Wow what a difference. I just had M7 springs, Alta lower control arms and an R-SPeed sway bar installed, along with SSR Comps and Yoko 100s. Hard to zero in on what it responsibe for what, but the whole package just flat out rocks.
Got a chance to grind some corners this morning and the car now has super hero grip and balance. The wheels and tires make it feel like I have new brakes and acceleration is noticably snappier as well. Cornering is a trip. The car stay flat and low without any of the lean that I had become used to.
I do have 2 problems however and this is the reason for this post.
First, the guy who did the install for me discovered that my right, front, upper strut mount is cracked. He says it's rather common, and almost always just on the right side. Have any of you had this same problem? I was concerned that the dealership I go would have a problem since I have evil aftermerket springs now, but they assured me that they would replace the cracked mount later this week. We'll see how that goes.
Second, I now have a moderate shudder/vibration while under hard acceleration. It's mostly from the right front so that mount could be the culprit but I read another thread where someone complained of vibration after lowering spings and the SM at the dealer diagnosed it as a CV joint that had worn itself a groove and now since the geometry of the car had been altered ny the springs, it would take some miles to wear a new groove. This theory sound a bit weak to me as the geometry is constantly changing with passengers and cargo being added and subtracted. And my car is incredibly smooth while at constant speed. No vibration or shudder what so ever. I tried a number of cruising speeds and it's perfect. But under WOT, especially from a stop, there's a pronounced shudder up through 3rd and about 60 mph.
Like I said, the strut top will get replaced Wednesday and hopefully that will solve my problem. But if any of you brainiacs out there have any onther ideas I'd love to hear them.
Other clues: I had the car 4 wheel aligned after the install. The wheels are freshly balanced. No other suspension mods.
Thanks

 

...well here's my experience:

I've had 4 different sets of springs on my car since day 1, almost 28k miles ago. My car occasionaly has a shudder/vibration under acceleration, however it seems to be a function of engine power and [front axle] rotating mass (as in the more power, and the lighter the wheels/tire/brakes, the more prone to vibration....not proven, just a theory), and not ride height. The worn-groove-in-the-CV-joint theory doesn't hold water due to the virtually equidistant mileage on each spring set.

About the front strut mount being cracked; I'm guessing you mean the rubber bushing part of it is split concentrically between the strut mount hole and the outer casing that mounts to the chassis. Yes, this has been known to happen, but only if you've hit a massive pot-hole. In my experience you'll bend the shock-tower before you'll crack the strut mount, but you might've gotten strange luck and had it happen the opposite. Nevertheless, please replace it ASAP, it's literally barely holding you car up!

I hope that helps out!
Cheers,
Ryan :smile:

 

Post a picture or two?

 

First replace the right upper strut mount and see if the problem is gone or much better. If the problem persists then check if anything else got damaged as a result of the cracked strut mount since you don't know how long you had it.

Your improved handling is a function of "all" those things you did plus the alignment. Just be careful not to test it too much before wednesday and stay away from those road hazzards which can be especially bad now that you have tuned your suspension.

 

I to have just installed the M7 springs and have the same vibration problem. The vibration starts around 26mph and then fades away. I have also adjusted the toe but have not installed the chamber plates. I'm thinking of buying the plates now as they will raise the car about 1/4 of an inch and allow me to adjust the chamber. I will be intrested to hear any solutions to the problem as I really don't want to drive the car until it is fixed. Rodger Krause Racing will be looking at the front end tomorrow to see what could be wrong.

 

I have the M7 springs and koni yellows on my car and there is no vibration whatsoever. I also have the rdr camber plates and h-sport rear arms but even before the alignment there was no vibration. I tell ya the yellows are tight.

 

Billcooper,
Could be the strut top mount which has the rubber mounts. Not sure but the rubber mounts could be causing the vibration. The camber plates especially the RDR are solid and might eliminate you vibration...

 

The guys at BMW Center in San Antonio fix the broken mount and the vibration was reduced by 90%. There's still a hint remaining but it's insignificant. Just gat back from All Mini Track Weekend in College Station and my car is just a blast all around the track. Acceleration is way better due to the weight savings from the SSRs and the sway bar and springs made a world of difference in the corners. The weekend was great fun. There were more instructors this time and I got some terrific tips and criticism from a couple of them. My times improved dramatically and aside from one "off track excursion" my girlfriend and I had a blast. A couple guys weren't so lucky though. One went off in the same turn I did but found a rock to slow him down. He ripped the bottom of his bumper off, broke a wheel and mangled some suspension bits. Worst of all, both front airbags fired $$$. Another guy caught an edge in a fast turn and rolled a couple times. He and his instructor passenger were unhurt but the car is a mess. Overall though the weekend went well. I think my problem was having so many new parts without time to really get to know what to expect while driving hard. I know that my new sway bar altered my car's dynamics in the turns and it deffinitely takes a bit to get used to. I think that may have been an issue in the 2 wrecks I mentioned above. Both cars were pretty extensively modified. I noticed that the car that met the rock had it's sway bar (a red one so I'm assuming Minimania) on the stiffest setting. And it could have been something that simple that suprised the driver in that corner. Everyone walked away and that's the most important thing. And I know, I walked away smarter for my experience. Thanks for your suggestions here. And thanks to the great and patient instructors at the AMTD.

 

 

LMAO