Chevrolet Corvette C6.Rs - Behind The Scenes In GT1

An Inside Look At Corvette Racing's Preseason Preparations

Dr. Greg Johnson Sep 1, 2008 0 Comment(s)
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Feeling Green
For 2008, the Sebring test session marked the team's first on-track evaluation of the C6.Rs' new E85 fuel. While the ethanol blend offers reduced emissions and is a potential public-relations coup, it also presents some interesting challenges. When alcohol burns, it releases more energy than gasoline, thereby generating greater horsepower per unit of fuel. The flip side is that more fuel is required to cover the same distance, as compared with the current VP100 race gas. In other words, fuel consumption goes up, and fuel mileage goes down.

To compensate, the team is allowed to use a larger fuel tank. But as of this writing, the ALMS hadn't decided just how big a tank the cars will get. The current tank holds 90 gallons, but most agree that an increase to 100 gallons or more will be needed to compensate for the disparity in fuel economy. Unfortunately, the C6.Rs are configured to allow a maximum fuel tank size of just 102 gallons. Practically speaking, the cars simply aren't capable of carrying any more fuel than that without major architectural revisions. If more-frequent refueling stops are required as a result, the Corvettes will be at a significant competitive disadvantage.

Running the Vettes on E85 may present other difficulties. Alcohol can play havoc with the rubber seals found throughout the cars' fuel systems. Other race cars that run methanol fuel (Indy cars, for example) must have their fuel systems completely purged at the end of every day. Gasoline is placed in the system overnight, then drained the next morning and replaced by the alcohol blend-a tedious task, at best.

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Corvette Racing didn't experience any seal problems during the tire test, but by the time the cars made it back to P&M the following week, they were hemorrhaging fuel. It seems the ALMS had decided to spec the new "E85 fuel blend" at 62 percent ethanol and 35 percent toluene. During dyno testing, the Katech crew was delighted to find that the toluene-heavy mix caused no problems for the engine, and actually increased horsepower by about two percent (roughly 12 additional ponies). But one thing no one could foresee was that once the toluene was fed into the fuel system, it literally dissolved the glue holding the C6.R fuel cell together.

The upshot of all this was that Corvette racing elected not to run E85 for the Sebring race, returning instead to last year's 90/10 blend. It, however, use a modified E85 formulation for the St. Petersburg race a few weeks later, encountering no mechanical hiccups along the way. Based on the C6.R's dominating performance in that contest, the team emerged confident that the revised ethanol mixture is fully compatible with all of the C6.R's fuel-system components.

Corvette Racing's New Look For '08
For 2008, the Corvette Racing C6.Rs have adopted a tough new mien. The most obvious change is the black racing stripe running the length of the cars. The stripe, known as the "Jake Rake," is said to simulate the team's unofficial skull mascot scraping his teeth over the car. The rest of the cosmetic tweaks are similarly menacing: black wheels, black on the rocker panels, a blacked-out rearend, and black in the headlight buckets. Taken together, the alterations make for a worthy update of a classic design. It's just as well: With no serious class competition in GT1 for the second year running, Corvette Racing will need to do everything it can to stoke fan interest.