Where to find 2nd Gen RX-7 5.12 diff gear

Doncan,
Here is the link to the 5.12 r+p
http://www.mazdatrix.com/getprice.asp?partnum=27-1100-1480
You will also need the long pinion from your 2nd gen, because the long pinion and the new 5.12 short pinion will be cut in half and welded back together to make the long nose 5.12 pinion .
While you have it apart, new bearings, disc's and seals.

Have fun, I know that I would not attempt this procedure.
 
Guys; thanks A LOT for all of your responses. :023: It's good to know I can count with your support and read the pro's and con's of the conversion. I think I won't have much problems at all if I make the mod because my RX-7 is normally aspirated and won't be making more than 210 hp to the wheels (much less the torque) and I never drag race it either, so it should hold on well. I think I will try the 4.875 set so I don't choke too much my car on the highway because it's still my daily driver. Also I'll be running 17 x 8 wheels with 235/45/17 Toyo RA-1 rubber. I just love how my 7'ven runs at the track and if everything goes up well, I'll be kicking some butt's this season. So if anybody out there has one in good condition and wish to sell it for a reasonable price, let me now to see what can be arranged. :cavallo:
 
Keep an eye out on RX7club.com - that's where I found mine. It was shipped yesterday via UPS Ground :026:

From an EP guy on that site...

Rear end for FC NA 5.12 gear.
Rear has about 6 events on it. EVERYTHING was new at that point, including bearings, gears and anything that moves. Competition LSD parts. It cost about $2000 to build this way, yours for $1200
 
Another option might be to use a shorter tire. That 17 inch with the 235 will look great, but is a pretty tall combination at about 25.3 inches. The stock tire was almost an inch shorter. If you had a way to run a 15x7 wheel with a 225/50, you could find a 4.30 diff/gear and have almost as much torque multiplication as with the 4.88. Another advantage of this setup would be that the whole car would be an inch closer to the ground without adjusting anything.

Just a different way to accomplish some of the same objectives. If you ended up with a set of 17's for the street, and a set of 15's for track days, it might not be cheaper(depending on the wheel choice)
 
Another option might be to use a shorter tire. That 17 inch with the 235 will look great, but is a pretty tall combination at about 25.3 inches. The stock tire was almost an inch shorter. If you had a way to run a 15x7 wheel with a 225/50, you could find a 4.30 diff/gear and have almost as much torque multiplication as with the 4.88. Another advantage of this setup would be that the whole car would be an inch closer to the ground without adjusting anything.

Just a different way to accomplish some of the same objectives. If you ended up with a set of 17's for the street, and a set of 15's for track days, it might not be cheaper(depending on the wheel choice)
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<span style="font-family:Times New Roman">Right now I have a set of 15x6 BBS wheels that came OEM in the RX-7 convertible that I bought as my primary option to use with the 225/50/15 RA-1 tires as you mentioned. I'm considering the 17x8 with the 235/45/17 for various reasons; because of the bigger contact patch needed to effectively turn and stop my rather heavy car (around 2,875 with me onboard) and because nowadays it's easier to find wider wheels and tires for autocross in 17''. But I'm very awared of the higher center of gravity issue and the heavier rotational mass the car will have to deal with. That's why I'm looking for the 4.88 or lower gear ratio among other things.</span>
 
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