What Fuel Octane
#4
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AM,
"Additional octane" over and above the design spec of an engine NEVER gives additional performance, if the engine is in a proper state of tune.
The higher the octane rating is, the slower the fuel burn is, and the less btu per pound the fuel has. This is true for all "pump gases".
(We're not talking about race fuel or horsepower cocktails employing oxidizers and/or high volatiles like Nutec for example).
Now if you choose to increase your compression ratio or advance your ignition timing beyond the factory specs then you *may* be able to increase your engine's octane needs beyond the design spec. In that case, you will indeed obtain additional performance because lower octane fuels will be handicapped by the knock sensor on the motor retarding ignition timing away from optimum.
If it makes you happy, though, run 93 in it. Some HP500EFI's will soot up the transom with 93 fuel, but it can always be wiped off...
"Additional octane" over and above the design spec of an engine NEVER gives additional performance, if the engine is in a proper state of tune.
The higher the octane rating is, the slower the fuel burn is, and the less btu per pound the fuel has. This is true for all "pump gases".
(We're not talking about race fuel or horsepower cocktails employing oxidizers and/or high volatiles like Nutec for example).
Now if you choose to increase your compression ratio or advance your ignition timing beyond the factory specs then you *may* be able to increase your engine's octane needs beyond the design spec. In that case, you will indeed obtain additional performance because lower octane fuels will be handicapped by the knock sensor on the motor retarding ignition timing away from optimum.
If it makes you happy, though, run 93 in it. Some HP500EFI's will soot up the transom with 93 fuel, but it can always be wiped off...
#5
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If I don't have to run the higher octane that is fine with me specially with the price of fuel this summer.
What octane is recommended the lowest on the pump or stay around the 87?
What octane is recommended the lowest on the pump or stay around the 87?
#6
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HP500 EFI - 500 HP
Specifications
HP: 500
Full Throttle RPM Range: 4800-5200
Compression Ratio: 8.75:1
Fuel System: MPI
Fuel Requirements: 87 Posted Octane (R+M)/2 (92 RON) International
Specifications
HP: 500
Full Throttle RPM Range: 4800-5200
Compression Ratio: 8.75:1
Fuel System: MPI
Fuel Requirements: 87 Posted Octane (R+M)/2 (92 RON) International
#7
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As long as you are in the good ole U.S. of A., the yellow 87 sticker on the pump will be just fine.
If you travel outside of the US, you will need to know what method they use to figure their octane...
If you travel outside of the US, you will need to know what method they use to figure their octane...