A 700HP Shootout Between Porsche Tuning Super PowersTPC Racing
A 700HP Shootout Between Porsche Tuning Super Powers
Seven-hundred horsepower.Seven… hundred. Whispering it a few more times to yourself doesn’t make it seem any less daunting. Consider for a moment that it exceeds the horsepower of two new Carreras! What will the first foot-to-the-floor spin to redline in second gear feel like? Nauseating?
Two gleaming 700-hp 997 Turbos sit in the paddock of Virginia International Raceway, waiting to answer the question. Today’s mission: Pit AWE’s 750R against TPC Racing’s 775 Blitzkrieg on road and track. What we want to know: Which best embodies the dual-nature “tuner Porsche?” After all, lap times aren’t everything when it comes to street cars.
Excellence regular Bob Chapman will help assess road-going performance while ALMS driver David Murry will help assess track performance at VIR. The ground rules are simple: No slicks, one set of tires for both tests, valid registrations and insurance, and no tweaks other than tire-pressure adjustments between the street and track tests.
We’ve all read articles about high-power cars that try to convey the feeling that such power imparts. But without personal experience of those g-forces, we’re forced to think about it in terms of something we have experienced. Is 700 horsepower like that vague recollection of the first time you crossed the 100-mph threshold. Is it laugh-out-loud fun? Or is it like the time you first did something fearless, like jumping out of an airplane — an electric feeling that is simultaneously terrifying and exhilarating?
The TPC Racing 775Blitzkrieg
Like many creations of its kind, the TPC 775B is a reflection of its owner. On first glance, it’s as understated as any Porsche can be. Well, any in Guards Red, anyway! It looks like it could have just rolled off the showroom floor. The only visible modifications are the stance, GT2 wheels, and a small sticker with the company logo. In other words, it’s a sleeper.
Owner Michael Levitas is a bit of a sleeper, too. The easy-going Baltimore native is a Grand-Am champion and a Daytona 24-hour winner, but he spends most of his days at his company, TPC Racing. He gets there in this car, his daily driver. Race wins, and especially championships, require attention to detail and Levitas has it. Ask him about the development of the 775B and he launches into a high-octane discussion of custom-valved shocks, proprietary springs, the impact of front versus rear spring rates on a 997’s handling, and how optimal setup differs from previous 911 platforms — complete with hand gestures that only race-car engineers can understand…
He says TPC achieved 700 horses on pump gas by modifying the turbochargers with larger compressor wheels, with major (exducer) and minor (inducer) diameters enlarged by 1.5 mm and 2.0 mm respectively. TPC also modified the turbine in an effort to create a wide torque plateau for a claimed 600 lb-ft available from 4000 to 6500 rpm. Says Levitas: “Our turbo is more efficient than a factory GT2 unit by one-third.”
TPC designed and built its own intercoolers, moving from Porsche AG’s tube-and-fin design to a sturdier and significantly larger (by 52 mm) 127-mm hybrid bar-and-plate core with tube-and-fin type internals. Levitas says the design significantly improves torque at lower rpm. The intercoolers bolt into the factory positions and use lightly modified factory ducts. The exhaust system is a collaboration between TPC and Europipe.
The last piece of the puzzle is custom TPC ECU tuning with adjustability offered via a plug-in switcher to select power modes based on octane. Of the power on tap, Levitas enthuses, “The car will run mid-tens in the quarter-mile at over 135 mph.” He goes on to explain that his last trip to the drag strip ended when he was kicked out for running a sub-11-second pass without a roll cage.
The Meteor Gray AWE car belongs to another racer, this one ALMS shoe Tim Pappas. Its color is tastefully set off byBBS LM-R wheels framing yellow PCCBcalipers. The only other visible modification is the small AWE 750R sticker. It’s understated and cool in a laid-back sort of way. Again, it doesn’t fall far from the personality of its architect, AWE’s Todd Sager, a measured man who seems to embody the maxim “Walk softly and carry a big stick.”
AWE’s approach to increased power follows a general OEM fitment philosophy. Comments Sager: “We wanted easy modularity to allow consumer choice across the broader parts market. We find that our customers value that.” Additionally, Sager aimed to develop parts that would operate safely within the limits of the stock engine’s internals: “We wanted to maximize power reliably, without having to crack open the engine.”
