Posted by RDavis on Sunday, October 05, 2003 at 12:36PM :
In Reply to: Re: Max RPM's posted by Tom in Oregon on Saturday, October 04, 2003 at 8:45PM :
All the old auto engineering books I have and have read say that the best fuel economy is found running a eng. at 65-85% of the max.hp rated RPMs which is usually around 3600 rpms for max.hp. So 70-75% of that is around 2500-2700 rpms.
For short high revs needed in certain situations, I'd assume 4000rpms would be safe. But what I'm sure we are referring to is sustained rpms which I would advise to stay at the best economy rpm for sustained speed and running,it will add longevity to the life of your engine.