Rpm??
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Junior User
Joined: Jul 2004
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Rpm??
I am wondering what other people are getting for RPM'S driving on level ground.
my truck is F-350 CC/SRW SB PSD 6.0L with 3:73 gears auto tranny and stock tires. here is what I get while drivng on level ground.
70mph 2100 rpm
75mph 2250 rpm
80mph 2500 rpm
is this normal
my truck is F-350 CC/SRW SB PSD 6.0L with 3:73 gears auto tranny and stock tires. here is what I get while drivng on level ground.
70mph 2100 rpm
75mph 2250 rpm
80mph 2500 rpm
is this normal
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Cargo Master
Joined: Jun 2003
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From: Carlsbad, California
That is about right.
The formula for determining the RPM at a given speed with a given rear end ratio is as follows.
RPM = ((Speed * 0.7 * 3.73) / (3.14 * TireDia) * 1056
Where:
- Speed is the speed in miles per hour
- 0.7 is the final ratio of the tranny in OD
- 3.73 the rear end ratio
- TireDia is the diameter of the tire in inches.
- 1056 is the conversion for miles/hr to inches/hr
Note, if you know the rolling circumference of the tire you can substitute that for the 3.14 * TireDia term.
The formula for determining the RPM at a given speed with a given rear end ratio is as follows.
RPM = ((Speed * 0.7 * 3.73) / (3.14 * TireDia) * 1056
Where:
- Speed is the speed in miles per hour
- 0.7 is the final ratio of the tranny in OD
- 3.73 the rear end ratio
- TireDia is the diameter of the tire in inches.
- 1056 is the conversion for miles/hr to inches/hr
Note, if you know the rolling circumference of the tire you can substitute that for the 3.14 * TireDia term.
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Tuned
Joined: Apr 2004
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From: Silverthorne, Colorado
Originally Posted by Tim Lamkin
I"ll tell you in two weeks...that is when I will drive it next...for 9 hours stright...
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