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Old 10-27-2014, 07:24 PM   #1 (permalink)
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Running 87 octane with ignition timed for 91

Hi folks,

Ok...I think I'm all sorted out on the taller 5th gear option, but my next interest is in an ECU flash. Of course the ECU flash is for more HP/TQ, but they also advertise "Increased Fuel Efficiency".
I asked the rep today about what could be expected for an increase in MPG...not expecting much mind you, but they didn't have much info to give.
The ECU flash will make it more fuel efficient, but the majority of people that go this route are not looking for efficiency...they want more power, and they use it. In the end, he said that if I drove it easy (like I am now), he guessed at gains somewhere in the 6-10% range.

However, since the bulk of the ECU flash benefits are in the ignition timing...I would have to start running 91 octane fuel....or 93 octane with the more advanced kit. (93 is not available where I live, so it's not an option).

Just curious I guess what would happen if I were to try running my usual 87 octane when the ECU ign timing is advanced for 91 octane? Would it simply have less power, or would it more than likely ping like a mofo?

I guess I'll check the timing advance with the Scangauge with the stock ECU, and then see what it is after the ECU flash to compare (before trying to revert to the el cheapo 87 octane).

Thoughts? Comments good or bad?


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