Looking to upgrade your 135i to a 1M or your 328i/335i to M3 standards? Is your suspension not as desirable as you thought after you put on aftermarket springs and shocks? Well if the answer is yes, pay attention. We teamed up with the guys from Performance Technic in Pleasanton Ca. to show you how to rectify this. After countless emails back and forth with Performance Technic we were able to put together a package of M suspension parts that will upgrade you to 1M or M3 standards. The following is the article that Joe Gaffey wrote for the BMW Golden Gate Chapters monthly magazine Bombe.
335i Suspension ///Mprovements
by Joe Gaffey
The 335i is a great model with potential for big power, but the suspension is a little on the soft side for performance driving. After purchasing a slightly used 335i sport and driving it around for a month, it was obvious the suspension needed some attention. Since it was a turbo model, it also made sense to add a little more power in the form of software.
First, the run flats came off in favor of a slightly wider wheel and tire combination. I went with Dinan Stage II software and their Stage I suspension system. The suspension upgrades consisted of new Dinan springs and Dinan adjustable Koni sports. The power increase was amazing the first time I drove the car, but the suspension still felt really soft. The car didn’t feel very balanced when driving through turns. It seemed like anti-sway bars could probably be the fix I needed. Looking under the car revealed that the rear sway bar is sandwiched between the rear subframe and body. It gave me the idea to swap out the subframe bushings if I planned on dropping the whole subframe just to change the sway bar.
Once the rear subframe was removed, I noticed the bushings were no match for the power coming out of this car. A little more research on the Internet and it seemed that a few others had found this as well.
Since we were going to take the suspension apart in the rear, I decided to check the front for areas needing improvement. The front wishbone arms and thrust arms use a hydraulic-style bushing that is able to flex a lot, but can also provide a softer ride and feel. This is great for street driving back-and-forth to work, but not the kind of handling I preferred. Some 335i and 135i owners were already swapping these front arms out to achieve a little more negative camber, plus the more performance-style bushings that came installed in the Motorsport parts.
After looking under more than a few e9x M3s, it occurred to me that I could probably borrow a lot of parts. The new 1M was borrowing the entire suspension from the M3, so I compiled a list of everything I knew would work. The rear subframe is unique to the M3, so I knew some of the M3 parts wouldn’t work. Once the part list was completed, I was looking at new control arms for the front and back, along with the M3 sway bars. We also threw in the M3 strut bar which allows easier access to the adjustable Koni struts. Lastly, the subframe bushings were replaced with M3 bushings. I had to replace a few other smaller partsto make sureeverything had a factory fit and finish. The last job was a proper alignment to get everything to come together.
This sort of upgrade may seem a bit extensive, but with the price dropping on the 335i and recent gas prices hiking up, the 335i is becoming a lot more attractive. I am happy with the upgrades and achieved an M-like feel from the handling that just wasn’t there before. Overall, the car has been transformed and handles beautifully while still giving a nice ride. Steering response is much better now and I can really feel the road while driving. I have to say that this may be the best upgrade to perform on the suspension. Perhaps that is why BMW took the entire suspension from the M3 and stuffed it under the new 1M Coupe. If you want that Motorsport handling for your 335i or 135i, these parts are direct bolt in and will transform the handling. Thank you to Dinan and IMBMParts.com for helping me find and source the parts for this project.
These are the stock arms from a 135i/335i
Upgraded M3 arms installed
You can see the size difference between the sway bars here
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