Re: RPM

Posted by Larry Jenkins on December 03, 1997 at 18:26:40

In Reply to: Re: RPM
posted by Mike Flanagan on December 03, 1997 at 17:30:56

: : : Has anyone done any testing regarding the engine rpm at different speeds?What is the "best" rpm for a babbit engine? It is very frustrating on a tour when one person refuses to drive over 40 mph ( which is relative ) because he fears the engine will explode due to the high rpm.Since most speedometers are not accurate, it seems that a "tach-check" would be good test for most cars.
: : :
: : D.An article by Ed Rossig in How to Restore Your Model A, Vol 1, page 101 has a chart which tells it like it is.While the author was writing about water pumps and fans, he includes a chart which basically says that the power curve of the Model a engine reaches its peak horsepower and efficiency at about 2250 RPM.His chart depicts tests on 28/29 Model A with 21" tires and a 3:77 to 1 ratio axle.The speed computes to approximately 40 MPH.Unmodified Model A's have a "comfort zone" of 40 to 45 miles per hour.From years of driving them, I have come to the conclusion that they seem to have 45MPH engines, 45MPH steering, 45MPH brakes....lights....supension and so on.When driven in those parameters they seem to give back the true feeling and joy of what a Model A really is.If my "purist" convictions are showing through, so be it.
: : Have fun!
: : Paul
: Paul, well spoken, I would fit comfortably in your mirror hour after hour....
: God Speed Under 50.
: The Model A Fool.
Mike..
Your "God Speed Under 50" is right on.YourSign off as 'The Model A Fool" is not even close..
Good luck with the establishment of your restoration shop.If anyone out there can help Mike obtain the tooling he needs, please help.He's pretty special..
Larry Jenkins

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