BMW e90 M3 LSL - Suspension
One hundred and thirty thousand miles on OEM shocks, bushings. Some of that with lowering springs installed by a previous owner. Time for a change.
The factory shocks with the lowering springs feel bouncy, with too much rebound or shot compression or just too much wear. The car crashes and rolls and just soft all around. To solve those problems the vehicle needs better bushings, better shocks and springs and better sub frame mounting.
With a wide variety of systems available I chose to work with MCS. Their shocks performed extremely well on some other builds with being very responsive, tunable and of high build quality. The valving works great and each adjustment has a significant change, impacting the overall feel. I did not want to deal with external reservoirs as the car would not see racing conditions to justify the components. Keeping in mind the goal of the vehicle and the LSL mentality - the setup had to be similar closer to what an OEM might come up with for a special model.
MCS offers the 2WNR shocks - which are 2 way adjustable (rebound and compression). The adjustment mechanism is quite unique in that the same little knob will do both, depending on position. You can click the knob down for one adjustment and release it upward for another. Easy.
The shocks are paired with Swift springs with front at 504lbs, with 168lbs helper and rear at 784lbs. This should provide enough compliance for roads and rougher tracks but also support the chassis well. Ground Control Race camber plates will secure the assembly along with their pivoting rear spring perches. The rear perches will pivot as the suspension travels, keeping the spring more square and not skewing the rate.
With better chassis control - need to ensure that there is minimal flexibility. Bimmerworld has a very comprehensive catalog of components to eliminate rubber and create a more direct chassis.
The rear subframe gets solid alum bushings along with the differential. Also eliminating the subframe side camber arm bushings in favor of nice sealed monoballs. The trailing arm bushings get replaced with a similar bushing. Also updating the front control arm rubber bushing to a monoball setup.
Bimmerworld uses nice sealed OEM like monoballs which will go a long way with reducing noise and increasing longevity. Monoballs are reliable and strong but most of the time they are exposed to the elements and wear prematurely - its not as relevant in motorsport due to increased service interval and more controlled conditions. BMW already uses monoballs on some suspension arms and I am merely finishing their job. A Porsche GT2RS (or 3RS ) does not have a single rubber bushing in the suspension, running the same sealed monoballs everywhere.
Im also adding adjustable drop links to aid in corner balancing the car (and the OE units are long dead) along with toe links. Ill address the bushings in the rear control arms at a later time if they prove to be too flexible.
One helpful note before installing coilovers is to measure the current ride height. This helps when resetting the car up, as you end up back in the ballpark of the alignment. This gives you the ability to use the car and have it drive more or less straight if you need to take it somewhere.
Getting new parts is fantastic, but installing them can be a “ride”. The rear subframe bushings are a real challenge. I decided to yank the subframe out with a friend, which was relatively easy. Using a press along with a lot of adapters and cylinders I got the bushings out, installed the Bimmerworld solid units. By the time that was done, we just wanted to get the thing back into the car.
I opted to do the rear monoballs, toe arms and diff mounts another time - for I could do those myself. Instead, we threw in the coilovers and set the car to previous ride height and camber. The trunk lining prevents easy access to the rear shock tower and over the tower itself was a rubber cover. I punched a hole in the trunk lining with a holesaw and re-used the rubber cap for a clean install. Easy access and looks intentional. The rear Ground Control spring adjusters are quite useful. Ride height tweaking is a breeze with easy tool access and a very effective design as the area is already so tight withouth easy tool access. No need to remove the wheels!.
Once the rear suspension upgrades are done, I will then corner balance the car and do a full alignment.
BMW e90 M3 LSL - Wheel and Tire
The E90 M3 was presented with 220 Style 19" wheels which featured a machined face and a 10 spoke design. The Fuchs-manufactured design fits the platform very well, but they are heavy at 29lbs and a bit narrow.
Commonly underestimated - the wheel and tire combo massively affects performance of a chassis. Low rotating mass, good grip and wheel rigidity is essential.
