[1970_240z]

which gear ratios will work better? accelleration and cruising RPM's are both a concern. this will be for a 240Z turbo. anyone have experience with both?

 

[yo2001]

78 5 speed trans dirves in higher rpm then 81zx 5speed on the top gear because 81 has better overdrives(taller?)

 

[Loosetoe]

If these two alone are your only choices, then I'd use the Z 5-speed rather than the ZX. The Zx gearing is too high for the 3.7 IMO and will give you less off the line power.

Have you considered the BW T5. It would mate much better with your 3.7

I have the 3.7 LSD in my 3.1L 240, but I have an older NISMO transmission which has some strange gearing.....

Nissan Motorsports 5 speed transmission
1st – 3.592
2nd – 2.246
3rd – 1.415
4th – 1.000
5th - .864

R200 Differential
3.7 clutch pack LSD – standard aluminum cover fitted
Final drive #s
1st – 13.29
2nd – 8.31
3rd – 5.24
4th – 3.7
5th – 3.108


I'd do the BW if this transmission was not available to me.....just my .02

 

[eboling1]

There will always be a tradeoff between accelleration and economy with the Z transmissions. If you have a 3.36 or 3.54 rear then you definitely want the early 280zx 5-speed with the 3.21:1 first gear or a T-5 with the 3.5:1 first gear. If you've got a 3.7 or 3.9 rear then using the early 280zx 5-speed will result in fairly high rpms at cruise, but awesome accelleration. The T-5 has the best all-round ratios with good accel and a good overdrive. If you've got a 84-89 300zx trans lying around then you can swap the overdrive gears from that into the early 280zx 5-speed and get a really good overdrive, like around 70mph at 2750rpm. The overdrive gear is the only gear in the z trans that will swap as the 1st-4th gears are a one piece unit on the countershaft side.