Quote:
Originally Posted by Dusty
I’m feeding you all this info on the dimensions of the bottom end for one reason. That is to talk about piston speed. It a hot subject among tech orientated F1 enthusiasts (of which I am one). Since the F1 design community has such tight lips we have to make some assumptions as to the bore and stroke etc. A little research here indicates the bore/stroke ratio of a 2.4 liter V8 F1 engine would probably be in the region of 1.4 to 16/1 and the rod stroke ratio about 1.5 to 1.7/1. From these numbers the possible range of bores and strokes can be calculated. Forget the FIA imposed 19,000 rpm limit for the moment. Rumor has it that Cosworth had tested to over 20,000 rpm so lets use 20,000 as a figure to calculate an F1 engines piston speed. This works out to be somewhere between about 7100 and 7600 ft/sec tops. It is only when the bore/stroke ratio drops to 1.3 that the F1 engine passes the 8000 ft/sec barrier. At a 1.3/1 ratio the piston speed would be 8193 ft/sec. However the general consensus is that the F1 engines are at larger bore/stroke ratio’s than 1.3.
John Kasse big motor spins to an almost unbelievable 8000 rpm! That works out to be 8200 ft/sec – faster than our estimated F1 engine by quite a margin. Sure this 900 incher hardly has to survive more than a few minutes compared to a few hours for the F1 engine but the big motor is built within the constraints of a stock block configuration. I am intrigued to think what John might create if he were free to start a V8 design with a blank sheet of paper and something even remotely approaching an F1 budget!
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Dusty,
Realize that a F1 motor is in the 96-98mm bore range (3.78-3.85") so the stroke is roughly 1.6" (40.6mm) that's in the area of 5300 ft/sec piston speed.
The problem is not the speed but the Piston G's @ TDC, Kaase might be getting much higher peak piston speeds by a considerable margin (154%)but the Piston G's are around 7160 @ 8200rpm. F1 motors with a 1.6" stroke are over 11,000! (154% more!)
Good Article BTW!
Bret