Just filled up the tank with 91 octane premium fuel - Toyota Yaris Forums

jkuchta · 05-09-2009, 03:34 PM

The Yaris DOES NOT Have Direct Injection. Direct injection is when the fuel in injected directly into the combustion chamber through an injector (usually a piezo injector) mounted in the roof of the combustion chamber. The Porsche LMP2 car has a direct-injection gasoline turbo engine, while both Audi and Peugeot run direct-injected turbo-diesel engines in LMP1.

The yaris does have indirect port injection (the injector is mounted just behind the intake valves in the intake port)....and in my testing does see gains from higher octane.

When running premium fuel (91 octane here in Cali.) I see more ignition advance than when running regular.

Octane only pertains to a fuel's resistance to detonation, and has nothing to do with flame front speeds, temperature, or the quality of it's burn (i.e. clean or dirty).

The yaris ECU is designed to run a minimum octane of 87 because it has enough range of adjustability to pull timing out to stave of detonation. Running higher octane will allow the ECU to run a more aggresive timing map, making more power.

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05-09-2009, 03:34 PM	#11
jkuchta View User's Garage Drives: 2007 Yaris hatch (red) Join Date: Sep 2007 Location: L.A. Posts: 557	The Yaris DOES NOT Have Direct Injection. Direct injection is when the fuel in injected directly into the combustion chamber through an injector (usually a piezo injector) mounted in the roof of the combustion chamber. The Porsche LMP2 car has a direct-injection gasoline turbo engine, while both Audi and Peugeot run direct-injected turbo-diesel engines in LMP1. The yaris does have indirect port injection (the injector is mounted just behind the intake valves in the intake port)....and in my testing does see gains from higher octane. When running premium fuel (91 octane here in Cali.) I see more ignition advance than when running regular. Octane only pertains to a fuel's resistance to detonation, and has nothing to do with flame front speeds, temperature, or the quality of it's burn (i.e. clean or dirty). The yaris ECU is designed to run a minimum octane of 87 because it has enough range of adjustability to pull timing out to stave of detonation. Running higher octane will allow the ECU to run a more aggresive timing map, making more power.