Could someone explain why we use high octane race fuel we buy in drums? What does it do “or not do” that makes it worth paying 5x normal gas prices?
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Whatever you use, don’t use anything with ethanol in it.
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Dom,
A lot of this comes down to engine compression. Higher octane fuel burns at a slower rate allowing it to with stand the compression in a race engine. The price thing I’m not too sure why they charge so much. Regular pump gas we put in our cars has additives in it, where race fuel is going to be “cleaner.” Also branding the fuel as race fuel may raise the prices as well but I’m with ya I feel like there really isnt a reason to charge $10-15 more a gallon just for fuel that comes in a drum.
This is something that is widely misunderstood by n00bs such as me. You’d figure higher numbers = more boom = faster. I.e. vp 98 vs 110. That isn’t it at all.
The higher octane wont pre-detonate at extreme temps or something, which I guess would mean a misfire and an inefficiency in the cycle of piston going up and down?
Yes exactly, everyone is required to get fuel from the same gas station and a sample is taken the morning of the race day to use as a testing method. This keeps the fuel as fair as possible and offers an extremely cheap way to race. With the exception of our ka100 classes, 206 has consistently had the most entries in the senior category for the last few years. I know for many, it’s because of the cheap running costs like fuel.
Yup you’re right on! Like I’m sure you’ve heard that if your car has a bunch of miles on it or you are experiencing any kind of engine knocking it’s smart to use a little higher octane to help smooth out how the engine runs. In a kart engine youre pushing every component to its absolute limit all the time also the engine is getting very hot so the higher octane is needed.
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Fresh 87 octane gasoline that day from the busiest station you can find. You want the most “light ends” and ethanol you can get - for the fastest combustion and highest available energy (total BTU, not BTU per gallon!). Keep it in a steel drum and only have enough in the tank for that heat.
Most of it comes down to consistency. In the KA and Yamaha classes, 93 octane for a club race was actually faster than the 110/112 we run at a Regional/National series, since the engines didn’t have enough compression to fully utilize the race gas. However, the race fuel is generally more consistent across an entire batch, so I imagine they can run tighter tolerances on fuel testing throughout the weekend.
For the X30/TaG/Shifter engines, I’m not sure if they’re at a high enough compression to benefit from race gas or not. That’d be a question for anyone familiar with, in your case, the X30 engines.
They charge so much because they can. First of all fifty years ago when I was a much younger man probably 50% of the cars on the road “needed” “Premium” gas. either they did or the car manufacturers convinced them that they did. Then in 1965 the “Unsafe at any Speed” thing hit, followed by the EPA in the early 70’s, and the S.A.E. method of establishing an engines horsepower hit, and the rest is history. The need for high octane gasses greatly diminished and presently we are sitting where most of the cars on the road burn gas made from corn. That leaves high octane out in the cold. They only refine a small amount of high octane fuel which very seriously brings the “economies of scale” up to the fore. Be glad that you can still get the stuff. The way that things are going we might not see the demise of internal combustion in our lifetimes but our grand kids just might. When the demand for high octane diminishes beyond a certain point you can bet that the oil companies will stop refining it. Count on it.
Bill,
I totally agree! I’m just glad we are still running internal combustion engines in karting and see it in majority of Motorsports. Before we know it everything will be electric.
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So in LO206 with a stock compression ratio of 8.5:1 anything over 87 octane goes right out the header pipe. It gains nothing. The reason you want a slower burn is because you want to avoid predetination. So basically what happens if I’m running high compression is: suck squeeze bang blow. With an 87 octane and high compression under the compression stroke the fuel will go bang before the spark sparks. With a slower burn higher octane it won’t detonate before the spark sparks. So if your track tells you you need more than 87 octane, they are trying to sell you fuel.
Caveat being we’re required to run 91 octane from one local gasbar. Reason being is 91+ octane here doesn’t have ethanol in it. Ethanol attracts moisture ie: water, gumming up rubber lines, and leaving residue in your float bowl, jets and otherwise leaving a mess if the fuel is left for awhile.
Go to your local gas station and pump $20 worth of 91 into your car (clears the hose of any other fuel) then pump your 91 into your fuel can. Good to go. Otherwise C12 or VP110 is just wasting your money in 206.
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If the fuel ignites before the ignition fires, it’s called preignition. Detonation is caused by excessive heat and/or pressure. It occurs after the spark plug wires. Octane is only a measure of the fuel’s ability to resist detonation. It has nothing to do with making HP. Raising the compression ratio makes more HP, and sometimes you need more octane to prevent detonation. Detonation is a real HP killer!
Some stations carry 88 octane E15, and if your track specifies “pump gasoline” that’d be my first choice for LO206scancel
[quote=“Charles_Kaneb, post:23, topic:7007, full:true”]
Some stations carry 88 octane E15, and if your track specifies “pump gasoline” that’d be my first choice for LO206s[/quote]
It will likely fail any kind of fuel testing though, unless for some strage reason the club tech has deciuded to allow oxygenated fuel
or if the club, track, or series simply does not tech fuel, or if the test is a lead test, or if the rules are written to allow oxygenated fuel - which is what this engine was designed for and the cheapest fuel you can buy.
CKNA speicified which station you could take fuel from and calibrated their meter against it. It was E10.
Use 93 octane. I do, it works pretty well.
If you want to play it safe, just buy the fuel they sell there at your local track.
Personally I don’t, I use non-ethanol 89, but they don’t tech fuel at my local. If they did, I’d just buy my fuel at the track.
I would be very interested in knowing why you chose that fuel. What kind of racing do you do? I’m not trying to be a smart ass, but do you know what the term octane refers to? Please don’t take offense, there is none intended.
You’re always going to get the most performance from the lowest octane rating you can run w/out incurring detonation and/or pre-ignition.