stock gear ratio
 

anyone got a good way to figure out what gear ratio my 88 vert came with?

A good way to figure that out would be by searching.

To answer your question it came with 3.90.

4.1 unless it's an automatic, which would be the 3.9. 89-91 GTUs came with 4.3

S4 would be a 3.90

Unless someone changed the diiff:
'88 Vert-3.90 whether a 5 speed or auto.
'89-'91 Vert-4.10 whether 5 speed or auto.

RX-7 Stock Rear Axle Ratios

Year / Model Ratio
79-82 3.909
83-84 12A 3.933
84-85 13B GSLSE 4.076
85 12A 3.909
86-88 5-spd All 4.10
86-88 Automatic 3.909
89-92 Turbo 4.10
89-92 non-turbo, non LSD 4.10
89-90 non-turbo, viscous LSD, "GTUs" only 4.30
93-95 w/manual trans 4.10
93-95 w/automatic trans 3.909

Where are you getting your info? Every thing I've read and every 2nd gen I've come across (and that's a shit load) has had 4.1 for ALL MANUALS and only automatics had the 3.9.

~Mike...............

Checked my FSM (88 FSM on the net, see sig.), and it too shows 4.1 manual, 3.9 auto. I was looking for the sticky or archive that had this info to confirm. Is that where the info above is from? Not sure where the other guys are getting the info from.

I was told that 88 verts had 3.9 a while back. I did some searching and found this:
https://www.rx7club.com/showthread.p...ble+gear+ratio

didnt all verts came in as auto in the US version?? Maybe thats why its listed as a 3.9
Not sure though.

NO! All verts in the US spec. came as Naturally-Aspirated, ie non-Turbo.

There were Automatics and there were 5-Speed manuals both sold. Axle ratio depends on the year and equipment. All Verts were also open diffs, no LSD's spec'd. There are rumors that some verts had LSD's that were simply put in during assembly as the factory used up the available parts stock. That is unlikely, but not impossible...

Straight from the showroom catalogs.

I am holding the original 88 brochure in my hand right now. It says:

M-5 Convertible
1 - 3.475
2 - 2.002
3 - 1.366
4 - 1.000
5 - 0.711
R - 3.493
Final - 3.909

However, there is no telling what is in the car 21 years later if you do not know its history.

why would they put a taller gear in a heavy ass car lol.
Must save some gas on the highway, though the weight is holding that back.