Level of performance on the TMS-G-4 927 and the TMS 872 Etec depends on what the customer wants to put for fuel quality in the fuel tank. Pump fuels that you think are 91? octane might surprise you of actually what it is. Most of our customers opt out for a 15-25 percent blend of a 110 inexpensive race fuel option. Better fuel= Power here at Trygstad Motorsports!