Big Block Dave

Well, I just don't know where to go from here. During the past year I added a lot more power under the hood, and I have been rewarded with wheel hop. Basically, if I just let the clutch out from an idle, and then mash the throttle, i get wheel spin and serious hop. Once this happens, I back off the throttle.

I have added the Toms aluminum discs at the diff crossmember, as well as the aluminum snubber at the pinion. A set of used bilsteins are in now, and I have the same replacement hd spring I added 7 years ago.

Ive seen threads suggesting 2 different sized half shafts, but I'm curious if anyone has done this with any success. What am I missing?

gkull

Just for the rest of the people here. What is your rear spring weight and do you have a rear sway bar installed?

If the rear end is solid like yours the next problem is uncontrolled vertical movement of the rear wheels. I had problems when I went down to a 420# mono with my 427. I had previously had a 500+ # custom steel. I'd did the disks and the aluminum snubber and in thinking about it I went back to a 520# mono in the same time frame.

Big Block Dave

George, thanks for weighing in.
There is a rear sway bar, although the bushings are in need if replacement. As for the spring, I don't know the rating. I just remember buying the heavy duty steel replacement spring when I replaced it years ago.

Les

What's your power level and what tires are you using out back?

Big Block Dave

Used Mark Jones 454. In it's previous life made 546/560. In my car I've got the pancake intake on it, so I anticipate the power levels have been reduced some. Tires are radials 235 55 17.

ajrothm

You likely need some QA1 double adjustable shocks, and probably a lot stiffer rear spring. You are probably better off with a steel spring to help prevent the spring porpoising and get some extra weight on the tires.

A lot depends on the tires you are running as well... A low profile, stiff side wall tire is a lot more prone to hopping.

I used to have a terrible wheel hop problem running 18" nitto drag radials on my C5Z... Even on the 26" bias plies, it would wheel hop at the track, and it ALWAYS broke something.

71VetteLover

Weak shock absorbers will allow a lot of wheel hop.

Les

You're getting good feedback, although that ajrothm guy is kinda crazy. Actually, he definitely knows what time it is with issues like this.

Even with the shallow intake manifold, you're very likely making more power than I am but not by a huge amount. I have QA1 single adjustable shocks and a VBP 360# composite rear spring. I keep the shocks set on the firm side and, when it's going to get serious, I go about 3 clicks firmer. That puts them close to the max setting. Even when I drop the tire pressure on my drag radials I have to work the throttle to control wheel spin unless I'm on a prepped surface. Whether they hook or not, I've never had wheel hop.

In addition to proper shocks, I think you really need to look into a set of drag radials. If the wheels aren't spinning hard, things should calm down a lot back there. Good luck and congrats on having enough car to even have this issue.

Big Block Dave

Thanks for the advice guys. Perhaps I shouldn't have put used bilsteins in there but i think they still have life in them.

I was wondering this though... I've got those 10" lowering spring bolts. Is it possible that with the longer bolts, the spring is more relaxed? Could this be a component of this issue?

gkull

Longer bolts only change where the body sits in relation to the ground

Your weight doesn't magically change

73racevette

While I really doubt this is all of the issue you have, it does change the preload on the spring some. A higher preload will reduce wheel hop. But as Gkull mentioned it is used mostly to adjust vehicle height in a corvette.

Big Block Dave

What if I wore looser pants... I could probably fool people into thinking I was thinner.

v2racing

Are the Bilstein shocks the HD or the Sport version?

As I am currently reworking my frame, I am putting an adjustable traction bar similar to the one in this photo I found on the web. I am putting a bung in the frame and laying the front heim joint 90 degrees to what is shown in the photo and will attach it with a button head bolt so it doesn't hang down so low at the cross member.

Mike

Big Block Dave

The Bilsteins are an older part number that cross to the modern Sport

v2racing

The Sport is the stiffer of the two, it's just a question of if the used shock still has all its damping qualities left.

Mike

gkull

I aquired all the parts to make Mikes above posted picture. My kit uses morroso solid motor mounts for the ends and vb&p strut rod with hiem joint ends.

I didn't install it because of my exhaust system. But today I was looking under the rear and I think it could be placed back to the rear. It would add some pumpkin stability over my solid cross member

MN80Vette

I have Bilstein Sport shocks, but wheel hop didn't end until I made an adjustable traction bar similar to the one you made. For my '80 with a GM Performance 350 HO crate, it didn't have to be super beefy to stop the wheel hop.

427Hotrod

It's all in the shocks and spring. I've never had mine wheelhop and it's been abused pretty hard. I had looked at a traction bar a long time ago just to figure out what it would really do since our differentials are essentially solid and shouldn't move much. Of course they do some so the bar could stabilize it.

Mine uses stock sombrero rubber bushings along with one of the aluminum disc kits. There's a Poly mount on the pinion end.

Though I never had any issues with things moving around, when I was installing the Dana 60 IRS, I extended a little "wing" out from the sombrero to mate to the welded in crossmember behind the diff. I figured it's just sitting there and needed to do something. So now...there's 4 bolts that drop down through that crossmember and mount the wing with a thin rubber cushion inbetween. The idea is if the rear end does move, it will pull down on the wing and not be allowed to move.

JIM