Cruising at 75 mph on the highway, the Dinan S2-335i is hardly breaking a sweat. Even in the sixth gear, with the revs below 3,000 rpm, torque is so abundant that if you find you need to pass someone, the process goes from the speed of intent to the guy in the right lane eating dust in no time.
Try this number for size: 429 lb-ft of torque at 3,700 rpm. That’s 46 lb-ft more than the M5’s 5.0-liter V10, at 2,400 rpm less, and 129 more than the stock 335i. The horsepower figure is 398, 98 higher that the stock engine’s.
The standard, mildly boosted twin-turbo 3.0-liter inline-6 seems custom-tailored for Dinan. Still the engine upgrade was more than 14 months in the making. Dinan’s software engineers spent most of that time cracking and then tweaking ECU. The reprogrammed computer raises boost from 8.8 psi to 13. Without increasing turbo lag. Peak power comes at just over 6,000 rpm, then rapidly falls off. Although the stock 7,000-rpm redline remains, anything north of 6,200 rpm is simply not worth it as Dinan significantly dials back the boost at that point to keep the driver from destroying the engine or cooking the turbos.
Temperature control has been the Achilles’ heel of the 335i engine since day one. Dinan dealt with this issue by increasing water pump flow and developing a high capacity oil cooler. It also fit’s a huge intercooler, which mounts in the factory location but offers 93-percent more volume.
The S2 wears Dinan’s Stage 3 suspension setup, which consists of custom lowering springs, Koni adjustable shocks, 28-mm front and 15-mm rear anti-roll bars and front camber plates that add an additional half degree of negative camber. The car is equipped with forged 19-inch wheels shod with non-run-flat Michelin Pilot Sport PS2 tires, 265/30ZR19 in the front and 275/30ZR19 in the rear. Massive 15- and 14- inch Brembo brakes lurk behind the lightweight wheels.
Modern BMWs equipped with optional sport suspension suffer from a variety of ailments. With the factory’s staggered, run-flat tires (there’s often a 30-mm difference in width front to rear) understeer is prevalent and harshness exaggerated. The S2, with just a 10-mm difference between front and rear tires are and the extra negative camber, banishes practically all traces of under steer, and amazingly, the ride quality is improved. The Dinan S2 costs $64,000 U.S. and the various components are sold separately.
Engine: Turbocharged 3.0 liter inline 6
Power (bhp): 398 @ 5700 rpm
Torque (lb/ft): 429 @ 4300 rpm
Transmission: 6-speed manual
Base price: $64,000
Sat, Oct 11, 2008
Rare Cars