Racing Fuel (110 Octane) Question

[oldmodman]

If this fuel is for sale at a gas station that is open to the public it can't legally have lead in it, at any concentration. That is a US law, not a state law. Lead has been banned for sale in a road licensed vehicle since January 1, 1996
It can still be sold for aircraft, off road vehicles, and racing purposes confined to a track.

See:

EPA Takes Final Step in Phaseout of Leaded Gasoline | EPA History | US EPA

 

[Chris _Scott]

running higher octane will hurt performance.

You actually want to run the LEAST amount of octane without detonation occurring to make the most power. NOT run the most amount of available octane you can get.

You would only net gains if you have a 110 octane dedicated tune [like mentioned previously]...otherwise you are making a mistake.

 

[Chris _Scott]

If this fuel is for sale at a gas station that is open to the public it can't legally have lead in it, at any concentration. That is a US law, not a state law. Lead has been banned for sale in a road licensed vehicle since January 1, 1996
It can still be sold for aircraft, off road vehicles, and racing purposes confined to a track.

See:

EPA Takes Final Step in Phaseout of Leaded Gasoline | EPA History | US EPA

You can purchase leaded fuel at public stations..you just aren't allowed to pump it directly into your vehicle and you are not allowed to run it on the streets. There is a Sunoco by me that I can pick up sunoco purple fuel..I just need to pump it into the gas container first.

Not sure if that is what you meant by your last sentence or not.

 

[ford_racer]

running higher octane will hurt performance.

You actually want to run the LEAST amount of octane without detonation occurring to make the most power. NOT run the most amount of available octane you can get.

You would only net gains if you have a 110 octane dedicated tune [like mentioned previously]...otherwise you are making a mistake.

+ 1 zillion to the bolded part. You make me so happy Chris. Montana seems smarter with you in it.

Octane slows down the flame front, which is what allows for higher timing and ultimately more power.

When you add more octane but don't change the timing, the flame front is created at the same time, but travels slower. This means it will be complete after top dead center has occurred.

Say you have a 93 octane tune with 18 degrees of timing that is spot on for everything. This will mean that the air/fuel charge is ignited 18 degrees before top dead center. The octane of the fuel will allow it to burn long enough that when the motor has turned 18 degree and is now at TDC, the air/fuel charge has been ignited completely and on time.

If you add 110 octane to this formula, but don't change the ignition timing, then the air/fuel charge is now being ignited at the same time, but the increased octane of the fuel is slowing the amount of time it takes for the air/fuel charge to be completely used up. So now that it's slower, the engine might turn 24 degrees before the charge is completely burned, meaning the charge is completely consumed 6 degrees after top dead center. Because we want the charge to be consumed at or slightly before TDC, than the complete consumption after TDC will hurt efficiency and power.

 

[thomas91169]

I was always under the impression that was the reason but looks like I have some digging to do. I will have to find out.

EDIT:
Octane rating - Wikipedia, the free encyclopedia

Might be true for Naturally Aspirated as shown in the article, but were talking forced induction.

running higher octane will hurt performance.

You actually want to run the LEAST amount of octane without detonation occurring to make the most power. NOT run the most amount of available octane you can get.

You would only net gains if you have a 110 octane dedicated tune [like mentioned previously]...otherwise you are making a mistake.

He is not trying to gain from it, he's using it as insurance. And he will only lose power if he pours in a full tank of 110/116 on a 91 tune. A mixture of 80% 91/93 and 20% 100 or better will not have any negative side effects while giving him a nice safety factor in the tune.

Running a mixture of higher octane while still running the same tune has been done by racers all over as a means of providing a little insurance against blowing their motors for years now. Its not some new trend.

 

[fire_4_effect]

He is not trying to gain from it, he's using it as insurance. And he will only lose power if he pours in a full tank of 110/116 on a 91 tune. A mixture of 80% 91/93 and 20% 100 or better will not have any negative side effects while giving him a nice safety factor in the tune.

Running a mixture of higher octane while still running the same tune has been done by racers all over as a means of providing a little insurance against blowing their motors for years now. Its not some new trend.

nicely stated! i will have to make sure that the 110 is unleaded (seems logical) perhaps a gallon or two at my next fill-up won't hurt. btw - alot of "back & forth" discussions on this topic... i really appreciate it guys; i'm learning as we go! :rockon:

 

[Chris _Scott]

He will be down some on power..not 15 or 10 hp..might be something as small as 2-5hp..but he WILL be down on power on some measurable level.

Unless your car was tuned ABSOLUTELY aggressive and to the very edge [and if that was the case..I'd find myself another tuner if I was you] there is nothing to gain.

However if the OP wishes to foul his plugs and waste more money while going slower....go for it and help stimulate the economy some.

