99c5vert

I keep reading they are "weak". How weak are they? My car is 1650 lbs, 375 rwhp. If I go this route, i will put Z06 wheels with slicks on. I don't want to waste my time if it's gonna granade on me. But it seems to have everything I need... (if you can confirm these)
Width 64.7
torsen diff (does anybody know what torque bias?)

Given the weight of my car, what are your thoughts? Ford 9" is always a safe bet (I already bought a used one), but if the 4th gen rear does the job, I can sell the ford rear and spend the money elsewhere.

Thanks.

'JustDreamin'

They're not all that stout.

They've got a 7.625" ring gear (vs the 9" Ford, 8.5" of the big 10-bolt, or 8.875" ring gear of the 12-bolt). The axles aren't all that big in diameter either.

It seems to be hit or miss as to whether they hold up. Some guys go 10's in heavy f-bodys on the stock rear with a manual transmission. Some guys blow up rears with stock auto powered f-bodys running low 14's. It seems to be hit or miss.

A couple of big factors:
How much traction will you really have?
Slicks for drag racing or roundy roundy racing?
Suspension set up for drag or road course?
Weight transfer?
How often will you beat on it?
What do you feel an acceptable failure rate is?
What kind of transmission? (sticks are harder on rears than autos)


Personally, I broke the 7.625" 10-bolt that's in my '93 Z28 (LT1 / 6 speed car, might be making 350hp). Broke it out on the street. Took 2 teeth off of the pinion (case was fine). Was hard on the gas in 2nd and went over a 1" drop in pavement (I'm guessing from frost heave or something) and it went BANG but kept right on diggin' (was trying to avoid being run over by an oncoming dumptruck). She made a funny ding ding ding noise as I coasted up to the next stoplight. Thought to myself "that didn't sound good". Drove it for 2 more days before the noise got to be bad enough that I knew I had to take it apart (started growling).

Your application is a tough call. It is a nice lightweight car. You're likely to have trouble getting enough traction to break it. But its still a hit or miss rearend.

'JustDreamin'

99c5vert

slicks for autox, not drag racing.

I generally don't dump the clutch - i'd have to roll into it even with big sticky tires (right now on 225 tires, starting in 2nd gear at 1500 rpm, there is no traction)

It's a 6 speed

Suspension setup is 4 link with panhard rod.

I put about 5000 miles a year on the car max... mostly cruising and autox.

Everything about it is just right for me, the width, bolt pattern, torsen... I'd just have to weld brackets and drop it in... and they can be had for very few $$$.

'JustDreamin'

My personal opinion is that it'd live ok in your application, but I'm no expert.

With autocross slicks (not wrinklewall drag slicks) and the general lack of traction, I think it'd be ok. And with 2nd gear starts and no clutch dumps, you are reducing the peak torque the rear would see and also a fair chunk of the shock loading.

I still think you run the risk of ultimately breaking it and that risk is higher than if you were running a 9" Ford or a Dana 60, but everything man can build can be broken (sometimes you just gotta try harder).


For the money, I'd say run the 7.625" 10-bolt. To set up the 9" Ford with the parts & pieces you need (probably needs to be narrowed, new axles, Torsen or TruTrac, gears, bearings, rear disks, etc) you're looking at a fair bit of money. I'd guess you'd probably start at $750 for just a TruTrac, gears, and bearings / install kit, with the price rising significantly (and quickly) depending upon what else you need / want (new axles, housing, nodular or alum carrier, brakes, etc.).


One thing to consider: The 9" Ford probably could be made to weigh less if that is an area that you're willing to spend money on to accomplish. Alum center sections, pinion supports, etc. are available. Lightweight housings, axles, and other parts and pieces are available too. But its all fairly pricey. I don't know how important weight is to you, so that'll be a decision you and your checkbook have to make. At least with the rear axle, the weight is fairly low (but it is all unsprung weight).

Just another thing to ponder.

'JustDreamin'

99c5vert

I think this is the way I'm going to go...

the ford 9" setup will cost me about 1700 minimum with a used rear, truetrac, axle shafts, etc..., not including any labor

I can get the 10 bolt for about 300 set up exactly the way I need it.

Neither has to be narrowed. Even though the body of my car is very narrow (43"), the wheels are completely outside, and Z06 wheels have just over 8" of backspacing... so I'll have just under 2" between the inside of each wheel and the body, which isn't bad.

Thanks for the advice.

'JustDreamin'

The 9" Ford has been used in so many applications that it might have needed narrowing, especially if you got it from a 1/2 ton pickup or a big old Lincoln.

For the money, I think that the 10-bolt will serve you well. Heck you could pick up two (maybe with different ratios) and have a spare for alot less than what it'd cost you to even get started on the 9".

'JustDreamin'

nine-eight

iTrader: (7)

If I read your post correctly, and you really are at 1650 pounds, the camaro axle will be more than adequate- your weight is what creates the resistance to accelerating forces- the forces that break parts at launch. compared to a 3600 # stock fourth gen camaro, you're essentially bolting a truck axle to a go-kart.

Edit: holy 2007 batman. I raised a zombie?

99c5vert

Yes you did

I did go with the Camaro setup, and it's been running fine for over 2 years.

The final weight of the car, with 4 gallons of fuel is 1750.

gear_driven

I personally have a 96 Camaro Z28 I have a Detroit True track and Moser Axles. with 315/35r17 in the rear And I still keep braking the rear gear set, its sitting in the driveway now with a broken gear set. so don't waste your money on such a small rear.

bczee

iTrader: (12)

The rear most likely will take for a while.. at a min.. a well built 8.5 shouod / will take it..a. 30 spline diff and HD alxes... will go deep into the 9's...it should hold ok for your light car ok... it woudl also be a lighter option..just saying.

BC

ls1nova71

iTrader: (4)

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