We left off in the E46 Racecar project series with pro skateboarder Rune Glifberg's 2003 BMW M3 receiving an six-point chrome-moly rollcage, fully fabricated and welded together by the metal artisans at Evosport in Huntington Beach, Calif. This was an important step in terms of race chassis prep, and quite possibly the most important safety system the car will receive. Now it's time to look at performance upgrades.
We'll start with the body mods. The great thing about this E46 is that it will be a dedicated track toy, so no purely cosmetic modifications (aside from the screaming orange cockpit and blacked-out fender gills and kidney grilles) need apply. By completely stripping the interior of all the unnecessaries-upholstery, back seat, carpet-this E46 already weighs significantly less than it did when it rolled off the dealer lot.
Even more weight savings couldn't be a bad thing. Evosport first punched out the factory roof panel and sunroof assembly and replaced it with a pure carbon fiber panel supplied by Vorsteiner. The new roof weighs just 6.5 pounds, saving around 40 pounds alone over the factory section.
The trunklid was replaced in similar fashion with a Vorsteiner V-CSL carbon piece. Vorsteiner offers a dry vacuum woven plastic (DVWP) unit, but this is the more expensive piece, full carbon on both the top and bottom, for estimated weight savings of 17 pounds. The hood was replaced with a Vorsteiner VRS Vented GTR panel, DVWP with carbon fiber vents (20 pounds lighter than stock). Finally, the glass rear window was knocked out and the gap sealed up with a Lexan panel, also sourced by Evosport, for a further 20-pound savings.
All told, the body panel replacements shed nearly a hundred pounds. The car tips the scales now at just under 2,900 pounds, so including what was pulled out of the interior, this E46 is about 500 pounds lighter than its factory weight-and that includes the six-point cage and the Sparco racing buckets bolted into the forward seating positions.
Speaking of those, the seats themselves are a Sparco Pro ADV on the driver side and a Sparco Pro 2000 on the passenger side, utilizing Evosport billet aluminum floor mount adapters. Both are fitted with Sparco harnesses. The quick-release steering wheel is a Sparco Mugello.
The stock shifter assembly was replaced with a unit from AutoSolutions, called the Ultimate Kit. Evosport likes it because it includes a lower carrier arm engineered to maintain proper transmission input rod alignment, using the same input angle as the factory system, to prevent premature wear on the transmission.
Chassis prep continued underneath the car with a full complement of proprietary Evosport and Evosport-recommended underpinning upgrades. First, to negate any inherent flex in the drivetrain connection points and essentially hardwire the system into the chassis itself, the squishy factory mounting bushings were replaced with solid metal units. These include a three-piece Evosport aluminum differential set and aluminum Evosport engine and transmission mount kit (four pieces, black anodized).
Likewise with the suspension. Solid rear shock mounts were procured from Ground Control, along with a rear arm "street stability" kit, which uses metal shims to shore up the rear trailing arm bushings and prevent excess travel to keep rear-wheel toe in line and optimize the tire contact patch to the drive wheels. Evosport adjustable rear lower control arms were added to enable rear camber adjustment and further dial in the suspension. Up front, Ground Control lower control arm bearings were added to, again, negate flex found in the factory units.