Uh.. lately I have been thinking.. since after I finish my mods, I will have about 270 h/p, and about 340-ish torque, will I need a new rear-end? I have a 3:23 limited slip right now. How much power will the stock one hold? Will I be ok w/ out a Posi? Now I am talking about BARE MINIMUM's here.. I dont want to hear "well, ya really should cuz they are BETTER.." I want to hear if i ABSOLUTELY NEED TO, as my budget is ULTRA tite.
Thanx a bunch guys,
Matt

 

Run what you have until it breaks then consider something stronger. With a few modifications, the diff can easily survive over 500 hp but the weak link will always be the tiny ring and pinion.

 

How long will my stock rear-end survive w/ the levels I expect to have? What kind of rear-end should I look at buying later-on? I have heard something about Zexel Torsens..??

 

Get a rear end cover with some sort of support on it for the end caps

 

Limited Slip = Posi

With the power levels you will be putting down, you will deserve some kind of reward if you manage to actually break the gears themselves. They are made of very strong hardened steel.

If you are still using the factory posi carrier, then that will most likely be the first thing you break (your chances are greater since you have a manual - the clutch shocks the driveline more than a converter does).

I say run it till you break it, then pick up an Eaton or Auburn Pro Series posi, along with a nice set of 4.10s. An aluminum diff. cover (Summit or Jegs for under $150) will help hold off that breakage for a while longer, as it will keep the housing from flexing under load.

- Justin

 

and since it is an 85 that means its got the aussie 9 bolt right? The power youre going to be making isnt much more then an L98 would and they put the same rears behind them. You wont break it unless youre stupid with it. One of the things that will break it is if youre breaking the tires loose and get really bad tire shake.

 

Well, I meant an open differential.. it usually does one-tire-fires, but occasionaly will do 2-wheel peels.

Yes, it has a 9-bolt.

So pretty much I can't burnout in it, or else risk breaking it? What is tire-shake?

And aren't I correct in thinking that the L98's came with a Posi?

In order for me to make my rear-end stronger.. all I need is a carrier? Or will a stronger girdle be fine?

 

And if the Girdle is all I need.. how about this one?
http://www.slponline.com/view_product.asp?P=65004

 

Nope, that's only for the 10 bolt rear. Only some of the thirdgens used the 9bolt, and there isn't a very big aftermarket for them. Most thirdgens, and all fourth gens used the 7.5 (or 7.625) 10 bolt rear. I would suggest doing a search on TGO for 9bolt info, unless there is anyone here that knows where to get parts for them.

Otherwise I would say go to a yard and buy a rear out of a z28 or trans am....they are usually only about $50.

- Justin

 

Oops.. sorry for the stupid link, lol.. I clicked that under the 1983-1993 section.. I dunno why that 4th gen is in there..

I have a Z28.. what year Z28 or Trans Am should I look for?