LS Engine Performance - LS Power For Less

GM Engineers Tell Super Chevy How To Build The Best Budget LS Combos With Factory Parts.

Jim McCraw Nov 1, 2009 0 Comment(s)
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Corvette LS7, 550hp.

SC: It's pretty apparent that if you use the right combinations of production parts, you can make a lot of reliable power and torque.

MD: If you take a 6.2 engine with the big heads and you're not running catalytic converters [in an older car], with a long-duration cam and low backpressure, you're getting tons of extra horsepower. The engines won't respond with the backpressures that we have to have, but when you drop the backpressure on these engines, they respond. The LS3 engine, the Corvette engine with the big heads on it, is rated at 436 horsepower with the flapper valve in the exhaust system. You should be able to make 475 hp with unrestricted exhausts.

DG: Our ability to put all this stuff together analytically these days will usually get us within three percent of what we ultimately get on the dyno. Our new engine lab allows us to replicate the duty cycle of any racetrack in the world, and we can even replicate what an engine's oiling system feels in cornering with a couple of our dynos. We used to have to rent a racetrack for a whole week with a bunch of different oil pan designs, hire drivers, hire ambulances, and then download data from the car and wait for three hours while it was analyzed. We don't have to do that anymore. We can do all that right here in the lab.

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SC: For those who do amateur road racing, club days and track days, do you have recommendation for those high-g cornering situations?

MD: The '05 Corvette oil pan is better than the earlier gullwing or batwing pan, because it actually controls oil better in terms to keeping the oil close to the pickup. It's functionally is superior in terms of max g's. You can run longer at the same g level without running into oil starvation. If you're going for sheer power and minimal windage, you want to use the larger truck pan, which has less windage and plenty of volume to handle the fore-aft acceleration, but if you're going around corners, the '05 Corvette pan is the one to use. The Z06, the ZR1 and the 2010 LS3 engine in the Grand Sport all have dry-sump systems that can be adapted to most of the earlier engines for road racing. But you have to use an LS9 crankshaft in order to drive the pumps. Because today's high-performance tires can give you three to four tenths of a g more cornering force, we had to change over to dry-sump for the high-performance engines. But remember, the starter ring gear on the flywheel is now going to be the lowest thing on the engine, so, while you can lower the engine in the chassis, you still have to have room under the car for that.

SC: You're now at 638 hp in the LS9 engine. Is there room for more?

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DG: I'm not sure, but I think it would be nice to get to 650! There are still a lot of people around here with a great deal of passion about the small-block.


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