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Earlier today while driving out East on Long Island I stopped to fill my tank with gas, and at the station, all the pumps had the usual Regular, Mid, Premium on one pump, but on the 2nd pump which typically holds Diesel, there was a sticker for Racing Fuel.

The button for the fuel indicated a 100 Octane level, whereas the Premium was 93. Now although I've seen Sunoco do 95 Octane for maybe a dime more than the Premium fuel, the "Racing Fuel" at this station (LukOil) was $8.99 a gallon!

At first I thought someone messed up the signage as a joke, but after putting my card in the pump to pay, the prices lit up and the 100 octane had $8.99 as the price. This also was the same at the other pumps, and on the major road sign when pulling out.

All the other fuels were from $3.65 to I think $3.90.

After seeing this, my main question isn't to ask about Premium vs. Regular octane levels, but rather I'm curious about if such fuel is safe to use in your typical stock engine on a passenger car, and in addition whether this "Racing Fuel" has anything more than extra octane because I know Sunono Super Premium is typically 10-20 cents higher than premium.

Also, is this a new major line of fuel that's going mainstream? I've only seen this once at the chain -- every other LukOil carries Diesel instead, so I'm not sure if this might be a regional offering.

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I just paid 7 dollars and 77 cents per gallon for 100 octane racing fuel. Put it in my miata up which requires premium and it made a huge difference in how smoothly the engine runs. It might be up a bit more compared to our regular 90 octane premium for power but not worth the super premium price. – user2972 Apr 3 '13 at 15:38
Damn. You could fly a Cessna with that gas. – Sponge Bob Apr 4 '13 at 2:33

6 Answers 6

up vote 2 down vote accepted

A lot of performance Japanese cars are tuned for higher octane fuels from the factory, and will often pink badly on anything less than 97. I suspect the "Racing Fuel" will have other additives as well. If your car is tuned for 93 it would probably still run on 100, but certainly won't run well. (out of interest, what ratings are "regular" and "mid" - here we have "premium" at 95 and "super" at 97 or 99)

The reason you will occasionally see "Racing Fuel" sold in petrol stations (usually near race tracks) is that a lot of series require competitors to use "pump fuel" - By making it available to the public it counts as pump fuel and so can be used in the races.

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The higher octane won't hurt it any. Just won't help either. – Brian Knoblauch Oct 12 '11 at 11:47
One point I forgot to mention - all my numbers are RON, while I presume the O/P is in the US and so will be using AKI measurements, which come out slightly lower. – Nick C Oct 12 '11 at 13:33
US is (RON+MON)/2, and typical values are 87 (regular), 89 (plus), and 91 (premium west coast), 93 (premium rest of the country), 94 (premium in very select areas). – Brian Knoblauch Oct 12 '11 at 14:02

The higher the octane, the less power per gram the gasoline contains. Use the lowest octane your car needs.

expanding on my answer: It's safe...ish to use on stock engines. The fuel burns cooler and may clog your catalytic converter. You certainly won't see any better power or mileage from it, unless you're tuned for 100 octane. It's sold solely for cars that are tuned for 100 octane: race cars and offroaders.

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100 octane is usually leaded and will slowly kill both your O2 sensors and your catalytic converter. I believe I saw 100 octane unleaded at a track once, but I'm not sure how they managed it as my understanding is that 98 octane is the theoretical upper limit on what you can get without lead. – Brian Knoblauch Oct 12 '11 at 11:49
Higher octane fuels (well over 100 RON) are perfectly possible by adding Ethanol or other alcohol bases. – Nick C Oct 12 '11 at 13:37
@insta, could you cite a source for your power per gram figure? – Bob Cross Oct 13 '11 at 0:42
@BobCross, I'm not talking about pure bomb-calorimetrics of combustion enthalpy. For that, heavier hydrocarbons will always win. ICE's are far from bomb calorimeters and depend heavily as well on combustion speed as well. For this, smaller molecules (such as the lighter heptane components of gasoline) will burn easier. Higher octanes are required for heavily advanced engines to help compensate for the slower burn. – insta Oct 13 '11 at 2:33
@insta, good points - I think you should inject your comments into your main answer. You might want to loosen your comment about "heavily advanced engines" - I think the requirement for higher octane also includes poorly designed turbo motors with insufficient cooling. – Bob Cross Oct 13 '11 at 12:34

Have a read of this question on the benefits of premium fuel and this one on what you should choose for your car, as it all depends on your engine and its tuning - a high compression engine can usefully use higher octane petrol, but a lower compression engine will just run badly (or fail to run).

Conversely, some higher compression engines can downtune in order to cope with low octane petrol...some can't.

