cj9694

so I have fond some internet posts that say the RX8 R&P might work in out diffs. Or at least that the ring is 7". I'm in the hunt for 4.44 gears and wondered if anyone has expereance with this?

damir130

AFAIK the ring gear in RX8s is 8 inch diameter, not 7. Your best bet is a Kia Sportage donor from a specific region (most regions received the 4.77).

Savington

iTrader: (31)

Not likely. The Rx8 shares a R&P with the FD, so it's almost certainly an 8" and not a 7".

4.778 7" Kia Sportage gears are virtually impossible to find in a junkyard, but they can be had brand new for <$300.

Madjak

Mazda 7" 4.44 Ring and pinion can be found in early mazda 4x4 or ford courier front diffs. 1989 - 1995 from memory. Not sure if they were ever sold in the US or what they were called.

bbundy

I don't know what junk yards you're looking in but I have easily found them. I've bought 2 at $50 for the whole pumpkin.

wow now I look and they are all gone on car-part.com. somebody must be buying them all up.

Savington

iTrader: (31)

I looked briefly in ~2013 when I was building my 4.77 OSG for PTE and had no luck. They were also so cheap brand new that it was hard to justify taking a risk on used gears (already spending ~$300 on setup, not to mention the $1600 diff).

bbundy

I'm one of the guys that found a 3.636 in a junk yard from a 1985 626 as well. I can't remember how many years I used that. Its been through a lot of transmissions and after blowing up the Quaife transmission gear set for the second time its back in the car now with another 6 speed.

Lexzar

iTrader: (2)

So our main option for lowering the gear ratio is street cars is still the 3.636? NO magic sauce?

Savington

iTrader: (31)

The inevitable T5 conversion will negate the need for anything lower than a 3.63

Lexzar

iTrader: (2)

Thought those were only rated at 300ft/lbs?

bbundy

for me 3.636 with the six speed only if your primary use is Autocross and street.

I used the 4.778 with the Quaife Wide. this makes second gear about the same as the 3.636 six peed actually a bit faster

For track purposes only Id probly run a 3.909 with the six speed and a 4.30 with the Quaife. Neaither of those transmissions has proven to be bullet proof reliable however with over 300ft-lbs of torque but the gear ratios are not bad.

Savington

iTrader: (31)

+1, Acamas has a 6sp/3.63s and Rover runs 6sp/3.909s. 3.63s aren't faster on track until you're making ~375whp.

Midtenn

iTrader: (15)

The 6 Speed with a 3.909 is basically a 5 speed with a 4.77, but with a nice overdrive for cruising.

Savington

iTrader: (31)

Or a racing overdrive for turbo cars

nbfather

Sexy Dirty Talk!


There is going to be quite a few dog box Miatas running around with a gazillion horsepower!

Trying real hard not to phone you every 5 minutes!!

Scaxx

They are, but they were also in cars that had at least another 1000lb on them. I would have used one behind my engine if I hadn't gone with an ls3, they're way lighter than the t56 which is like 130lb. But there's plenty of high 300, low 400hp 302 miatas running around. How many of them are tracked I couldn't tell you, but t5s can also be rebuilt and bought used for nothing.

Savington

iTrader: (31)

~260-310ft.lbs depending on which box you use, which will be enough for most people. If you need more, you can buy inexpensive gearsets and case upgrades that push that torque cap up to nearly 600ft.lbs.