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Close to pulling the trigger on e30

6134 Views 53 Replies 13 Participants Last post by  JaBoogedy
Like the title states, oh so very close. I live in Iowa so (obviously) e85 is everywhere. My only real hesitations are economy and testing, this being my daily driver. Basically how much milage should I expect to be sacrificed to the corn gods when just driving it normally and should I be testing the e85 on every fill-up? I see you can get a gauge but it doesn't seem like most people do that.

Edit: finally came across the "Calling all e30 tunes" thread. I feel like this is a must read for anyone considering ethanol, a TON of good info in there. Hopefully this isn't a dumb question, would there be any harm in filling up 30 gals (I have 36 gal tank) and using a gauge to check the ethanol content, using the last 6 gallons to correct if necessary? I don't know why I am so against testing 馃槄
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You can always test a tank of e30 and see if you like it. No tune is needed to run e30 on your truck. If anything, OAR will just be maxed out and you鈥檇 have literally 0 KR.

I鈥檝e ran E30 in my raptor and 11. No issues at all. Makes a huge difference in drivability, especially on hot days.

A tune would just capitalize more on it.
Oh鈥 did not even notice that till now, hahah.

OAR is your Octane Adjust Ratio. To put it in simple terms, it provides you a good idea on if your fuel is adequate. It will always be specific to who wrote the tune, and/or how the tune was designed. No two trucks will be the same.

This ratio allows the calibration to use a multiplier which either advances/retards on-top of the base timing tables. Hence the performance difference when running 87 to 91. Overall it uses KR feedback to determine fuel quality for the calibration.

Negative OAR - Good.
Positive OAR - Bad/Ok.

There are others who can explain it far better than me.
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KR is not actual knock. It鈥檚 the amount of timing the truck pulls( retards ) to prevent knock/detonation. The sensor itself picks up frequencies in which it references a table. Ford spent thousands of hours dialing in knock sensor feedback.

Some positive KR is not an issue at all. The calibration is just fine tuning the amount of timing it can add based on the fuel. It鈥檚 all about efficiency. That鈥檚 why you will always have more KR under light load. The calibration runs as much timing as the table will allow for emissions and fuel efficiency.

OAR will do it鈥檚 job and adjust the timing tables if the KR is excessive. If your OAR were maxed out positive(crappy fuel), then I would start to worry. But the truck would throw itself into a Knock Performance Limp mode.
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OAR can be very different between tunes. The stock tune is very conservative.
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