Project90: Shocks

Welcome to another instalment of Project 90, our 2009 BMW E90 335i project car. In Part 2 we fitted the E90 with brand-new Michelin Pilot Sport 4 tyres and put the run-flat tyres in the bin. The new Michelins are a much softer tyre than those that came from the factory, so our attention is now on improving the car’s chassis and suspension to match. 

Our concept with these projects is to test our product range and apply them to our vehicles to gain first-hand knowledge of how our products perform - helpful confirmation of where we can improve or expand our offerings. We’ve mentioned some of the driving dynamics of our 335i were not to our liking, and so OEM like-for-like replacement parts were not the right path for this particular project. Our goal was to make the car we truly wanted, all while being cost-effective and usable for everyday use, and providing an example of how we could help others to do the same at home.

In the next two articles, we’ll explore fitting Bilstein B8 Performance Plus shocks, along with front and rear aluminum M3 control arms and subframe bushings to our 335i. 

BMW E90 Suspension Refresh

Let’s first discuss the shocks. We’re often asked what the differences are within the Bilstein range, and how they compare to the original BMW shocks. In short, there are three Bilstein options to choose from (for most vehicles), all of which are made in Germany to the highest standards. Here’s how they line up:

-- Bilstein B4: A direct replacement for the original shocks, offering a level of hardware and tuning that originally came on the car. 

-- Bilstein B6: A premium shock absorber with superior internal hardware and design, providing better vehicle dynamics for comfortable street performance. 

-- Bilstein B8: A premium sports shock absorber with superior internal hardware and design. For M Sport models, lowered vehicles, or those looking to upgrade to the best sports shocks for usable street and track performance.

To understand what ‘superior internal hardware and design’ means, it helps to understand a little about how new cars are produced. Underneath the shining paintwork and high quality soft-touch interior materials of a new car, many parts are made to a cost. The reality is that all car makers will strip manufacturing costs from areas that are not obvious to the customer, and unfortunately, the internals of the shock absorbers fall into that category. The damping hardware, while admittedly made to a good standard, simply lacks the sophistication of a premium shock absorber found in the likes of a Bilstein B6 or B8. 

Higher quality damping hardware allows for a much more finely tuned shock absorber to all of the different frequencies in the road surface, smoothing out the ride on big bumps, and helping the car to cope with multiple smaller jitters that are encountered in quick succession. Better damping control can provide the vehicle with more traction, cornering ability, and better ride quality, depending on how the shock is tuned.

The original suspension was engineered to be softer to accommodate the run-flat tyres from the factory, but many years on the road had already worn the original shocks out. Ride and handling are most obviously linked with a car’s shock absorbers, but one aspect that is often overlooked is the safety factor. Without shocks being in good condition, the tyres are not maintaining constant contact with the road when they need to, meaning the brakes, steering, electronic safety equipment (like traction and stability controls) all struggle to do their jobs properly. 

Although Bilstein B8s can be used with factory height springs, for this project we decided to match them with a set of AP lowering springs (also from Germany) to ensure we got the right balance of ride, handling, and looks. The combination of B8's with lowering springs gives owners the freedom to space out modifications, which is a great option for customers not looking to purchase a whole package all in one go. For owners considering upgrading their suspension all at once, Bilstein’s PSS coilovers (B8 internals with adjustable height springs) are our first recommendation. 

Our AP lowering springs come with the German government’s TÜV approval. They’re as low as is legal in Germany but still must be able to carry five people with luggage safely. The result of this is the rear was a touch higher than we would like, but certainly an overall improvement from the factory stance while retaining the everyday usability.  

Lowered BMW E90 335i on Bilstein B8s

On the road, and it’s no exaggeration to say that the combination of the Bilstein shocks and AP springs were a big transformation of the car, placing the 335i in that perfect sweet spot of something that’s daily driveable, but also a serious performer. It went from being a fast car to a fun car. 

What we loved most about the B8s is their ability to translate all of the feedback from the road surface back to the driver without being harsh or tiring on longer journeys. For us, it felt exactly how an M Sport vehicle should have been delivered from the factory – offering a notable improvement to the overall vehicle dynamics during more spirited driving, yet without the trade-off of being uncomfortable during everyday driving. A welcomed change of character from the 335i. We were getting closer to that classic BMW feeling we were chasing. 

Make sure to give us a like and follow on Facebook to see the next instalment of Project 90.

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