Rumors have swirled about it for a couple of years, but it now appears the introduction of a new 380-horsepower LS6 engine is a fact. Better still, its intro is right around the corner-as an option in the 2001 Corvette Hardtop.
Chevrolet has been pretty quiet about the new LS6, but from documents we've seen, the new engine will be available in '01 'Vette Hardtops under RPO Z06. The Z06 option is a race-ready package that should give the Corvette better than 1g cornering capability (thanks, in part, to a second-generation active handling system), along with the added thrust of the all-new LS6 engine.
Of course, the original LS6 engine of 1970 was a big-block. This time around, the LS6 is a modified version of the LS1 small-block. Enthusiasts will spot it immediately, thanks to a bright red "beauty" cover, compared to the LS1's black engine cover.
But the LS6 isn't simply a warmed-up LS1. There are significant mechanical upgrades that complement the engine's 35 extra horses. We'll detail those improvements in a moment, but first we'll delve into where those extra horses came from.
Since an internal combustion engine is really just an air pump, getting more air in and out of it will result in greater horsepower. That's just what the engineers did with the LS6. A larger-diameter mass airflow sensor (from a Vortec truck engine) and a revised intake manifold help draw more air into the engine (higher-flow injectors bring more fuel, too). Revisions to the composite intake manifold include larger intake passages and runners that have been redesigned to eliminate some of the LS1 intake's "dead spots," thereby increasing the volume of air getting to the cylinder heads.
Speaking of cylinder heads, the aluminum versions for the LS6 feature smaller pent-roof combustion chambers. This bumps compression to 10.5:1, compared with the LS1's 10.1:1 figure. Also, the LS6 heads' intake and exhaust ports are cast more precisely, which enhances overall volumetric efficiency.
Putting the squeeze to the new heads are new cast M142 aluminum pistons. Compared to the LS1's slugs, these pistons have a slightly barrel-shaped profile. The M142 alloy is said to increase engine durability, particularly under heavy-duty, race conditions.
The biggest contributor to the LS6's 380 horsepower (and 380 ft-lbs of torque) is an all-new, higher-lift camshaft. We don't have all the details on the cam, but it allows the engine to rev to 6,600 rpm (up from the LS1's 6,200 redline). To keep up with the extended rev range, the LS6 gets stronger valve springs, too. Although based on the same steel wire as the LS1's springs, the new springs are wound tighter for a higher spring rate.
To send out air in the engine, the LS6 features all-new cast-iron exhaust manifolds. They're more durable, flow better, and are a lot less expensive that the dual-wall stainless manifolds of the LS1.
Finally, to manage the increased airflow and lumpier cam profile, the LS6 features a revised PCM computer.
As we mentioned, the LS6 is more than just power upgrade of the LS1. Chevrolet developed the engine with racing in mind and significantly upgraded its structure and tolerances.
One of the improvements includes the elimination of machined holes in the aluminum block's bulkhead in favor of honed "overtravel" windows. This allows better cylinder bay-to-bay breathing. On the pistons' downstroke, they push air back toward the crankcase, creating backpressure that sacrifices some power. The overtravel windows help reduce this backpressure.
At the bottom end of the engine, the LS6's crankshaft incorporates a new reluctor ring that allows a larger air gap to the timing sensor. This setup is less sensitive to engine wear and promotes optimal ignition timing in virtually all conditions. Also, the crankshaft gets a lightweight torsional dampener that reduces rotating mass and engine spin-up inertia.
There's a new gerotor oil pump, too, which is driven off the crank. It boasts better low-temperature delivery and lower parasitic power loss.
The LS6's main bearings feature significantly higher tolerances, compared to the LS1's. This means a tighter fit for the crank and, with luck, increased durability.
Because of the expected cornering capability of a Z06-equipped Corvette on the track, the crankcase ventilation system (PCV) was redesigned for the LS6 to keep oil from being vented out of the engine. This means the LS6's PCV system was moved to the engine's "V" between the cylinders. An aluminum valley cover has composite oil-separating baffles and PCV plumbing built-in.
Also, the revised PCM contains new algorithms that monitor engine temperature and length of operation at a given temperature. With the use of synthetic oil, this revised measuring allows an oil-change interval of up to 15,000 miles on the LS6.
So, there you have it. The LS6 is a reality. We haven't yet had the chance to drive an LS6-powered Corvette, but with 380 horses on tap, we expect it to rival the vaunted performance of the original 375-horsepower ZR-1.
At the very least, it resurrects the performance heritage that only Chevrolet can create with a simple alphanumeric sequence. Our only question is, When can we expect the next LS7?
But What About the Camaro?
The word is that the LS6 will make its way into a limited-production, 35th Anniversary edition of the Camaro for 2002. So as not to step on the Corvette's performance toes, the engine probably won't produce the 'Vette version's 380 horsepower.
The 2002 LS6-powered Camaro may be the car's swan song, too. From what we understand, '02 will be the last year of the F-car as we know it. Sales of the Camaro (and its F-car sister, the Pontiac Firebird) simply have not been high enough to keep its cavernous Quebec, Canada, assembly plant running. (Rather than a traditional two-week shut down in the summer, the F-car plant will close for a whole month this year to "adjust to market demands.")
For 2001, the Camaro will soldier on as the best performance value for the money. And despite its slow drive up death row, the '01 F-cars receive some significant upgrades under the hood. The Z28 gets a new intake manifold and revised camshaft, which bump its horsepower rating from 305 to 315.
Although the horsepower increases in the next couple of years probably won't be enough to stay the Camaro's execution, you can certainly enjoy it while it lasts. We say, buy a new Z28 and go smoke some Mustangs, NSXs, or any of those annoying imports with the trash-can-sized exhaust tips. Think of it as your civic Chevy duty.