suspension help, what am I doing wrong.
12-22-2010, 09:32 PM
#1
suspension help, what am I doing wrong.
I just finished watching some footage of my truck and no wonder it can't run worth a crap. Please take a look and give me some info on what might help this. My rear set-up consists of 2" shackle with hanger, caltracs, 29x9x15 slicks, 3.42 gears with eaton posi, and relocated adjustable shocks.
http://www.youtube.com/watch?v=O7-OMvP0kKs
http://www.youtube.com/watch?v=OXiPKUsXz8E
http://www.youtube.com/watch?v=fv6bJnfB_mk
http://www.youtube.com/watch?v=yr_Gngvm4eQ
http://www.youtube.com/watch?v=JOFoOVRq9U4
http://www.youtube.com/watch?v=O7-OMvP0kKs
http://www.youtube.com/watch?v=OXiPKUsXz8E
http://www.youtube.com/watch?v=fv6bJnfB_mk
http://www.youtube.com/watch?v=yr_Gngvm4eQ
http://www.youtube.com/watch?v=JOFoOVRq9U4
12-23-2010, 01:07 AM
#2
The way your rear suspension is set up with the drop hangers and caltracs isn't putting the "instant center" out in front of the truck like it's supposed to. You want the front eye of the leaf spring, and the lower pivot(at the front) of the caltrac to simulate a 4 link. Imagine those 2 points as the front end of a 4 link, and the center of the rear axle & the lower rear link of the caltrac to be the back end of a 4 link. If a 4 link was angled that high going towards the front of the truck, the instant center is too far back, and it won't hook.
Does that help at all?
Also, have an alignment shop check your thrust angle. It looks like your truck wants to go almost sideways down the track.
Does that help at all?
Also, have an alignment shop check your thrust angle. It looks like your truck wants to go almost sideways down the track.
12-23-2010, 01:13 AM
#3
Quote from Mark at Calvert Racing.
Tuning Your Tires and Suspension - Hooked! - Tips, Tricks, And In-Depth Info For Ultimate Starting Line Bite
Q&A: Mark Tallent Of Calvert Racing
CHP: CalTracs bars have a reputation for tremendously increasing traction on leaf-spring cars. Just how do they work?
Mark Tallent: Each of the CalTracs bars uses a front pivot, a Force Transfer Link, and a rear mount. When the car accelerates, these components change the pushing point on the car by redirecting the turning action from spring wrap-up on the rearend, through the Force Transfer Link, and into the front pivot. As this happens, the front pivot-spring stop bolt holds back the turning motion and controls the bending of the leaf spring at its narrowest point. Consequently, the pushing force into the front pivot enables the car's weight to shift rearward because of the new directed angle of force moving to the front of the car. This causes the instant center to move farther forward and, in theory, it acts similar to a four-link system; plus it'll keep the pinion angle constant.
Tuning Your Tires and Suspension - Hooked! - Tips, Tricks, And In-Depth Info For Ultimate Starting Line Bite
Q&A: Mark Tallent Of Calvert Racing
CHP: CalTracs bars have a reputation for tremendously increasing traction on leaf-spring cars. Just how do they work?
Mark Tallent: Each of the CalTracs bars uses a front pivot, a Force Transfer Link, and a rear mount. When the car accelerates, these components change the pushing point on the car by redirecting the turning action from spring wrap-up on the rearend, through the Force Transfer Link, and into the front pivot. As this happens, the front pivot-spring stop bolt holds back the turning motion and controls the bending of the leaf spring at its narrowest point. Consequently, the pushing force into the front pivot enables the car's weight to shift rearward because of the new directed angle of force moving to the front of the car. This causes the instant center to move farther forward and, in theory, it acts similar to a four-link system; plus it'll keep the pinion angle constant.
12-23-2010, 01:21 AM
#4
I agree 100% it looks like the rearend is trying to drive around the front of the truck. It also looks like the back is too stiff, creating your bouncing problems on the first video. I would maybe try to make some new front brackets on those bars and get them more parallel with the ground, they look like they're on a wicked upward angle. What's your pinion angle set at right now? I'm not near the power you are, but I experienced all kinds of traction issues after I did the same changes you did in the rear and didn't have my pinion angle set. The truck sounds great and definately shows the power it needs to go faster.
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12-23-2010, 10:47 AM
#8
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How are you launching? In the "shitty10.8" video it looks as though you're foot braking to build boost. But as you do that I can see the rear rise. You want the rear suspension to seperate, but not before you launch. All your anti-squat is used up and I bet your suspension is topped out. And then there's nothing left to plant the tires. You're not getting the hit that people talk about.
How do you build boost then without loading the suspension? 2-step or transbrake. I took a few GN guys to tell me that and see what I was doing wrong. :nunchuk1:
What hole is the force transfer link in BTW? Try the lower hole if you haven't already. That will move the IC forward.
How do you build boost then without loading the suspension? 2-step or transbrake. I took a few GN guys to tell me that and see what I was doing wrong. :nunchuk1:
What hole is the force transfer link in BTW? Try the lower hole if you haven't already. That will move the IC forward.
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