Track fuel

[Grant4514b]

I would use at least 93. Don't worry about the fuel trims unless it is labeled as alcohol fuel. I use higher octane when on a track just for the added knock protection. I think your idea of starting out with 93 and adding 110 as needed is a good idea.

I see you are in Louisville, what track are you going to?

I wish they had finished Bluegrass

Putnam

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[Grant4514b]

I misunderstood when I called the track earlier. Unleaded is 104 Sunoco 13% E. He said the 500s run it all the time with no issues. Thanks to all for the help

 

[K4fxd]

One other thing, make sure it is unleaded, most 110 I've seen at tracks is leaded.

 

[K4fxd]

Unleaded is 104 Sunoco 13% E.

You can run this without any issues.

 

[Jstang23]

I misunderstood when I called the track earlier. Unleaded is 104 Sunoco 13% E. He said the 500s run it all the time with no issues. Thanks to all for the help

You'd be absolutely fine with 110 as well. There would be no risk with running 110 unleaded. I used to put 100 my old (2016) v6 and it was totally fine, lol. It has the same type of adjustment technology

 

[Tomster]

All the higher octane will do is that the pcm will advance your ignition and produce more HP (up to a point). The bang vs buck is not worth the extra $$ for a simple track day. I don't know what the ratio of 91:110 would have to be to give a full tank an equivalent octane rating of 93, but I don't think it would be more than 5 gallons of 110:10 gallons of 91.

Either way, the engine is rated to take 91, so you'd be fine with that by itself.

 

[K4fxd]

Either way, the engine is rated to take 91, so you'd be fine with that by itself.

I like to use 100 octane when at the track, either by using race gas or E85 simply for the peace of mind. I'd rather have the gas not detonate instead of relying on the knock sensors.

But yes, it is not really needed.

 

[Tomster]

I like to use 100 octane when at the track, either by using race gas or E85 simply for the peace of mind. I'd rather have the gas not detonate instead of relying on the knock sensors.

But yes, it is not really needed.

Yea, I was looking at it from a cost analysis. As long as you have a min of 91, you won't do any damage and will maintain the warranty. Putting higher octane fuel will theoretically decrease preignition and detonation, but the pcm will advance the timing until the knock sensors begin to detect preignition. I domt think that the ignition advance will catch up to 110 octane fuel. Which octane fuel will coincide with maximum benefit without overkill? I dont know. But for the purposes of the OP, you can safely run 91, just understand that the PCM will retard ignition and there will be less HP. Just as the ignition can only go so far forward, the compression in the cylinder combined with ignition reduction cannot overcome fuel with too little octane. This can lead to knocking that can cause engine damage. This is why you need a minimum of 91.

Me? I'd probably use a ratio of 2:1 of 91 octane to 110. Or just fill it with 91 and forget about it.

Keep in mind that if you are going out for a full day of track (4 sessions) you will need about 60 total gallons of fuel (unless you are driving conservatively). I go through a full tank each time I go out. That is one of my few complaints, it's almost impossible to run flat out without running out of gas.

 

[ClayDee]

FWIW, Every 110 octane I have ever encountered at a pump was leaded fuel .

 

[Traffic22]

If you want to mix to save some money, this may help…..

http://www.bazellracefuels.com/Calcs/OC1.htm

We don’t get 93 in California so I have to run 91. But when I go to the track I’ll put a splash of 100 to get 93. The idea is a little extra knock protection when running the engine hot and hard.

 

[Angrey]

I question some of the discussions in this thread.

GENERALLY SPEAKING, most hydrocarbon fuels follow a curve where an increase in knock rating corresponds to a decrease in chemical density. That's a fancy way of saying, if you want higher knock rating, it generally comes with higher fuel flow requirements (and less fuel economy by volume and less range).

The stoich for methanol for instance is 6.5:1 and has an octane rating of around 110. (but has a much HIGHER effective octane rating when accounting for cooling and near 100% resistance to detonation.

The stoich for ethanol (depending on whether it's aziotrope or 100% pure) is around 9:1 with an octane rating of around 109/110. While it's MON/RON are similar, the "effective" rating (especially when paired with direct injection) is lower than that of methanol.

Then you throw in curve balls for stuff like nitromethane, which is chemically dis-similar in that it brings some of it's own oxygen to the party. Typical A/F ratios for nitro are around the 2:1 range.

