In early 1996, when GM officially announced a new motor called the LS1 (Gen III), many traditional enthusiasts were shocked. This new engine, which looked nothing like the small-block they had come to know and love, would surely be junk. Some people proclaimed the end of an era, saying that GM was crazy and had finally lost all hope. The skeptics told us the LS1 could never make big power; it had a plastic manifold for crying out loud! But a small group of people knew better. Instead of running from the new technology and hoarding small-block cylinder heads in their basements, they went out and started tinkering, and before we knew it a 400 rear-wheel horsepower heads and cam LS1 that got 25 mpg was commonplace. The LS1 became king, touted by enthusiasts as a high-tech wonder capable of huge power, excellent driveability, and great gas mileage.
All was well in the world of pushrod GMs until 2006, when the ante was upped again with the Gen IV L92. Immediately people began to fear this new engine, which utilized a new block that was a few cubes larger than the first Gen IV motor (the LS2), now at 6.2 liters, and added variable valve timing (VVT)-nearly unheard of with a pushrod engine. Much like those naysayers at the launch of the LS1, people began telling us that the VVT would be more trouble than it was worth and that a computer-controlled, moveable camshaft might work OK in a stock car, but wouldn't be of any use in a modified race or street engine. Enter Mast Motorsports, a daring group of engineers and builders from Texas who specialize in high-end LS-based engine packages. Immediately upon hearing of the L92, Mast began researching a way to upgrade the engine, working with the new technology, instead of against it. Fast-forward to 2009 when the new Camaro rolled off assembly lines with the passenger car version of the L92 for automatic models, the L99, as well as the LS3 for stick models, Mast acquired several stock L99 and LS3 engines and began dyno testing a variety of components to work on each, focusing on maximizing each engine's capabilities, without sacrificing what makes each unit unique.
Along the way, Mast began to notice that the L92 and L99 were nothing to be feared at all. Once they figured out how to control the camshaft, both mechanically and electronically, they found gains in torque and horsepower under the curve. Not only that, but they were able to run smaller camshafts with less lift in the L99 and make very similar peak power to the LS3. With this news, we were intrigued, and decided it was time to take a trip to Texas and see what Mast was up to. What we saw was both interesting and encouraging, with both the L99 and LS3 engine making upward of 550 hp using relatively small camshafts and some sick L92/L99/LS3 CNC Black Label cylinder heads. Follow along with us as we watch the Mast crew work and make sure to spend some time comparing the VVT and traditional camshaft dyno graphs, the results may surprise you.
In order to test both the...
In order to test both the LS3 and L99, Mast purchased two stock motors and hooked them to its in-house SuperFlow (SF-902) engine dyno. Both engines wore a set of Kooks Tri-Y dyno headers (1.75-inch long tubes) and an electric water pump for consistent coolant temperatures throughout our testing.
Before making any changes,...
Before making any changes, Mast Motorsports established a baseline dyno number for our L99 engine. Rated at 400 hp from the factory, we saw 466.9 hp and 465.2 lb-ft of torque on this SuperFlow dyno, which made sense considering the lack of an emissions compliant exhaust and accessories, along with the Kooks long-tube headers.
With stock numbers in hand,...
With stock numbers in hand, the crew from Mast pulled down the front of our L99 and prepared to remove the stock VVT camshaft.
You're looking at the heart...
You're looking at the heart of the L99 VVT system, a piece known as the camshaft phaser. This front-mounted vane-type phaser uses oil pressure, controlled by an actuator solenoid to rotate the camshaft relative to the cam sprocket. Basically, it allows the ECU to retard and advance the camshaft in real time to maximize performance.
Working on the camshaft phaser...
Working on the camshaft phaser requires some special tools, many of which come in the Mast Motorsports camshaft phaser restrictor kit. The large P-shaped tool allows us to rotate the phaser on the bench, while the "music note" shaped piece holds the phaser in place after rotation.
With the P-shaped tool and...
With the P-shaped tool and "music note" in place, we flipped the phaser over and removed all but one of the 4.5 Torx bolts. One Torx bolt, which partially covers the cam phaser spring only needs to be loosened, allowing the cover to pivot out of the way without shooting the spring across your shop.