Gearing question
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Hello - Question . . . How can you figure out how fast a car can go per gear, per RPM? Would you use gear ratios? Final drive? Wheel size? I've been confounded by this question for months, and nobody can seem to give me a straight answer . . .The only way I've have found to calculate this is from actually driving the car . . . Would anybody like to clue me in? (ex. how fast would do you travel at 6000RPM in 4th gear)
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2kturkey - Ha Ha. I meant the math to get the 12.9 . . . the gear ratio for the S2K in 4th is 1.161, and the final drive is 4.1:1, and the wheel size is 16" (minus tire size) . . .can you somehow get 12.9 from this?
Joined: Oct 2000
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From: WA
It is extremely challenging to make a transmission that shifts well at 9000 rpm, so one of the unusual things is the S2000 transmission is a secondary reduction shaft.
You are missing the 1.160 output reduction. Do one more multiplication and I bet your math will come out.
You are missing the 1.160 output reduction. Do one more multiplication and I bet your math will come out.
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Originally posted by RT:
You ready for this?
9000 Rev/min x 1/1.161 x 1/1.160 x 1/4.1 x 1/837 Rev/mile x 60 min/hr = 116.84 mph for 9000 rpm in 4th gear.
To get the 12.9, take the 116.84/9 = 12.98@1K rpm.
This number differs from the target by about 1/2% (assuming all given ratios were correct) either due to rounding error or a wrong assumption that the stock Bridgestones roll 837 times in one mile. (If we used 842.3349 rev/mile it would come out dead nuts).
You ready for this?
9000 Rev/min x 1/1.161 x 1/1.160 x 1/4.1 x 1/837 Rev/mile x 60 min/hr = 116.84 mph for 9000 rpm in 4th gear.
To get the 12.9, take the 116.84/9 = 12.98@1K rpm.
This number differs from the target by about 1/2% (assuming all given ratios were correct) either due to rounding error or a wrong assumption that the stock Bridgestones roll 837 times in one mile. (If we used 842.3349 rev/mile it would come out dead nuts).