What are the gear ratios and rear end on a 91 convertible RX7 (manual transmission) and on a 88 Anniversary turbo RX7 (manual transmission). I had thought the rear end on the vert was 4.1, but I recently read somewhere that they went back to a 3.9 for 1991. What is correct?

thanks,
Kris

 

1991 'Vert
Ratios --------1st----- 2nd--- 3rd------4th-----5th--- reverse
5-Speed ---3.475--- 2.002 -1.366--1.00-- 0.697-----3.493

Final Drive 4.100 (manual) and 3.909 (automatic & convertibles)


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88 AE
Ratios --- 3.483----- 2.015--- 1.391--- 1.00-- 0.762 --------3.288
Gear ------1-----------2----------3-------4---------5----------R----

Final Drive 4.100

 

Correction: all of the auto coupes had a 3.9 rear. All of the auto verts had a 4.1.

 

But the manual transmission vert also had a 4.1 differential?

 

Yes. Mazda put the 4.1 on the auto vert to make up for the extra weight of the vert, so acceleration wasnt affected as much ofer the 5 speed.

 

The 88 brochure lists a 3.909 for all convertibles of that year. The 89 FSM lists a 4.1 for all convertibles of that year. I don't have any stats on the 91 models. Since a previous owner could have installed just about anything, I guess the best way to find out is to take the rear end apart, and count the teeth on the gears. You could also calculate the speed with different rear end ratios, and then see which is closest to your actual speed at a given rpm and gear.

 

All the 88 and 91 'verts got the 3.9 rear end.

And I also have notes that say (and confirm) that the 5 speed manual vert's got a .711 5th gear, not the .697 that the coupes got.