Opening up the engine for a rebuild.... At the last Enduro race I could not afford to get any race fuel so I used boostane to get the fuel from 93 to 98 Octane... Have a 93 race tune from Shaun at AED. It took two quarts for roughly 50 gallons.

When possible, I use Sunoco GT260 plus to mix in and raise the octane level for safety.... My logs show no Knock, and it advances 3 degrees from 27.5 degrees with our local 93 pump gas..

But looking at the spark plugs and valves, you can see how orange the are!!!

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AND!!! Then when I look up the problems with MMT additives........ Guess what... The Sunoco GT260 plus has it as well!!!!

VP isn't available near you? Just say 'no' to additives/boosters with pump gas.

I have no direct experience with the Sunoco. But wouldn't be surprised if all race gasolines have some MMT in it.

Just an FYI

MANGANESE (MMT): Sometimes referred to as manganese, or more correctly Methyl Cyclopentadienyl Manganese Tricarbonyl (MMT). This can be an effective octane improver at very low concentrations YOu can gain one or two octane numbers using the recommended treat rate. Problems with emissions, injectors, spark plugs, oxygen sensors, and catalytic converters have all been traced to the use of MMT, which is why it is not legal to use by U.S. Refiners in Reformulated Gasoline. As indicated above with the alcohols and the ethers, it is tough to know what octane number you have attained.

100 OCTANE UNLEADED RACING GASOLINE: An alternate solution to using additives is to use 100 octane Unleaded Racing Gasoline. This is a street legal 100 octane unleaded gasoline that can be used in its pure form, or it can be blended with any street gasoline. You will always know what octane you end up with because we can provide you with a blending chart that helps you to determine that. In addition, if the 100 octane gasoline is used in its pure form, the engine will make additional power due to the "improved burn" characteristics. This is because 100 Unleaded Racing Gasoline contains a very select group of hydrocarbons that vaporize and burn much more readily than those found in conventional street gasoline. When more of the gasoline is burned in the combustion chamber, the engine makes more horsepower. This phenomenon is known as improved combustion efficiency.

Too true..... I was buyng Sunoco Gt260 plus to aviod using additives thinking it was as close as I could get to race gas..... but found out has MMT.... My valves and sparkplugs are as orange as can be. Am looking to see my alternatives down here...

Skip the additives, save your engine. The orange coloration isn't a big deal but the lack of true Motor Octane is. Additives are what caused me to replace my short block back in 2014. Since then, I have advocated that anyone needing the octane that race fuel provides, to only use actual race fuel.

Easier said then done at the end of the world!! But will see what I can do!

Not sure if the blends in South America are any different, but based on the MSDS sheet here it doesn't look like 260GT Plus contains MMT.

https://www.sunocoracefuels.com/wp-content/uploads/2017/02/SUNOCO-260-GT-Plus-_US-SDS_05Jan2017.pdf

Maybe the orange was just from the Boostane.

Is 260GT (non-Plus) available down there?

ArizonaBOSS said:

The orange coloration isn't a big deal but the lack of true Motor Octane is. Additives are what caused me to replace my short block back in 2014.

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@ArizonaBOSS - Did the additives themselves cause a mechanical failure? Or are you saying that fuel with Octane based on MMT behaves differently with respect to knock than "true" octane. I understand that the MMT boosted fuel may not have the same combustion efficiency and will result in reduced power. But I don't quite understand how it damaged your engine.

Cos here is the part thats not that easy to find unless you really look for it...


I have been logging the car regularly now, using the logs to see the best gas. So far its almost always 27.5 with a extra 3 degrees the Knock added. The last gas station gave me 26.5 but now I don"t know how much a broken piston ring had to do with it....

Interesting. Sunoco's main page for the 260 GT Plus is completely silent on this. I found what you posted on a overview of octane ratings.

Don't know how they get away with not including this on their MSDS.

Best of luck on your rebuild!