experiences with final drive ratio
#23
I like the 4.1 but i sometimes miss the torque feeling the 4.3 gave me sub 2K rpm. I think i am still about the same speed from point to point so there is a minimal acceleration loss just a little bit of loss in crispness. Fwiw spinning it around in 3rd on a 4.1 and not worrying about it breacking is priceless. Gotta love those low speed corners with plenty of straight away run out.
#25
For example: A 4.1 rear would cruise at 80 mph at 3700 rpm(guessing), a 3.9 rearend would cruise at 80 mph at 3300 rpm.
You get more use out of your gears due to this. 1st gear becomes much more usuable.
I'm going from 4.3 to 4.1 with my torsen swap and i'm really excited about it.
#27
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The number is the first half of a ratio representing the number of turns of the propshaft relative to the number of turns of the wheel. The second half of the ratio, unless specified, is assumed to be 1. So on a '92 Miata with a 4.3:1 R&P ratio, for every 4.3 turns of the propshaft the wheels will turn once. The larger this ratio, the greater the mechanical advantage through the diff. For those people familiar with NASCAR, at Bristol they run a very high R&P ratio because they need maximum acceleration out of the turns whereas top speed is relatively low. At Daytona they use a lower R&P ratio as they need a much higher top speed, and spend much less time braking and then accelerating.
So all else being equal, a larger number on the R&P will give the car better acceleration, at the expense of higher RPMs and a lower top speed in any gear. A lower R&P number will give you lower RPMs and a higher top speed in gear, but reduce the effective amount of torque available at the wheels.
One way to visualize it is to think of yourself removing a lug nut with a breaker bar. If you have a very long bar then the nut is easier to twist, however you must move the wrench further through space to turn the nut.
#28
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no, all 94-97 have a 4.10:1 r&p
99+ 5 spd is 4.30:1
00+ auto is 4.10:1
6 speed is 3.90:1, but certain euro 6 spds are 3.636:1
The lower the ratio, the higher top speed the car will have, but will sacrifice acceleration. The higher the ratio, is the opposite: lower top speed but quicker acceleration.
99+ 5 spd is 4.30:1
00+ auto is 4.10:1
6 speed is 3.90:1, but certain euro 6 spds are 3.636:1
The lower the ratio, the higher top speed the car will have, but will sacrifice acceleration. The higher the ratio, is the opposite: lower top speed but quicker acceleration.
#32
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I run a 3.90 with the 1.6 5 speed. It is much better than the original 4.30, first gear is useable. I do a lot of highway driving though, I wanted to keep the revs as low as possible w/o opening up the case, so I got a 6 speed torsen.
#34
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I went with a 4.10 for the Torsen in my '92. I can still spin the tires (T1S) in first gear, they break loose at around 4,000RPM. This isn't a big change- only 4.6%. I did not change the speedo gear, and according to my GPS receiver my speedo is now less inaccurate than it was before.
My speedo seems off though...the 4.30 would tap the revlimiter in second at 62...now it only reads 60 when it should register around idk? 64-65?