A forged wheel is a must and I went looking for something in the 18" range. I really liked the Style 219 wheels in that gunmetal color with the concativity and spoke design, but they are still a bit conservative on widths. Combing through the usual offerings I stumbled across the Titan7 brand via EAS. The manufacturing specs were very good as well as the price point. My usual go-to would be the Apex wheels, as they are a staple and I've owned a set before, great wheels to daily on and not worry about. As with the day-job - we try to stay on top of new brands, tech and offerings. The people behind Titan7 have a vast history in the industry and track record. The products resonated with my own standards for detail, design and execution. My other choice would've been the Bimmerworld wheels, but I wanted to deviate from the classic design some. Ill be looking to pick up a set of 18x10 for a square track setup, but for now the 18x9.5 and x10.5 fitment is just right. The wheels are designed for the platform so no spacers are needed and they are light at about 19lbs each. (also easy to clean!)
The tires for a daily application were a no-brainer - Michelin. I opted for the PSS tires because at the time the PS4S was not available for the front size of 265/35R18 (rear is 285/35R18). In my mind - these PSS tires are a gold standard with great wet/dry condition and cornering performance. The car sees a 70 mile daily commute and they maintain a level of comfort and holding their ground when called upon.
BMW e90 M3 LSL - Refresh
Primary concern was the engine and its health. Oil analysis of what was inside when purchased was perfect, and now, about 5 oil changes later, its still consistently clean with no sign of excessive wear. The actuators were slowly failing and I replaced those with new units. All else on the engine is clean, with no leaks or issues.
I serviced the vehicle fully with new Motul engine oil (Xcess 10w60) and now most recently with Torco SR-5R with which it runs great. Have yet to do an oil test with the Torco, but seeing how it performs in the Porsche engines - I don't think there is much to worry about, especially with its MPZ chemistry.
Replaced the differential fluid with Motul and had a full DCT flush, filter and pan refresh done by the experts at Performance Technic when I visited the Bay Area along with a full alignment check.
Installed new plugs, cabin filters and new engine air filter on the pre-existing AFE intake as well. Suspension showed normal wear and tear and is slated for upgraded anyway. Brakes were worn out and I just recently overhauled the whole setup.
The felt undertray thing was pretty beat up and was missing one side. It seemed only logical to go with a metal unit and I opted for the Turner part. Very strong unit thats well designed and rigidly mounts to the bottom of the car. I've now scraped it a few times, but it holds up well.
The car is driven 70ish miles a day and runs like clockwork. Only major things left would be a coolant flush (with a cooling system upgrade) and power steering flush. Need to get the GTS DCT calibration done as well.
A full paint correction and ceramic pro treatment was completed by Polished Detail in Orange County which brought the Silverstone paint back to showroom look along with a deep shine. All the gloss black elements are back to new as well. Being skeptical at first - the ceramic pro layers really do wonders for keeping the LA dust and elements from sticking to the surface. A quick wash every week or two is a much easier affair with the right soaps. The wheels got a treatment too and its night and day with keeping them free of brake dust.
BMW e90 M3 LSL - Intro
BMW e90 M3 LSL
Limousine Sport Leichtbau
2009-10-21
2010 BMW M3 Sedan
4.0L V8
DCT
Silverstone Metallic II
Novillo Palladium Silver
The BMW CSL vehicles were based on coupes with performance and weight reduction enhancements. Over the years BMW has made a few special sedans like the E90 CRT and now the F80 CS which follow the same mentality. I was always attracted by the notion of minimal, performance oriented machines like the E46 CSL and the spartan GT3 Porsche which maintained street sensibility with full track readiness.
While the E90 M3 CRT was a great technical exercise in carbon technologies it was still a fully loaded sedan which, in my mind, contradicted its purpose. It is also unobtainable. The sedans are unique, well proportioned vehicles. The S65B40 is a phenomenal engine, clearly built with purpose with the large intake, port matched individual throttle bodies and equal length headers. When paired with the DCT makes for quite the driving machine. Being around the Porsche PDKs brought me over to the double clutch world. The BMW DCT is a very solid unit, especially with the GTS update. My only real preference when seeking out the E90 M3 was to have minimal options along with the DCT transmission. I also liked the Silverstone Metallic II color as its less common and quite elegant in person. A 2010 sedan with 85k miles popped up with the sunroof and the leather seats as the only things I didn't care for. The car had failing throttle actuators which were an easy replacement and needed some general maintenance to refresh critical components. It came with lowering springs, primary cat delete and “exhaust mod”. It’s almost the perfect platform to start with to build the e90 M3 LSL (Limousine Sport Leichtbau). Its a sedan based nod to the CSL and how I believe the CRT could’ve been to some extent.
I am a professional working in the automotive aftermarket and motorsport industry and this is my personal R&D project building an e90 M3 LSL.
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