‘Leroy’ the Corvette Gets New Heads, Injectors And More To Set New Dyno Numbers!

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Get ready: Leroy’s horsepower is now a 4-digit number.

Over the first few weeks of 2018, some things have changed on Cleetus McFarland’s Beloved “Leroy” C5 Corvette. A good majority of it has been done to increase flow of air and fuel in and out of the engine. Coming in as the most significant change is new cylinder heads meant to give better flow to the turbos, aided by new exhaust plumbingĀ as well. Downstream from the engine is a new performance clutch and a new transmission. May as well take those new components out to the drag strip for a quick test.

McFarland knows that with an engine built like this, any change might present another problem to iron out. Sitting in the burnout box, he says, “we’ve got the new heads, we’ve got the new turbo exhaust housings, we’ve got a new transmission and a new shifter… A lot of variables so this pass will probably be ugly.” It was. The new transmission and shifter made swapping gears a bit cringe-worthy, and the clutch needed a learning curve for the best launch.

Back in the shop, McFarland makes another change, this time to bigger injectors for better flow. Leroy formerly had used 1650lb injectors, but 2150lb injectors were chosen to reduce the duty cycle. That should allow better flow on race fuel while lowering the workload.

 

ALSO SEE: Leroy the Corvette Takes on Sebring International Raceway

 

Despite the issues at the drag strip, the dyno testing went far better. Even the initial pull on just about 5psi netted more horsepower at that amount of boost than ever before. McFarland, clearly is excited about this: “we are getting more horsepower, so those heads are rippin!”

After a bit more tinkering with the tune to account for the injectors, boost was gradually moved up ever farther, with more fuel map adjustments with each increase. Ultimately, the highest number on the dyno came in at 1125 horsepower.

Excited with the number and the tune, McFarland lets us know about his next event. He says, “it’s time to go to Texas and TX2K this weekend, and Leroy seems to be set to go.” How will he do in Texas? We’ll be watching.

Patrick Morgan is an instructor at Chicago's Autobahn Country Club and contributes to a number of Auto sites, including MB World and 6SpeedOnline.

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