What causes wheel hop during a posi burn-out? My 1987 Z-28 has terrible hop during a wheel spin. The trailing arms and the adjustable panhard bar are Edelbrock, springs and shocksare new(but cheap) and the brakes are in new shape. Can anyone shed some light?

 

Not exactly sure, but im fairly certain torque arms are also made to help reduce wheel hop.

 

wheel hop is basically the suspension gets into a resonant situation and doesn't dampen itself out.
Under acceleration, the rear suspension compresses. Due to inertia, the wheel continues traveling upward. This unloads the tire, reducing the acceleration force. The spring then pushes back down on the wheel, and it regains traction, forcing the wheel back up.

 

okay. wheel hop, wheel hop is when the wheel moves faster than the body of the car wants to. so the wheel darts forward, metal and suspension stop giving/bending, and the wheel sling shots back into place. and reapeats over and over again. that's wheel hop. unlike what most believe, it is NOT vertical movement, it is horizontal movement.

for RWD, i don't know how to fix it, but on FWD, you use engine/tranny mounts, to stop engine from giving. but that still leaves some wheel hop, and horrible vibration. they recently came out with traction bars(B-woody grade 8 steel bars) for FWD cars, i have a couple pics i'll upload of them. work WONDERS. i'm sure there's something similar for RWD cars.

only problem i have with my bars, is i have about 2 inches of clearnace, and if i hit something, it wont shear/break the bolts or the bar.. it'll bend my frame. has happened to alot of people.

 

ill get more pics and a burnout video tommorrow or friday.

 

my bad, that top pic is my new sway bar endlinks.. also grade 8, and 3/4"s think...

here's the Trac Bars:

 

yenko, sorry bro but, at least for rwd, hop is vertical movement. tire pushes against suspension components. force on the tire is mostly foreward, but partially upward due to the way the tire spins. suspension effectively squats and tire lifts up losing traction. spring forces it down, resulting in alot of traction, repeating the cycle. this is possible because the suspension components are made to swing up and down. horizontal movement of even an inch is enough to exceed the elastic thresh hold of the metal and permenently bend it.

now, relocation brackets bring the axle further downward with relation to the LCA. since the LCA is on a pivot the axle must swing backward in order to travel upward, this is fine and dandy when the car is stationary, but iwth some torque applied the tires squish the axle against the lca eliminating backward swinging and thus eliminating hop. any minor flexion of the control arm can allow is to swing up and allow the hop.

i feel like drawing a picture. brb

 

spec, everywhere i've read, hop is 90% horizontal movement for front and rear wheel drive, and i dunno bout RWD, but on my car, my A-Arms can move up and down just as much as they could before the bars, but now, i have no hop what so ever. because those bars prevent wheel from slinging forward and backward. even in rain, i have absolutely no wheel hop. now, RWD could have some vertical movemnt, but im still pretty sure it's mostly horizontal. as to how to get rid of it, i don't know.

before the bars, i NEVER was able to spin without hopping... and it hopped BAD, to where steering wheel was shaking, and CD player skipped horribly.

 

ok, in the first pic, this is the stock axle to LCA orientation. axle is the big circle. diagonal line is the LCA. if you notice, upward travel of this doesnt really change the horizontal distance from the axle to mounting point.

now, if you look at the bottom, using same LCA length (this is not a real angle, i used an extreme to make the point but remember were talking about mostly inflexible metal components so a little is a lot) the axle must swing backward in order to lift up. this backward swign is opposed by the foreward force the tires are applying to the axle. in this way you eliminate knock with the LCA relocation brackets.

as i said before, a little flex in the LCA will allow hop again. the middle diagram is more akin to the modified setup.

 

its a horizontal binding, vertical movement for rwd. i dont know fwd