Street Legal…and Sold Out

To celebrate the M3’s 25th anniversary, BMW let us loose at Ascari in the limited-production M3 GTS. With each of 150 examples already sold, it was an extra-special day in a superlative BMW.

August 24, 2010
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For the M3’s 25th anniversary, BMW has given itself and 150 customers a very special present, a car that every track day enthusiast would be happy to have in the garage. The new M3 GTS is, in effect, a street-legal race car, at least in Europe. As such, it’s an E92 M3 whose weight has been reduced, reflexes sharpened, ride height lowered and aerodynamics improved.

It’s also an E92 M3 whose motor has been modified to produce another 30 horsepower and 30 lb-ft of torque—numbers that can’t do justice to just how special this eight-cylinder powerplant truly is.

The heart of any car is its motor, and the GTS uses the naturally aspirated S65 V8 already well known to those familiar with the current M3. Here, however, stroke has been increased from 75.2 to 82.0mm via new pistons and rods, bumping displacement from 3,999cc to 4,361cc even as bore remains the same at 92.0mm.

The steel crankshaft remains as original, as does the S65’s 12.0:1 compression ratio, but each of the two twin-cam cylinder heads have been ported and polished. A modified intake system improves gas flow into the cylinders, and spent gases are extracted via new headers and downpipes, more efficient primary metal catalytic converters and the beautifully crafted, ultralight Akrapovic titanium muffler, whose distinctive acoustic signature contributes mightily to the beefier, more intoxicating exhaust note of the GTS.

With the fuel and ignition curves in the ECU remapped to take all these mechanical changes into account, power goes from 420 hp at 8,300 rpm to 450 hp at the same engine speed, while torque increases from 295 lb-ft at 3,900 rpm to 325 lb-ft at 3,750 rpm.

Zero to 62 mph tumbles by 0.2 seconds to 4.4 seconds, the standing kilometer (0.6214 miles) is covered in 22.5 seconds instead of 23.3 and the unlimited top speed goes up to an impressive 189.5 mph from a restricted 155 mph.

One of the truly great engines

As impressive as those numbers are, they don’t tell the whole story. To say that the change in the engine’s character is spectacular would be an understatement.

I have long thought that the standard M3’s S65 felt a tad restricted. This is partly down to the 3,476-lb. weight of the car, and partly because the 4.0-liter motor has to rev out some to deliver its torque. Even blipping the throttle at rest gave the impression that the flywheel could be lighter.

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