Too Cool, Too Hot, Too Late

A look at the rarely-seen-before mid-engined 1993 911 G93 IMSA racer.

Too Cool, Too Hot, Too Late 1
March 2, 2018

In the early 2000s, watching Porsche’s stretched-to-the-limit 911 GT3 RSRs struggle on the track against rivals like Ferrari, Corvette, BMW, Aston Martin, and others, the question of just how much longer the 911’s classic rear-engine layout could justify itself often arose.

While displacement had been punched out to a full 4.0 liters and the car had state-of-the-art suspension and engine management, frustrated Porschephiles were asking: “Why won’t Weissach produce a mid-engined 911 that offers the kind of performance, balance, and handling that its major competitors were bringing to the table?”

When the new mid-engined 991-generation RSR finally broke cover in late 2016, it was a radical departure from 53 years of past practice. The factory had swallowed its pride at last. Mid-engined was better in all respects. This latest iteration of the evergreen 911 is still a work in progress, but if past is prologue, Porsche will soon return to the top step of the podium. Part of

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that past must include some much earlier efforts by privateers to re-engineer the 911 as a production-based, mid-engined race car.

Although there was a short-lived effort back in 1975 by Australian Jim McKeown, the green 911 IMSA GTO racer seen on these pages—built in the early 1990s—may be the most extreme of these independent projects. Faster and better handling than anything else bearing the 911 name to that point, it ran headlong into political reality when it reached the race track. It was too fast for some people to swallow, a problem that Porsche seems to face on a recurring basis.

From Setback to Super Race Car

Kevin Jeannette, the founder of Florida-based Gunnar Racing, is well-known for restoring and racing important Porsche prototypes. He’s also built some very rapid 911-based race cars. The birth of this project, dubbed the G93—“G” for Gunnar (his son’s name), “93” for the year in which it was built—occurred when a medical student from Chicago asked Jeannette to construct a radical twin-turbo 1989 911 with 935 underpinnings.

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Then one of the student’s friends wanted Jeannette to create another along the same lines and provided another 1989 sunroof Turbo. But six months into the project, that client walked away, leaving the whole thing to Jeannette. So, what’s a free-thinker to do with this partially-built project taking up space in his shop? Craft a new GT race car, of course!

“The original FIA/Auto Club l’Ouest rules for a homologated car specified that at least 25 identical units had to be built,” says Jeannette, “but at the same time, ACO also wanted to get privateers and others to begin manufacturing GT-category cars. Therefore, it reduced the requirement to just one car. For 1994, IMSA adopted the ACO’s rules in full, and that meant I could build one car—not 25.”

Not wanting to run afoul of IMSA’s rules, Jeannette approached his friend Charles Slater, a fellow racer who had recently bought control of IMSA, and posed a specific question:

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“What would you think about a mid-engined, 962-powered 911 in GTO, if it were based on a production tub?”

Slater was supportive, but he took the question to his racing director Mark Raffauf. Raffauf sent Technical Director Amos Johnson over to Jeannette’s shop three times to talk. The GTO regulations stated only that the layout remain unchanged, i.e., a rear-drive car must remain rear-drive, but engine/gearbox placement was otherwise free.

Jeannette explained that he intended to install an “unlimited” (no intake restrictions) 3.2-liter, air-cooled, twin-plug, twin-turbo 962 flat six into the steel 911 monocoque, placing it so the engine was behind the driver and its five-speed transaxle was hanging out behind. Reversing the engine and gearbox end-for-end would allow the axles to remain in their stock position. But since the 962’s drivetrain is rather lengthy, the 911’s wheelbase would have to be stretched 3.0+ inches.

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“The rules said we could have a maximum of 95 inches, and we came in about 94,” explains Jeannette.

He already knew that IMSA was phasing out tube-framed cars in GTO, but if the car retained its unibody construction and the rear-wheel-drive system did not change, he believed it would meet the letter of the law. Johnson gave a green light. So far, so good—but Jeannette was by no means done.

“If we were going to move the motor forward to get better balance,” he says, “I thought, we might as well do everything we can to make this the all-time, really greatest 911.”

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Like NASCAR innovator Smokey Yunick, Jeannette found rules so broadly written that there was lots of room for innovation. Construction began in 1993, with Jeanette aiming for the 1994 season.

Function Over Form

Jeannette’s approach to engineering is straightforward: Identify a problem, then find the best solution, no matter how far “out-of-the-box” it might seem. Example: The G93’s driver’s seat is mounted right on the floor. With just a fiberglass shell and some padding, the driver can’t see over the instrument panel.

“If I can’t see over the dash—and I wanted a standard 911 dashboard in the car to keep the car in a stock street-going appearance—I’d have to cut the whole dash out of the car and lower it two inches,” says Jeannette. “But to keep the car symmetrical and looking good, I wouldn’t just lower the dash and windshield apron separately; I’d lower them along with the whole roof so the roof and standard window openings would come down approximately 2.0 inches.”

