These are “real” dyno tests performed with calibrated sensors. A Ford NGS Scanner also monitored fuel, spark, load, temps etc. to guarantee accuracy of tests.The vehicle was a 100% stock ’03 Cobra. The Kenne Bell BOOST-A-SPARK™ was added at 10 psi to insure adequate ignition. The fuel system was 100% stock except for the Kenne Bell BOOST-A-PUMP™ and SWITCH CHIP®. The Kenne Bell BOOST-A-PUMP™ was necessary to increase fuel pressure.
CRANK PULLEYS – There is a wide selection of crank pulleys available from Metco (7.8”, 8.5”, 9” and 9.5”). The chart covers the stock 7.5” and 6.55” Metco. The 6.55” Metco ring MUST be used if 15.0 psi is required. The largest pulley that will fit under the hood with the Mammoth™ is a 3- 1/2”.
SUPERCHARGER PULLEYS – Use ONLY Kenne Bell billet steel pulleys. Warranty void with other pulleys. Mammoth™ 2.8H sits higher on engine so the 3.5” (17 psi) is max for hood clearance. Use the 6.55”x3.5” (15 psi) or 3.25” (17 psi) for max street. Some hoods may clear 3-3/4” depending on engine height.
OCTANE GUIDE (Pump Gas)
15 psi – 91 octane
17 psi – 94 octane or 91 w/Torco Octane Booster
BOOST – Boost ratings are at 6500 rpm with Bassani exhaust. Stock exhaust will have slightly higher boost. Cams and headers also reduce boost.
IDLER KITS – A Kenne Bell 3” pulley will make 23.5 psi without “idler kits” etc. The Kenne Bell 2.8H requires 56 less HP to turn than other twin screws – and much less than an Eaton – so the big 8 rib provides a lot of belt surface area.
Crankshaft Pulley ÷ Supercharger Pulley= Ratio. Ratio x engine rpm = Supercharger rpm. Maximum rpm for racing is 18,000 rpm.
Example: Max RPM = 6000 engine x 3.0 Ratio = 18000 Supercharger rpm
NOTE: Keep engine rpm at 6000. If raising rpm to 6500, reduce ratio to 2.76. 18000÷6500=2.76).
Note how the undersized and less efficient 2.3 uses up to 95 MORE engine HP to drive the supercharger. That extra drive power also requires tensioner belt and pulley considerations. Note: The higher the boost, the greater the PC/HD gap between the 2.3 and
3.2 (16-95HP). That’s more HP than headers, cat back, cams, x pipe, heads, etc. which, while improving HP, further reduces the supercharger boost. These engine HP enhancers actually rob boost from an already undersized 2.3. That’s why there are bigger superchargers like the Kenne Bell capable of 35 psi boost. Then there’s up to 88° hotter supercharger discharge temp at only 20psi. Who doesn’t know that hot air kills HP, limits boost and promotes engine damaging detonation?
The Kenne Bell upgrade Kit simply offers more HP and boost potential, with plenty of room to grow, without expensive bolt ons. And you will never be intimidated or embarrassed to lift the hood of your Shelby – or worry about a 2.3 out powering your KB. Ever hear of ANYONE “upgrading” a KB with an Eaton?
