On went the new head gaskets secured by ARP head studs, followed by a Kenne Bell 3.6L supercharger. Designed for a 2012 Camaro, the Kenne Bell supercharger featured a dedicated air-to-water intercooler, massive single-blade throttle body, and 4.5-inch air intake system. Also present to ensure uninterrupted airflow to the supercharger was the Kenne Bell Mammoth intake manifold. Supercharger systems are only as efficient as the airflow going to them. Recognizing the fact that airflow restrictions to the blower equate to reduced flow and boost out of the motor, the gang at Kenne Bell took all the necessary steps to maximize airflow through the induction system.
Due to available dyno time, we did not have the opportunity to test the 418 in NA trim after reducing the static compression ratio. In previous testing, we know that every point of compression was worth 3-4 percent in power, so 6/10ths of a point could drop power by roughly 2.5 percent, or around 15-16 hp. Since the Kenne Bell supercharger also eliminated the factory long-runner intake, the comparison between NA and supercharged power was less direct anyway.
What we do know is that as much as LS engines love boost, modified LS3-based strokers love it even more. It does, however, bear mentioning that the key to a successful supercharged motor is starting with a healthy normally aspirated combination. With our stroker pumping out over 600 hp in normally aspirated trim, we were already well on the way to reaching our self-imposed goal of 1,000 hp.
Testing the supercharger kit from Kenne Bell required installation of the factory accessories. The blower shared the same belt as the accessory drive, and required the components for proper belt orientation and tension. Obviously it was necessary to augment the fuel system to feed the supercharged stroker. Normally the kit comes with 47-pound injectors when run at 9 psi on the stock motor, but we stepped up to 75-pounders combined with 60 psi of static fuel pressure and a boost-referenced fuel pressure regulator. Aeromotive supplied both an A1000 pump and adjustable fuel pressure regulator for our testing, so we had no concerns about fuel delivery.
Tuning was provided by a Holley Dominator EFI system, while exhaust chores were handled by a set of 1-7/8-inch headers from American Racing Headers. Initially the boost was set at just over 10 psi and run on pump gas. Putting a maximum of 10.75 psi of boost to Monster Mouse on pump fuel resulted in 883 hp at 6,700 rpm, and 769 lb-ft of torque at 5,100 rpm. True to form for a positive displacement supercharger, torque production was impressive, exceeding 700 lb-ft from 3,500 to 6,500 rpm.
We added a mixture of Rocket Brand race fuel to the mix before cranking up the boost, then increased the pressure to a maximum of 13.5 psi. Monster Mouse responded with a jump in power to 951 hp at 6,500 rpm and 866 lb-ft of torque. Being ever so close to our goal of 1,000 hp, we turned up the boost one more time to 18.7 psi. The supercharged stroker pumped out 1,051 hp at 6,600 rpm and 988 lb-ft of torque.
We can't help but suspect this is about the reasonable limit for the 8-rib serpentine system, though race applications have run successfully at higher boost and power levels. The most impressive thing about this exercise with Monster Mouse was how easy it was to make 1,000 hp. Time was when 1,000 hp was the holy grail of power outputs, even for a big-block. This thing could be driven around on a daily basis at a reduced boost level, and then with a pulley swap and race fuel, transformed into a serious track animal.
An argument can be made about just how necessary 1,000 hp is in a street car (or many racecars!), but the fact remains that combining a big-bore Texas Speed stroker LS with big Kenne Bell boost can yield four-digit power levels. Stick around--we aren't done with Monster Mouse just yet.