The modifications to our 2011 BMW M3 Competition Package are well underway. To date, we fitted carbon fiber pieces from BMW Performance and Turner Motorsport, including dash and door trim, mirror shells, hood and fender vents and kidney grilles. Mechanically, there's been a six-piston Brembo brake conversion, which are incredibly powerful, and some TMS wheel spacers to give the car more stability and a better stance.
This month, we're looking at fitting some lowering springs and new Forgestar wheels with Continental tires to further improve the stance, grip and handling.
Unfortunately, this is very similar to the mods on our B6 Passat project this month. We usually prefer to stagger the projects so we don't get conflicts, but every so often a plan doesn't come together.
Springs
The BMW M3 can be ordered with optional $1000 Electronic Damping Control that automatically adjusts the shock absorber settings to meet changes in vehicle speed, load or road and driving conditions.
Since our car had the $2500 Competition Package, it included revised EDC settings with an enhanced Sport mode, as well as reprogrammed stability control, 0.5" wider wheels and 10mm lower ride height than a stock M3. By changing the wheels and lowering the car, we were undoing most of its good work but we wanted to keep the versatility of the EDC system for a while longer before we eventually fit a complete coilover system. Therefore, we decided to fit a set of H&R lowering springs first on the recommendation of BMW road and race specialists Turner Motorsport (TMS).
Rear
1 BMW Hazet inner spring vice removal tool
Actually, they recommended the stiffer H&R Sport Plus springs that are geared toward track use but we opted for the Sport version since we wanted a little more comfort for the time being...
Our concern was that since the Competition package cars are 10mm lower than stock, the Sport lowering might not be noticeable. According to the TMS website, they lower the car 1" front and 0.6" rear.
As it turns out, the difference is just about noticeable and the improvement in handling is appreciated, without a significant increase in harshness. You definitely feel the road more precisely and gain sharper steering response.
2 Place Hazet silver discs into top and bottom of rear spring, pass shaft through control
As before, the springs were fitted by Derek Vieira, a tech at a local BMW dealer with intimate knowledge of the latest cars and installations. He brought a special BMW rear spring compressor to help out, but you can do the task as easily without one by using a jack under the control arm and lowering it slowly.
This task is certainly DIY but take great care removing the factory springs under tension. A lift and air tools are a definite advantage.
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3 Removed compressed spring
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4 Compress spring until it can be pulled out from control arm
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5 H&R Sport spring only slightly shorter than stock "Competition" spring but rates are di
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6 Place stock top and bottom rubbers on H&R spring before refitting. The lower rubber has
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7 H&R spring stiffer and harder to compress as much, so we removed bolt from bottom of da
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8 Slowly unwind spring vice to release tension and ensure rubbers are aligned and in posi
Front
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1 Disconnect EDC plug where fitted from top of strut. Then use 16 and 17mm wrenches to re
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2 Undo 16mm pinch bolt at bottom of strut. Then undo three 13mm bolts on top mount. Push
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3 With strut on bench, compress spring and undo 21mm nut on top mount to remove. Note H&R
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4 Fit H&R spring followed by washers and top mount in order shown. Spring is short enough
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5 Use 10mm socket and 21mm wrench to tighten top mount bolt to 64Nm
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6 Slide strut into lower clamp and finagle top under fender. Align studs in strut tower w