Forged aluminum, CNC-machined compressor wheels replace the stock cast-aluminum compressor parts, increasing reliability at higher rotational speeds. Intercoolers are direct bolt-on replacements, designed in-house and 37 percent larger than stock, yielding a 55º F temperature drop with a one-psi pressure increase. Sachs’ Racing Stage 2.5 clutch ensures enough clamping force to handle a claimed 646 lb-ft at 5000 rpm.
AWE designed headers that incorporate HJS200-cell cats which feed into AWE mufflers. It also designed a ten-percent-larger throttle body adapter, which measures 82 mm. Finally, in collaboration with chip tuner GIAC, a unique tune was created that offers five profile options: premium fuel (700 hp), 100-octane race fuel (750 hp), valet mode (50 hp with a 30-mph speed limit), ignition kill (car will not start, even with the key), and stock boost — all accessed using a handheld switcher that plugs into the OBD II port under the dash.
One look at the stance of these 997s is enough to know that they’ve got chassis upgrades. The AWE 750R’s suspension modifications are pretty modest, consisting of Bilstein Damptronic coil-overs, a 24-mm H&R adjustable rear anti-roll bar set to full soft, and GT3 two-piece lower front control arms. TPC’s 775B has more extensive changes: Bilstein Damptronic coil-overs with custom valving and custom springs, a front anti-roll bar that’s 50 percent thicker than the stock piece, a rear anti-roll bar 30 percent thicker than stock, TPC’s adjustable drop links, 997 GT3 Cup control arms in front (machined to fit), and front-end geometry changes to TPC specs. While AWE was running stock ceramic brake pads for the 750R’s factory PCCB brakes, TPC chose Pagid Yellow (RS19) pads for the 775B.
On The Road
Time to get moving. I nab the bright red 775B’s keys first and Chapman climbs into the gray AWE 750R. Levitas’ final imperative (“Don’t disengage PSM!”) includes a cautionary wag of the finger. I never kill PSM on a first drive, but his words keep echoing in my head.
Tooling through VIR’s interior roads at 20–25 mph, the 997s feel remarkably stock. Both start and drive almost exactly like their unmodified counterparts. At this point, the only noticeable difference between the two is the sound: the AWE 750R has a more explosive, raspier note than the 775B, a facet that magnifies exponentially under more aggressive throttle.
A lengthy flat section of road comes soon enough, and I see and hear Chapman disappearing down it in the 750R. Game on. With this first exploration of the car’s power, Levitas’ cautionary advice, along with everything else in my brain, is compacted to the back of my skull.
Literally is a word misused too often, but it’s appropriate here: Literally, I’m not sitting on the seat; the full weight of my body is suspended against the seatback. Even so, there’s no explosion of power, just relentlessly increasing acceleration. The steering wheel feels smaller, further away as I reach for the shifter. The shift from second to third is violent.
It’s like an aerobatics lesson — physically taxing and almost sickening — and yet it’s utterly amazing and surreal in its intensity. Your brain can’t quite comprehend all that is happening, but your body knows something’s not right. Even for a veteran Porsche racer, it’s an altogether new experience. While my mind struggles to process the rate at which the 775B gains speed, I simultaneously want to lift to make it stop and keep the throttle pinned to see where exactly it might go.
My internal debate is decided for me, because I soon find Chapman sitting at a stop sign. Thoughts are mixed. Should I try this again? Or should I just bring it back now and pronounce the car too powerful to handle on public roads? The very same voice that whispers “Second place is just first loser” refuses to accept anything less than victory pipes up. And it wins the argument: I’m jumping out of this airplane again!
After more time spent acclimating to the 775B’s amazing acceleration, we’re on a series of interconnecting roads that form a perfect street-test course. It’s a combination of a long straight, curves, and gentle hills. Just as confidence is growing and familiarity with our test circuit is reaching a comfortable level, Chapman pulls over to switch cars for the first of several exchanges.
