Over revs type 1 and 2

[Steve Tinker]

Has anybody got the calculation for interprating overrevs?

If your DME says you have (say) 1,000 Type 1 overrevs, how many second or crankchaft revolutions is that?

I know I nearly fainted when I saw my engine had 22,000 Type 1 overrevs, but that was about 100 hours run time ago and I'd already had the car for a year when I discovered it...... Looks like the car had been on the dyno in its previous life, but up to now no mechanical problems, touch wood.

[san rensho]

Originally Posted by Steve Tinker

Has anybody got the calculation for interprating overrevs?

If your DME says you have (say) 1,000 Type 1 overrevs, how many second or crankchaft revolutions is that?

I know I nearly fainted when I saw my engine had 22,000 Type 1 overrevs, but that was about 100 hours run time ago and I'd already had the car for a year when I discovered it...... Looks like the car had been on the dyno in its previous life, but up to now no mechanical problems, touch wood.

The brain counts over rev ignitions, since there are 6 cylinders, divide the over revs by 6 to get the number of revolutions at over rev.

To calculate the time at over revs, the formula is 60 seconds/7500 revolutions = x seconds at over rev/number of over rev revolutions. Solve for x and you get the seconds at over rev. Or, 60/7500*(over rev revolutions)=seconds at over rev.

So in your example,, it translates to 1.4 seconds at over rev.

[billj18]

With due respect, I question this formula. Four cycle engines fire every other revolution, on the compression stroke, but not on the exhaust stroke. Thus, it would be only three ignitions per rev; six ignitions would equal 2 revolutions, right?

Bill

[san rensho]

Originally Posted by billj18

With due respect, I question this formula. Four cycle engines fire every other revolution, on the compression stroke, but not on the exhaust stroke. Thus, it would be only three ignitions per rev; six ignitions would equal 2 revolutions, right?

Bill

I think you may be right.