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Since the tops of the fenders have to match the windshield apron, he canted the roof. Rather than chopping it symmetrically and making it look like a 1952 Hudson or an old chopped-top Chevy, he lowered the front. He then altered the rear quarter window behind the B-pillar.

Tilting everything forward provided better airflow over the roof. That relieved Jeannette of the need to build a false rear window to maintain laminar flow to the wing, as the JLP 935s produced by John Paul Racing in the 1980s had done.

“We took the car out to Moroso Motorsports Park (Now Palm Beach International Raceway) and did a test with the yarn tufts and everything, and ran it at various speeds, and all the air ‘kept laminar’ right up to the rear wing,” says Jeannette. “The wing worked great without raising the rear window.” He stresses that he never cut the car in half, which is what Porsche did with its 993 in creating the 911 GT1 for LeMans. “The rule was given that if you mess with the integrity of the chassis, the stiffness or strength, it wouldn’t work properly.”

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Inside, the G93’s stock 3.0-inch-diameter torque tube was replaced by a 5 1/8-inch tube and moved forward to serve as an engine mount and make way for the modified rear suspension.

“So we regained that integrity by putting in the bigger tube which greatly improved the chassis’ torsional stiffness,” explains Jeannette. He says he borrowed that idea from Glen Blakely, designer of Preston Henn’s one-off 1982 935-L Andial Moby Dick racer. But another problem now appeared.

The stock door opening would not only give access to the cockpit but also to the relocated engine. So Jeannette shortened both doors by 2.0+ inches at their rear edges. He then brought the door jambs and rear quarters and windows the same distance forward, preserving the car’s proportions and sealing off the engine bay. Instead of having a huge vent window and side window and a tiny quarter window in back like a 1940 Ford, Jeannette made the quarter window larger. “It is a lot more appealing to see the larger quarter window because the roof is lowered and everything looks standard,” he says, “but it’s not.”

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Then, another issue: The quarter-panel distance between the rear wheel centerline and the relocated door jamb is now almost 5.0 inches greater because of the extended wheelbase and shortened doors. In fact, it appears that there’s almost room for another door. Jeannette’s solution entailed some visual trickery.

“I masked this by designing a ‘running board’ where the angle of attack or the curvature of the top of the ‘running board’ gracefully sneaks up in the corner,” he explains. “This gives you a sense of not seeing the 4.0-5.0 inch distance.” NACA inlets for the turbochargers were added to the “running boards” after testing; they pick up clean laminar airflow and avoid the dust and debris from the front tires. Jeannette also extended the taillight section 3.0 inches, matching the wheelbase change. The car, however, would not be finished in time for the 1994 season.

Late that year, the Gunnar team took it out for some test runs, starting with three days at nearby Moroso with Derek Bell. The names of John Paul, Jr., Charles Slater—who was paying for a ride—and the late actor/racer Paul Newman appeared over the driver’s door, but JP Jr. did much of the early testing. The first time out at track speeds, says Jeannette, everyone was amazed that the car did not understeer, as most 911s do.

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“When Paul really got on it, the car had big-time power oversteer because there wasn’t enough bite,” says Jeannette. “At the end of the day, the only thing he said was that the car needed more tire because of the power the thing was making. Speed is really a determination of a particular gear, but I like to think of the car as very slippery.” He notes that since there were no added downforce tweaks beyond the rear wing, it would be a lot more slippery than the 935s that were good for perhaps 220 mph. “If I took this car and trimmed it out, meaning that I flattened the wing, it would easily top 220 mph in a straight line.” That’s faster than a 962C.

Interestingly, says Jeannette, they hadn’t touched a thing on the car. “We didn’t change springs; shocks, or wing angle, nothing,” recalls Jeannette. “John called the car the best 911 he had ever driven, including the 750-hp JLP3 in which he won the 1982 IMSA Championship and was one of the best 935s ever.”

Another factor was tire size; later 935s wore 19-inch wheels at the rear, 15 inches wide. The G93 used 18-inch wheels, just 14 inches wide in the rear, which dictated a smaller contact patch. That was an important difference since both cars produced similar power. One positive was that the G93 would utilize the 962’s rocker-arm rear suspension, which was far superior to the 935’s adjustable trailing arms; but where the rubber hits the road, more is clearly better.

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“If we ran the car in IMSA,” says Jeannette, “we would have to run restricted, leaving us down 100 hp. That would help offset the smaller contact patch. We were pleased that all we had to do was put new tires on the car.” Stopping power was more than adequate, with 935 struts, rotors, and calipers up front, and huge 962-spec Brembos out back.

Politics as Usual?

Jeanette had what he believed to be an IMSA-approved GTO race car when he entered the season-opening Daytona 24 Hours. When he arrived at Daytona for pre-race testing in January of 1995, JP Jr. took the car out for a shakedown run. Junior, Newman, and Slater were all signed up to drive. Soon afterward, a stranger wandered by the garage, snapping photos and asking questions. Jeanette didn’t mind; he was flattered that someone was taking an interest in the new car. Then came a rude surprise.

