3 speed Automatic - no overdrive
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Joined: Apr 2004
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Use the calculator here:
Novak Conversions - Gearing & Gearing Math for Jeeps
You need the axle ratio and tire diameter.
Your trans ratio is 1:1, TC ratio is 1:1.
Novak Conversions - Gearing & Gearing Math for Jeeps
You need the axle ratio and tire diameter.
Your trans ratio is 1:1, TC ratio is 1:1.
Super Moderator
Joined: Apr 2004
Posts: 34,475
Likes: 2,800
Duplicate post.
Dude, no one can answer the question without the tire diameter--not the wheel size, and the gear ratio. Gear ratios are found via the axle code on the door jamb sticker or the tag on the axle, or by counting the teeth on the ring and pinion, or rotating a wheel and counting the driveshaft revolutions.
https://www.ford-trucks.com/forums/9...at-60-mph.html
Dude, no one can answer the question without the tire diameter--not the wheel size, and the gear ratio. Gear ratios are found via the axle code on the door jamb sticker or the tag on the axle, or by counting the teeth on the ring and pinion, or rotating a wheel and counting the driveshaft revolutions.
https://www.ford-trucks.com/forums/9...at-60-mph.html
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Joined: Dec 2007
Posts: 7,987
Likes: 104
From: Boise, Idaho
Here is the exact formula to find your RPMs at any speed:
RPM = (Speed * Transmission Gear Ratio * Final Drive * 336) / (Overall Tire Diameter in inches)
So, an example:
I'm going to assume 30" tires and a 3.55 final drive. You're in 3rd gear (which is a transmission gear ratio of 1.00), and going 60mph.
RPM = (60 * 1 * 3.55 * 336) / 30
RPM = 71568 / 30
RPM = 2386
That's assuming at what your final drive and tire diameter is. When you find those out, plug them into the formula above for any given speed and it'll give you your RPM.
It sounds like you have a C6.
3rd gear: 1.00
2nd gear: 1.46
1st gear: 2.46
RPM = (Speed * Transmission Gear Ratio * Final Drive * 336) / (Overall Tire Diameter in inches)
So, an example:
I'm going to assume 30" tires and a 3.55 final drive. You're in 3rd gear (which is a transmission gear ratio of 1.00), and going 60mph.
RPM = (60 * 1 * 3.55 * 336) / 30
RPM = 71568 / 30
RPM = 2386
That's assuming at what your final drive and tire diameter is. When you find those out, plug them into the formula above for any given speed and it'll give you your RPM.
It sounds like you have a C6.
3rd gear: 1.00
2nd gear: 1.46
1st gear: 2.46
Moderator
Joined: Dec 2007
Posts: 7,987
Likes: 104
From: Boise, Idaho
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Super Moderator
Joined: Apr 2004
Posts: 34,475
Likes: 2,800
OK, in the 3rd thread you started on this, you indicate axle code 18, but STILL NO TIRE SIZE.
Axle code 18, according to the decoder found in "articles/specs" at the top of the page, is a 3.08 ratio.
https://www.ford-trucks.com/article/...de_Chart_.html
ONE MORE TIME, what size are your tires?
Use the calculator in post 3 or the formula in post 5 to determine rpm/mph info.
Axle code 18, according to the decoder found in "articles/specs" at the top of the page, is a 3.08 ratio.
https://www.ford-trucks.com/article/...de_Chart_.html
ONE MORE TIME, what size are your tires?
Use the calculator in post 3 or the formula in post 5 to determine rpm/mph info.
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ok, I got it. Thanks for the patience folks.... new to the site.... Just picked up an 1988 E 150 (6 cyl) off the orig owner with 76,000 miles. Super clean, very minor rust. My 6th E 150 since 1981. Taking it from NY to Fla next week, towing a 5x8 motorcycle trailer and I was curious about the RPM's. Thanks everyone - Bill
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Have been doing a bit better than that - Got 18mpg (strictly hwy, 60 mph) returning from Pa. to NY. Just changed oil to synthetic, lets see if I can squeeze 20 mpg out of this baby !