Eaton vs. Kenne Bell vs. Vortech vs. HP Perf Boost Curves (11 psi)
To some extent, the power curves simply mirror the boost curves, but check out the differences in the boost curves offered by the four forms of forced induction. The positive-displacement blowers (Eaton and Kenne Bell) have similar boost curves, though notice how the boost curve supplied by the Kenne Bell rises after 5,000 rpm while the Eaton tapers off. The Vortech centrifugal blower produced a rising boost curve, producing peak boost pressure only at peak engine speed. The HP twin-turbo system offered only slightly more boost than the centrifugal at the lower engine speeds, but came on strong about 3,500 rpm. Real tech heads that compare the boost readings from this boost curve to the power readings on the power curves will realize that the turbo system started producing more power than the Roots blower well before the boost pressures became similar. The crossover point for the turbo and Eaton in terms of power was at 3,650 rpm. At this point, the Eaton was producing 11.5 psi while the turbo was only producing 8.5 psi. The turbo equaled the power output of the Roots at 3-psi less-boost-pressure. No wonder the turbos went on to make more power.