 215 (not 225 mm type or the 930 245 mm), it can stand the ‘abuse’ necessary slipping to modulate the trailing throttle compression load.

Part of that is the sheer physical size to absorb the energy. Part is the ability to dissipate the heat.
Part is the ability to modulate the ‘slip’ and load (a racing disc is particularly poor at this, it is designed to be in-out, never slip).
Durability and cost always are in play.

If serious cooling is necessary and you can’t use a humongous clutch, liquid Halon injection might be a cooling solution.
What do drag racers use with their 1000++ hp?

I smoked a new 200 mm disc in my 904 (1700#, 220 hp) at an AutoX once. Almost flames coming out of the top of the bell housing.
I won and I drove home just fine. Another new disc was $23 at the time. The flywheel and PP were slightly discolored but fine.



904-017 Summer 1969





Can you imagine the programable finesse possible with four electric motors, one at each wheel?


From © 2008 Ludvigsen, Karl; Ferdinand Porsche – Genius of Genius: Road, Racing and Automotive Innovation 1900 to 1933; #048, Bentley, Cambridge, MA.
Original from Porsche Historic Archive.




Best,
Grady