Powerful, fast and luxurious, today's crop of sports cars is without question more capable than their ancestors. Spend a few minutes in a new M3, SL or 996, and it becomes almost laughably obvious. And while credit must be given to the engineers who built them, you start to wonder if in making these cars so good, they've also made them somewhat detached from the driving experience.
There is a growing trend among serious gearheads to get back to their roots, be it an aircooled 993, GTI 16V or, in BMW's case, the E30 M3. If you wanted an example of German excellence, this car would do just fine.
Spawned during the mid '80s, the E30 M3 was thoroughly refined road car with all the equipment needed to homologate it into a pure competition machine.
The E30 M3 Sport Evolution was BMW's counterpunch to the Mercedes 190E 2.5-16 Evolution, a multi-wing creation which produced a rapid reaction from Munich. The M3 was built to an exacting set of specifications to comply with the FIA's Group A Touring Class regulations, which required an initial run of 500 road cars. Unlike the later E36 and E46 M3s, the original E30 M3's main purpose in life was to win races on the track, not the street. It got the job done.
Beginning with an off-the-floor 3 Series coupe, BMW gave its Motorsport division free rein to build a winner. After experimenting with several different engine combinations, BMW Motorsport settled on the M10 block as the starting point for its S14 plant. The original M3's head design was essentially a sawed-off 2.3-liter version of the 3.5-liter inline six unit from the M5/M6 line. A forged crank, improved oil flow and stout internals filled the short block. A Bosch Motronic injection system fed the four-valve head, the engine ultimately cranking out a respectable 192 bhp at 6750 rpm. It was linked to a close-ratio, five-speed dogleg gearbox hooked to a limited-slip diff.
The basic 3 Series suspension package was retained but augmented with thicker anti-roll bars, firmer springs and dampers and lower ride height. Extra-fat fenders were installed to accommodate larger running gear, and a pronounced spoiler and wing aided aerodynamics.
Over the next few years, BMW advanced the Evo program. Though significantly more expensive than a standard 3 Series, the M3 sold out every year. And they remain a most coveted hunk of machinery.
Gustave Stroes, a Ph.D of mechanical engineering and certifiable car maniac, has continued development of his 1988 M3 and created what is arguably the finest street/club racer we've seen. With pieces from the factory bin and parts he developed on his own, Stroes' M3 resembles what might have been had BMW continued the exercise.
"Since I first acquired my 1988 M3, I considered converting the engine to a 2.5-liter 'Evo III style' unit," said Stroes. "That day came sooner than I expected when I spun my #3 rod bearing at Laguna Seca in November 1999."
That mishap set in motion this grand adventure.
"There are a bunch of custom 2.5-liter S14s running around the racetracks of this country, putting out anywhere from 250 to 300+ horses," said Stroes.
"But the risk is that in developing the top-end power for the track, you may lose driveability at lower rpm. I like to autocross my M3 (as well as track it), and for this purpose it really helps to have a wide powerband. Thus my thinking was to build an engine similar to these 'monsters,' but to back off a bit on a few of the specs in order to retain higher flow velocity and therefore a little more torque in the lower part of the powerband. I figured I would be happy if I came close to the lower horsepower range of the truly high performers."
The engine was fitted with an Evo III crank, featuring an 87mm stroke versus the stock 84mm dimension. While it increases in displacement to 2.5 liters, it also provides a big increase in torque. The internals include forged 95mm JE pistons with Total Seal rings and Pauter rods linked with ARP fasteners. The block itself is a "seasoned" unit with polished crank journals to reduce stress risers, and the timing chain tensioner is an uprated and preloaded BMW S52 unit from an E36. Running a heady 11.35:1 compression, APR fasteners are used throughout the engine--better safe than sorry.
The 16-valve head was ported by Don Fields and retains stock intake valve sizes. According to Fields, the porting job is aggressive but not over the top. The goal was to retain flow velocity at lower rpm. Thus the stock-size intake valves were retained as opposed to the larger Evo III units. Stiffer Evo III valve springs are employed in order to handle the accelerations imposed on the valves by the higher lift Schrick 284/276 cams. A Turner Motorsport adjustable cam gear allows additional fine-tuning of the torque curve.
Fields then enlarged and ported the throttle bodies to Evo III specs. They now have 48mm butterflies, while the stock units are 46mm, a cross-section increase of almost 9%. Fields matched the throttle bodies to accommodate the larger, 48mm butterflies and ported the remaining body to match. The result is not quite as efficient as the Evo III units, but it's close--and far less expensive. The larger throttle bodies are matched to the larger Evo III intake trumpets to keep things balanced. The intake plenum is an extremely rare BMW Motorsport unit (one of only three produced) fabricated from carbon fiber; it weighs a paltry 1.5 lb. A larger Evo III airflow meter works with BMW "Big Green" injectors and specially tuned TMS/Conforti Software.
