TurboBuicks.com - View Single Post - Viper Differential Install Into '93 RX-7

Orlando_87GN · 02-10-2007, 08:17 AM

I thought by making this thread it would motivate me to actually get this done! As some of you know the Mazda RX-7's came with a pretty undesirable rear end gear ratio for us LC2 lovers. The absolute tallest gear possible for the RX-7 is a 3.90 ratio which came in automatic transmission cars. The rear ratio I am currently using is actually 4.10 which came in a standard transmission. Needless to say this gearing isn't optimal for the Buick engine. At the track the gearing is so short I am shifting into OD before the 1/8th mile.

. While the car runs out OK (128mph) it's not optimal and it can do much better.

Time for a different solution. I purchased a Viper 3.08 pumpkin off eBay a few years ago. It's a Dana44 and will probably be indestructible for my application. The 3.08 gears will be perfect for the light car and short tires. I will modify the stub axles on it to accept CV axles and fabricate a way to mount it properly in the Mazda sub frame. The only work that I have done so far is I have removed the rear (thanks Scottie) and started measuring/planning my options. This weekend I am going to start breaking down the CV's, taking measurements to determine what axles I am going to use. I am hoping to use the CV's from a TurboII car which already have a 4 bolt flange pattern on them.

Here are a few pictures of 'the beginning'.

02-10-2007, 08:17 AM	#1 (permalink)
Orlando_87GN Resident Idiot Join Date: Sep 2000 Location: Orlando, FL USA Posts: 11,442	Viper Differential Install Into '93 RX-7 I thought by making this thread it would motivate me to actually get this done! As some of you know the Mazda RX-7's came with a pretty undesirable rear end gear ratio for us LC2 lovers. The absolute tallest gear possible for the RX-7 is a 3.90 ratio which came in automatic transmission cars. The rear ratio I am currently using is actually 4.10 which came in a standard transmission. Needless to say this gearing isn't optimal for the Buick engine. At the track the gearing is so short I am shifting into OD before the 1/8th mile. . While the car runs out OK (128mph) it's not optimal and it can do much better. Time for a different solution. I purchased a Viper 3.08 pumpkin off eBay a few years ago. It's a Dana44 and will probably be indestructible for my application. The 3.08 gears will be perfect for the light car and short tires. I will modify the stub axles on it to accept CV axles and fabricate a way to mount it properly in the Mazda sub frame. The only work that I have done so far is I have removed the rear (thanks Scottie) and started measuring/planning my options. This weekend I am going to start breaking down the CV's, taking measurements to determine what axles I am going to use. I am hoping to use the CV's from a TurboII car which already have a 4 bolt flange pattern on them. Here are a few pictures of 'the beginning'. Attached Thumbnails __________________ Check Out MikesStuff4Sale.com to view my used parts! ------------------------------------------------ 1987 Buick Grand National Budget 4.1, 204/214 cam, TA-49 Turbo, Stockish Heads, V4, MSD50's, TH DP, JayJackson 62mm TB, Translator plus Extender powered. 3680# with pilot ------------------------------------------------ 1993 Mazda RX-7 4.1 Buick Powered 11.20 @ 128mph (2.4 60')!