Just wondering what rear end to go with....I have a old ford 9 inch just sitting there but Idk if thatll be too heavy for just autoX hopefully someone could help me out... Thanks
-eddie

 

What class are you planning to run the car in?

 

Give us some info on the power plant. Personally, I think a 9" is absolutely unnecessary , and likely a large hindrance, for any Autox usage. I say stick with 1st gen Rx-7 axles w/ a LSD. They're lighter than most other axles, while still offering moderate strength for most 2 rotor NA apps, disc brakes, LSD's... The biggest axle ide consider goin would be a Ford 8.8, and even then it would be heavy and overkill for autoX in the Rx-3, unless you also drag race with boost and slicks in the same car

 

find out what the tripoint RX3 is running and do that

 

Well I just got a slightly modded t2 motor it. So I'm not pushing massive power, and I have a sp LSD . and I hear of a bunch of people breaking Mazda rear ends with stock t2 motors
-eddie

 

That's because of nasty pinion angle change from junk geometry, not because the axle itself is weak.

Fix the geometry, handle more power.