Fuel injection timing

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Fuel injection timing

Post by Tuffcountry1 »

Question about timing with fuel injection
I'm using a full fitech system, completely original motor and trans never been touched, added disc brakes as well.
I'm running at 18 advanced with the timing light because it starts clean and idles great at about 600rpm in drive.
Any opinions on if that's too far?
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Joined: Fri Jun 12, 2020 11:35 pm

Re: Fuel injection timing

Post by mitch0537 »

A lot depends on what fuel you are running. Fuel will ignite if the pressure ifs too high and the higher the octane, the more resistance it has to ignite at higher pressures. In the combustion stroke, the combustion happens in waves traveling starting at the spark plug and moving away from it. If the pressure is too high, the air/fuel mixture will ignite in a place other than in line with the wave pattern. assuming 10:5 compression in the standard T-Bird 390, the more you advance the ignition the higher the pressure for unburned fuel because you are igniting the fuel earlier in the compression stroke. When it does this, it causes predetonation or ping as some people call it. I've successfully ran my engine at 22 deg BTDC with 100 octane low lead .
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