Ross Fowler wasn't expecting to be lined up for the final race in the BMW M-versus-AMG class in the Shift Sector half-mile race in Portland, Oregon, especially not against an 800hp, twin-turbo E63. In fact, just making it to Portland was a miracle in itself. Two weeks earlier, he was driving his new C63S off the dealer's lot and heading straight to his tuner, ACG Automotive in San Diego, California, for some mods to make the car more competitive. Only problem was, those parts didn't exist.
Nevertheless, James Wie and his team at ACG had a plan of attack. They started by taking out the ECU, a nine-hour process that required removing everything between the bumper and the engine and sending it off to Evotech Motorsport in Germany for some new code. Then they pulled the transmission so they could remove the stock downpipes and take measurements for a pair of freer-flowing, cat-less downpipes.
While the downpipes were being welded up, ACG got together with KW for a set of new V3 coilovers, also the first of their kind for the new platform. And then they called HRE for a set of custom-spec RS101M (19x9-inch front, 19x10.5-inch rear) wheels with the hopes that the rear 295/30-19 Toyo R888s, which tend to run a bit wide, would fit without rubbing. And they did.
While waiting for the ECU to arrive from Germany and the downpipes to get finished, ACG had the car covered with Auto Armour's Expel Ultimate paint protection film, in this case a satin finish that gives it a matte sheen. They also painted the silver trim and three-pointed star for a complete monochromatic effect.
Before they installed the re-programmed ECU and new downpipes, the car was dyno'd for baseline numbers, 400 whp and 441 w-lb-ft or approximately 460 hp and 507 lb-ft to the crank on 91 octane. With the new downpipes and ECU tune, the car registered 531 whp and 585 w-lb-ft on VP MS109 race gas. The dyno chart shows the gains start early with a huge torque spike that starts at 2,600 rpm and then peaks at 3,400 rpm and plateaus until 4,900 rpm. The steep curves of the modified car make the baseline curves look like speed bumps.
Compare the baseline's 340 w-lb-ft at 2,950 rpm to the modified engine's 480 w-lb-ft and you get a good picture of the differences. And at 3,400 rpm, the chasm becomes even more dramatic, with torque peaking at 585 w-lb-ft compared to the baseline's figure of 420 w-lb-ft.
And that means you barely have to nudge the throttle to dial up serious velocity. On the tight, twisty two-lane roads on my test drive, you didn't need full throttle to make things interesting, nor did it require the full rev range. With so much grunt in the low- and mid-range, and power dropping off after 5,600 rpm, going for the redline was unnecessary.
The freer-flowing, cat-less downpipes emit a gruff and gravelly sound that tickles your eardrums and gets your adrenaline flowing. ACG also bolted on an iPE Valvetronic exhaust system that you can switch from muffled to wide open. The exhaust pipes are slightly larger 3-inch pipes compared to the stock 2.75-inch pipes.
One area that M3s always seem to have an edge over their C-Class adversaries is in the chassis department, with the M3s feeling sharper, more tossable, predictable, and stable at the limit. The KW V3s keep the hefty, 3,935-pound chassis stable, flat, and free of wasted or un-wanted motions that detract from the experience. Dive under hard braking and squat under hard acceleration are kept to a minimum, and the car turns in sharply without much body roll and doesn't ask for many steering corrections to get through the corner quickly. The Toyos, essentially a street-legal track tire, offer uncanny amounts of grip, testing your nerve and daring you to push harder. The front tires give ample warning when they start to lose traction, which is easily corrected with a slight lift of the throttle or a brush of the brakes. ACG swapped out the stock front brake pads for Endless MX72 pads and added braided stainless steel brakes lines for a firmer, faster-reacting pedal. The brakes bite early in the pedal stroke and are a welcome change compared to the soft, hard-to-modulate brake pedal on recent Mercs. All of this adds up to a chassis that can devour the twisties without drama, carving fluid arcs corner after corner. It's easy to imagine this modified C-Class keeping up or pulling away from an M3/4 in corners.
Fowler handily beat the BMWs that competed in the M vs. AMG class that weekend in Portland and found himself lined up against a Weistec-tuned E63 featuring bigger turbos and a claimed 800 hp. On their first run, Fowler said neither car got off the line as well as they could've and they both crossed the line at the same time. The photo finish was deemed inconclusive so they lined up again. Fowler said he made sure to keep the car in second gear and in Race mode during the roll out, hoping that would help him get the jump on the E63. From then on, he just prayed the E63 wouldn't reel him in a half mile later.
He nailed the start and managed to hold off the E63, crossing the line at just over 150 mph. Even if he'd lost to the E63, Fowler and Wie would've called the weekend a success because just getting the downpipes fabricated, the engine tuned, the suspension installed, and adjusted in such a short time seemed insurmountable when the car first came in.
But that was just phase one. Wie said they're working on bigger turbos, going the hybrid route by machining the stock housings to accept larger turbines. With those in place, 800hp E63s will need to up their game to even pose a threat.