BILSTEIN B16 (PSS10) COILVOVER KIT FOR BMW E46 M3 Coupe 48-126687

Street / Track Recommended Use Case

The E46 M3 is already an exceptionally capable chassis, so our goal with the B16 isn't to turn it into a race car. It's to give the car more control, useful damping adjustment and a better-supported chassis while keeping the refinement that makes an E46 M3 such a good road car.

Out of the box, we see this as a true Street / Track suspension. It can be driven every day on the softer damping settings and still be comfortable enough for normal road use, but it gives you enough control to start doing autocrosses, HPDEs and occasional track days. The supplied progressive springs are 342 lb/in front and 565 lb/in rear, which is a good place for a dual-purpose car without pushing the suspension toward the spring rates we'd normally associate with a much more serious track build.

Adjustable damping

The B16 gives you 10-position damping adjustment, which is useful on a car that may be doing two different jobs. For street driving we'd generally stay toward the softer side of the range and let the suspension move. When you're heading to an event on a more aggressive tire, you can add damping support and then bring it back down again for the drive home.

We think the standard package works well with normal performance street tires and moderate 200TW tires. Where we'd start to look elsewhere, or consider revalving the dampers, is a car moving toward a very wide Super 200 front tire, R-compound tire, fixed seats, roll bar and more serious track use. The B16 can be developed farther by a competent damper tuner, but that isn't what the standard valving is designed around.

Monotube and inverted construction

The B16 uses monotube dampers with the gas and oil separated by a floating dividing piston. That gives the damper a large working piston and helps maintain consistent damping as temperature and workload increase.

The front struts use an inverted design, which gives the strut a very strong structure for dealing with the side loads generated by a MacPherson-strut suspension. The rear dampers are also mounted shaft-down, which keeps more of the damper mass attached to the chassis rather than moving with the wheel. It's a thoughtful piece of hardware and a meaningful step up from a basic twin-tube replacement damper.

1W/car Setup Recommendation: Ride Height and Rake

The B16 provides a substantial range of height adjustment, but we would resist the urge to set an E46 M3 based purely on the tire-to-fender gap.

The front fender openings on these cars sit visually lower than the rear, so trying to make the gaps look equal can result in the front of the car being set much too low. We prefer to retain something close to the factory rake and keep the front suspension high enough to preserve useful travel and front-axle geometry.

There is a tendency in the BMW world to really drop the front of an E46 for appearance, but that's not where we think the car works best. Set the ride height around the suspension and the way the car drives, not around making the fender gaps perfectly level.

Front top mounts

For most street and occasional-track cars, the factory front top mounts are a very good choice. They're durable, quiet and they preserve the stack height the suspension was designed around.

This is important on the E46 because the OE mount has an unusual relationship between the spring and damper stack heights. Some aftermarket camber plates shorten the damper stack significantly, which can drop the front of the car farther than intended. The installer then has to raise the spring perch or add substantial preload just to recover ride height, which can leave the suspension with very little droop travel and make it easier to unload the inside front tire.

If you need additional camber for more serious track use, choose a camber plate that has been designed to preserve the appropriate spring and strut stack heights for the E46. Unlike some higher-end motorsport dampers, the B16 does not have an independently adjustable damper length to compensate for a poorly designed top mount.

Rear shock mounts

While the suspension is apart, we do recommend considering an upgraded rear shock mount.

The original rear mounts are relatively soft, and there are good aftermarket replacements that use a stronger stamped-steel construction with a properly compliant rubber bushing. That can give the rear damper a more stable mounting point without turning it into a solid connection.

We would avoid excessively stiff rear mounts on a street car. The rear shock still needs enough compliance to accommodate normal suspension movement without introducing unnecessary side loading into the damper.

Tires and track use

For a street-driven E46 M3 on a good summer tire, the standard B16 package is already more than enough suspension for most owners. It also gives someone who is starting to attend track events enough adjustment to learn the car and make meaningful changes without immediately moving into motorsport hardware.

If you're progressing toward more serious track use, talk to us before simply adding stiffer springs, large sway bars or aggressive camber plates. A modest spring-rate change can be accommodated within the B16's adjustment range, but there is a point where revalving or moving to a more track-focused damper becomes the better answer.

Our goal is to make the fewest changes necessary to get the result you're after rather than stacking parts onto the car because they're available.

Why we trust BILSTEIN

BILSTEIN has decades of experience in original-equipment suspension development and motorsport, and that background shows in the construction and durability of the B16. The monotube dampers, inverted front struts, matched spring package and application-specific damping aren't there just to add features. They're proven solutions from a manufacturer with a long history of building dampers that last.

We put a high value on that with the E46 M3 because this is already a very well-engineered car. There are opportunities to improve what BMW had to compromise for cost, comfort and a broad range of drivers, but an aftermarket part isn't automatically better because it has more adjustment or a lower price.

The B16 costs more than a lot of coilovers available for an E46, but we think it's worth it. It's a durable, well-developed suspension that can improve the car without asking you to give up what makes an E46 M3 so enjoyable in the first place.

For a car that still sees real street mileage but is starting to spend time at autocrosses and track days, that's exactly where we think the B16 belongs.