Road Racing - What Rear Axle???
09-23-2011, 04:49 AM
I started an 8.8 4 link build, but decided to go back to the TA and a bolt in rear axle after running into a lot of problems. I considered going back to the stock axle, but I have destroyed 2 of them with 275s and I have recently stepped up to some 315 Nitto Nt555s, so I don't suppose that the stocker will hold up too long.
I was thinking about a 12 bolt, but a 9" would be lighter. But then I get into a Fab 9 and blah blah blah. My car makes 415 rwhp and I have plans to up that to the mid 500s over the next couple years. I do some drag racing, but I use street tires, no drag radials, no slicks. But my suspension is being built for a corner carving street car.
Also what would be the best limited slip and what are some good brake setups?
Thanks in advance
Also what housing would have the most clearance? My car is rather low and I intend to keep it that way :)
09-23-2011, 09:26 AM
Were you destroying the stock rear-ends on the drag strip? I have over 17 auto-x's and about 6 hours of balls-to-the-wall road course time on my rebuilt 10 bolt and it is still quite and working just fine. All I did was have it professionally rebuilt with an aftermarket diff (auburn) and GM axles. The pinion is leaking a little but that is typical, should have replaced it anyways.
If you want to do both drag and corner racing, you are going to have to make A LOT of sacrifices and compromises in your build. You simply can not have the best of both worlds. If you are even thinking about doing drag radials or slicks then go to the 12 bolt. Im not sure what diff options there are for the 12 bolt and if they are even that great at taking corners. However if you just want to drag on street tires every now and then and auto-x road race occasionally, stick with the 10-bolt but keep GM axles in it, even moser axles will cause problems combined with certain diffs. have it professionally done so that the tolerances are correct and everything is shimmed correctly and a 10-bolt will last a lot longer than most people claim they will.
A good rule of thumb is 400hp + slicks + dump clutch at the drag strip = failure. Ive seen it in person twice.
If you go to the 12-bolt get double adjustable rear shocks so you can get the extra weight under control and that will bring some of your handling back. The road courses will not like the extra unsprung weight.
09-24-2011, 03:16 AM
I mostly race some friends occasionally, once or twice a year at the track. I'm not trying to build a dual purpose car, its a street/autox/road race suspension that will make a few passes at the track every once in a while.
And I killed the past axles with 4.10 gears, stock diff, stock axles. First one was wheel hop, which isn't the rear axles fault, and the 2nd one was just thrashing my car on the street. Neither exploded, but developed some strange noises and whining.
I'll give the stock axle another shot, but I just don't know if it will last.
But now that I don't have stock brakes anymore for the 10 bolt, whats a good upgrade? Possibly one that can be transferred to a 9" or a 12 bolt if I end up breaking the 10 bolt again.
09-24-2011, 03:24 AM
What TA setup would you suggest? I currently have a full length UMI adjustable arm, but am considering buying the Global West arm and giving that a try. If I keep the UMI arm I plan on getting a relocated TA mount to get the TA off of the trans.
09-26-2011, 08:38 AM
Dont know about rear brake options for 10 bolt because for me, stock brakes work. If its for looks then cool, but even stock brakes with race pads and fluid will perform pretty amazing for factory brakes. I ran a 45 minute session flat out and never ran into fade and I dont even have any brake ducting.
I have same TA as you right now, UMI mounted to trans. Would also like to convert to get off trans mount. Havent done it because I am going to get the de-coupled TA made by Unbalanced Engineering the same time I do my cage. If you can afford it then this is the final key to making the best of a solid rear axle design. It uses the TA to help with braking as well as acceleration like usual.
Youll be fine with the 10 bolt just get a good diff and new GM axles. The gear size is not going to cause any more or less stress on it. Go back to a 3.73 IMO its a better gear for what your wanting to do. There are a couple of companies that make diff covers that cradle the diff for a little extra support, I have the thunder racing one.. If you have a welder handy you can clean up where the axle tubes hit the center section and throw a few tack welds around there just for the hell of it. And like I said have someone good do it, the guy I took it to does nothing but rebuild axles for off-road trucks all day long he has probably done close to 10,000 rebuilds over the past 20 years lol
09-26-2011, 02:30 PM
I talked to the wife and I'm going to get a Moser 9" and transfer the watts link over to that and put the UMI arm back on the car with a relocated front mount. I don't want to spend another ~$800 on a stock rear and break it again. And for me I like the 4.10s, I'm almost considering going to 4.30s when I get the 9". 3.73s would be pointless where I live, I wouldn't even get to use 6th gear with all of the hills I drive on everyday.
I'll look at the Unbalanced Engineering TA, did Global West make theirs similar? GW says theirs helps with braking as well as acceleration.
Thanks for the responses, I appreciate the info.
09-27-2011, 03:34 AM
Or I may work on a TA bracket for the 8.8 that I have built already, just grind off the 4 link mounts, leave the watts link mounts on and build a mount for the torque arm. I have a design in my head, but getting it to work in the rear world may be tough.
I think I'm going to try this option out first before I spend a bunch more money on something I already have. Then if it works out I'll get a different TA and start tuning the suspension in