2004 Chevrolet Corvette - Engine Of Desire

A Big-Cube LS7 Transforms A Staid C5 Into An Object Of Automotive Lust

Steve Temple Apr 1, 2009 0 Comment(s)
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Jonas also threw on a slew of performance parts to reach his goal of exceeding 600 flywheel horses. Comp Cams supplied an aggressive camshaft that emits a hot-rodded rumble through the 2.5-inch Kooks headers and Corsa pipes. (Jonas says there's not enough room for 3-inch tubing.).

The oxygen-sensor-equipped headers are particularly important for maximizing the output of the LS7 while keeping it smog legal, but there are other key elements as well. Chief among them are a larger, 900-cfm throttle body (for compatibility with the LS7's drive-by-wire system) and a K&N air intake fitted with a VaraRam ram-air scoop. With the stock intake setup, the engine tended to run hot and rich, killing both performance and combustion efficiency. But the K&N/VR unit picks up air from under the front bumper, dropping intake-air temperatures by as much as 80 degrees. According to Jonas, that reduction in heat was essential for tuning at idle.

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Other swap-specific hard parts include modified engine mounts as well as a new timing-chain cover, wiring, ECM connectors, and sensors supplied by Katech. (Note that the crank sensor on the LS1 is on top, while the LS7's is mounted on the bottom.) In addition, the LS1 has a wet-sump oiling system, while the LS7 has a dry sump.

With the LS7 nestled neatly in place and up-fitted with performance parts, the next stage involved custom mapping with HP Tuners' VCM Editors Flash system. This utility allows the user to read the VCM/PCM's flash memory and save it to a binary file for calibrating and modifying parameters such as spark, fuel, rpm limits, temperature, transmission shift points and pressures, speedometer settings, and so forth. The unit also features automatic recovery capabilities for protection against any reflashing problems that might be encountered.

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This phase required nearly a month of fiddling and tweaking, as the computer calibrated itself to Jonas' driving style. He's not one to baby his Corvette, having dropped the hammer on several previous rides, such as a '66 big-block coupe, a '72 LT-1, a '78 Silver Anniversary coupe, and a '67 small-block convertible.

Also adding to the car's accelerative credentials are a Fidanza carbon-fiber clutch with a lighter aluminum flywheel. Rolling stock consists of Forgeline three-piece wheels (18x9s up front, 19x11s in the rear) wrapped in Goodyear Eagle GSD rubber (sized 245/40 and 285/35, respectively).

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With all this extra go-power, at some point you've got to think about stopping as well. To bring this hot rod to a halt, Jonas dipped into his company's parts bin, using Stainless Steel Brakes' V-8 calipers. Each one has no fewer than eight pistons (!) to clench the two-piece, 14-inch rotors, which also feature slotting and cross-drilling. Jonas claims the stopping distance from 60 mph is now 113 feet, compared with 125-135 feet with the stock C5 brakes.

Space doesn't permit going into all the other suspension and body upgrades that went into the car, but suffice it to say that the project was a long time in the making. Looking back, Jonas admits it took longer than planned but adds that the Vette "turned out way better than I expected." While not all LS1 Vette owners will be inclined go to these lengths, if they do, they'll be glad to learn that there's a light at the end of the tunnel. And it sure as heck won't be anybody else's taillights.

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