So I went to the track last night and tried leaving on a 300 shot and these were the results. What I think is the cause are the u joints. The driveshaft was pretty beefy but I don't really remember being specific about the u joints when I had the driveshaft cut and balanced. Maybe I forgot to mention it would be used for a racing application . I'm going to get a new driveshaft and solid u joints is this something I'll have to keep worrying about or do do I need to invest in a progressive? Couple of weekends ago I left on a 200 and everything was fine.

Just trying to determine if I need to leave on less gas or if the u joint was just the culprit and if a heavier duty one will rectify this problem.

 

I think a solid non-greaseable joint may help but not a 100% cure. Got to have a weak link somewhere I guess and a U-joint is cheap/easy fix compared to a rear.

Swap U-joints and try 250 ???

What size joint is it ? 1330,1350 ???

 

Has to do with the poor casting quality of the stock 1350 joint, + the use of a greaseable joint in your application.

Pick up a high quality casting, solid, non-greaseable u-joint like the ones Mark Williams sells. Be sure and pick up billet steel caps as well.

 

Sucks to see that be ause that car was leaving hard too. Lol

 

U-Joint or bumper was going to need replaced on that launch I think.

How much power are you making with out the juice? The tottal power will help decide if you need stronger joints or a differant solution.

 

It makes 520 without the nitrous.

 

I would get one build by someone who builds racing driveshafts (like Denny's).

 

Shiny area on the fracture might indicate it had been running cracked for a while before it failed.