Wheel hop issues

[Winter.M3]

Sorry, I know this issue has been talked about a bunch and I've looked at and done the supposed fixes for them... however I'm still having problems more then normal.

About a year ago I replaced my entire subframe with another oem one, and put in akg 95a black poly subframe and diff bushings.

Didn't want to go solid because the small risk involved and my car is a street car.

Anyways, at relatively light launches (hard launches are completely out of the question), on dry pavement, with 285 width ps4s, I feel like the car should grip... or at least break loose...? But nope, I've done the rear subframe work, and I still can't launch the car.

I don't do any hard launches which might be why it's not gripping, but I really don't want to push it. I've had my diff bolt break 3 times, and my diff completely snap on me. The diff snap was when I learned my lesson about the wobble, the other 3 times were completely coincidental. Is the issue me not sending it hard enough? I used to be able to launch it from a light dump at 3k rpm. Now if I try that I get the craziest wobble.

Just wanna hear if there's anything else I can do or if the car itself is just not built for launching, even with the mods I've installed.

[amrazM]

I have everything solid in the rear and still was experiencing wheel hop, the only thing that fixed it for me was adding monoball training arm bushings. Im guessing the wheel was bouncing.

[omgzirra_exe]

This also depends on your ride height and coilover settings, if you have them. Also, as stated, your trailing arm bushings could be torn or worn out, and replacing them with a monoball solution should still assist in some manner.

Did you also replace or get all your bushings inspected as well? If you have OEM bushings, those are soft, so they don't help much in this case.

Originally Posted by Winter.M3

I used to be able to launch it from a light dump at 3k rpm. Now if I try that I get the craziest wobble.

Going back to my questions, if you are low, your axles are no longer squared with the car. It is going to take some time for the axles to correct themselves as you accelerate.

Solid rear subframes do not correct this fully, but they do help, as they absorb more of the energy being transferred, which helps with improved acceleration and rear grip.

Wheel hop is usually caused by a multitude of factors: tires, suspension (hardware and settings if you have coilovers), temperature, and bushing conditions.

Additionally, not to disregard your concerns about a street car, but rear solid subframe bushings do not cause any NVH or create an unsafe driving scenario.

With that said, you can't fully eliminate wheel hop on these cars without going to the extreme of a diff lift kit to fully correct the rear suspension geometry.

[Winter.M3]

Originally Posted by amrazM

I have everything solid in the rear and still was experiencing wheel hop, the only thing that fixed it for me was adding monoball training arm bushings. Im guessing the wheel was bouncing.

hm ok. I'm looking at upgrading my entire front suspension soon. Maybe I'll try this while I'm at it. Haven't looked into this too much though.

Hopefully it'll fix my issue

[Winter.M3]

Originally Posted by omgzirra_exe

This also depends on your ride height and coilover settings, if you have them. Also, as stated, your trailing arm bushings could be torn or worn out, and replacing them with a monoball solution should still assist in some manner.

I'm surprised I haven't seen anything about this. I wouldn't say I'm an expert and have done tons of forum digging but I've done a fair bit especially on this topic. I will definitely be doing this soon.

Originally Posted by omgzirra_exe

Did you also replace or get all your bushings inspected as well? If you have OEM bushings, those are soft, so they don't help much in this case.

No I definitely should've but I thought the majority of all the problems and most of the actual performance that you could gain in the rear was just diff and subframe bushings. I did have an experienced shop (long term bmw techs, take pictures and insanely in depth diagnosis and checks) do the bushings and I would presume they would've let me know if there was a need / want to address the others. On this topic, what other rear bushings are there that aren't completely out of budget to look into replacing. Subframe and diff bushings were not very fun to replace and install for my pocket. If the others are somewhat easy to replace myself I wouldn't mind doing them.

Originally Posted by omgzirra_exe

Going back to my questions, if you are low, your axles are no longer squared with the car. It is going to take some time for the axles to correct themselves as you accelerate.

Solid rear subframes do not correct this fully, but they do help, as they absorb more of the energy being transferred, which helps with improved acceleration and rear grip.

Wheel hop is usually caused by a multitude of factors: tires, suspension (hardware and settings if you have coilovers), temperature, and bushing conditions.

Additionally, not to disregard your concerns about a street car, but rear solid subframe bushings do not cause any NVH or create an unsafe driving scenario.

With that said, you can't fully eliminate wheel hop on these cars without going to the extreme of a diff lift kit to fully correct the rear suspension geometry.

I'm on lowering springs, definitely low but on a bigger diameter wheel (19). Maybe it is out of line geometrically; however, I find it hard to believe it's as bad as it is. I used to launch before bushings upgrades just fine. Definitely still had normal issues though. I didn't do solid bushings as I have plans to make it a track car in the future and didn't want to go through the headache of a subframe cracking or something as I read stories of solid bushings doing so. I'm no professional and read that black poly bushings were the next best thing, and still a major upgrade from oem.

But anyways, thank you for the help! This is exactly what I was looking for as a response.

[omgzirra_exe]

also my launch control is set at 5.5K so it's much easier to be dramatic off the line...

[Winter.M3]

Originally Posted by omgzirra_exe

also my launch control is set at 5.5K so it's much easier to be dramatic off the line...

I wish I could do launches at that rpm freely... another clutch replacement is not on the to do list

side note I love your build looks great!

[amrazM]

some people get wheel hop and try to send it harder, I blew up my e36 m3 rear diff like that.