Wow, finally I get to ask a 3rd gen. question of my own.

The 5-speed manual comes with a 4.10:1 differential gear set. The automatic comes with a 3.909:1. I know there are 4.33 gear sets available, and heard rumors of a 4.50, but are there any lower than 3.909 that anyone's heard of? I don't need more gear, I need less.

If anyone's seen a Japanese company with ring and pinion gear sets for the FD, let me know. I'm looking for a 3.70 range gear set, or possibly even lower. If I have to have one made, I will, but it'd be nice to find one ready to bolt in, for once.

Thanks!

 

y in the hell would you wanna do that?

 

The first time Jim asks a tech question.

 

when you have un-rotary-like torque, you need un-rotary-like gearing.

honestly Jim, i have searched for lower ratio gears too. one day i just thought "Whats the highest top speed possible for a street-driven FD?", and searched and searched for gears, but there were none that i found lower than auto-spec.

your best bet is to try and get a set costom made. or you could contact Racing Beat and ask what gears they used in their 240+ MPH FD.

 

no, by no means is it the first.

 

400 ft. lbs. of torque at 2,000 rpm...

 

Couldn't find any higher than 3.909, but if you ever feel like launching in 5th gear I found some 4.777's.

 

I've never heard of any gears for the FD lower than the auto's 3.9. (Which coincidentally I happen to have for sale if your interested.) If anyone would know about lower gears it would have to be Racing Beat, I'm sure there Bonneville car had at least a 3.9 if not some custom lower gear set.

 

Anyone else want a set of 2.91s, then?

 

nice.

how much is it costing you to get them custom made?? also, what do the cartest numbers look like with those gears??

 

Eh? Where'd you find 477's? I had two sets made about 5 years ago. I think Troy Wilson has a set on a shelf and I haven't the slightest idea who ended up with the other set. Someone else is selling them now? I don't have a set for myself is why I'm asking.

Jim if you need info on a place to manufacture the ring and pinion let me know. You can even select materials etc.

Kevin T. Wyum

P.S. You making some headlights then? I need some that have room for the air filters underneath.

 

RP sells 4.777 gears.

Click here

 

Ouch over $700? I don't think it cost me that much to make unique ones, not intended for sale.

 

Kevin, send me any information you have, if you would. jimlab@earthlink.net

I talked briefly with Mark Williams Enterprises, but I haven't settled on a manufacturer yet.

Yep, me too.

 

I don't have the spreadsheet with me, but I'll post numbers when I get back home tonight.

 

The 4.77's I found are on Amemiya's site.

 

I know this is not helping jimlab, but does anyone know the difference between the 4.30 and 4.33 gears available? Are both factory options or is one aftermarket? I've seen both of these listed at various Rx7 web sites...

 

hey, kevin, arn't you the one that started A-S-P a while back????

 

Scoot in Japan makes a gear for the FD... they used it on their 200mph+ Street car... might want to try and contact Scoot of Japan...

 

Jim

Awhile back I was talking to Bryan at rotorsportsracing.com and he said they have a jig or something to set up second gen ring and pinions in thrid gen housings. He seemed to indicate there was no limit to what he could put in there. You may want to contact him and see what he could do for you.

Steve Bertok

 

I searched but didn't see any posts describing your setup or a dyno sheet. You'll have to excuse me for being new, but what do you have?

 

5 times the displacement of a 13B-REW and 8 more pistons...

 

OMG!!! My hero. Welcome to the forum Kevin. Where the hell have you been? Did you get another FD and get rid of that Audi???

 

Oh and Rotary Performance sells 4.777 for around $800.00.

 

0-60 mph (seconds):
2.80 - 3.15
2.91 - 3.04
3.00 - 2.96
3.33 - 3.33
3.45 - 3.35
3.70 - 3.38
3.89 - 3.36
4.11 - 3.25

0-100 mph (seconds):
2.80 - 7.38
2.91 - 7.37
3.00 - 7.31
3.33 - 7.24
3.45 - 7.22
3.70 - 7.10
3.89 - 7.01
4.11 - 6.94

Quarter mile (seconds, mph):
2.80 - 11.30 @ 137.03
2.91 - 11.26 @ 137.63
3.00 - 11.22 @ 137.98
3.33 - 11.16 @ 132.86
3.45 - 11.18 @ 133.15
3.70 - 11.19 @ 134.52
3.89 - 11.18 @ 135.82
4.11 - 11.18 @ 135.71

0-200 mph (seconds):
2.80 - 27.09
2.91 - 28.16
3.00 - 27.88
3.33 - 27.16
3.45 - 27.23
3.70 - 28.53
3.89 - 28.08
4.11 - 27.73

Top Speed (mph, drag limited):
2.80 - 234.29
2.91 - 232.95
3.00 - 231.89
3.33 - 234.09
3.45 - 234.74
3.70 - 233.47
3.89 - 231.74
4.11 - 230.04

40-70 mph (seconds):
2.80 - 1.91
2.91 - 1.82
3.00 - 1.75
3.33 - 1.56
3.45 - 1.51
3.70 - 1.43
3.89 - 2.21
4.11 - 2.05

40-100 mph (seconds):
2.80 - 4.01
2.91 - 4.64
3.00 - 4.59
3.33 - 4.61
3.45 - 4.61
3.70 - 4.56
3.89 - 4.35
4.11 - 4.15

70-140 mph (seconds):
2.80 - 7.12
2.91 - 7.07
3.00 - 7.69
3.33 - 7.52
3.45 - 7.37
3.70 - 7.12
3.89 - 7.22
4.11 - 7.92