If you look at the page on HRC's site with the Stage 2-4 dyno graphs, you'll see that stage 3 is quoted as a mix of 100 and 91 octane, but stage 4 is quoted as pump gas. The highest numbers do not state what fuel is used.
So what does it take to achieve the 373whp on stage 4 as the "soul-food solstice" did? Is it only possible on race fuel or are all these numbers doable on 93 octane? Is there a whp limit on the 2.4 w/ stock compression?
Also, I cannot find details on the "high boost" option. I've read that its a valvetrain (dual coil springs) upgrade and thicker head gasket, which would lower compression slightly. Is this why stage 4 is operable in pump gas?
Fow what its worth, I know it would be easiest to just call up HRC, but I like to hear from end users/ those with real world experience. If ECOBOOST chimes in, thats cool too
