Hello everyone,
I think it's about time to help the community out with the BMW M3. Current vendors, installers, DIY'ers have all done a great job this far, and I feel that sharing 9 years of car building and engineering expertise into this mix will only be of help to everyone.
The car we are going to be talking about today, is the 2011 M3 Coupe, COMPETITION PACKAGE. Many have so far wondered what is different about the ZCP's suspension and have been skeptical about installing lowering springs. In general, many have opted that lowering springs are a poor choice for the BMW M3, especially the ZCP.
I will try to keep things as simple as possible, as I don't want the non-technical people to feel confused in any sort of way. The techy people, feel free to pose questions either in this post, or through PM, I will be glad to answer questions on findings, experience and anything else for that matter the best I can.
Common concerns to date with lowering the M3 (EDC and non EDC and ZCP cars):
1) Reduced suspension travel and articulation within.
2) Handling characteristics become worse than stock.
3) More uncomfortable, and unbearable to some.
Now, first lets discuss WHY most lowering springs, make the car handle potentially worse, and how we address this. From the factory, our beloved M's have very minimal front to rear "rake". Meaning, if you wanted to judge by wheel gap, the front has more gap than the rear. This is party due to the shape of the fender arch and of course how the suspension sits. ALL lowering springs kits lower the front more than the rear!!! This is not ideal, as creating an unwanted rake will create a bucket full of handling characteristics that we do not want. Most people install lowering springs for looks, and most manufacturers believe that keeping the same gap front to rear is ideal. Personally, I am not a fan of that look cosmetically, but that's subjective. Lowering the front will increase nose dive upon turn in, it will make the rear feel less planted, and it will also increase understeer under certain situations, and in turn, as a reciprocal effect, it can induce oversteer on a car has that tendency already.
Why are ZCP car's lower? Based on my findings yesterday and night, ZCP car's use a smaller/thinner spring pad than NON ZCP cars to lower the rear. Based on findings, the springs measure out to the same length in the rear. The front, unfortunately I did not measure as I was running out of time, but I will do that to see what they did for the front on ZCP cars. But on sheer observation, it looks that the spring perch sits a small bit lower than non ZCP cars.
What did we do yesterday to achieve a proper performing M3 that eliminates the gripes people have with lowering springs, including H&R's. On my car, we used the H&R sport springs for the BMW M3 and this write up will apply to all lowering springs.
What else did we buy and need and do:
1) 1996 BMW M3 coupe front bump stops
2) Reinforced rubber tubing (used as bottom coil springs pad in rear)
---REAR SPRING PADS WERE REMOVED TO MAINTAIN FACTORY RAKE
3) Strut guides were trimmed 8.5MM (0.35"). Once compressed with the 1996 M3 stops, we were able to achieve 0.66" more suspension travel. This is more than Dinan has been able to achieve as well.
***Pictures at the end of the first post to see everything done***
Now for the most important part.. Driving feel, performance and etc.
The car is even better than before. The ZCP suspension was already pretty brilliant and great, but it's now even better. It is extremely planted and controlled, EDC maintains it's dampening control and it isn't any less effective. All 3 modes are absolutely apparent with the car shining most in sport plus mode which should be pretty obvious.
Comfort? It's practically the same. If anyone can come take a ride in the car and complains, a beer and dinner is on me. The only noticeable difference is how much more controlled the vehicle feels through transitions and braking. There isn't much to be said in regards to comfort, because there isn't much change. Up to 130 MPH on an empty desolate road, the car is 100% happy and doesn't feel squirmy at all.
Overall, I am happy with how it all turned out, and I hope this helps a lot of you guys and gals out. It looks great, it feels great (as it should).
-Malek
P.S. Car is currently equipped with MS wheel spacers from EAS. 15MM front, 12MM rear.
REAR SPRING VS. H&R SPRING
TRIMMED FRONT GUIDE SUPPORTS
1996 BMW M3 COUPE FRONT BUMP STOPS
REINFORCED RUBBER TUBING ON BOTTOM REAR SPRINGS TO AID IN INSULATION. REAR FACTORY SPRING PADS WERE REMOVED ALL TOGETHER.
ZCP FRONT STRUT MEASUREMENT.
HOW SHE SITS
