Guest Anonymous Posted December 9, 2002 Share Posted December 9, 2002 From what little I know, you have about two (2) 5 speed Z transmissions to choose from and a third one from a 1980 zx (unless you go to the L4 5 speed tranny which will work). For fast accelearation the 1977-79 "wide ratio" has lower 1st and 2nd gears. The 1981 to 83 "close ratio" has a higher 5th gear for mileage and higher 1st and second gearing The 81 to 83 Turbos were coupled to 3.90 diff...1985 200 SX turbos had 4.11 rear diffs.For highway use:R200 3.54 diff and 81-83 tranny. For autocross 4.11 200 SX diff and 77-79 tranny. For track: 81-83 zx diff and tranny.(my opinion) Quote Link to comment Share on other sites More sharing options...
Mike C Posted December 9, 2002 Share Posted December 9, 2002 There is also the T5 which has an overdrive close to the late 5 speed and a first gear the same as the early (240-260) 4 speed which is more than the late 4 speed which is the same as the early 5 speed. For the street, my choice would be the T5 and 3.54. Same for drag racing. For autcross or road racing and the turbo I would go with the 3.54 and the late 5 speed. For an NA motor, the T5 and 3.90. Actually, after thinking about it for a STRICTLY drag race vehicle I would run the early 4 speed with 3.90s or 4.10s as the early 4 speeds are much cheaper to replace than any of the 5 speeds if you break it, and for a drag car, who needs OD? Quote Link to comment Share on other sites More sharing options...
Brad-ManQ45 Posted December 9, 2002 Share Posted December 9, 2002 I have an '83 Turbo and it came w/a 3.54 Quote Link to comment Share on other sites More sharing options...
ianz Posted December 10, 2002 Author Share Posted December 10, 2002 Hey Everyone, I searched for posts on tranny/diff combos and didn't come up with anything...I have also put together a spreadsheet with the gear ratios from Z and ZX 5 speeds with different diff ratios and tire diameters... So the question is, what are your thoughts on ratio combos for street, autocross, and track use? since 3.36, 3.54, 3.7, 3.9, 4.11, 4.37, and 4.65 rears are available.... what’s a good top speed in each gear (1-4) for autocross and track use?? What’s a good 5 gear ratio for freeway driving?? I am prepping to build a turbo 240 street car in the 200 to 300 rwhp range so I have hp to spare for taller gearing which means less shiftin!! I was about to derive an equation correlating torque/hp to gearing given the extra hp but why reinvent the wheel if I don't have too... what do ya think? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.