Project M3 with its new D-Force wheels from UUC Motorwerks and suspension upgrades
In part 7 of our series (et 1/09) we unleashed a usable 12whp peak with a cat-back, pulleys, throttle body and coils, then we made sure it was running cool in part 8 (et 2/09). This month, we're set to improve the car's handling.
Because our M3 is daily-driven, we initially chose not to make it stiffer or lower. An M3's stance is already fairly aggressive, and with a stock suspension the ride and handling are perfect. In fact, in '97 Car & Driver chose the E36 M3 as the best handling car over $30k, which included exotics costing more than twice as much. So the challenge would be to improve the handling without introducing too many compromises.
Before changing anything, we decided to test the car against a different set of wheels and tires. Our previous setup employed ultra-light 17x8" SSR wheels with inexpensive 235/40 Sumitomo HTR+ tires (et 9/07).
With outer tread blocks (left) to promote elasticity and stability, our Conti SportContact
For the last two years the tires have worked well through the changing seasons in Kansas City. But how good were these all-season M+S tires for spirited drives in the warmer months? To find out, we ordered a Racelogic PerformanceBox from VBox USA.
Using GPS technology instead of standard accelerometers, The PerformanceBox accurately measures acceleration times to any distance or speed as well as lateral acceleration. The information can be viewed in real-time or logged onto the supplied memory card for viewing on a laptop. It can also display altitude, calculate wheel and flywheel horsepower, and has compass and velocity readouts as well. We'll be playing more with it as the project progresses...
For our baseline test we performed a series of passes through a 180 turn that could be taken at around 60mph in third gear. We recorded our average G-force through a defined sector as well as peak G-force. Bear in mind, this isn't skidpad testing, which takes the average G-force through a portion by calculating sector time on a flat surface. We're simply looking for the improvement with a new suspension part through this turn only.
As with dyno testing, certain factors were taken into account to maintain accuracy. That said, the same driver tested the unloaded car with the same half tank of fuel, in similar weather (40-43F), with the same tire pressures (37psi cold) on a still day.
Confirming our satisfaction with Project M3's handling, the stock setup provided moderate understeer, making it easy to throw the car around and find the grip limit. We managed to average 0.95G using our PerformanceBox, but our peak registered a spouse-scaring 1.09G
Our handling upgrades included UUC SwayBarbarian adjustable sway bars, StrutBarbarian magn
The first order of business was ordering a set of summer tires to maximize the current suspension and get more from future upgrades. For this, we mounted 235/40-17 Continental SportContact2 tires on a set of D-Force semi-forged wheels from UUC Motorwerks. At 17x8.5" they weigh the same 16 lb as our slightly narrower SSRs, and the extra width will help with grip.
Once they were installed, the car felt slightly stiffer because of the stronger sidewalls. At our test turn, the extra grip was instantly apparent, and the higher levels of grip took more testosterone to get the most from them. Keep in mind, the low air temperatures don't favor summer tires at all, and yet the setup averaged 0.99G through the turn, and a peak of 1.12G. Yet we could expect considerably more in warmer weather.
To improve the handling without compromise means not lowering the car, so we looked to stiffen the chassis. In '95, BMW supplied the "X-brace" chassis stiffener in the M3 Lightweight and Z3M to reduce body flex under hard cornering. While regular E36 M3s got a single "I-brace", their subframes were pre-drilled for the X-brace. So we ordered ours from Bavarian Autosport - our one-stop shop for all our factory BMW components.
1. Starting at the front bar, remove both end-links. If the bolt wants to spin, using a na
2. Remove the 13mm nut from the bushing brackets on each side. The bar can now come off
8. Using the supplied grease, lube the urethane bushings to prevent squeaking
4. In order to reduce understeer, MKC set the front bar to full soft using the bottom hole
5. When removing the rear bar, MKC found access to the bushing bracket by removing the rea
6. Pushing down on the spring perch or brake rotor to release the spring. Once out, access
7. Before putting in the new bolts in the UUC end-links, ensure they fit. The holes on nee
8. Fitting the bar around the exhaust requires wiggle room, or you can remove the cat-back
9. We set our rear bar to "medium" to lessen the oversteer. Pictured here is the passenger
10. To finish installing the bar, secure the bushings using a 16mm socket on one side of t
11. Refitting the rear springs didn't prove as easy as taking them out...