Stroes developed his own GSP Magnecor ignition wire kit featuring a low-crossfire design.
"The ignition wires on the E30 M3 have always struck me as odd--the way they are crammed into that small, hard plastic loom does not seem like a very good idea. Moreover, they tend to rub up against each other at various points along their path," said Stroes.
"The insulation surrounding the ignition wires can start to wear through and allow crossfire to take place between the wires, which in turn causes the engine to misfire. The effect may be subtle, but there will be a reduction in power nonetheless. The dust cover fitted over the distributor makes things even worse. It causes the ignition wires to come together at a point almost as soon as they leave the cap."
Stroes fabricated a bracket from 2024 aluminum alloy and treated it with a hard black anodizing to prevent scratching and, more importantly, prevent it from acting as a pathway to ground. The unit includes MSD wire separators and mounts in the stock valve cover location. The wires are from Magnecor, considered by many to be best wires available (they're certainly the most expensive), and use a metallic inductive-suppressed conductor to transmit spark energy rather than copper. The end result is not as tidy as the factory's solution, but in this case it's more functional.
The M3 exhales through an Evo III exhaust header and a custom GSP 3-in. stainless-steel exhaust with a Borla Y-pipe. The header is connected with a 0.5-in. GSP oversize flange that offers great sealing and thermal characteristics. GSP also supplied the gapless exhaust clamps that feature band clamps welded to stout stainless-steel tubes.
All told, the engine produces 225 whp with 173 lb-ft of twist--and it has the reliability of a framing hammer.
The oiling system was augmented with a Canton Mecca remote cooler, mounted under the air intake, and an Accusump 3-qt quasi dry sump system mounted in the trunk. Stroes retained the factory radiator but modified it with a 318ti fan switch. The a/c and mechanical fan and clutch systems were removed for additional weight savings.
The suspension is comprised of Ground Control's height-adjustable coilover package, which uses Eibach 450-lb springs in front and 700-lb springs out back; Koni adjustable dampers reside at each corner. Ground Control provided the front camber plates, spherical-bearing control arm pivots and heavy-duty rear shock mounts. Aluminum front control arms and reinforced rear trailing arms are supplemented with the original anti-roll bars (19mm front/14.5mm rear). BMP's spherical-bearing drop links have been adjusted for zero preload at static ride height.
The transmission is based on the European close-ratio "dogleg" box, held in place with BMW E28 transmission mounts. A UUC short-shift kit makes shifting chores more precise and offers an adjustable-height lever. The entire assembly sits about 0.5-in. lower thanks to BMW 750iL engine mounts. A BMW Motorsport limited-slip diff features a 75% lock-up, runs a 4.10:1 ring and pinion and includes an M Coupe finned rear diff cover. The driveshaft was modified with an E35 M5 "guibo," a flex disc much more robust than the factory unit.
Stroes retained the factory brakes but removed the ABS system and replaced it with a Tilton adjustable proportioning valve--the brake pads are a secret recipe. Earl's custom braided stainless brake lines are at each corner, and the rears are now one-piece instead of two. Evo III brake ducts were modified to accept 4-in.-diameter "desert ducts," and first-gen "Bimmerworld" brake backing plates have been reworked to accept 4-in. hose. Volk Racing provided the running gear--forged TE-37 (ET 38) wheels measuring 8x17 and using 18mm BBS spacers. These 15.5-lb. wheels affix to hubs modified with a TMS wheel stud kit. Stroes uses Kumho Ecsta V700 rubber measuring 235/40WR-17.
The body is clad largely in Evo III components, including the rear wing, front undertray, mirrors and front grille. Stroes designed his own front splitter for a fraction of what a factory unit cost and has it set at position four. "This splitter project started off as an experiment to see if I could, or would, see any benefit in buying a real Evo III splitter," said Stroes.
"This one worked so well and was so 'disposable,' I choose to keep it and not buy the real thing. After all, it's a track car, not a show car."
The cabin has been rigged with a Sparco Corsa driver's seat and Sparco Evo passenger seat. The rear bench was removed and a gorgeous four-point custom rollbar was fabricated and welded in place by Sean McLean. Willans six-point harnesses keep the occupants firmly in place, while Stroes mans the MOMO steering wheel, modified with a GSP quick-release hub.
Stroes has meticulously documented the development of the M3 on his Web site: www.e30m3performance.com. It is perhaps the most methodical, informative and no BS assessment of a project car this writer has ever seen, produced by a person obsessed with building a better M3.
Judging by the purity of the end product, I'd say Stroes succeeded--and then some.