Hi everyone,

I did a bad thing and it all started so innocently. In the quest for lower E.T.'s my very loving and understanding wife bought me a set of M/T ET Street Radials for my birthday, awesome b-day gift! Well, M/T's maiden voyage was Wednesday night and it proved to be very Titanic like. On the fifth pass of the night I broke the driver's side half shaft, that is of course after twisting it up like a pretzel. I tried to upload pics for everone to see, it looks like a compound fracture sticking out the bottom of the car, UGLY! I never in my wildest dreams thought this would happen, I've never heard of these cars breaking the half shafts. Have any of you? I've got a '90, ZF6, L98 that is basically stock. I've got most of the free mods and a cat-back exhaust, no big power like some of you are producing. I backed into the water box, gave them a little spin to get them wet, stopped on the burn-out pad, tached the engine up to 5000 to 5500 and dumped the clutch to get them kind of warmed up. I don't have a line lock, so that's the best I can do at this point. They would spin pretty hard for a couple of seconds and then bite like a snake! I would then get staged and launch at 4500. I didn't think I was doing anything to aweful extreme. Have any of you had this happen? I know I have to replace the half shaft, probably be a good idea to give the differential a thorough inspection. Rebuild the posi unit while I'm in there and I probably ought to inspect the other half shaft. What do you guys suggest? Do I reinstall an OEM half shaft, or do I upgrade to something stout? Any suggestions that you all have will be greatly appreciated. Thanks in advance!

Adam.

 

Twisted mine like a pretzel before too. I'm sure Jesse (ski_dwn_it) has been through a couple already as he and others are putting down some pretty crazy numbers.

I've heard of people cry-treating them or getting Denny's Nitrous Ready Half Shafts. Don't have a link, but I'm sure you can google it.

 

Thanks for the info, I'll Google that see what comes back. I've Googled racing half shafts and didn't get much. Mark Williams Enterprises, but they didn't have that part specifically. Thanks again!

 

Red L98 had a set of half shafts available from his 86 that are croyed by Jeb. I seen them a couple of weeks ago. He is switching over to a solid axle. You might try contacting him.

 

ET streets are too sticky for stock rear end parts. Even automatics blow them up on ET streets. ET streets will destroy Dana 44 diffs too.

You might get some life with Drag Radials.

 

I did a search of the forums before I posted this thread, what I found was for a different situation, but they also mentioned that the BFG Drag Radials were as sticky as they would go. I guess I should have asked the forum before I specified what tires I wanted for my b-day. Thanks for the input, all of you.

Adam.

 

I had NeverLift install a solid axel in my car, just got tired of changing parts. You will too someday.

 

sorry,,,, where your time's better till it broke

 

thats one of the drawbacks with sticks you are 10 times more likely to break rear parts than autos
stock danas 44 can run down to bottem 11s high 10s with autos and slicks anything more than that you will start spitting out rearend parts
with sticks its just to much drivetrain shock
take 85vet on this forum he is yet to lose any drivetrain parts knock on wood hes been running bottm 11s every week for 3 years now on drag slicks

 

Well, that's the part that's even movre puzzling than the broken half shaft. They improved my 60' times by a 0.2, improved my R.T.'s by a lot, but I lost mph and my E.T.'s weren't that much quicker. Previouly I was running a weather checked set of GY Eagle GS-C's, 275/40-17's. My best with those was a 13.974@100. I installed the M/T's and had a best of 13.909@99. The only thing that I can come with is that the M/T's are shorter because the air pressure is so much lower. M/T recommends a pressures of 12-16 psi for 275 and smaller tires. They say to start low and work your way up, which I did, got them up to 16 psi and then the half shaft broke. If I had run a 13.7, then I might be able to justify the parts breakage, but a 0.07 improvement was a lot less than I was expecting. Wasn't a good night all the way around.

 

I'm never going to be turning those kinds of times, I also use the car for autocross. I do not plan on running any quicker than mid 13's, how much should I beef up the rear to run those times?

 

A 4500 rpm launch is a bit much for stock rear end components on a C4. Mr Mojo just engages the clutch and gets it hooked at about 1200 rpm and goes from there. He's still getting 1.9x 60 foot and quick times.

Without a solid axle rear you're never going to be able to do high rpm clutch dump starts, ET streets or DRs.

 

ET Steets area bit much for most stock Corvettes IMO. I have a very strong LT1 6speed (13.45@108 on Sumitomo street tires) and was also tired of the 1.9- 2.0 60fts, spinning throught 2nd gear, having to baby it off the line only to spin like crazy once I went WOT, ect ect. So I bought a set of 26X11.5 15 ET streets and a set of Weld Wheels. Mounted them up (after grinding the calipers) and went off to the track. Broke a rear spindle upright after about 6 passes. I was a bit faster with them for those 6 passes thou. Ran a 13.30 and 1.68 60ft with a 5500rpm clutch dump and it left hard with no tire spin, I thought "Yea this is the ticket" until it broke. The car would not spin the tires no matter how hard I dumped it and it broke from the abuse. Mostly stock C-4's just don't have the power to utilize those tires properly.

With your goals of mid 13's maybe 12's, I think you would be much bettter off with a set of Nitto or BFG 315/35R17 Drag Radials. I have been just as fast as the ET Streets in good weather (with my BFG's) and haven't broke anything since.
Will

 

Thanks to all of you, I appreciate your inputs. My season is over, but I've got a lot of good ideas for next season. Thanks again CorvetteForum!

 

4500 is a little much for the launch, keep doing that and you'll be replacing parts again.

 

:o I found that out the hard way, have taken everything that all of you have said into account. Thank you!

 

What does your car weigh?

 

I've never had it across the scales, so don't really know. I haven't lightened it at all.

 

The lighter your car the less likely you will break stuff. Did you remove your space tire and compartment cover? There are a few things you can do without spending a penny.

 

I've got the spare tire out of it, but not the cover. What else do you suggest? Thanks in advance!

Adam.