He says he had a near-identical experience in the AWE 750R, and was at least as floored by the intensity of its power. “The first time the boost came on, it literally pushed all the air out of my lungs,” he notes. “I was momentarily disoriented.” However, we both agree that once acclimated to the power delivery, the flash of uh-oh-what-have-I-gotten-myself-into desperation is replaced by an all-consuming thrill. No, an addictive, all-consuming thrill. Before turning the 775B over, I say to him: “This car is nearly perfect, and if yours isn’t, I don’t want to switch.” He admits the 750R isn’t perfect, but promises I’ll like it anyway.
He’s right. Incredibly, the 750R feels even faster. Acceleration seems stronger and begins lower in the rev range. It’s an overstatement to characterize its boost as an on/off switch, but it comes on significantly stronger than in the 775B. But it also wanes sooner.
Through the curves, AWE’s 750R displays a more agile character. It feels lighter (it’s not). Its steering feels faster (it isn’t). Interestingly, unlike the 775B’s custom-valved and proprietary-sprung Bilstein Damptronic electronically adjustable suspension, the 750R is suspended by off-the-shelf Damptronics. Some difference in feel on the street may be attributable to the car’s much-lighter PCCB ceramic-composite brakes and, more likely, its Michelin Pilot Sport Cups versus the TPC 775B’s Toyo R888 tires.
The Michelins display all the characteristics so polarizing of that tire: very quick turn in, stiffer ride, difficulty in maintaining desired slip angles at the limit without entering a stuttering slide. By comparison, the Toyos endow the 775B with more suppleness but deaden and delay feedback in their slower response. Like so many things, it’s a tradeoff.
In some ways, the edgy Michelins go with the car. The 750R is more brutal and aggressive. It’s no less sophisticated under normal driving conditions, but it’s clearly more primal near the limit. And that’s only enhanced by its ripping-100-yards-of-cardboard exhaust note. Chapman finds the 775B to be softer and more compliant as it rotates around the driver rather than the more pointy, nose-first corner-entry feel from the 750R.
“In the TPC 775B, I always felt it was underneath me,” he says. “In the (AWE) 750R, I sometimes felt like I was a hair’s width away from getting way sideways,” he explains, indicating that he found the quicker reflexes of the AWE 750R more intimidating on these roads. That said, he admits a preference for the deft initial turn-in offered by the 750R. We are in agreement here, as I prefer to be more involved in a street car, and perfection does not always go hand-in-hand with one-with-the-machine immersion in the driving experience. The driver is more responsible for the outcome of every maneuver in the 750R, and I like that.
Even so, when pressed to pick one, Chapman gives a slight nod to the 775B for spirited road driving, finding it more manageable at the limit and easier to catch. I prefer the 750R better for its more involving driver experience; to me, TPC’s 775B lacks a bit of…what was that old VW commercial?…Fahrvergnügen.
We agree to head back to VIR’s 3.27 miles to let the cars duke it out, with AWE holding the barest of advantages.
Our comparo ramps up a few notches with the participation of an obviously enthusiastic David Murry. He promises to bring considerable experience and talent to the driver’s seat, even in the midst of the bustle of his first David Murry Track Days event. Also, the addition of a Traqmate data-acquisition system will yield objective measures of performance. Murry is first behind the wheel of the 750R, so I grab the keys for the 775B. After a few laps, we’ll switch.
AWE specifies Sport on and PSM off for the track run — and that’s how Murry goes out. Entering some corners hard, he triggers the 750R’s ABS, causing PSM to intercede even though it’s off. He has no complaints about that, though, feeling that, with PSM on, some unwanted slide angle might be reduced. The PCCBs display noticeable front brake bias as delivered, which Murry says hampers deceleration a bit by overworking the front tires, causing them to overheat. The pedal gets a bit soft after a couple laps, and Murry suggests that a different proportioning valve might be a simple cure for track work with an experienced driver. I wonder, though, whether a few other tweaks might be in order first, as great braking feel can often be found with improved chassis setup.
Heading out in the 750R, I find it has less body roll than the 775B. It feels good in the corners until it reaches the actual limit. At that point, it’s challenging to maintain your desired slip angle because the drop in grip as the tires slide is significant, scrubbing off a bit of speed and costing you time in the corners. Also, its suspension is a little harsh over bumps and curbs, upsetting the car just enough to briefly lose grip and more time. This is likely due, in part anyway, to the Sport Cups’ at-the-limit characteristics.
