Thread: engine/trans shake when burning out

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Check this out about pinion angle and vibration.
Does pinion angle =vibration - Team Camaro Tech

IMG_2822.jpgI didn't change to heim's in a day, I wish. Last month I lifted the bed off the frame and added a panhard bar, a sway bar, and changed from poly ends to heim's. It took me about 5 weeks or so. The sway bar addition was solely to help with the fact that my truck handled like a boat, but the panhard and the heim's were supposed to solve the shaking problem. I was focused on modifying axle components because I just assumed the shaking was coming from there.
Unfortunately after all that work I had the same problem.
I'm going to try to attach the 2 video's my buddy took from two different perspectives. They aren't the greatest and you can't see the whole vehicle in the framing, but it definitely got me thinking in a different direction. You can't see much of the cab in the video's, so you'll just have to take my word for it that from inside there was significant shaking.
-attached should be a pic of the suspension set up long ago before I even got it on the road, but it is still the same except now it has a panhard and heim's.
I can't see how to attach video's. They aren't showing up the way they do to attach pics. So for now here is just the pic, I'll keep looking on how to do video's.

Probably the easiest way to attach the video is to upload it to youtube then copy & paste the code in the message box here.

I know the videos are terrible, there is a tiny portion of time where the wheels are actually slipping, but the reason I so quickly got off the throttle is because of how much the trans starts shaking and how bad it seems inside the cab.
I wish I got a video from inside the cab too.

Also, my axle pinion at ride height is point slightly down in relation to the ds, I think about 3 degrees, and the trans shaft is pointed above the ds about the same degree, so as accurately as I can tell they are basically equal and opposite angles.

Looks like you've done a good job and alls' about where it should be, the suspension geometry and pinion angle. Not shown is the panhard bar and an antiroll bar? I don't much care for a panhard bar and it can cause some binding with that type of suspension - but it isn't affecting anything at launch. The antiroll bar, is it one of those kit types similiar to competition engeering? Did you adjust it to neutral on both links with a driver behind the wheel, fuel etc so that it is at starting line weight? By neutral, i mean can you rattle both links that drop down to the rear housing? They should be loose so that you can slide the attachment bolt in or out?
The one thing that i thought odd is that at low rpm, not much power at all there is smoke coming from the tire - try throwing some weight in the bed, a couple hundred pounds of sand in bags and see what happens.
I tubbed a pickup and tried to drive it out of my shop without the bed on it. It got stuck at the curb in front of my rollup door to keep rain water out of the shop - i had to back up and get a running start. There isn't much weight at all in the back of a pickup and maybe that that is what you're seeing the results of.

right, the sway and panhard are not shown in that pic only because that pic is from 5 years ago and I just put those on last month. I chose that pic anyway because it was the best picture to show the suspension.
The sway bar wasn't from a kit, I had to make it custom. I did not actually check it was completely neutral with me in the cab, 99% of the time I am single handed so that stuff is tough, or if I'm really in a pinch I ask my wife for help and listen to her complain the whole time. It was definitely neutral with nobody in the cab because I checked that.
but yes, in the video from the rear perspective you can see smoke come up right away with only a few revolutions of tire spin. I did re-locate the fuel tank behind the rear axle so there is at least a little more weight back there, but it is still light.
I do think the video does show that the axle is very stable, and from inside it feels like the trans is going to launch to the moon.

Sorry - read the post wrong....