SliceIROCZ

SliceIROCZ

IROCZman15

iTrader: (25)

well, I do NOT claim to be an expert about rearends but I can only tell you what I have learned so far. For expert advice, there are a few very knowledgeable people on here that might eventually read your post and reply. hopefully

I have had a Gm 10 bolt in my car since 1987. It has 172,000 miles on it, and it gets removed from the car PERMANANTLY on monday; 2days from now. I am upgrading the rear to a super strong 12 bolt built by Moser. The car is(and always will be ) a street car, but I enjoy drag racing, aggressive street driving, and long multi-state drives. However, I do use the car for autocross, and have done two track days on the 1.9mile road course at new Jersey Motorsports Park. I AM NOT COMPETITIVE AND HAVE ALWAYS BEEN DOING THESE EVENTS FOR FUN AND TO FIND THE LIMITS AND WEAK POINTS OF THE CAR. The posi diff on my car is completely wasted and 1 of the 5 bolts that holds the diff case to itself is sheared off.
Starting in 2020, I plan to get much mroe aggressive with the power levels and racing the car. probably more drag racing than autocross, but it will be a mix of both. I have done a fair amont of research and I decided on a 12 bolt because I am somewhat familiar with the nomenclature of it. i don't know much abotu teh workings of a ford 9" or S60 type rear. those are also heavier, and while tehy are stronger, they have been linked with more drag racing type performance. the ford 9" requires an additional bracket that allows it to mate-up to our torque arms, and I have read that if your car is lowered a bit, this bracket will constantly bang into your driveshaft's tunnel and the underside of the car. my car is significantly lowered, and i was not going to contend with that bracket interference at all.

Check out Mark Williams rear-ends. I know that they are more versed in tracks with turns as opposed to drag racing. maybe give them a call and ask questions.

As many will tell you (or if you do a search on the rear-end forum here) its a unrewarding process to spend $ putting work into a 10 bolt rear that will most likely always be failing you in some way or another.

lots and lots of threads on this TGO site, just do some digging. do a google search using thirdgen.org keyword too. spend some time doing the research

here is mine: https://www.thirdgen.org/forums/tran...ice-input.html

QwkTrip

iTrader: (22)

Plenty of people running 10 bolt with regular maintenance. Personally, I did autocross once with my original 10 bolt when the car was about 5 years old and I went home with both axle seals blown and oil drenched brake pads. That repair was too rich for my pockets back then so that was the end of that.

Probably not much chance of actually breaking a 10 bolt during autocross because you can't use much throttle. Still probably not much chance of breaking it on a road track since it is a lot of high rpm driving and the need to change gears smoothly.

SliceIROCZ

Thanks for the answers guys. I did do a search but everything I came up with says “get a 9” or 12 bolt to hold up to launches with slicks” which doesn’t help for my scenario. I just figured that I can’t be the only person doing something other than drag racing my car.

I’ll admit that stronger is definitely better, but I have to prioritize somewhere as funds are certainly not endless. I’ll look into that shop you suggested as well.

plum92_camaro

If you only "beat" on you car by autoX or road racing, a 10 bolt should last a long time if cared for properly. A better differential (wavetrac, etc) might be necessary too. It's my understanding that shocking a 10 bolt is what really hurts them. The small gears cause minimal gear contact that only gets worse with lower (numerically higher) ratios and small differential is to small to be strong. In short, theres just not enough room in a 10 bolt for beefy parts.

Yes, anything else is probably better than a 10 bolt and at some point financially its smarter to upgrade. AutoX/RR is my thing but sometimes I go to drag strip so I'm going with a Quick Performane 9" as soon as I get the money together. I'd love to get full floating axles but the the aftermarket brake kit that requires puts it WAY out of my budget.

I'd dare to say that the strongest 10 bolt is still weaker than a factory 9".

Tibo

iTrader: (15)

As long as you stay away from numerically high gears and slicks, a ten bolt should be fine. I imagine clutch dumps on the street with 400 horsepower and street tires would kill it though. There are videos on YouTube of guys in stock or lightly modded ls1 fourthgen breaking the ten bolt. Converting an 8.8 would be the best choice for you.

SliceIROCZ

Thanks everyone for the responses. I think for now I am going to stick with what I have for a short term solution. To really get the most of the car (performance and life) I guess I will have to look into a new rear in the future. Sounds like the 10 bolt will at least get me through the swap and a season. Guess that’s life when you start adding torque to an older car not designed for it 🤷🏻*♂️

MKM

iTrader: (1)

Here is my two cents. I ran a 10 bolt for years in stock trim I would only get 16-17 months before braking the gears. Now that was in ESP trim so 300 hp at the wheels.

Then went to CP the rules open up. Had the gears polished and Cryo, added a girdle, and ran Red Line 75-250 shock proof oil. With 425 hp at the wheels managed to make the gears last 3 Years. Now that was with huge slicks. The 10 bolt can be made to last but you got to mix up some special sauce.

Hope that helps.

Mark

scooter

iTrader: (11)

I would say the worst part of the 10, and even 12 bolt, is going to be the C clip axles. You're likely to experience a lot of pad knockback on the twisties. And like QwkTrip's issue, you may have problems with the axle seals blowing out. The newer revised 10 bolt seals may be better than the old factory style. I have a 9 bolt in my car, and it held up on my road course stint since it is a retained bearing

427seven

IMO a build should start with a strong rear end. If you're gonna go live, and you're gonna go around corners, I agree with scooter, you need to have the axles held in the housing. The rear end is the transition point between the engine's torque and the contact patch. If you're going in a straight line a 12 bolt has a good ring gear, but if you start putting lateral force to it, it can fail. For arguments sake, go 9", relatively easy to gear change, bulletproof. Heavy and expensive, but you will never likely spend money on it again. Wont matter how much you put in front of it....