Hey Fellas,

I have a 2000 F-150 w/ a 4.6 that has been Troyer tuned. My question is... How do y'all w/ more that one tune change tunes when changing octane tunes ie: 87 perf. to 93 perf. Right now I pull the fuel pump fuse and reflash at the gas station when I fill up w/ the different octane. I was wondering if it was ok to drive my truck the 1 mile from the gas station to my house ( i try to use the same station) then reflash there. I would only do this on say a 87 to 93 reflash not vise versa. Will running a higher octane on a lower octane tune hurt the engine for that short distance? I want to know so I donk have to keep my tuner in my truck plus hogging up a pump for longer than necessary.

Thanks,

Ed

 

You won't hurt anything to have an 87 octane tune loaded and burn your 93 fuel while you drive home. A Chevy driver might be looking over your shoulder at the gas station.

Of course some folks think that a 93 octane tune should always be loaded and 93 octane fuel always used................just in case there's ever a Chevy around needing to be beat down......

 

Hi Ed,

I agree with OFT's response, that won't hurt.

The thing that happens when you use significantly more octane than what the engine is tuned for is simply that the engine will not make the power that it should, as it does not have enough time to burn that higher octane fuel - the higher the octane, the longer it takes to initiate the combustion event (though once it IS lit, it tends to burn at a relatively uniform rate between about 87 & 98 octane or so).

For example, I had a customer in California take his 5.4 3V F-150 to a dyno, and he was running 91 octane on his 87 octane tune - what happens was, it made great power until 4200 rpm, but then did not make any more ADDITIONAL power after that, simply because it didn't' have enough spark advance to compensate for the higher octane.

But doing this over a short drive back to your house is perfectly fine - I don't care to flash my PCM at the gas station, either!