Did I just f*ck up??

[Darnellbe]

I had the Ford performance Tune on my car for maybe a week or so now. I know it claims 91 octane or higher. I’ve been running 93 octane exclusively since I’ve had the car. Today I had a brain fart and hit 87 octane, I put about 2-3 gallons in before I realized it and I switched it over to 93. I did have to start my engine but I always fill up at half a tank, do you think I should get it drained?

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[GotNotch]

You will be fine.

 

[cmxPPL219]

If it's literally just a few gallons, you'll be fine. The remainder of the tank capacity in 93 is so much more than the 87 of a few gallons.

 

[StangTime]

You're fine. 2 gallons of 87 mixed with 11 gallons of 93 is nothing to worry about. Your car will knock if it's a problem.

 

[Jaymar]

You're fine. The Ford Performance tune is rather safe for reasons just like this and it can accommodate all gas types sold domestically including the 91 octane crap. If it makes you feel more comfortable you may wish to drive easy on this tank and not put it under any high cylinder pressure scenarios like WOT pulls.

 

[coz0502]

If you're really concerned, you could fill it up sooner the next couple of times. This will further dilute whatever 87 octane is still in the tank. But like others said, you're probably fine anyway.

 

[Darnellbe]

If you're really concerned, you could fill it up sooner the next couple of times. This will further dilute whatever 87 octane is still in the tank. But like others said, you're probably fine anyway.

Thanks that’s a good idea!

 

[NoVaGT]

Or just go get a can of octane boost.

 

[Dave2013M3]

Just dump a few gallons of 100-101 racing unleaded or a few gallons of E85.

 

[silverbullet85]

The car has adaptive octane logic. Worst thing that would happen is you'll loose a few hp to slightly less timing. I wouldn't give it a second thought

 

[Biggus Dickus]

I had the Ford performance Tune on my car for maybe a week or so now. I know it claims 91 octane or higher. I’ve been running 93 octane exclusively since I’ve had the car. Today I had a brain fart and hit 87 octane, I put about 2-3 gallons in before I realized it and I switched it over to 93. I did have to start my engine but I always fill up at half a tank, do you think I should get it drained?

No drive slow until it clears - you can also throw some Torco in there or put in 2 gal of real E85 and drive normal

 

[WildHorse]

Your fine. 87 + 93 is like 180 octane.

 

[lacanteen]

If you have an automatic, you'll be fine, but a manual will need a full fuel system flush. Just kidding, it's fine.

 

[ORRadtech]

So, you've got a 16 gallon tank 13 gallons of which are 93 octane and 3 are 87 octane. If my quick and dirty calculations are right you currently have a tank full of 91.875 octane fuel.
You better drain that inferior crap out before your tune freaks out and self destructs...

 

[libtrucker]

I had the Ford performance Tune on my car for maybe a week or so now. I know it claims 91 octane or higher. I’ve been running 93 octane exclusively since I’ve had the car. Today I had a brain fart and hit 87 octane, I put about 2-3 gallons in before I realized it and I switched it over to 93. I did have to start my engine but I always fill up at half a tank, do you think I should get it drained?

No your fine. I haul gasoline for a living. And this is literally how you make mid grade. So two gallons of 87 and say 10 of 93 would make like 92 or so octane. Gas stations have blend pumps in the pumps that blend regular and premium.

Back in the day we used to blend it when we loaded it in the truck. But gas stations have gotten rid of the big "mid grade" tanks in the ground to make more room to inventory more regular.

There are only two widely available octane ratings (most of the country). 84 octane, 90 octane, and ethanol. The ~10% ethanol blend upgrades the octane rating around 3 points.

Back in the day to make 89, I think it was 35 prem, 65 regular, depending on the time of the year and temerature, etc...

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