Training Wheel Hero
Join Date: Feb 2006
Location: Bellingham, WA, USA
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The reason for premium gas ("no lower than 89 octane") has nothing to do with power--well, not directly.
Contrary to popular belief, premium gas is not super fuel. It does not burn hotter, it does not (in itself) create more hp. In fact, it does quite the opposite. It burns cooler and slower. In other words, is much less volatile. You use premium gas in an engine like a 600 sportbike--that's got a 12:1 compression ratio and 14,000rpm redline!--so that it doesn't blow up! Those kinds of conditions are quite insane compared to the 3,000rpm and 8.5:1 compression ratio that your family minivan is exposed to. Tons of pressure. Tons of heat. Build up some carbon in there or in some other way create a hotspot, and with fuel that's too volatile, it will ignite in the cyclinder BEFORE the piston reaches the top and tear the sh1t out of your engine (otherwise known as "knocking"). Almost any modern FI engine has sensors and computers that can compensate for this problem. But they're going to do this by retarding your timing. Which robs you of power. Especially at the high RPM range where pressures and temps are going to be seriously high and knocking is going to really come on strong.
There is no modern sportbike that will run optimally with anything less than premium pump gas. They are tuned for it. Sure, they'll eat the cheap stuff and compensate with workarounds, but it's not "right." If your bike seems to be running better with lower octane gas, you'd better get that thing to the tuner and get it sorted...
"...But check your lease, Man, 'cause you're living in F*bleep* City!"