Quote:
Originally Posted by Old Tele man
Here's an equation for MPH when you know GEAR, AXLE and engine RPM:
MPH = (60/(G*A))*(RPM/rpm)
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Thanks for the formula... I had done plenty of math on this by making up my own formulas... which turned out were fairly accurate.
With this formula, still none of the mentioned ratios worked... I reversed the formula to solve for A, and still... I'm looking at a 2.3'ish:1 ratio depending on which 5th gear ratio I decided to use...
So something is still off... The only two variables left to play with in the formula are the accuracy of the tire rev/mile (927) and the accuracy of the tach readings... And probably my RPMs are to blame.
But thanks for the Formula. Much appreciated.
Quote:
Originally Posted by LittleBlackDuck
Simple one - is the tacho set for three cylinders? Does it read accurately when compared to a known one?
2100 rpm at 60mph on those teensy wheels sounds wrong to me.
Simon
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Yeah, at first glance it seemed wrong to me too...
The tachometer is and induction type, so there are no cylinder setting... No different than a timing light.
Now you do bring a valid point in relation to its accuracy, which I had questioned as well...
I don't have any other tachometers laying around, and definitely not a 3cyl one... But I do have other vehicles with OEM tachs, the Mazda and the Disco both have wires... I can test the e-bay tach's accuracy against those two OEM tachs and see what I get. Thanks