considering 3.73s
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Pro
Joined: Mar 2013
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From: Huntington WV
considering 3.73s
A friend of mine has some 3.73 gears but wanted to check here before I dropped any cash on them. My car is a stock 94 vert with a 4L60E. What kind of rpm will I see at highway speeds? Car is just a cruiser and I have no intention of modding the motor. I have the 3.07s now.
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Can't help with RPM's as I have a ZF6. But I can say I love my 3.73s. 
Team Owner
Joined: Sep 2003
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Simple math I believe should work without reference to any tire sizes, trans gear ratios or other information required by some of the on-line calculators. It would work for any direct ratio replacement from a "known" ratio in that particular car. Substitute the "known" where I've used 3.07 and multiply by any ratio of your choice.
XXXX/3.07=YYY.YYYY multiplied by 3.73 for the new RPM value. Drive your car in your usual manner and do the math for direct comparisons.
XXXX - any RPM value you choose YYY.YY the results
If you wanted to do some comparisons use this calculator with these:
GEAR RATIOS:
First: 3.06 (rounded up)
Second: 1.63 (rounded up)
Third: 1.00
Fourth: .70 (rounded up)
matching your tire size/diameter and inserting axle ratio where it requests final drive.
http://www.cargister.com/calculator-...l_ratio_teeths
Last edited by WVZR-1; Apr 19, 2015 at 09:27 AM.
Racer
Joined: Dec 2007
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Around 2400 at 70 rpm.
The calculator I use (is any) the formula is:
Gear ratio x trans ratio x 355 or 336 x mph / tire diameter = rpm.
355 is for an unlocked torque converter with stock stall speed.
336 is with the torque converter locked or a manual trans.
The rpm and mph above was calculated like this:
3.73 x .7 x 336 x 70 / 25.7 (an assumed tire diameter) = 2390 rpm rounded off.
I only use this because it can be used anywhere, no website required. It can be used for everything related- to see what rpm will be with different tires, different gears, different transmission, adjusting shift points, etc, etc, etc. I only need to remember one formula for all...
The calculator I use (is any) the formula is:
Gear ratio x trans ratio x 355 or 336 x mph / tire diameter = rpm.
355 is for an unlocked torque converter with stock stall speed.
336 is with the torque converter locked or a manual trans.
The rpm and mph above was calculated like this:
3.73 x .7 x 336 x 70 / 25.7 (an assumed tire diameter) = 2390 rpm rounded off.
I only use this because it can be used anywhere, no website required. It can be used for everything related- to see what rpm will be with different tires, different gears, different transmission, adjusting shift points, etc, etc, etc. I only need to remember one formula for all...
Team Owner
Joined: Sep 2003
Posts: 25,362
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Around 2400 at 70 rpm.
The calculator I use (is any) the formula is:
Gear ratio x trans ratio x 355 or 336 x mph / tire diameter = rpm.
355 is for an unlocked torque converter with stock stall speed.
336 is with the torque converter locked or a manual trans.
The rpm and mph above was calculated like this:
3.73 x .7 x 336 x 70 / 25.7 (an assumed tire diameter) = 2390 rpm rounded off.
I only use this because it can be used anywhere, no website required. It can be used for everything related- to see what rpm will be with different tires, different gears, different transmission, adjusting shift points, etc, etc, etc. I only need to remember one formula for all...
The calculator I use (is any) the formula is:
Gear ratio x trans ratio x 355 or 336 x mph / tire diameter = rpm.
355 is for an unlocked torque converter with stock stall speed.
336 is with the torque converter locked or a manual trans.
The rpm and mph above was calculated like this:
3.73 x .7 x 336 x 70 / 25.7 (an assumed tire diameter) = 2390 rpm rounded off.
I only use this because it can be used anywhere, no website required. It can be used for everything related- to see what rpm will be with different tires, different gears, different transmission, adjusting shift points, etc, etc, etc. I only need to remember one formula for all...
I've done the math several times before ever mentioning the calculator I did in my original post. If you use accurate tire dimensions and provide correct information that calculator "works". I don't ever post a "web-based" solution or comparison unless I've done and understand the math. Wouldn't think of it.
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Joined: Dec 2007
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I'm very familiar with the math and I generally "do the math". In the OP's post he's maybe only interested in a "quick reference" to his general driving habits so either "QCVette's" or mine is a very quick reference for the OP.
I've done the math several times before ever mentioning the calculator I did in my original post. If you use accurate tire dimensions and provide correct information that calculator "works". I don't ever post a "web-based" solution or comparison unless I've done and understand the math. Wouldn't think of it.
I've done the math several times before ever mentioning the calculator I did in my original post. If you use accurate tire dimensions and provide correct information that calculator "works". I don't ever post a "web-based" solution or comparison unless I've done and understand the math. Wouldn't think of it.
Thread Starter
Pro
Joined: Mar 2013
Posts: 697
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From: Huntington WV
Thanks for the input guys. Was just looking for a general reference. I have a complete 2.59 pumpkin with fairly low miles that I was going to stab the 3.73s into. If I don't like them I can always put the 3.07 unit back in.
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Joined: Dec 2007
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2.59 is series 2 size carries
3.07+ stock is series 3 size carrier