Hey guys

I had a few questions about my possibly purchasing a 92 Z28 5 Speed and was pointed here for a few questions that I had.

Firstly, can someone explain to me what a Limited Slip Differential is (sorry to sound like a newb... i am lol)?

Secondly, I keep hearing the term One Wheel Wonder; aka leaves only one tread mark on a peel out. Is that a problem with this particular year??

Original discussion link: https://www.thirdgen.org/forums/tech...amaro-z28.html

Thanks for all of your help!!

 

You've heard the term "Posi" or "Positraction" right? That's GM's name for a limited slip differential (LSD). Other Companies have their own names as well.

I have a loose understanding of the actual mechanical pieces and gears that do this, but I can give you basic rundown.

Our cars come with either open or LSD rear ends, depending on model, options, years, etc. etc. When going around a turn, we can agree that the outter wheel has to turn faster than the inner wheel, right? In an open rear, one wheel is allowed to slip, so very little power is going to it. This allows for a smooth turn with the two wheels at different speeds. Problem is when you want a hard launch, you often get power to only ONE wheel, which can't hold traction, and you get a "one legger" or "one wheel wonder". There's nothing "wrong" with this, but it's just not a performance option.

Limited slip rears keep power going to both wheels, but they do allow a "limited" amount of slip to allow for different wheel speeds around turns, etc. etc. They are MUCH better at keeping power going to both wheels for hard launches.

Lockers, which are aftermarket 4wd or race rears are either totally open or totally locked. GREAT for traction to both wheels for 4 wheeling or drag launches. BAD for smooth turns and street driving. You'll actually have the wheel chirping around turns as it locks and unlocks itself.

 

Thank you very much for the rundown on that! You explained that very well. I was wondering why GM would ever do such a thing but that makes sense, in terms of ride quality. If the car does not come with that, is that something that can be added?

From what I am understanding from the other forum, the G92 comes with that and as long as it has the RPO N10 (dual system exhaust) with the dual cats, then it should be already installed and with the higher hp to boot.

You guys are all awesome!

 

The G92 is definitely a performance option, and I'd bet lunch you couldn't get it without the performace "posi" rear. Why would you want the lower end, right?

....that being said, G92 or not, I'd bet Any 91-92 Z28 would have a LSD "posi" rear end. That's not fact, just saying I'm pretty sure. Could be wrong.

As for what can be done to change from open to LSD? You can "buy" a new differential, but our cars came with the relatively weak 7.5" GM 10 bolt rear, or the stronger, but still relatively small 7.65" Borg Warner 9 bolt rear. (Pretty sure no 91/92 cars got the 9 bolt). For daily driver/sunday driver purposes, it'd actually be cheaper to find a used 9 bolt rear with a posi and whatever gear you wanted. There's always 2 or 3 floating around the classifieds. I replaced my 2.77 posi rear with a 3.27 posi rear for $250 bucks. Cheaper than a brand new posi unit, and for my purposes, it was cheaper than buying a new gear set. For performance applications, you'd be better off upgrading the whole rear to an aftermarket part. That can get pricey, but it'd be WAY stronger than any part you can buy for a 9 or 10 bolt.

What's your goal for this car? Is this your only car? First car? Is this a toy? Sunday driver? Project car?

 

Well, not exactly a project car and no, neither my first nor my only. I guess to over simplify, I would say that it will be my summer toy. lol. There is something about Camaros that really just rev my motor. This would be my second after my 88 IROC-Z 5 speed that had to be sold a couple years ago due to pricy repairs.