slow motion of launch

[o2camaross]

I asked my friend, who video taped my run, to make a slo mo video of the launch to see how bad I spun. You can see it dead hooks off the line but when the nitrous kicks in it spins a good bit. My suspension setup is a djm 4/6 drop with flip kit and drop shocks. I made some tracion bars that are identical to caltracs. Im running 28x10/16 hoosiers with 13 psi on that run. I noticed the other day when I was looking under the truck that my pinion angle looks to be a couple degrees positive. Is that my main problem? I cut a 1.64 60' on that run. How much can I improve with setting my pinion angle and how negative do I want it? Here is the video

[ecld_07]

I have the same 4/6 drop and run the same slicks. My pinion angle was horrible to get right. With the truck so low I wound up raising the rear of my tranny to help me get the pinion angle where I wanted. Might be something to look into. I run a 200-400 shot without caltracs and hook.

[o2camaross]

damn thats a big boy shot. I might try that then. Thanks

[farmtruc]

I'm no expert with pinion angle but like it was said, my truck is so low that I raised my trans up quite a bit. About 2".

Hey I just did the same thing with my passes last week, got them in slow mo.
It really shows what's going on. I'm gonna mount my gopros underneath next time.

Btw that's moving off the line.

[o2camaross]

Thanks Allen, thats your tuning! Djm makes these pinion shims that go between the rear end and the bracket. Would these help?
http://djmsuspension.com/products/Accessories.html

[farmtruc]

They will help and are probably needed, however, you can make up some of the adjustment by raising the tailshaft, if it's needed.

thanks for the feedback on the tune, running good it seems.

[o2camaross]

ok well that will be my project this weekend. Its running great, only thing is if I try to spray through the shifts, it takes too long to shift and hits the limiter barely. Then I changed the window to close at 5700 and it shifted fine but i was passing the line at 5900 or so and it stopped sparying before the end of the quarter. I then set it to 5900 and it shifter a little late again. What do you think we can do about that?

[farmtruc]

transmission needs to hit harder at wot. basically it's slipping.
we can increase line pressure, but it'll need to be quite a bit if the trans is taking few hundred rpms to grab the next gear.

[ecld_07]

Thanks Allen, thats your tuning! Djm makes these pinion shims that go between the rear end and the bracket. Would these help?
http://djmsuspension.com/products/Accessories.html

I got the kit with a bucket that the rearend sets on,on top the leafs. Then there's another piece on top the housing that clamps it. I can adjust the front and back bolts to raise or lower pinion. Then reclamp the u bolts to hold it. Like Allen my transmission is raised about 2in. I also had to clearance some of the crossmembers under the truck for the larger driveshaft I run. Stock might not have problems.

[o2camaross]

I did the same but my bracket and bolts are maxed out. How do you raise the tranny tailshaft?