RPM's

E

Eddie Finch

New Member
2004 Ford Ranger Edge 2wd,has 3.0 automatic, 4:10 limited slip rear gears tachs 2800 RPM @ 70 MPH, Is that normal or just mine?
 
Thanks Eddie.
Since you failed to tell me, I had to search out the high gear ratio of your transmission.
The reason I ask is because there's an easy math formula you can use (with the aid of a simple calculator) to answer your question.
What you do is figure out the overall gear ratio (transmission x axle) you're using when driving at whatever speed you're curious about, then multiply that number by the speed (mph) you're driving at, divide by 336 and then multiply by the height of the tire.
The end result will be the approximate speed of the engine, in rpm, at whatever given speed you're driving at.
If the transmission is an automatic that DOESN'T use a lock-up torque converter, add 6.5% to the engine rpm.

Dean
 
Last edited:
Eddie Finch said:
31/10.50/15
Click to expand...
DeanMk said:
Thanks Eddie.
Since you failed to tell me, I looked up the high gear ratio of your transmission.
The reason I ask is because there's an easy math formula you can use (with the aid of a simple calculator) to answer your question.
What you do is figure out the overall gear ratio (transmission x axle) you're using when driving at whatever speed you're curious about, then multiply that number by the speed (mph) you're driving at, divide by 336 and then multiply by the height of the tire.
If the transmission is an automatic that DOESN'T use a lock-up torque converter, add 6.5% to the engine rpm.
The end result will be the approximate speed of the engine, in rpm, at whatever given speed you're driving at.


Dean
Click to expand...
Thanks
 
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