Richard Holdener
September 19, 2012

Satisfied with our baseline, it was time for boost. Off came the TFS intake and on went the dedicated lower manifold for the Kenne Bell Mammoth kit. Designed to accept a 2.6L or 2.8L supercharger, the intake offers exceptional flow and a dedicated air-to-water intercooler. The intercooler was important as we planned on running serious boost. Feeding the beast were billet fuel rails and Injector Dynamics 85-lb/hr injectors fed by an Aeromotive fuel system. We chose a 2.6L supercharger for this application, but the Mammoth system also features a revised intake manifold, massive single-blade throttle body, and 4.5-inch air-intake/MAF assembly. Airflow into the blower is critical, as inlet restrictions result in a drop in boost (and flow) out of the blower. Why restrict your 1,000hp supercharger with a 600hp inlet system? The Mammoth system was designed to maximize flow into and out of the Twin-Screw supercharger.

Installation of the Kenne Bell Mammoth blower required use of the front accessories. We installed the alternator (in its revised location), the A/C and power steering pump along with a Meziere electric water pump and idler pulley. Pulley swaps on the Kenne Bell were a snap, allowing us to start with a 4.25-inch pulley that provided over 10 psi, and finished the day with 22.6 psi using a 3.0-inch pulley. Belt slippage was eliminated with the use of the eight-rib upgrade from Kenne Bell. This required swapping out the stock six-rib pulleys on the alt, PS and A/C along with the installation of a 7.5-inch, eight-rib crank pulley. Running the 4.25-inch pulley increased the power output to 552 and 482 lb-ft of torque. The Mammoth offered a slightly rising boost curve, starting at 8 psi (at 3,000 rpm) and finishing at 10.7 psi at 6,700 rpm. In typical positive- displacement fashion, torque production was impressive, exceeding 450 lb-ft from 3,400 to 6,200 rpm.

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After dialing in the supercharged combination, it was time to crank up the boost. We installed smaller and smaller pulleys on the 2.6L, stepping down in 0.25-inch increments. The 4.0-inch blower pulley brought 586 hp, while the 3.75-inch pulley stepped things up to 627 hp. Equipped with the 3.5-inch pulley, the 4.6L produced 670 hp at 17.5 psi. Stepping up to 20 psi with the 3.25-inch pulley brought 698 hp, but our final pulley swap to 3.0-inch pulley netted 742 hp. We tried a new radiused air entry designed by Kenne Bell on the oval throttle body that pushed the peak power output to 749 hp at 22.6 psi, but we stopped our testing there.

The blower will support considerably more power, but what we needed was more engine to start with. That would simultaneously increase power and decrease boost, making the blower even more efficient. Don't get us wrong, 750 hp is serious power from a supercharged Two-Valve, and we can't help but think there is even more power lurking in the Wooly Mammoth.

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Kenne Bell Mammoth--10.7 Psi vs. 22.6 psi. The great thing about forced induction is the ability to crank up the boost. Stepping down in pulley size from the 4.25-inch blower pulley to the 3.0-inch pulley increased peak boost pressure from 10.7 psi to 22.6 psi. Naturally the increase in boost had a positive affect on power, pumping up the output of the 4.6L from 552 hp and 482 lb-ft of torque to 749 hp and 685 lb-ft of torque.