Choupique

I drive a 2013 5.0 and I keep my edge evolution programmer on either tow or race mode which both require 91 octane. I don't use economy because I tow a lot and the economy mode uses 87, so I just use the tow and race that require the same gas. The problem is that 9/10 gas stations in my area don't have it. I found 1 close to my house that has 91 and is ethanol free but I move around a lot and it's gonna put me in a bind one day when I'm away from home.

Anyone know of any way to search for 91 octane stations wherever I am? Or if it would hurt to just put 93? Or anything else I can do?

MGD

Anythin' higher than 91 woon't hurt a thang.

Search: http://pure-gas.org/

OR - if ye looks in ye man-well, it'll tell ye how to 'detune' any of those calibrations to run on 87.

Whatever ye do - DO NOT use any octane booster product (except Torco if ye's be rich, lol).

FWIW - remember that you still have yer fallback STOCK tune - which will be safe to tow to yer trucks's max ratings and will happily run on 87 (or higher) if yer ever in a bind.

MGD

Tothemax

You can use gas buddy. They have a smart phone ap but like others have said, anything over 91 is just fine.

Choupique

Thanks for clearing that up. I was under the impression that it had to be 91

Tothemax

91 might not actually be 91. It just has to be a minimum of 91.

Choupique

Gotcha. I always thought that I had to have a specific octane in order to burn at a specific temperature that the programmer was tuned to.

MGD

Octane does not affect combustion temps - it's an indicator of how resistant to pre-detonation a fuel is.

Higher octanes also are a bit harder to ignite (but once ignition begins the burn rate is about the same). Hence, the advance curve needs to be adjusted to start ignition a bit sooner on the compression stroke to compensate.

Typically using too high an octane for a specified tune may cause a slight loss of power at high rpms due to incomplete burn from suboptimal timing. This assumes the engine management system does not have any corrective algorithms (and is not using inputs from the knock sensing subsystem, for example) to adjust advance based upon available octane/characteristics of the fuel. Many do, these days.

Rule of thumb - it's best to match the octane to the tune. Higher is safe, lower is NOT.

MGD

RLXXI

You can run any tune with 93 octane fuel but not the other way around, if your tuned for 93 you MUST use 93, if your tuned for 87 you can use any octane fuel 87 and higher.