Guest Anonymous Posted April 21, 2002 Share Posted April 21, 2002 K guys, I finally opened-up the R200 that's been sitting on my garage floor for 5 months. These are the numbers off the ring gear: J H 39:10 J U 3 4 26 Written on the ring gear with a marker(?) was 371 O It's out of an '84 ZX turbo. Not sure of the year. My guess is it's a 3.90:1 ratio? Am I right? Thanks. Jon Quote Link to comment Share on other sites More sharing options...
fl327 Posted April 22, 2002 Share Posted April 22, 2002 hey jon are you doing a cv conversion to your lil monster there? i always thought non-turbos zx's had 3.90s and the turbos had 3.54-3.70's? Quote Link to comment Share on other sites More sharing options...
Mike C Posted April 22, 2002 Share Posted April 22, 2002 I would concur. 39/10=3.90 I'm going to get a 3.90 diff from a ZX and the limited slip from Reider Racing if they ever come in... Quote Link to comment Share on other sites More sharing options...
Modern Motorsports Ltd Posted April 22, 2002 Share Posted April 22, 2002 "My guess is it's a 3.90:1 ratio? Am I right?" Yup:) Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted April 22, 2002 Share Posted April 22, 2002 I'm not sure if the car that this came out of had CVs or not... are you guys telling me I gotta do CVs with this rear end? It does have a 2" pilot flange that I'll have to change out. On another note, I'd much rather have something around 3.50 (3.80 on the high end) or so... I just don't wanna be reving that high all the time. Anyone wanna trade? Jon Quote Link to comment Share on other sites More sharing options...
fl327 Posted April 22, 2002 Share Posted April 22, 2002 man i can just bearly tell and r200 from r180, but i think 3.90s would be good gears for your car, you do have an overdrive trans. i didnt think after 83 r200s used halfshafts anymore, could be wrong, i was already wrong once, but i thought the whole of diffs went cv when the 300zxs came out? Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted April 22, 2002 Share Posted April 22, 2002 Len, I saw the car it came out of. It was a 2nd gen... It had a weird mount- a mount that had single bolt mount in the back that bolted to the chassis. Anyway, if I wanna drive the Z to LA, 3.90 would be extrreme, no? Hell, maybe I outta just face the music and build me a race car! jon Quote Link to comment Share on other sites More sharing options...
Guest greimann Posted April 22, 2002 Share Posted April 22, 2002 Another sure way to determine the ratio is to count the number of teeth on the ring and divide by the number of teeth on the pinion. ie, 39 teeth ring / 10 teeth pinion = 3.9 ratio Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted April 22, 2002 Share Posted April 22, 2002 counted teeth (Thanks greimann)... 39 on the ring. I coundn't get to the pinion but curcumstantial evidence points to a 3.90 ratio. Anyone wanna trade for a 3.70? Or 3.50ish? Jon Quote Link to comment Share on other sites More sharing options...
fl327 Posted April 22, 2002 Share Posted April 22, 2002 jumbo-you came to race right? that 3.90 would be great in your setup i think, dont you already hav e a nice deep overdrive? im stuck with 3.54 or else i would not dare drive on the freeway, its buzzy as is. yeah the zx's do have a weird mount, i think its stronger though, it uses all four of those mounting holes whereas the z series only uses two of them. mounting from up top seems to be better because the diff wants to hit the tunnel of the car and the mount goes with that motion better. the rear mount looks tougher too... Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted April 22, 2002 Share Posted April 22, 2002 Yeah, I guess 3.90s would scream. Fairlady, why are you stuck with the 3.54s? 4-speed? Quote Link to comment Share on other sites More sharing options...
johnc Posted April 22, 2002 Share Posted April 22, 2002 All Nissan ring gears have this "39:10" (or a similar) notation indicating what ring and pinion ratio is in the car. Just divide the bigger number by the smaller number and you have the ratio. Quote Link to comment Share on other sites More sharing options...
Hybrid240z Posted April 22, 2002 Share Posted April 22, 2002 Hi Jon, I have 78 5-speed with a 4.11 diff on my 71 240Z. It is fast and very streetable. It runs 70mph at a little over 3000rpm. Not too bad. I was wondering if anyone knows if it is possible to swap the 5th gear from a 83 5-speed(non-turbo) and swap it into my 78 5-speed. That would give me better highway fuel efficiency and better top end speed. Don't get me wrong, my Z can still make it up to 130mph with this gearing. I took it up to 115mph this weekend and the previous owner had taken it up to 130mph before. I want to keep my lower gears and just change the fifth gear from the 0.864 it has to the 0.745. This would be perfect. If this is not possible does anyone know who makes aftermarket gears that I can drop in. Marcos Quote Link to comment Share on other sites More sharing options...
fl327 Posted April 22, 2002 Share Posted April 22, 2002 i guess i could stick more gear back there, 3.54 isnt giving me issues though, i would like to use that 3.70 posi rear setup one day. i am gettin tired of always being in fourth on the street too, but i dont get tired of bangin the crap out of the four speed box-theres something so evil about it, the clicking and the notchy feel to it, feels real mean real nastylike. imma go t5 so i can take longer trips once i can afford to do the swap right, and yes it might involve a jtr pushback ok already Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted April 23, 2002 Share Posted April 23, 2002 This may be a dumb question. Why can't you just flip the '72 mustashe bar around and run that? I haven't looked at it very closely but the ends would be facing towards the back and maybe give you the extra clearance? I don't know. I'm just cheap that way. Jon Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted April 23, 2002 Share Posted April 23, 2002 BTW, LT1240Zmech, thanks for the info. I had a 3.80ish rear in my mustang 8" and C4 trans. I think I was at 3K at 55 mph during the gas shortage days (1977-78?). Maybe the 5 speed will knock that down to 2K at 65mph? Anyway, thanks. I'll let you guys know how it runs. Jon Quote Link to comment Share on other sites More sharing options...
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