Project BMW M3 Lowering Spring & Wheels Install - Eurotuner Magazine

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).

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.

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.

Front

Wheels
I'm sure we've all looked longingly at the iForged website, dreaming about which design might look best, before having to take a deep breath when considering the cost. And while many people won't settle for anything but the best, the company has created a more affordable brand called Forgestar for the rest of us.

The idea was to bridge the gap between expensive forged and regular cast wheels with a range of flow-formed designs. The process uses high pressure applied to a cast rim to shape the wheel, reducing its weight, while giving it similar strength to a forged wheel. Heat-treating technology has also improved the resistance to impacts without needing to add more metal.

The proprietary flow forming technology means Forgestar can offer a wider range of offsets and widths to ensure aggressive fitments for a variety of vehicles, and clear high performance brake upgrades such as our six-piston Brembo big brake conversion.

With the new range starting with a handful of modern designs, we opted for the Forgestar F14 design with a brushed titanium finish (there are five standard finishes but infinite custom options, including pinstriping, matte, paint, polish, etc).

Our new F14 19x9" ET20 front wheels are the same dimensions as our stock "Competition" (Style 359M) wheels, but wider than a regular M3. The one-piece design is also significantly lighter compared to stock, making a noticeable difference to turn-in. We also increased the tire width from 245/35 to 265/35 to put more rubber on the road

On the rear we have a 19x11" ET23, which is a full inch wider than the 359M wheels and seem to have given the car incredible stability. Fitted with a massive 295/30 tire, it's almost impossible to spin the wheels now in the dry, and the DSC light flickers less frequently when the full 414hp comes out to play.

It's been suggested the F14 design is similar to the 359M, and they certainly bare a passing resemblance from a distance. However, we were going for an OEM+ appearance. We wanted them to be subtly different in design and finish, while giving us the mechanical advantage of less weight, a wider footprint and wider track. Mission accomplished.

Tires
It's a familiar story at eurotuner: we get a project car and fit Continental tires with H&R suspension. Right now this combination offers an unrivalled pairing of grip, handling and durability that's hard to beat. And while there are undoubtedly cheaper alternatives on the market, we repeatedly find that "you get what you pay for".

Regular readers will remember that the US-developed Conti ExtremeContact DW won our '09 Tire Test (et 12/09) outright and has been a popular choice for our project cars ever since. However, sales have been so good that supplies were low, so we were offered the ContiSportContact 3 as an alternative. Not only were these excellent tires fitted as standard equipment to our M3 "Competition" wheels, but the outstanding braking and agile steering abilities put it at the top of the list. The asymmetric tread blocks with the continuous outer shoulder helps responsiveness and cornering stability, while the center grooves help disperse water to great effect. Perhaps our only complaint is an increase in road noise because of the additional width. However, the sidewall compliance is exceptionally good.

As we said, we fitted a wider 265/35 ZR19 on the front and a humungeous 295/30 ZR19 rear on Forgestar's recommendation. Apparently, we could have gone to a 305 rear, but not without rolling the fenders. Although that's possibly something we can look to in the future.

TPMS
Every new car is fitted with a tire pressure monitoring system (TPMS) by law. It's designed to avoid accidents caused by sudden or slow tire deflation. It uses a radio transmitter in the wheel to send a signal to the car, illuminating a warning light if deflation is detected.

When changing wheels and tires it's often possible to swap the TPMS sensors from your OE wheels to the aftermarket set. However, we needed to keep our OEs intact, but wanted to avoid the annoying light on the dash we've had with previous projects.

The most convenient solution was to obtain a new set of sensors and valve stems from our local BMW dealer. You simply assemble them and screw into the wheel. After resetting the car's onboard computer, the system operates as stock.

We had the TPMS installed, tires mounted and wheels balanced at The Wheel Supply in Walnut, CA. Again, this is our regular specialist for wheel mounting because they offer a no-nonsense service with expert knowledge to overcome many of our unique fitments. If different nuts are needed, they always have them, or when spigot rings are forgotten, they're on the shelf ready for us. If you're in the LA area, we definitely recommend TWS for specialist wheel and tire sales, mounting and fitting.

Next Month
In part five of our M3 makeover, we hope to move onto some engine tuning with an intake, exhaust and software. Can't wait to hear the V8 breathing freely!

PART SUPPLIER PRICE H&R Sport springs (4) BMW Performance $318 F14 19x9" ET20 front (each) Forgestar $800.23 F14 19x11" ET23 rear (each) Forgestar $800.23 265/35 ZR19 front (each*) Continental Tire $325 295/30 ZR19 rear (each*) Continental Tire $406 TPMS sensors (each) BMW $83.64 TPMS valve stems (each) BMW $15.13 * prices from tirerack.com