What I'm getting at is if you're not seeing an actual live, real time log reading of your fuel trims and A/F, just because you CAN run a fuel, (and it hasn't hurt the motor yet) doesn't mean you should.

Could you dump 110 (set aside the leaded part) in and run it? Probably, but again, unless you're reading the values on the fuel trims, while you're getting a nice bump in knock resistance and advanced timing, you may in fact be MAXING OUT the PCM's limits on A/F.

Better fuels aren't infallible if they don't come with a retune. While you may be reducing knock and preignition risk with better fuel, under the right conditions you may be introducing those same risk factors via lean conditions if the computer is capped at 20% max adjustment on asking for more fuel from the injectors.

In summary, I'd be very cautious about flogging a car at the track on fuels that are very dissimilar in chemical density (i.e. optimal A/F and fuel flow requirements) without a retune.

Could it work? Sure, until it doesn't and you have sad face when you smoke your motor.

The OEM tune has "flex fuel" type adjustability in it but it's not limitless.

Could you run a very dissimilar fuel (chemical density) if you need to limp it home or to the next station,.......sure. I'm just not hip on the idea that you can dump 110 into it without a retune and everything will be hunkey dorey. I'm betting if you were to live log the fuel trims you'd see the car is crying uncle and can't add any more fuel to get to where it wants to be in optimal A/F.

Have people done it and survived? Seems like it, but then again, it's like saying "I smash random strangers without a condom all the time and I've never gotten HIV." It works until it doesn't.

Better to either blend fuels (so that the volume ratios are comparable to what the motor is tuned to run) or better yet, just bring the fuel you want to run and know works.

 

[Angrey]

And another thing. NO, I would not trust pump 91 on a 12:1 compression motor on a hot, punishing track session. I don't care what Ford says. I have no way to back it up, but my personal opinion is that a lot of the late model engine problems are due to the inconsistency in pump fuel quality paired with high compression. I PERSONALLY (my opinion) think GM is going to see the same levels of warranty claims on a motor that's 12.5:1 compression relying on a thousand variables and threats to the fuel. It only takes one suspect batch of fuel to result in carnage and that can come from dozens of potential sources (crooked station owners or distributors, an error by the delivery driver, last pump/nozzle contamination, etc, etc, etc). At least with ethanol you can test/verify the quality of the fuel and adjust your use accordingly (i.e. don't flog the piss out of the car when it's 55% E). With pump, you're just relying on a lot of trust that it's of the same quality that OE engineers are relying upon when they develop the car.

 

[K4fxd]

Sunoco GT 260, 14.1 stoich

VP C-10 14.3 stoich

VP C-16 leaded 14.7 stoich

None of these fuels will cause any issues with any S550 mustang. Except for the lead in the C-16. Many racers consider o2 sensors as consumables.

I like to have over 95 octane in the tank when racing. This is high enough the knock sensors will add full timing and it is high enough it will not knock.
93 and lower the computer adds spark till it hears detonation then pulls some, wash rinse repeat.

 

[Angrey]

Sunoco GT 260, 14.1 stoich

VP C-10 14.3 stoich

VP C-16 leaded 14.7 stoich

None of these fuels will cause any issues with any S550 mustang. Except for the lead in the C-16. Many racers consider o2 sensors as consumables.

I like to have over 95 octane in the tank when racing. This is high enough the knock sensors will add full timing and it is high enough it will not knock.
93 and lower the computer adds spark till it hears detonation then pulls some, wash rinse repeat.

I trust boutigque/race fuel quality and consistency more than I trust 93 from a random station pump.

Is 93 octane the same across all gas stations? Proof inside - YouTube

But if VP is getting elevated MON/RON ratings using long chains and aromatics (vs alcohols) then it makes sense that it wouldn't be a drastic change in volumetric ratios.

 

[PUR_SPD]

$12/gal which I’m not worried about. I’ll just fill up with 110 between each session just wanted to make sure there were no negative effects. Didn’t think there would be as long as it’s unleaded. Thanks

Holy sweet Jesus. $12/gal. For how much these cars drink when opened up that can make for a 3rd mortgage on the house.

I know everyone has their opinions. I traditionally run 93 and from BP or Shell if at all possible. Many places you can't get 93 and are either forced to go to 91 or race fuel. I did 91 octane earlier this year at OIR and didn't notice any difference at all. Must be said that OIR is not a wide open throttle (WOT) track except for 2 places.

Used to have to run 91 at Road America in my Boss 302 because the nearest 93 octane place was miles away (since remedied).

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