racing rear end gears.. need info from pros
 

Hello .. my 84 gslse's ring and pinion teeth were broke off when i was racing last week .. my car has a 4.076 rear end gear stock and i was wandering since i have to buy a new ring and pinion if i should get a 4.078 , 4.444 or a 4.875 rear end ... the 4.875 rear end would be realy high gears and accelerate fast but would it be to much of a acceleration where my top speed will be 80 or some thing.. i autocross and drive my car a couple times a week..
thanks in advance for the advice

Since you auto-x, I'd check the rule book to see where changing rear-end gears will put you. If going to a different ratio would put you somewhere where you wouldn't be competative then I'd suggest against it. If, you're already in a class (or ok with going to a class) that allows the swap, then 4.444's might be a good choice. There's a guy in the local area with a MG midgit w/ a half-bridge 13B w/ 4.444 rears, and it really is noticeable off the line. Also, with the stock 4.076 ratio my -SE holds 70MPH @~3200RPM, the 4.444's would move that into the 4000RPM range. Not too much of a loss I don't think.

Just my 2 yen,

matt

Yeah the 4.44 is a good compramise. You won't lose to much top end but you will gain low end acceleration. Some people will tell you that the 4.44 is too much. I think it is perfect for the street. A buddy of mine got a 4.11 and wish he would have gotten a 4.44.

Good luck,
Mike

I went from a 3.9 to a 4.44 and the difference in acceleration is very noticeable.:D IMO 4.44:1 is the best compromise ratio for street driving/track use.

Rear end gears
 

Personally, I would go with 4.88 gears. This would give you the best accelleration without going to the weaker 5.13 gears. 4.44 performance is just too moderate for the cost. And, the 4.88 gears only cost $250 through Mazda Comp. Since it's a "competition" part, no Team Support Program membership is required to order them.

If you need to figure out your new gearing as it relates rpm to speed, I have an Excel spreadsheet to calculate all of that (see attachment).
--
Blake Qualley
Rotary Engine Illustrated

Excel Spreadsheet
 

Sorry, the attachement didn't go through. I'll try again. If it still doesn't go through, shoot me an email if you want a copy....