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Author Topic: Maximum RPM at 3500 Feet/Second piston speed.  (Read 2331 times)

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Offline PaPiTo Paul

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Maximum RPM at 3500 Feet/Second piston speed.
« on: July 14, 2014, 17:24:20 PM »
I have been doing some research on the maximum RPM for the BOA engine. The formulas are applicable to any engine. The factory limit is 6250 RPM with the 2.83 inch stroke. This gives a piston speed of 2947 FPS (feet per second) well below the almost standard recommended maximum of 3500 FPS probably to make the engine more relieable.
The theoretical redline would be 7420 RPM for 3500 FPS. For racing, the recommended limit is a maximum of 4000 FPS which would be 8480 RPM.

Formulas for piston speed:
Piston Speed (FPS)=Stroke (inches) X RPM / 6
RPM = Piston Speed (FPS) X 6 / Stroke (inches)

Of course there are other parameters to consider like valve float, more wear, reliability, HP and torque falling off, et cetera.

Has anyone raised their ECU RPM limiter? Has their engine self destructed or any other adverse effects?

-PaPiTo Paul

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Re: Maximum RPM at 3500 Feet/Second piston speed.
« Reply #1 on: July 14, 2014, 18:32:26 PM »
The weak link in a stock 24v are the rods and pistons and the rod and main cap bolds.

So raising the rpm limit is not such a good idea with stock parts. That's why Ford limited the rpm at 6250 rpm.
greetz Paul.

Capri V8 Driver.


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