Four Questions re: wheel hop 2 tranny drop

[GS-T drop top]

Wheel hop = unlike burning rubber from spinning the tires when you engage hard throttle in the low gears (1st & 2nd) the front ended shakes thunderously and sounds as if the car is going to pull itself apart, the dash board rattles, and it sounds like absolute sh!t.

Following are four questions (a challenge for the tuning wise man) to test the educated DSMer on DSM tuning academia, while simultaneuosly educating me on how to prevent it when I hit 400 whp:

1.) How much power (turbo, fmic, etc.. install) can you have before the stock front end and tranny suffers from wheel hop? How does it occur?

2.) Will it adventually damage or break the tranny? Is it a dangerous condition if you stomp on it and the front end shakes thunderously?

3.) How can it be solved? Totally remedied? Slightly remedied? LSD's?

4.) Have you had it before, how did you get it and what did you do to fix it?


Please EDUCATE ME! I have some good parts going in and I rode in another powerful DSM eclipse and the wheel hop in 1st & 2nd alarmed me.

I want my car powerful but smooth. Any recommendations?

 

[onepimpclipse]

Polyurethane motor mount inserts and an LSD would be a good place to start. Thats about all I can give you.

 

[jtmcinder]

When you try to accelerate, not all of the power is used to turn the wheels. Some of the power is used to rotate the engine within the chassis, instead. When the engine cannot rotate any further, there's a brief impluse to the wheels, which can break them free. When they break free, the energy stored in the twisted motor mounts is released all at once. Then the process starts over again and repeats rapidly, which produces the huge amount of shaking, as well as lowering the averaged-over-time tire grip, which means that you are sitting there shaking at the line like a 2-digit-HP Honda lined up against Buschur.

So, I agree with the above: replace the motor mounts. An LSD isn't really necessary.

- Jtoby

 

[GS-T drop top]

1. Motor mounts w/ urethane bushings?

2. Good tires, shocks, & springs?

3. LSD?

4. Anything else?

 

[pneumo]

Wheelhop can occur at stock power levels, there is no magical number where it starts, but high powered cars are more prone to it.

The most common part inside the tranny that breaks from wheel hop is the front differential. Actually, it's just one small roll pin in the diff that breaks, and that causes other stuff to break. The roll pin holds in the cross shaft that the spider gears ride on. Once the roll pin is gone the cross shaft drifts out of it's hole and either grinds a circular channel through the tranny case, which dumps all oil, or one of the spider gears gets kicked out and turns to shrapnel.

LSD inserts like the BM tranny insert or Phantom Grip don't do anything to strengthen the roll pin or cross shaft. Quaife and Kaaz LSD's are a completely new diff and are stronger.

This hasn't been mentioned much, but there is another way to strengthen the stock diff; weld the cross shaft to the diff housing. That way the roll pin isn't the only thing holding the cross shaft in place.

When I had Prothane motor mounts it reduced wheelhop, but it still happened sometimes. When it did happen it hit harder and faster. I prefer the feel of the window weld filled mounts. They still reduce wheelhop, but when it happens they feel softer and more forgiving.

 

[dave99gst]

Originally posted by GS-T drop top
1. Motor mounts w/ urethane bushings?

2. Good tires, shocks, & springs?

3. LSD?

4. Anything else?

4. urethane bushings on entire front end.
Jon @ tre recomends that the bushings on the front shocks are among
the most importain. ( also the easyest to install )

 

[jtmcinder]

While stiffening the upper shock bushings might help with wheel-hop, this whole thing really needs to be thought about carefully when the car is lowered. The front wheels on a 2G are connected to the car using a very funky twin offset lower ball joints. These cause lots of twisting on a lowered car when the wheels are turned. This twisting imparts a lot of stress on the shaft of the shock, because the twisting makes it such that that shock does not want to point at the middle of the upper plate. If you stiffen the upper shock bushings, this force can bend the shock's shaft or do some damage inside the shock. Better to just jump straight to pillow-balls (i.e., infinitely stiff upper shock bushings) than install stiff upper shock bushings.

- Jtoby <- about to send his shocks out for a rebuild