While the crew was trying to resolve an issue with a hose that kept blowing off the intercooler, Mark Raffauf walked over and called Slater aside. Visibly upset, Slater told Jeanette not to take the car out again, that Nissan had seen the car and was angry that its own tube-framed GTO 300ZX Turbo was being legislated out of the series and it would be unfair to allow the G93 to run. As Jeanette tried to explain to Raffauf that the Porsche was not tube-framed and thus should be legal, “He would only say that ‘It’s politics, that’s all.’” Even Slater couldn’t help. There was even a suggestion that Nissan might even pull its planned sponsorship of the Daytona 24, but Nissan’s racing director at that time has told the author that no untoward pressure was applied.

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Slater told the author—without naming names: “We often felt political pressure from someone at one time or another if something new or threatening came along—ultimately it rests with those who interpret the rules.”

Dave Klym, the imaginative owner of FabCar, also built a couple of mid-engined 911s to race in IMSA, but those were tube-framed on a stock wheelbase and were to run with smaller engines. Although Klym, too, says his design had been approved before the fact, there was intense political heat when his cars appeared at the track, and they—surprise!—were disallowed.

In truth, it was more than politics. The FIA, ACO, and IMSA had all taken a major step in 1994 toward what they hoped would reduce the costs of racing. The new top guns of the Exxon World Sports Car series would be the open-topped WSC race cars, not the frightfully-expensive prototypes and factory GTs.

In an interview, Raffauf told the author: “We stayed away from the million-dollar-plus costs of the then-developing FIA GT1 cars both because of their absurd purchase costs as well as their equally absurd operating costs.” The new WSCs, said Raffauf, were barely half the price of the new factory GTs that Porsche and McLaren were planning to offer to their customers. The old GTO and GTU classes would be replaced with GTS-1 and GTS-2. Tube-framed, turbo cars were out.

“The decision to go normally-aspirated in GTO was simply based on cost and availability,” said Raffauf. “The turbo stuff was ‘manufacturer-centric’ and unavailable to customers without buying into the million-dollar vehicle package. Therefore, you could not get a turbo engine from someone as a customer to put into your tube-framed car.” Production-based turbo cars (i.e., Porsche’s 930) were to follow FIA rules with IMSA restrictors and were allowed.

But wait a moment. The rule change targeted tube-framed race cars. And the G93 was based on a production Porsche tub. No matter, IMSA decided that the G93 was illegal. To this day, Raffauf believes the G93 was a tube-framed car with a Porsche 911 GT1-inspired body, although the factory’s GT1 hadn’t yet been unveiled.

Needless to say, Jeannette was speechless, as he had invested a quarter of a million dollars in the G93 on IMSA’s go-ahead and now he couldn’t race it. Politics aside, one year earlier the car might have made an important statement; now it was just a great idea. Frustrated, Jeannette took the G93 home. He tried to enter it at Sebring the next season with Exxon sponsorship, but he was again turned away.

Later that year, a friend called Jeannette, saying “Your car is in the new issue of Autoweek!” Sure enough, in the December 4th, 1995 issue there was an artist’s concept drawing of a new, mid-engined 911—but it wasn’t the G93; it was Porsche’s new 911 GT1.

The 911 GT1 was intended to be an FIA homologated LeMans GT sports car. Despite its name, it had fairly little in common with a 911 except for things like its roofline, headlights, and taillights. Based on a Group C 956/962 floorpan, one of the only 911 production parts on the carbon-fiber monocoque was a 911 Speedster windshield. It featured a mid-mounted, twin-turbocharged and intercooled flat six with four-valve, water-cooled heads that produced some 600 hp.

While the GT1 and its Evo successor would go on to race with success, the FIA’s GT class would, as Raffauf had predicted, fade away due to excessive costs. Still, Raffauf muses of the G93, “That was a very cool car.”

A Rarity Comes Back to Life

For more than a decade after it was banished, the G93 slept quietly in Jeannette’s Florida shop, stripped of its engine and transaxle, but in 2008, its hibernation ended. Invited to display the car at the Porsche Parade in Savannah, Georgia, Jeannette embarked on a full restoration that included a fresh 962 drivetrain. It also included an update to 996 taillights (“I liked them better,” he says), installation of twin-caliper ATE brakes in the rear, and a full repaint to the car’s 1994 appearance. It also appeared under the “Big Top” at Rennsport Reunion V.

Notwithstanding some curious stares, most onlookers strolled past without any idea what they were looking at. Although it was drivable, the G93 hadn’t been sorted, so an audience that would have most appreciated its strange history never had a chance to see it on track, where it might have shown an impressive turn of speed. Jeanette planned to test it after returning to Florida, but the press of ongoing business meant that the G93 was pushed to the back of the shop where it rested until he pulled it out last spring and freshened it for the Luftgekühlt show in Los Angeles. Most of another year went by before it was truly drivable at Palm Beach International Raceway.

This most extreme 911—a brilliant demonstration of rulebook interpretation—never got the fair chance it deserved. Did a jealous rival manage to squelch the G93—or was it something else? We may never know for sure.

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