Live Wire

James Clay fell in love with the S65 V8 engine—and the E92 M3 wrapped around it—but he wasn’t satisfied with its performance until he’d made his M3 a supercharged screamer.

Live Wire 1
January 20, 2017

Ask any enthusiast what makes the E92 M3 special, and almost everyone will name the engine, a high-revving V8 derived from BMW’s Formula One-inspired V10.

“I love the engine in that car, and I don’t think it’s on the horizon for BMW to ever make a normally aspirated V8 engine like that again,” says James Clay, who as the owner of BimmerWorld Racing has raced more than a few fast BMWs, including an E92 M3.

Thinking the car would be the last of its breed, he bought one for the road just before production ended. To make it extra-special, Clay ordered his car in medium blue paint from BMW Individual and with blue stitching on its black leather seats.

“After going through the hundred or so colors that you can order from BMW Individual, I decided to order Santorini Blue,” he says. “I took Performance Center delivery, and in the front room was this dark blue E92 M3. ‘That’s cool,’ I thought. ‘I wonder who’s getting that?’ Then they told me it was mine!”

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Rather than Santorini blue, Clay’s car had been sprayed the darker San Marino, an M6 color.

“It was too late to order another one, so it came down to take it or leave it,” Clay says. “I’ve grown to love it, but it took me a while to warm up to it.”

Clay’s E92 M3 was delivered in June 2013, and he started modifying it as soon as he got it home to Virginia.

“I’d already planned the basics, with wheels, exhaust, intake and suspension,” says Clay. “The tricky part of being here [at the BimmerWorld shop] is that we’re constantly working on developing new parts. This E92 M3 started to become a bit of a test mule, because we needed an E92 M3 to test parts on. It’s become a little over the top.”

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The process may have been inadvertent, but the result is no accident.

For the last naturally aspirated M engine, a supercharger

“I wanted a car that makes me sweat a little when I drive it,” Clay says.

Ironically, that meant boosting the naturally aspirated 4.0-liter S65 with forced induction. Clay installed a Roots-type supercharger that uses Eaton’s TVS (Twin Vortices Series) technology, with twin four-lobe rotors and high-flow inlet and outlet ports. The kit was sourced from Harrop, an Australian company that builds superchargers for OEM applications.

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“They really know what it’s like to engineer something properly and get it to fit well,” says Clay. “The typical issue on supercharging these cars is [getting equal filling of the cylinders]. Getting the plenum to direct air correctly on a centrifugal charger is critical, and having a Roots-type twin-screw charger takes away some of that problem. This type of charger is a perfect complement for the S65 V8, which doesn’t have a lot of low-end torque. It develops boost at the low end, so it really reinforces the weak point of the motor.”

On the other side of the engine, Clay fitted BimmerWorld’s own Tri-Y equal-length headers and freer-flowing exhaust system, also with the goal of producing more usable low-end torque.

The mods take power from 414 hp and 295 lb-ft at the crank to 465 hp and 350 lb-ft at the rear wheels, figures that Clay expects will improve as the engine accumulates more miles. A JB Racing lightweight flywheel and a Diffsonline limited slip differential (with the stock ratio) complete the drivetrain modifications, while a higher-volume CSF radiator and coolers for engine oil, steering and transmission fluids ensure reliability.

Bigger brakes, stiffer springs

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The E92 M3 was built before BMW got serious about high-performance brakes, so Clay installed a Performance Friction (PFC) Z54 front brake package that’s nearly identical to the setup used in BimmerWorld Racing’s E92 M3s. The kit replaces the stock single-piston calipers and 360mm rotors with four-piston calipers clamping 372mm rotors. At the rear, a PFC Z45 brake kit replaces the stock single-piston calipers and 350mm rotors with four-piston calipers and 355mm rotors. All PFC components weigh less than stock, which reduces unsprung weight as well as rotating mass. So, too, do the 20-inch Forgeline GA3 6061-T6 alloy wheels, mounted with Nitto Invo tires.

Reducing unsprung weight improves handling, and so does a set of Hyperco springs rated three times stiffer than stock. They’re used with Motion Control Suspension monotube dampers adjustable for rebound and compression (via a single switchable knob) as well as ride height. Ground Control front camber plates and an assortment of BimmerWorld suspension bits like bushings, bearings and arms complete the chassis upgrades.

Race-car fast…and loud!

Clay’s E92 M3 may look nearly stock, but a push of the starter button makes its extensive modifications evident immediately. It’s loud, race-car loud, and as I pull away from BimmerWorld headquarters I wonder if I’ll be able to endure it for the 140-mile drive to Virginia International Raceway for the IMSA weekend. This car was made for fast weekend drives, not long road trips, and you can pretty much forget about listening to the radio or hearing GPS instructions—or even talking with your passenger. (If you must subdue the supercharger whine, BimmerWorld offers a carbon insert that blocks the intake vent on top of the hood.)

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The car has ferocious acceleration to go with the sound, particularly in the midrange, and the prodigious power keeps the traction control working overtime. Even with DSC, careful throttle application is required to avoid overwhelming the rear rubber exiting turns. And it’s easy to get exuberant, since the upgraded springs and dampers improve handling notably without much harshness.

To get a feel for the speed of this car, it’s best to find a long stretch of road, nail the throttle and hold on as the car rockets through the gears and the exhaust note goes into another dimension. When the experiment is over, the Performance Friction brakes provide great stopping power and pedal feel, though I’d need to make repeated hard stops to get a full sense of their capabilities.

As extreme as it is, Clay’s M3 remains easy to drive around town, with tractable, user-friendly power delivery belied by its ear-splitting exhaust note. Again, though, it wasn’t really built for civility, and to complain about the noise is to miss its essence.

“At the end of the day I love what it is, with its sound, power and handling,” says Clay. “It could certainly be tamer, but I’m not taking parts off to make it tamer. It’s how I like it.”

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