G35 Coupe wheel hop

[nuclearcarnie]

Hey kids, My 06 coupe (6MT) has a problem with wheel hop under a hard launch. Anyone have any insight into this and what the fix might be?

Thanks.

[TurboDurbo]

I have noticed this too. I think it mostly has to do with tire temperature in my opinion. Upgrading the suspension would probably help prevent it but I am not sure that it would be worth it. I have had very good launches though that the tires hook up and I go. When the tires are warm is when I notice the hop the most. Cold they just spin.

[keithjack]

Same car same problem but don't know the answer. Traction bars?!

[gwoods]

Axle hop is hard on the pinon seal inside the diff so if you can avoid it thats best.

If you can't avoid it you need a "pan hard rod" to connect the center of the diff to the body of the car. Its basically a shock absorber that bolts to the underside of the car and to the top of the diff. It absorbs and limits axle wrap and pushs the axle into posistion. Since we don't have leaf spring rear suspensions traction bars are not going to cut it.

The cause of axle wrap is a combination of torque and traction. Imagine the rotational force when you floor your car. IF you are making enough power and have sticky enough tires instead of the tire spining or the vehicle moving forward the force binds the suspension as far as it will go in the direction the tire is turning. When the suspension reaches the limits of its travel it springs back and the car hops.

I went through 3 differentials in my Hemi Ram. I had leaf springs so I clamped the leafs together on the front side of the axle and put on traction bars. I still have a complete master rebuild kit in my garage for a Chrysler 9.25 rear axle LOL. I remember the first diff I lost at 16,000 miles right after the cam swap. I was driving home after putting on a smoke show in the work parking lot and I thought that my 3.92 gears sounded a little louder. The next day when I took my foot off the gas the rear end would buck and try to lock up. At the shop the pinon bolt had backed itself most of the way off and the sleeve was completely crushed onto the pinon gear. It took an air hammer to get it off! 600 miles later I was back with the same problem. I finally invested in Cal-Trac traction bars and the diff lived another 14000 miles! 125 hp shot of nitrous and Nitto slicks destroyed the clutch packs in the limited slip at around 30,000 miles and almost put me into a wall. I rebuilt it again. The diff was howling on sharp turns when I traded the truck..... I think I could rebuild a Chrysler 9.25 blind folded!

[C-Kwik]

I doubt axle wrap will be of any significant concern on the G or any other IRS vehicle. While any movement of the diff could be called axle wrap, the actual range of movement in an IRS suspension's diff is going to be quite small. The Diff is attached to a subframe that is attached to the chassis with bushings. The only amount of pinion angle change will be to the extent the bushings deflect.

By contrast, the axle wrap in a truck occurs as the axles pivot under load causing the leaf springs to deflect in the direction of an S shape.

That said, wheel hop in most IRS vehicles do occur due to some subframe movement. Subframes are typically installed with rubber bushings so they are relatively soft to get lower NVH. Wheel hop can also stem from softer suspension settings, but I doubt this is as much of an issue with the G.

[gwoods]

I see what your are saying and agree with you. The term axle wrap is still correct, the axle is wrapping up all the suspension travel instead of moving the vehicle forward. Whether its wrapping a leaf spring or a rubber bushing.

If its an everyday issue a pan hard rod will fix it. If its not just try not to hop too much so you don't break anything.