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Question regarding Race Fuel

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I want to go to the track before the end of summer. I was wondering if anyone has run race fuel (100+ octane) in their new Boss and if so, did it make a difference. I have run it before in older cars without computers but wondered with all the electronics, if the higher octane was needed. Any thoughts are appreciated.

Not sure about the regular key but TracKey is rumored to make adjustments for up to 100 octane.
Personally I would not run a higher octane fuel if it is not needed e.g. experiencing detonation. A higher octane fuel is actually harder to ignite and as a result you could lose horsepower.
MrGT5oh said:
Personally I would not run a higher octane fuel if it is not needed e.g. experiencing detonation. A higher octane fuel is actually harder to ignite and as a result you could lose horsepower.

I agree but don't know where the line would be for the Coyote engine, I would guess around 95 on the stock tune? Personally I run only only pure gas (non-ethanol) in the Boss, for the street I use 90 since it it all that is available near me. Some of the tracks have 93 and I was thinking in time to mix in a gallon or two of 100. You can try that if you want a little boost.


BOSS 771
FYI. Octane numbers in Europe are approximately 4-5 above those in the US and Canada for the same fuel due to the way they figure it......So a 98 in Sweden is about 93-94 in the US.
What is you exchange rate to the dollar? The 98, 100 and 112 has been running around $10.50 gallon at the best stations. I remember in Panama the 91 was 87 and 95 was 91.

By the way I was talking to the guy at CJ Ponyparts and he said a guy from Sweden has been ordering the same parts as I have, told him I knew who he was talking about. He said the ordered did not get finished so you may want to contact Joe there.


400lb Gorilla
Denver, CO
Apologies for bringing this thread back from the dead, but I had the same question and given that it has been almost seven years I assume more research and experimentation has been done?

Thought about running Sunoco 260GT

  • Octane (R+M)/2

  • Research Octane

  • Motor Octane

    Any suspected issues?


Tramps like us, Baby we were born to run...
Exp. Type
Exp. Level
3-5 Years
Brighton, Colorado
It's hard to find 100 octane around the Denver area but when I head out to High Plains usually mix 91 with the 100 octane I can get there. (About half and half) Next tyme I'm there, I have two 5 gallon jerry cans that I'll fill up for the future. I have never run the car on just 100 octane but have never had any issues running the mix. I'm sure if I did some research, perhaps I could find somewhere closer to the Denver area to get race fuel.


400lb Gorilla
Denver, CO
Thanks. Given the storage life of the prepped Sunoco being ~ 1 year it could be good to have around. Here is a site I am referencing for locations.

This station as 100 octane and many other variants at the pump

Sinclair Station
6291 West 58th Avenue

Arvada, CO 80002


720-214-5726 (fax)

As an FYI there are no longer any ethanol free fuel stations in the Denver/Front Range area based on calls made yesterday.
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I've run Sunoco 100 octane in my Boss with Trackey. Car runs fine on it, but can't say I noticed much difference in power. But it was summer, hot temps, so PCM probably moderated the ignition advance curve. Otherwise I'd surmise you'd get some power benefit from a bit more aggressive curve, but it's probably only on the order of a few HP I'd guess. It'd be interesting to see somebody experiment with this and see dyno results.

Sunoco 100, here at least, has ethanol in it, so worse fuel mileage. Also, race gas does not contain the additive package of detergents used in street fuel to help keep valves and combustion chambers clean, so extended use of race fuel will likely be detrimental to carbon buildup on valves and such.
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Because racecar.
Arizona, USA
It cannot hurt your car. If anything, it will protect it while on-track. My local fuel depot has Sunoco 100 at-the-pump and that's all I run in my race car. If you are running on-track, for a street car I'd suggest dumping in 5 gallons of 100 prior to filling your tank with 91 or 93.

Bill Pemberton

0ld Ford Automotive Racing Terror
Exp. Type
Time Attack
Exp. Level
20+ Years
Blair, Nebraska
Good question to ask the Engineers for those of you that come out to the Mustang Roundup ( usually 4-6 engineers come down from Dearborn). Was told by one of them, a few years back, that 93 was what they would recommend at the track. Full blown race cars, recommendation is 98+.
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I just purchased a 2012 Boss 302S and the owner's manual for that car says I need to run Sunoco 260 GT which is 100 octane. Interesting to note that the 2013-2014 Boss 302S owner's manual says to run Sunoco 260 GTX which is 98 octane. I wonder why the difference? Do you guys know if the 2012 Boss 302S has a different tune than the 2013-2014 cars? As far as I can tell, the engines are the same so maybe they had different ECUs and/or tunes?

In any case, has anyone here raced or tracked their 2012 Boss 302S with 98 octane fuel and, if so, did you experience any issues? I only ask as most of the race tracks near me have 98 octane gas but not 100 octane gas.

Grant 302

basic and well known psychic
I don't think it would matter at those octane levels. I'm pretty sure the running change is because use of 98 was requested or more available or worked the same with the previous tune.

In your shoes, I'd give Ford Performance a call and listen to their recommendations.
I'm making the move to E85, today actually, on a 2017 S550 GT. I've been dealing with Lund and have been dialling in the tune and have the Flex Fuel tune loaded. I just have to get the tank down as low as possible before filling with E85 so I can run the datalogs on fuel as close to E85. Idea is to run the flex fuel tune for a daily and then when racing, fill up with E85 and install the E85 Race tune. This tune assumes that the E85 ethanol content is 85% and increases timing in the low to midrange.

I did install Ford Performance M-9593-LU47 injectors, didn't have to with 15-17 Coyotes, but with sustained high rpm the duty cycle of the injectors with E85 consuming more fuel, Duty cycle would be pretty high. LU47's for insurance.

The car doesn't have a true flex fuel sensor, but rather infers an ethanol content through fuel usage, a learn period that starts with 80km of fuel left in the tank and the AFR change with E85, believe stoic is 9.89:1 instead of 14.7:1

All new to me but so far everything is going to plan, car is running well with the tune and E85 going in today for the first time. I'll report back how I go.

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