New look, new things to fix. First shot made an easy half track run, second pass broke the top bar on the torque arm, which threw the rear end up and broke the drive shaft. At least it wasn't at a race? lol

 

what torque arm? A buddy recently had his spohn one blow up like that and it took out a ton of parts

 

It was the Spohn standard duty TA. never really payed attention to the pinion angle until this winter we noticed the rear end was angled up slightly so checked the pinion angle and it was +4, readjusted to -1.5 and it snapped on the first good hit? Bought it back in 04 and has been 1.37 best 60' with it. Broke on the top tube right where the flat gusset connects before the hyme joint.

 

Car looks great sorry for the bad luck. What unit are you going to replace with?

 

how did you go about checking your pinion angle? just an angle finder on the rear, or did you compare it to the driveshaft?

 

Car looks good. Sucks about the torque arm tho. Take some pics of it if you could. I'd like to see where it broke.

 

I measured the angle of the driveshaft to the pinion with the angle finder. Going with the pro series torque arm this time. I'll take some pics tonight or tomorrow. That arm had a ton of passes on it. We race alot, usually from March to November sometimes 2 to 3 races a month.

 

Maybe it was just a coincidence that it broke, but I wouldn't think changing the angle to whats recommended would cause it to break like that? I was hoping it would take strain off the drive line

 

shouldnt have broken with the pinion angle change, for sure. mustv'e just been its time to go. i asked how you did the measurement because everyone i talk to does it the wrong way. they just stick the angle finder on the rearend and point it 2 degrees toward the ground and call it a day. so i ask them what their pinion angle would be if they jacked the front of the car 4 feet off the ground. lol

 

madman just goes off pinion angle and not based off driveshaft or anything else, just that car is on level surface. His stuff seems to fly as well.

I've always done crank angle off balancer, driveshaft and pinion to make sure all three are close for a reading.

 

I'm just glad I didn't just go race and not make a few test runs. Here's where it broke.

 

Man the car looks great! Sorry to hear you broke some parts though.

 

Have you shown that to Steve Spohn to see what he thinks about it? Or do you think it was just fatigued from years of launches? Doesn't look like there can be much done to it to reinforce that area. I'll keep a close eye on mine for cracks or bending in that area. Thanks for the pic.

 

I didn't send them a pic or anything. Just told them what happened and my set up. I beat on it for years with more than what they recommended it for. 3600-3900 rpm trans brake launches since 2004. So I say it held up pretty good. Hopefully I won't have anymore problems with the Pro Series.

 

i know he has worked on some fast cars, but its flat out the wrong way of doing it. i know for a fact that if you take a stock ride height fbody and point the pinion 3 degrees to the ground you will have 10+ degrees of pinion angle. if you look at the adjuster on the broken arm above, the adjuster will have to be nearly all the way unthreaded to acheive -3 degrees on a stock ride height car. (or slightly higher than stock if using 3" axle tubes + stock springs)
i can't think of any reason to do it his way (the wrong way).

a friend of mine bought one of his first torque arms he brought to market. it had no slider joint on the front so it bound up. he wound up fixing it himself. i believe the arms he sells now have a slider in them.

 

i don't get how you can't take the angle of the output shaft on the transmission into acct for the # to mean anything?

 

in theory, you should try to make the front u joint angle the same as the rear u joint angle to avoid vibrations. it can take alot of time putting everything in the right spot once you get into moving the engine/trans around as well as the rearend.

 

I have read when people take the angle from the engine and compare it to the diff that they use the vertical part of the balancer and diff. Can u do the engine crankshaft method and do it on a horizontal plane so you don't have to remove the driveshaft to put the angle finder on the rear diff yoke? Xpndbl where do u take your angles from on the engine and rear diff? Thanks

 

i use the output shaft on the transmission, throw an angle finder on the bitch and subtract 90 degrees, then throw it on the rear diff yoke .

 

i think i need a picture...

 

I go off trans angle and match the pinion to that.

 

put in the new TA and set the angle in relation to the drive shaft to -1 and I think it helped. I was able to run more mph in 7.0 trim than normal this past weekend.

 

Glad to hear it.