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Old 03-15-2012, 09:20 PM   #1
jollyblue84
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Default Fuel question for a ej20g

What is the highest octane I can run in the stock ej20g?
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Old 03-15-2012, 09:45 PM   #2
eg33GC
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anything over 91?
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Old 03-15-2012, 09:48 PM   #3
jollyblue84
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So I can run 104 octane?
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Old 03-15-2012, 09:56 PM   #4
eg33GC
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yeah but it won't do you any good over 93. and don't use leaded fuels.
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Old 03-15-2012, 10:32 PM   #5
jollyblue84
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I thought in the jdm motors it would run better with a higher octane. Don't they use higher octane then the. U.S.?
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Old 03-15-2012, 11:16 PM   #6
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it could be, but in US I guess you'll find 93 octane as the highest. For example, if you buy airplane Avgas, it has 100/130 octane but is leaded fuel.

Airplane engine use leaded gasoline so this way they can lubricate valves seats.

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Old 03-16-2012, 02:27 AM   #7
ciper
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The way they measure octane in Japan is not equivalent to the US. If you don't have cats it is ok to use leaded gas at the track. Higher octane than the car was tuned for lets the computer max out the timing even as ambient temperatures increase.

I regularly fill up our two track cars with 110 leaded even though they are tuned for 91 and meth
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Old 03-16-2012, 02:31 AM   #8
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The 02 sensors will fail quicker with lead, and the early ecus really like their 02 readings. So keep that in mind
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Old 03-16-2012, 02:39 AM   #9
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The will fail faster. But universal sensors are pretty cheap, maybe I shouldn't assume but if he is asking about higher octane I assume its not for street usage.
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Old 03-16-2012, 06:23 AM   #10
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About the early ECUs liking their O2 readings - if you totally disconnect the 02 sensor, the car will drive fine (although the AFRs will be a bit rich at idle - about 12.0 AFR IIRC)

Universal sensors are cheap and also seem to fail fairly quickly.
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Old 03-16-2012, 11:54 PM   #11
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don't say that i just put mine in today
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