Compared to non-M E9x cars, with exception of a single rear trailing arm, every single suspension component is unique to the M3.
Aluminum subframe. Aluminum control arms. Aluminum everything in the name of weight savings. The suspension bushings are heavier duty materials. The suspension geometry is different due to the mounting points, pivot points and arm lengths. This results in different camber and caster as well as being different along their travel. The struts on the M3 mount over a much larger surface area into a much beefier front hub assembly. The M3’s springs are shorter and stiffer, the car is lower and compression and rebound damping are tuned differently.
In short, the M3 is an entirely different animal than any other 3-Series.
Springs and Dampers
The E92 M3 included 2 suspension options. Both are coil on strut in the front and a separated spring and shock combo out back. The standard suspension included non-adjustable dampening. This means the struts and shocks retain the same settings at all times. The optional suspension was called Electronic Dampening Control, or EDC for short. EDC equipped M3’s had the same springs as non-EDC cars, but the dampening on the struts and shocks could be configured to one of three settings by pressing a button labeled EDC, positioned next to the shifter. Available EDC modes are: Comfort, Normal, and Sport.
Springs on non-Competition Package M3’s are progressive rate, meaning they start off soft and gradually increase resistance through compression. Street cars generally use this type of spring. The spring rates are 160 lbs-per-inch up front and 550 rear. Converted to wheel rate, that’s 147 front and 185 rear.
Front Suspension Components
The front springs and dampers are a coil on strut design. All arms and components are made of aluminum, with M stamping – just so you know it’s an M part. There is an upper control arm and a lower control arm. The upper control arms and swaybar wrap up and over the steering tie-rods. An end link then shoots straight up to connect to a cast-aluminum lower spring perch residing atop of the strut.
Note in the picture above, the steering rack and tie-rod are mounted ahead of the axle. This is one design BMW uses to achieve the level of steering feel and precision they are known for.
Camber is not adjustable on the M3 from the factory but there is an alignment pin that can be pulled to give a little extra – maybe half a degree. Not much, but it’s something.
Rear Suspension Components
Unlike previous generations, the E9x shares nothing with any other M or 3-series when it comes to the rear suspension. The spring and shocks are separate. All arms are alumnium and bolt to a steel rear subframe. Camber and toe are adjustable in the rear from the factory.
Free Camber Mod
Pull the pin from each of the front upper strut mounts to gain roughly half a degree of negative camber. It’s better than nothing, and it’s free!
Adding negative camber to the front of the car will do wonders to reduce understeer on track days! Dinan sells non-adjustable camber plates, which are offer an advertised -0.7 degrees. At $200 for the pair, that’s not bad. You’ll spend double that if you want adjust-ability.
For track day junkies, you’ll want a fully adjustable plate. You might start your search with a visit to Vorshlag or Ground Control. Both are widely popular and sell camber plates for stock spring style or aftermarket coilovers. Plan on dropping $500.
Replacing the stock springs with an aftermarket spring will change the stance. You’ll want to be cautious, as a spring that is not matched to the damper (shock or strut) can result in poor handling and uncomfortable ride quality.
There are easily a dozen springs on the market for the E92 M3. Eibach, H&R, Swift and Vogtland, just to name a few. Of those, Swift’s Spec R springs are the only linear rate springs available for the factory dampers. Go with those if you’re looking for the most responsive spring to fit factory style dampers for competition purpose. They work okay with factory dampers, so long as they aren’t high worn and need replacing.
Shocks and struts are dampers and are partially responsible for ride quality and handling. They do so by helping the spring absorb bumps and return the suspension to optimal position, increasing traction.
Just like springs, there are a number of options out there, however, there is a wide price range for dampers. The performance gained from new shocks and struts truly depends on how much you want to spend. Lower end non-EDC dampers from Bilstein are available for about $400 for their OE replacement and upward of $600 for their B6 and B8 line, which are designed for aftermarket springs.
If you have EDC, know that replacement dampers are expensive (~$2,400 for all four). The only aftermarket solution is Bilstein’s B6 DampTronic shocks and struts. Supposedly they are very good, and much more cost effective at $1,700.
If you have EDC, but don’t want it, there are EDC-delete kits available that prevent the car from throwing codes and illuminating the gauge cluster. Then you can install any suspension you want.
The vast majority of suspension options for the E9x M3 are coil over setups. KW is popular for the price point under $2,000 but isn’t optimal for track days. If you’re performance oriented, you’ll want to jump straight to a clubsport coilover. KW and Bilstein offer track focused coilovers. Ohlins, MCS and JRZ offer them, too. These setups will run well over $3,000 but if shaving lap times is the name of the game, these are the options you’ll be entertaining.
The Good and Bad
|Suspension Geometry||Camber Limited Stock|
|EDC Dampers for Street||Limited OE Damper Replacements|
|Aftermarket Support||Expensive Aftermarket Options|