johnd

My car has right rear wheel hop on heavy acceleration in first and second gear.
Car has a track suspension, urethane bushings (new), FLTA2 suspension Kit, 12kg front and 9kg rear. Has Martin Wilson's kit. Racing Beat rear sway bar, Mazda Speed end links. 255/40/17 Yokohama Advan Neova AD08. Any suggestions?

tbone heller

Are you using urethane bushings on the rear differential mounts? Those along with installing a set of door bars helped mine some.

charchri4

Interesting door bars helped wheel hop. I'm glad to know that!

johnd

Tbone, thanks again for jumping in. I will check the condition of the diff bushing. I have the FM frame rail reinforcements. Will install when time permits. My car definitely flexes in the center. This is probably a main contributor to the problem if you think your door bars helped.

tbone heller

Everything that I added seemed to improve the situation.

charchri4

John how did you come out on this? I suffer from the same problem even with insane chassis bracing. I have not tried replacing the diff mounts yet but will when first thing. Too bad there is no good way to stiffen up the rear diff mount on it. Wonder how nasty it would be to just go solid...

MRM331

I had a lot of luck alleviating this with my first car when I went to urethane differential nose bushings. That car had relatively low power and brand new stock suspension bushings so that seemed to be all it needed. My second and third builds had a bit more power. Adding urethane upper differential bushings took care of most of the wheel hop on those cars. My current and most recent car has a lot more power than the other three. It has the wheel hop pretty bad even with all urethane differential front and upper bushings, (old) urethane suspension bushings, all the 1994+ bracing and door bars. Here's my thoughts and plans for it:

1. The donor car came with the current suspension bushings. I don't know what the brand is but they are blue and FM used to carry them. They were installed without zerks and never greased yet do not squeak. I'm thinking the reason they do not squeak may be because they have worn themselves out (a little dry rust dust is always present near the bushings). I think replacing them with new urethane or IL motorsports bushings may help the wheel hop issue. I'm currently leaning toward the IL motorsports bushings.

2. Like many V8 Miata owners I've removed my rear sway bar to give the car more "bite" when exiting a turn. I've read that reinstalling the stock bar with good end links may help alleviate wheel hop by equalizing the two sides of the suspension. This sounds like a pretty cheap (free) experiment which I'll try next summer.

So, in conclusion, things that have helped me with wheel hop in the past:

-Urethane Differential bushings-Modified Miata ones for the uppers and Cobra IRS ones on the nose.

-New rear suspension bushings.

-Bracing the rear of the transmission (see my posts about this in my build thread).

-DIYRoadster door bars (to a certain extent)

-Using 2nd gear for burnouts, not 1st.

And things I hear may help that I have not tried myself:

-Reinstalling stock rear sway

-Reinforcing your lower control arms by welding metal across them

-Creating a set of trailing arms (not sure of the geometry that would be required to make this work...)


Hope that helps,
-Jason

charchri4

I'm running the fancy flyin miata V8 rear bar and never tried the stock one. It would be like going from 4 gauge to 24 gauge and as an autocrosser I'd just a soon run the big one if I can. My wheel hop really is not bad, just happens now and again if I bang 2nd hard. It's not worth spending a lot of time on but I have seen lots of damage done by wheel hop so I thought if it was an easy fix I would take care of it.

My diff and control arm rubber is stock and has well over 150,000 miles on it. One short coming of the 8.8 diff is the only urethane rear mount is 300 bucks. The front ones are 30 so I'll probably change those and figure out something DIY for the rear. A 3/8s bolt run through the thing would stiffen it right up!

cvx_20

I've used this approach a couple of times:

v8 Miata Forum - Home of the v8 Miata Conversion - jreid1000's Album: Jim's LS V-8 Build - Picture

It uses another set of the same bushings as used on the front.

Mike

charchri4

Hey that is good stuff Mike ^^ THANK YOU!!!