Oct 30, 2009

Exploring The Limits

Porsche's 911 Turbo engines have been attracting high-performance tuners for decades, each one pushing the limits of engine performance further and further into the high-horsepower stratosphere. In the past, elite tuning firms like Ruf and TechArt were forced to replace dozens of internal engine components with bespoke, strengthened parts to handle the loads that 600+ horsepower put on them. All that changed, however, with the introduction of the 997 model Porsche Turbos in 2006.

“The 997 engine is really an incredible piece of engineering,” says Tym Switzer, who has spent the last few years exploring the limits of the 997 Turbo engine, inside and out. “When we set out to develop more horsepower with the 997 Porsche, we approached it the same way we approach any new platform: we analyze the factory components and the way they were designed to handles stress loads to establish an upper limit of what the engine is capable of. When I first looked into the 997 engine, I was very impressed with the quality of the entire assembly.”

What Switzer saw in the 997's engine was the result a no-holds-barred engineering program that culminated in Porsche's 964/GT1 racecar – a turbocharged monster that developed staggering horsepower with enough ruggedness and reliability built in to stand up to the punishing abuse of 24-hour endurance racing. As such, the 997 Turbo engine ships from the factory with many of the components necessary for making big horsepower already in place. “It's like they took a checklist from the page of every tuner out there that was rebuilding these engines, and decided to just put all that stuff in at the factory. Forged connecting rods? Check. Reinforced crankshaft? Check. Dry-sump oil system? Check. It's all there. In fact, just about every component in the 997 was over-built. Inside, it looks more like one of the cutting edge import race engines we were building in the 90's than it did any kind of street engine.”

With a high degree of confidence in the 997 Turbo engine's internals, Switzer moved to develop a line of bolt-on power-builders that would take advantage of the car's strengths, while addressing some of the limiting factors. “The turbos and intercoolers had to be upgraded to produce the the airflow and efficiencies we needed to reach our objectives. That was a given. Working with our technology partners, we were able to come to market with new upgrade turbo solutions. We also worked diligently to develop our own 'MONSTER' intercoolers and intake plumbing. I think our overall upgrade strategy compliments the overbuilt nature of the 997 perfectly.”

Switzer's tuning program eventually led to the firm's L4 PKG, which delivers over 700 horsepower on 93 octane gasoline with upgraded versions of Porsche's excellent factory VTG turbos – all while remaining emissions compliant. “You could never do something like this ten years ago on stock internals,” he explains. “The older air-cooled Porsche engines just couldn't handle that kind of power without a fully substantially reinforced engine.”

Eventually, though, Switzer's customers wanted more than 700 or 800 hp. “Too much is never enough for some clients,” offers Tym, “so in order to develop a solid engine program for these more ambitious projects, it was essential to see just how much power some of these stock components could stand up to, when tuned properly. We then spoke to a few of our more adventurous clients and decided to see exactly where the limits of the 997 really are.”

Last fall, Switzer and his crew reached 850 all-wheel horsepower (approx. 1000 crank hp) with their SLEDGEHAMMER project car. That prodigious power output and the car's standard all-wheel-drive traction delivered enough performance for repeated 9.7-second quarter-mile runs at over 145 mph with 60-130 times in the 4's – performance that falls well into “Superbike” territory.

This week, one year on, Switzer's SLEDGEHAMMER is still pulling strong, serving as the company's 997 development mule and astonishing everyone with its engine's longevity and durability. “Everyone who has been in this industry for a number of years is surprised by these cars,” says Tym. “Really, though, there's no surprises here. When we reached 700 hp a year and a half ago, we were told the engines were time-bombs. Dozens of customer cars and literally thousands of road - and track! - miles later, the cars are still running strong. The P800 kit we introduced earlier this year proved that the limit wasn't anywhere near 700 hp, and earlier this week, the original SLEDGEHAMMER came back to the shop and did back-to-back dyno pulls at 915 horsepower with nearly 800 lb-ft of torque. We've made some minor updates to the fuel system and standalone engine management system, but that's still 50 hp and almost 100 lb-ft more than the car's best numbers a year ago, and it's still holding together. As expected. I think, more than anything, these huge power levels serve to show just how good the Porsche 997 Turbo is from the factory. As a tuner, you couldn't ask for a better, stronger foundation. The real challenge has been to make the most of what's already there.”

So, what's next for the 997-engined SLEDGEHAMMER? A good deal more abuse! “We're going to run a few more experiments with this development car. There are still a few questions I have that I would like to answer for future product development. There is still an enormous amount of potential in the 997, and we're all curious to see how far this particular rabbit holes goes!”

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