Wickedly Civil
Behind the wheel of a rare 964 Turbo S2
Story and photos by Bob Chapman

With only one exception, a stroll around this stock 964 Turbo provides no evidence of its distinction. From nearly every angle, it looks like most other 964 Turbos from the 3.3-liter years. Which is to say, at the very least, it makes the soul ache with single-minded anticipation.

To these eyes, the 964 years marked the zenith of 911 Turbo aesthetics. Whereas color-keyed bumpers brought a touch too much civility to the Carreras of that 911 generation, they only served to call keener attention to the impiety of the Turbo’s wickedly jutting curves. The simple act of staring at a 964 Turbo’s rear fenders necessitates a trip to the confessional booth, this despite Leviticus’ ignorance toward any four-wheel-related depravity. But it’s from just aft of those rear fenders that the uniqueness of this particular Porsche becomes apparent. One letter and one number occupy real estate normally reserved for the Turbo script. Centered below the rear wing, this car says simply S2.

As the 1990s got underway, the nascent North American-based IMSA Supercar series garnered enough attention to attract the eyes of Hans-Joachim Stuck, who reportedly lobbied Weissach to support an entry. IMSA designed the series for near-stock mid- and high-end production sports cars like the Chevy Corvette, Acura NSX, Dodge Stealth, Nissan 300ZX, Porsche 944 Turbo, and Lotus Esprit Turbo. Porsche’s successor to the 930 seemed to fit nicely at the sharp end of that stick, and Jacksonville’s Brumos Porsche eagerly stepped forward to shoulder the responsibility of preparing a two-car team for the series’ inaugural season in 1991.

First-year results supported Porsche’s decision to step into the fray. On the strength of three wins by Brumos’ Hurley Haywood and a fourth by Stuck, Porsche grabbed the manufacturer championship in 1991, with the driver crown going to Haywood. 1992 would see a repeat of the manufacturer championship for Porsche, but with the driver title going to Doc Bundy in a well-sorted Lotus. Stuck dominated the driver championship the following year, winning seven of nine rounds, enough for a well-deserved manufacturer three-peat for Weissach before Porsche Motorsport shifted its attention elsewhere for 1994.

The race car and the road car equivalent were required to share most major mechanical components. In fact, to keep the race car close to stock, the air-conditioner was even required to be left intact. Recalls longtime Brumos mechanic Don Leatherwood of one of the first tests with the Brumos Supercar: “We were testing the car and Alwin Springer [then head of PMNA] said, ‘Whoah, whoah!’ as the car left the pits. There was a puddle of water, which kind of worried us. Well, Hurley had the A/C on! We called in, ‘Hurley, turn it off!’ He said, ‘It’s hot!’”

Leatherwood notes that the engine mechanicals and nearly all of the electronics and engine management were required to be identical between the race and road versions. The same held true for the brake system, though Brumos found some room for interpretation when it came to the brakes. Says Leatherwood: “In the middle of ’91, we played with the ABS control units. Then (IMSA) started monitoring that in ’92, so we had to make provisions for that.”

Beyond a semi-stripped interior and some safety items like a full cage and a Halon fire system, perhaps the biggest difference between the competition and street S2s was in the suspension. The race car featured 37-mm anti-roll bars (vs. 21 front and 22 rear on the road car), re-valved Bilstein shocks, and stiffer springs. A lot of stiffer springs were tried. “Hans Stuck loved to see a crew sweat,” chuckles Leatherwood. “We’d put 20 sets of springs on that thing in a day’s practice for Hans’ car, as opposed to maybe four sets for Hurley’s car.”

IMSA’s homologation rules required a minimum of 20 road-going versions of the race car to be produced, and that’s precisely the number Porsche built. Or rather, that’s precisely the number Porsche authorized to be built. With the 1992 Turbo S2 intended for the North American market (Europe and RoW got the Turbo S), the short list of performance upgrades that comprised the TS2 option package were installed stateside, primarily at Andial in Santa Ana, California.

The upgrades included more aggressive camshafts, a larger K27 turbocharger mated to a larger and more efficient intercooler, and various hardware for these performance bits: a camshaft drive adaptor, an air hose and clamp, and a pulley bolt. Interestingly, a brake upgrade was not required. Stock 964 Turbo brakes, sourced from the 928 GTS and 944 Turbo S, were deemed more than sufficient to handle the on-track competition. For $10,065 in upgrades, Porsche advertised 322 hp at 6200 rpm and 354 lb-ft of torque at 4800 rpm. It certainly didn’t seem like much thump for the investment, not on paper anyway; a 964 Turbo was already good for 320 hp at 5750 rpm and 332 lb-ft at 4500.

