ASP

To summarize my issues the rear end of my car pulls left and right under heavy acceleration to a point I feel it is unsafe. I am pushing out about 580hp at the wheels so traction is a problem but not the cause for the car acting this way. I have a quiafe diff in there and had it before I installed my MB arts stability toe arms and never had this issue before. I can't even floor the car on the freeway going 60 because when I do the traction light just blinks and the car pulls me into other lanes. Please let me know if anyone else ever had this issue, I am leaning toward the MB arts bars since it's the last thing I've done to my car after this issue arose. The alignment is 100% to factory specs except for camber being -.5 off in the front and -1 degree in the back.

tbal

wow wish I had that problem LOL...

What size tires you running in the rear?

ASP

I am running 285 hankook's

chiromikey

plenty of reading on this subject. try the keyword "wiggle" to get started.

tbal

hankooks are garbage!!!!!!, try a better tire that sticks! It should make a difference, a lot people over look this, but not every tire is the same.

I've found falkens to hook better than hankooks, but Im sure somebody can suggest better tires than falkens/hankooks...

tbal

I saw a post talking about `waggle`

Here are some tires people with traction have used with success...
Pirelli Rossos, Nitto NT555R2, and Conti Sport Contact3s

AMGPilot

Did you check your MBArts arms for contact marks? I'm betting that your arms are bottoming. That also tends to bend the camber adjusters on the MBArts arms

ASP

Thanks for all the help guys, I did notice my tires rubbing against the fender slightly but nothing that I would think might cause this. I will roll my fenders tomorrow and see if it gets any better.

tbal

Also I noticed I get better traction in comfort mode rather than sport1 or sport2... (sport2 especially causes a lot of "wheel hop")

ASP

Yes I have definitely noticed that also, so basically it's my tires ? I had these tires on the car for a few months really noticed the problem only after the mbarts toe arms. But it is possible that a hp increase might have caused it also since I did do a 180 ml pulley and fixed a tensioner that was not keeping the belt from popping off at all, at the same time. I guess I will just raise my car up and see if it still shoes the same symptoms.

shardul

iTrader: (1)

i think tires are your problem. get some Dunlap SP Sports of Nitto Invos.

mikey33

I have never heard anybody on this forum claim to put down 580 to the wheels. What mods u have?

cls55

i have cls55 with 295 PS2 ,quaif,520 rwhp and i have this issue.

Rust bucket

Better tires.

ASP

180ml pulley, 82ml throttle body, ported manifold, ported sc inlet/output, EC long tubes, EC stall, custom 3" mandrel bent exhaust with resinator and cat deletes, Custom heat exchanger, green filters that will do it on the performance side and got a quiafe and mbarts stability bars.

FlyByNight

I have had this issue forever... it started after I went with a Kleeman diff and 285 PS2s 4 years ago. Since I couldn't see any rubbing whatsoever, I started leaning towards the diff (and the other hp increasing mods at the time). I had it like crazy on drag day in Fontana in 06... UNTIL i put the stock tires back on... gone!. So, I know there is some dynamic here I haven't figured out other than the obvious tire size issue. For me, it also gets worse on sport 2. If I raise the car and leave it on soft, it works best. When I went to 295 PS2s on 20s it stayed the same. Again, I have chalked up the wheel well, driven around the block and can't find any detectable rub. So weird. I have undone all of my washer lowering (and rear bolt adjustment) and it is better, but still sways. And yes, at 60 if I mash it, it is downright scary. I lose many a race off the line as traction control spazzes out and the car wiggles to 65 or so. I'm going to replace the tires with 285s next time around and try and find some sort of compromise. I too have posted on this subject for ages, and just when I thought I had it licked (extended my wheel wells, custom metal job), it returned after a while. Ugh.

wsybert

Just a thought... could the control arms be moving so much that they are putting the rear alignment out of whack? Would better bushing material help?
I don't know the suspensions on these cars well enough to know if this is a consideration.
Bill

AMGPilot

You already have your answer. the stock tires with their taller sidewalls are providing more directional stability since they are loading up less than the rubberband sidewalls you have with your 20's (A horrible choice for drag runs and handling anyway due to the centrifugal force increase over the 18's because of that the 18's will ALWAYS be faster) Even if you heim jointed your rear suspension you would have the waggle as the car bounds off the sidewall as you load them from a launch

FlyByNight

Well, I wish it were as simple as you make it sound... and I do like your fresh angle on the problem. However, I think there would be far more people with 19s and 20s with this problem if your assumptions were correct. The problem is there are way more people with low profile tires that don't have the problem than those that do.

And my first experience came with it merely after have Kleeman mods on the car (lsd, pulley, ecu) ... my existing Kinesis 19s with 285s then reflected the same problem, and they previously hadn't.

So, if your theory is true this happens on low profile tires on 55s who have crossed some sort of horsepower barrier with mods... which I would LOVE to believe.

As a note, yes, we know 20s aren't canyon carving champions... but not being someone that relies on my 55 to out handle anything to begin with, that's not a concern of mine. I have different sets of wheels for different things, and the 20s were awesome looking at the time. I wish they made this style in 19s... but they didn't.



Loren

AMGPilot

You can make any car have this issue especially if you have a tire pressure mismatch.

This is not a magical problem, it's a simple issue with a simple solution

KLR CLS

I make in the same power range, and have factory P030 LSD with 305 T1-R's. I have no such problem. Might be camber arms throwing it off somehow.

chiromikey

imho, it's more an issue of tire width compared to rim width more than sidewall independently. iirc, most issues were seen when people were mounting 275's on the stock rim or 285's on rims less than 10" wide and 295's on less than 10.5". obviously tires with a softer sidewall will be more prone to causing the problem.

ASP

From what I know I am running 285's on 10.5 inch wheels, also my tire's were rubbing and after rolling the fenders the stability issue got way better but still present. After doing some more work on my car I noticed that my front drivers side inner and outer tie rods were bent. This is weird considering I just got an alignment about a month ago and it came out to spec. I will change the parts tomorrow and hope this is the fix to my issue, and if not them ps2's are next on my list.

E55amg01

hello bro
did you find the issue cuz i have the exact problem as you and im not finding the problem the alignment its correct i dont know whats going on