Remember how the 775B felt faster, lighter, and all-around more powerful on the street? In the experienced hands of David Murry, that starts to make sense. It’s down to turbo-lag characteristics. It isn’t a huge difference, but it’s enough of one to be noteworthy. Says Murry: “The 750R builds boost at low rpm but is very hard coming on,” says Murry. “It was nice to have that power down low but a bit hard to drive.”
At the top end, the 750R loses boost earlier than the 775B. When the 750R’s boost drops during shifts on the straight it recovers more slowly than the 775B, interrupting acceleration as boost rebuilds. So even though the 750R has good power in the lower range, it is more difficult to modulate in corners and it falls off with each shift. Ultimately, this costs it both while exiting corners and on the straights.
Shifting in the 750R is noteworthy for another reason: its short-shift kit. The concept of speeding up shifts by shortening the physical movement of the stick seems a good one at first blush. It feels good, too. But in execution, especially with street-car transmissions in a track setting, the transmission itself turns out to be the limiting factor. Notes Murry: “The shorter shift loses feel of where the gate is, and it ends up being harder on the gearbox and really no faster.” Murry’s best lap in the 750R? A 2:06.499.
On the track, TPC specifies Sport off, PASM stiff, and PSM on. So from the outset, we are destined for a different experience. Exiting pit lane, the first thing noticed is power delivery. Here, the TPC Turbo comes out on top. Says Murry: “I never had to worry about the boost giving more power than I called for. It was so subtle I could drive the car and not worry about when the power was going to explode. It just didn’t.”
For all its power, there is little turbo lag in the 775B, and the flow of torque is controlled and consistent, building gradually with revs — evidence that a lot of work went into theECU mapping. In the upper range, even when it feels like it’s time to shift, the 775B just keeps pulling. And shifting the car feels just like Porsche designed it, with longer throws and easy-to-find gates resulting in confident shifts.
Speed and power are only part of the track equation, though. Stability, braking, and overall handling are the components that inspire speed and ultimately provide the confidence to push outside the traction circle. The 775B is great on its brakes. The pedal is solid and doesn’t seem to lose anything during a three- to four-lap stint. This gives the driver confidence to carry the brake point to the limit and push that much harder.
The 775B is easy, and telegraphs every signal before making a change. In contrast to the 750R, this 997 Turbo is very good over VIR’s bumps, maintaining better grip. It’s also easy to slip at the desired angle through the corners, maintaining your line and picking up speed through the turn. That means speed can be carried deeper into the corners, too, without having to focus as much on driving the rear of the car. Clearly, Murry is impressed: “The more power a car has, the harder this is to accomplish.” A high compliment, and part of why he was able to turn a best lap of 2:03.405 in the 775B.
At the track, Murry and I agree: TPC’s 775B takes it — and not just because of the faster lap. No, it’s because of its better level of driver comfort at the limits.
So, which one? If your primary interest is street use, you can’t go wrong with either car, though we’ll give a slight nod to AWE’s 750R for its fun factor and more engaging experience. If your interests lie at the track — or if you are looking for a clear dual-purpose car — the TPC 775B is a better-rounded package thanks to its smoother power delivery and confidence-inspiring handling.
As for the price of taking a 997 Turbo to 700 horsepower? Both AWE and TPC charge roughly $23,000 for the privelege (the AWE parts run $20,326, plus $2,645 worth of installation while the TPC setup goes for $21,500 plus installation). That’s a lot of coin — on top of a car that came with a six-figure price tag when new and trades in the high fives used. On the other hand, just ten years ago there were only a handful of circuit-racing cars with the kind of horsepower these road cars churn out. Some would argue the same is true even today. In either case, there’s no possibility of driving such a race car on the street, and certainly not in the do-anything comfort of a modern Turbo.
Yet here are two factory 911s with bolt-on kits and 700 horsepower which, on the street, are every bit as docile and comfortable as a stocker. Just remember: When you first push the gas pedal to the floor, we recommend heeding Levitas’ warning: “Don’t disengage PSM.”