(Examples - My Impreza with PPP can downtune, but my Forester STi really can't - it is happiest up to 102 RON (UK version) but won't run on less than 99)

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... I'm curious about if such fuel is safe to use in your typical stock engine on a passenger car

If they've added lead, no. I suspect that it's very unlikely that anyone is selling leaded gas at a common access pump (at the race track, maybe).

If no lead, then it's quite likely fine but a waste of money for most cars and drivers. Cars (especially forced induction) can be tuned to utilize the lower probability of detonation inherent in high octane fuels to advance timing or increase boost in order to create much higher power outputs.

Also, is this a new major line of fuel that's going mainstream?

That sounds very unlikely in this economy. What's more likely is that there is a population of racers or those who consider themselves such nearby. Where is the nearest drag strip in relation to this station?

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There's a Speedway a couple miles from my house that sells Cam2 110 octane leaded fuel from a pump. It's off to one side (like is also done with diesel), has a really short hose and big stickers that say "not for street use". – Brian Knoblauch Oct 13 '11 at 12:58
To be honest I'm not sure about any raceways nearby, although there are a few college campuses so I'm guessing that might be the reason. Also, @Brian, yep the fuel is Cam2 -- I forgot the name but saw it yesterday driving by -- so it looks like it isn't just a one time thing – theonlylos Oct 14 '11 at 14:46
Interestingly, the gas station by me that has Cam2 is nowhere near any college nor any racetracks. No idea why they happen to have it there. Perhaps the owner of the gas station owns a racecar. :-) – Brian Knoblauch Oct 14 '11 at 15:07

Working at drag strip has taught me one thing. That 1500 horsepower cars can and quite often run on pump 93oct. So does it. not really for street. Yet if you have I'd say 10.1 or higher compression with say 500 horses or more yeah but be careful timing is important. Most modern engines auto correct their timing by advancing or retarding ignition. If lower than 10.1 and boosted or nitrous is used still have to account for timing. So many modern kids and yes I said kids just slap on a turbo or nitrous and add exhaust then go racing with high octane often leading to breakdowns or blowing the motor entirely.

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You may have that backwards. High octane fuel is more resistant to detonation, which means you wouldn't need to adjust timing to safely run it. you COULD actually advance timing a bit. The reason those "kids" blow their motors is because they do stupid things like adding bigger air intakes and exhausts without paying for a retune, which screws with the MAF sensor and causes boost spikes respectively, making them run too lean under WOT and thus makes them detonate. – Juann Strauss May 7 at 7:37

Just some interesting info on high octane fuels the original method of refining fuel had an added amount of lead. The added lead increased the octane value of the fuel which gave the engineneers of old a better way to control the combustion rate in the internal combustion engine. an added benefit of the lead in the fuel was cooler temperatures at the exhaust valve meaning they could mmachine the exhaust valve seat right out of the existing cast iron of the cylinder head. Some companies still practice this however most have switched to aluminium cylinder heads with pressed interference fit hardened armored exhaust valve seats. However those older made cylinder heads are the reason for the " lead substitute" sold at most parts stores today. Anyways emissions restrictions are why in most cases "leaded" fuels are few and far between. Also lead fouls ooxygen sensors at an astronomical rate so running them in just about any factory equipped electronic fuel injected engine is NOT recommended. Also another note is very high octane numbers can be achieved by adding alcohol. This however reduces efficiency. As an example, E-85 (85% ethonal - 15% fossil) is considered to be 110 octane. the problem is that the stoichiometric ratio (efficiency ratio) for (fossil) gasoline is 14.7 parts air to 1 part fuel. For E-85 it is only 9.7 parts air to one part fuel. So as you can see, although it raises its octane level, it decreases its efficiency to only 66% that of good old fashioned gasoline (another point to the theory that todays gasoline doesn't go as far as it used to as it contains about 10% ethonal everywhere in the U.S.) also this is the reasoning for the moniker "flex fuel" equipped vehicles. These vehicles have an extra sensor that in layman's terms shines a light through the fuel into an eye that can determine the amount the light "flexes" as it passes through the fuel and can adjust the fuel/air ratio of the engine according to the amount of ethanol in the fuel. - Have a nice day, all.

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I read an article about a month ago about why it is believed many racers will be using ethanol in the future instead of gasoline (I'm not talking nitro based racing). While E-85 reduces efficiency, it's stoichiometric ratio is far better, which means you can dump a lot more fuel into the mix and an engine will still run. This does two things, first, it will make more power because there is more fuel to burn. Second, it will decrease knock without increasing the octane of the fuel because of the cooling effect. Good stuff. – Paulster2 Feb 1 at 0:55

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