Save yourself the trouble..stick w/ 91/93

+ 1 zillion to the bolded part. You make me so happy Chris. Montana seems smarter with you in it.

:lol: Nice seeing them tuition dollars starting to pay off.

 

[KILRSVT]

On hot days... Over 85f I've dumped some 100 on my 91 octane tuned car...I picked up some power for sure...when I would do open track events at infineo at 90f weather I would fill up with 100 great power and assurance.... It sounds like you just have an itch to try stuff out... Lol..just dump a gallon or two and get it over with haha.

 

[Chris _Scott]

On hot days... Over 85f I've dumped some 100 on my 91 octane tuned car...I picked up some power for sure...when I would do open track events at infineo at 90f weather I would fill up with 100 great power and assurance.... It sounds like you just have an itch to try stuff out... Lol..just dump a gallon or two and get it over with haha.

Do you have dyno graphs to prove said gains?

 

[fire_4_effect]

He will be down some on power..not 15 or 10 hp..might be something as small as 2-5hp..but he WILL be down on power on some measurable level.

Unless your car was tuned ABSOLUTELY aggressive and to the very edge [and if that was the case..I'd find myself another tuner if I was you] there is nothing to gain.

However if the OP wishes to foul his plugs and waste more money while going slower....go for it and help stimulate the economy some.

Save yourself the trouble..stick w/ 91/93

:lol: Nice seeing them tuition dollars starting to pay off.

the majority rules - i'm sticking with 91/93! thx for all your inputs guys :thumbsup:

 

[thomas91169]

He will be down some on power..not 15 or 10 hp..might be something as small as 2-5hp..but he WILL be down on power on some measurable level.

Unless your car was tuned ABSOLUTELY aggressive and to the very edge [and if that was the case..I'd find myself another tuner if I was you] there is nothing to gain.

However if the OP wishes to foul his plugs and waste more money while going slower....go for it and help stimulate the economy some.

LOL if 2-5hp lost hurts his output that bad (which I doubt youd lose even that with a 80/20 mixture of pump/110), the last thing he should be doing is racing....

Youll lose that on improperly gapped plugs alone, especially when youre talking cars with 400-500hp. Especially seeing most people on here think plugs are always pre-gapped from the factory and spot on.


IMO the benefits of increased tune headroom when running a mixture of 91/110 far outweigh the negatives.

Id rather lose 2-5hp (like i said, if that) than an entire motor because I was pushing it hard and didnt know i was over the edge, which is what happens when you rely on other people to tune for you (much like most in the domestic world where "take it to a dyno" is standard response to anything tuning related).

 

[Competition]

My racecar is right in the neighborhood of 13.5:1, I run VP 110 in that. And sometimes with the Cobra I mix a few gallons, simply because I like the smell of it. Lol.

 

[HotStart]

think of it as an insurance policy.


Say you get your car tuned in the summer. Come winter the cooler air (denser=more oxygen) starts to lean out your tune.

you'd be surprised how much environmental variables affect your tune. And since your tune was based on a summers day in a controlled environment, your tuner took no consideration for the winter night you were out there pummeling the competition all the while your tune went from a bit on the safe side to over the edge.

Unless the mass air meter is undersized for the car, any halfway decent tuner won't have separate tunes (or the need for them) for summer/winter. It's always nice to get an accurate range of the MTF but if it's accurate on an 80* day, it's more than likely not off by much (if any) on a 30* day. The only way detonation should come into play is if the spark table's load axis can't go any higher.

What I haven't seen any one mention is the possibility of Stoichiometric differences between the fuels. I don't know what "110" this fuel is, but it is more likely than not that it doesn't have the same stoich ratio as the pump gas in your area (especially if one has ethonal content and the other does not). This will change your Lambda values, or what you see as A/F ratio on your wideband.

 

[fire_4_effect]

My racecar is right in the neighborhood of 13.5:1, I run VP 110 in that. And sometimes with the Cobra I mix a few gallons, simply because I like the smell of it. Lol.

so it's ok to mix a gallon or two with each fill-up... i see. i'm confused since there are opposing comments for this topic. what the heck... i'll give it a try today! :thumbsup:

 

[Competition]

so it's ok to mix a gallon or two with each fill-up... i see. i'm confused since there are opposing comments for this topic. what the heck... i'll give it a try today! :thumbsup:

Leaded race gas is horrible on cats (if you have them) and your o2 sensors. You can buy unleaded VP 109, but it's like 9 bucks a gallon. I've mixed leaded 110 50/50 with regular 91 and never had an issue.

 

[fire_4_effect]

Leaded race gas is horrible on cats (if you have them) and your o2 sensors. You can buy unleaded VP 109, but it's like 9 bucks a gallon. I've mixed leaded 110 50/50 with regular 91 and never had an issue.

thx!