Our Stage 4 (previously stage 3) upgrade was developed for our customers who want to run 10 second quarter mile times and beyond supercar levels of performance!

The Stage 4 power upgrade for the ISF Supercharger kit achieves 650whp on e85 fuel (about 760hp at the crank @ e85 content of 70-80%). Internally stock ISF engines are recommended to run 50% e85 blend or higher for maximum safety/reliability.

Stage 4 upgrade kit includes:

• Innovate Motorsports e85 gauge
• Upgraded port fuel injectors
• Fuel surge tank with integrated fuel pressure regulator
• Radium surge tank with TI Automotive fuel pump
• All fittings required for fuel system installation
• Teflon lined braided fuel hose
• Revised ECU tune as well as base maps for external fuel computer for pump gas, e50 blend, and e85.
• Upgraded port fuel injectors (necessary for power levels over 600 whp)




Please note that running on regular high octane fuel will require switching the tune file. Running on regular high octane fuel without 55% ethanol is not recommended at full throttle. Also, using the upgraded pulley may void the Rotrex warranty.