Additional power typically comes at a substantial premium from Porsche, but $5,033 per horse? Really?! Happily, as is also sometimes the case, the truth laid somewhere beyond Porsche’s marketing errata. Car and Driver’s Csaba Csere managed to put his hands on one of the twenty S2s and noted that acceleration from 100–150 mph was eight ticks faster than in a regular Turbo, at 19.7 seconds vs. 27.7. Csere estimated the S2 was producing something in the 370-hp range. Perhaps it was even a bit north of that, as the RoW Turbo S produced 381, and the Brumos race car reputedly netted 400 with a less-restrictive exhaust setup.

In addition to option TS2, the one-of-twenty that sits gleaming before me includes a sunroof, supple leather seats, and wheel rim caps with colored Porsche crests. Other than a new stereo, installed in March of 2008, the Guards Red beauty is bone stock. Current owner Greg Klovanich found the car quite by accident while perusing the Internet.

“Someone had posed the question on the Rennlist site, ‘What is a Turbo S2?’ The contributors on the site noted the rarity of the (Porsche),” says Klovanich. The owner of the referenced car had been unable to get it to pass Virginia’s emissions test and was informed by his wife that no more family money could be spent on it —the gentleman admitted to spending $30,000 in maintenance during five years of ownership, including a top-end rebuild that, luckily, maintained the integrity of the S2’s mechanicals.

Klovanich had long considered buying a 911 Turbo, but the time hadn’t been right until that moment. Faced with the prospect of owning such a rarity, Klovanich jumped at the opportunity, parting with his first Porsche — a 1985 911 Carrera Targa — in the process.

This morning, the folks at motorsports country club MSR Houston have given us the run of the facility for photography and a few exploratory laps of their 2.4-mile, varied-corner road course. The chance opportunity for a ride-along with Haywood in the Brumos Supercar nearly a dozen years ago has me salivating at the opportunity to put the road version through its paces on track. But I soon learn that driving the S2 can be a bit of a hurry-up-and-wait affair. Burbling through pit lane and rolling on the throttle at exit, this Porsche is...well...quite anemic. Before anything exciting happens, there’s time for a quick lunch, perhaps a phone call to Editor Stout: “Pete? Bob here. Just driving the S2, waiting for the turbo to spool up...”

Both hands better be on the wheel and all attention better be forward when the tach hits the big 4, however, because 6600 rpm is only a blink away. Power delivery is every bit as wicked as the curves of this 964’s fenders — there’s nothing, nothing, nothing, wait...was that something? Wham! In fact, in both first and second gears, the final 2600 revs come so quickly that it’s tough to time your upshift without banging off the rev limiter. By then the S2 is only a couple miles per hour shy of 80. Care to try third? That’ll take you to 110! This Turbo needs considerable room to stretch its legs. Car and Driver’s test results yielded roll-on acceleration results from 5 to 60 mph that were nearly a second slower than the regular Turbo. Drive the S2 hard enough to keep revs north of 3500, though, and it’s a brutally satisfying rush.

Squeezing on the brakes, initial bite is dramatic. Nearly 20 years on, these brakes still feel exceptional. There isn’t quite the nicely progressive feel through the pedal that Porsche’s current lineup enjoys, as the initial bite takes some getting used to. But overall stopping power is still deeply impressive in 2009. One additional thing is noticeable under braking; the amount of dive at the front end is more than anticipated. And that portends things to come.

At turn-in, body roll is pronounced. Firmness is surprisingly lacking in a sport model that served to homologate a race car. But then again, suspension upgrades were not among the items on the TS2 option list. I’m reminded that the early 1990s were a period during which Stuttgart seemed convinced that all Americans desired an, uh, overly compliant ride. Pitch this car into a corner and it feels like the back disconnects briefly from the front. Smooth out your inputs on both the brake pedal and the steering wheel, however, and you’re rewarded with a bit of understeer on entry that transitions nicely to a touch of oversteer on medium throttle through the apex and exit. And with smoothness comes very clear and timely communication from the suspension as to what the chassis intends to do.

Back in pit lane, I marvel at the S2’s top-end power. Klovanich reaches into his folder and produces a dyno sheet from Pro Technik, the shop that currently services the S2: max torque of 295 foot-pounds, max horsepower of 321. At the wheels. It seems 322 hp at the crank was a significant understatement, and the torque curve on the sheet is every bit as steep and peaky as it felt on track.

Reflecting on the half-dozen laps I’ve just completed, the overall driving experience of the Turbo S2 is an interesting dichotomy. The suspension is suit-and-tie civility, much like those color-keyed bumpers. The powerplant is exquisitely wicked, much like those rear fenders. And man, I do love those rear fenders.