The Science of Speed, Pt 1
We each have our own unique reasons that draw us to this glorious hobby. I know some people that simply love racing. It becomes an addiction and they’ll do whatever it takes to go faster. At the other end of the spectrum are problem-solvers. They love the build part of it, and barely put any actual mileage on their hot rod. I’d probably put myself somewhere in the middle of these two groups. I love the creativity aspect of building a car or truck and the seat time that occurs after. But what really turns me on is technology.
When we talk about technology, most people think of cutting edge. But what about leading or even bleeding edge technology? Bleeding edge is being at risk of failure in the name of science – pushing the limits of knowledge. A perfect example of this is the Gale Banks’ twin-turbo Trans Am that became the world’s fastest passenger car in 1986 (at 268mph) and again in 1987 (at 283mph). Today building a twin-turbo EFI combination with this kind of power and sufficient aerodynamics certainly isn’t unheard of. But 25 years ago? It was hard just getting a transmission and clutch to hold up to anything approximating 1,000hp, let alone 2,200hp. This car was the epitome of bleeding edge.
In the early- to mid-2000s we saw this again in the LSx community long before it became the powerplant du jour of the pro-touring scene, or before everybody and their mother started dropping junkyard 5.3L’s with turbos into anything with four wheels…there was Wheel-to-Wheel Powertrain. Kurt Urban was the man with the plan to dominate the LS1Tech.com racing series with a twin-turbo entry. At the time there were no aftermarket blocks or high-flowing splayed valve heads for the LSx.
Kurt started with a 6.0L truck block, filled it, and designed a main girdle and thicker head studs with the hopes of withstanding 32psi of boost from two 80mm turbos. Copper head gaskets with O-rings and receivers cut into the iron block were another first for the LSx engine, which were needed to keep the engine sealed as the 10-head-bolts struggled to keep the heads from lifting. The valvetrain was another area that Wheel-to-Wheel put considerable R&D into, using a Cam Motion solid roller to spin up to 9,000rpm. Starting with a set of worked-over Air Flow Research cylinder heads, a Jesel rocker arm system was designed to optimize the geometry and allow more room for bigger valvesprings. A GM cast intake manifold, Wilson 105mm throttle body, and Big Stuff 3 engine management topped off the combination, which made 1,900 horsepower on the engine dyno.
Ultimately the class rules changed, so the relatively small 351cid engine found a home in Mike Moran’s famous “Casper Camaro.” This same car became the first to run 6s in the NMCA’s Pro Street class, so it was only fitting that it became the first to run 6s with an LSx engine. Casper not only surpassed the Michigan shop’s crosstown rivals, but also took the world record from the folks at CV Performance in Australia. Wheel-to-Wheel’s 6.86 at 205mph stood as the fastest LSx in history up until fairly recently when it was surpassed 5 times in the last two years by the likes of Stephen Fereday, Mark Carlyle, Tom Kempf, Dave Adkins, and Andreas Arthursson.
This was truly an exciting time to be apart of the late model GM scene, and it is happening all over again with the C7 Corvette’s Gen V small-block. Besides the usual unknowns with a new engine platform, the Gen V LT1 and LT4 are two of the most powerful direct-injection engines in production. Unfortunately this means that at present there aren’t any aftermarket injectors, so there is a definite limit to the power potential. It’s also taken a steep learning curve to figure out how to account for various differences in tuning. I recently visited The Tuning School to get a firsthand look at what it took for Late Model Racecraft to set the current record (1,270-rwhp). I can assure you it is an entirely different mindset from the Gen III/IV.
On the plus side, by modifying the camshaft lobe that turns the mechanical high-pressure fuel pump, a significant increase in fuel supply can be achieved on the Gen V (thank you Comp Cams). Without the use of methanol injection, as a supplemental fuel, or a wet nitrous system, the limit is around 1,000-rwhp. However, we’ll eagerly be awaiting the next breakthrough. With the release of the 2015 Corvette Z06 looming, I suspect it won’t be long.
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