Sunoco 94 with Elf HTX 909

Took my young one to the track yesterday.
He is not there yet but I see improvement.
He is not pushing the kart hard yet. We did 7 sessions yesterday and had to fill up the tank 2 times.
We plan on coming more often but he is no where near racing yet.

I need to start mixing my fuel.

At my local track I was recommended:

VP MS98L
VP C12
Sunoco 112
All Leaded.
All mixed with Motoul oil.

However, doing some research I found that some guys especially in Europe run on pump Gas.
The US manual for “Iame Mini Swift 60cc” only states to run either leaded or unleaded gas. Does not mention octane spec.

Do I need leaded gas?

Can I run Sunoco’s 94 AKI fuel mixed with the Elf HTX 909?

Anyone running on pump gas?
Am I looking for trouble?

What motor? Is it fully optimized by a builder or box stock?

It’s the Iame Mini Swift 60cc motor.

I believe it’s optimized.
We got it used along with a Fox and Sons blueprinted one.

If you are just starting and the driver is not pushing you will be perfectly fine running on pumpgas. A lot off races In Europe mandate pumpgas, and no where will you be allowed to use Leaded fuel.
Off cause you need to be aware when he gets up to speed

But yes the Sunuco 94 AKI with Motul will be fine unless you are looking for the very last % of performance

Likely it will be fine. If the pump gas has ethanol you may need to run it a little richer on the needles too.

If you search “octane” on this board you will find several threads on this topic as well.

if it’s blueprinted the timing will be set at a place where it will be closer to the limit of detonation on pump gas, but in general I think you’ll still be OK on 94 pump and elf oil and the proper heat range plug. Make sure you’re leaving the mixture on the rich side. I’ve run pump gas in my KA before without issue but not for prolonged periods, just a quick test session.

While the rest of the world has moved towards unleaded gas, the lead content in our US race fuels provides more protection / lubrication for our engines so keep that in mind that you may see increased wear, thus reducing rebuild intervals if you run unleaded only fuel through the motor.

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Question, is octane booster an option or not recommended? Always wondered.

You can most definitely use the Elf. It is in fact the mandated oil by a couple of series in the US.

As Andy mentioned you could be close to to the limit on pre-ignition/detonation on pump gas. This will be influenced by the fuel additives mandated in the region of your state for emissions control, and it does vary. It is also influenced by how the builder tuned the engine.

Leaded gas will reduce wear, but these motors are designed in Europe where they do not run leaded fuels. So I think that is less of a concern than the octane rating.

In short, yes you can most definitely adjust the carb and the spark plug to compensate for the pump gas. However, if you are on here asking, it may not be the safe place to start out at.

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Thank you.

Still not sure about the 94 unleaded.

The previous owner ran VP M98L with Motul.

The engine builder told him to run 98 octanes and he did.

I don’t want to destroy the engine.

But #1 I can only find Sunoco Supreme 112 octane around me and no VP gas.

#2 He is just starting out and I don’t want to spend $60+ on gas each day he drives and doesn’t push the kart.

MS98L is a leaded race gas with a 100 RON octane. The Sunoco you mention is 115 RON octane, likely overkill for your engine but safe to use. Both Sunoco and VP have tools on their website to help find sellers of their fuel. It is my understanding that the lead in race gas is a source of increasing octane. In pump gas, the ethanol is one of many sources of octane boost and is why your higher octane 93 and 94 labeled at the pump will have up to 10%.

It is interesting to me that IAME does not spec fuel octane for this motor as they do with their other motors.

Based on what you are saying about your sons pace, running fresh 94 is likely to work fine. Is there a chance of a problem, yes, but I would say a it’s a low chance.

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I agree you will prob be ok on the 94 but if you have access to the Sunoco you could mix it 50/50 with pump 94 and know you are safe and get some cost savings at the same time.

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Hi Andy,

You mean take the Sunoco 112 leaded and mix it with the Sunoco 94 with ethanol?

Or should I try to look for ethanol free 91 or 93?

This might be hard to find.. at least where I’m at.

Have you thought about using rec fuel, mixed with octane booster? I believe rec fuel is ethenol free, but I think the octane might be a bit low for what you need, even with the octane booster.

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I don’t think you have to be that picky if you mix pump gas with race gas as a price savings for testing. Get yourself to the octane count that won’t risk detonation and make sure your oil mixture is right and send it.

Going Ethanol free just makes it more expensive, and potentially adding back in an octane booster negates price savings. The big concern with alcohol content in fuels is corrosion and we have far too simple of fuel systems to really worry about that unless you leave it sitting in your carb for 6 months after running it. Heck I’d run E85 if I could in my kart if I knew I could get the thing enough fuel as it runs cool, makes good power and is resistant to detonation.

Fuels in karting are more about controlling consistency for rules regulation than anything else. When you throw that out the window for testing it shouldn’t be too hard to figure out ways to save a few bucks here and there.

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Thank you all!
Will get some fuel today.