Fuel Consumption and Now Gearing (Another Noob Question)

Maintenance, Repair, Equipment & Tools
1

Ok so time for another one of my stupid noob questions :joy:

I’ve been trying to calculate how much a season would cost in 2 stroke like ROK GP, but I have no idea about fuel. I’m assuming gas from the gas station won’t do, so I found different fuels with minimum 95 octane and whatnot. How much fuel should I look to bring at a race day and how much oil would I use along with the fuel, since it says I need to fill 4% of oil in the gas pump as well. Thanks in advance for the help!

Also, how many litres/gallons are even in a fuel tank

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Keep in mind wherever you’re racing probably has a spec fuel they require you to use. I would find out what that is first so you can price that out.

I think most fuel tanks are 9 liters but on a typical club day you won’t use all that much fuel.

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Me and nick would go through a 5 gal drum for two of us for practice day and race day. 100 bucks, basically. This was x30 using VP98 and a bottle of oil.

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Yeah I was looking at a VP98 fuel, so if I buy 5 gallons of VP98, I would to buy one for each race day?

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No, you won’t need 5 gallons of fuel per day. A gallon or so should be adequate per day.

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Race fuel comes in 5gallon drums. So you are buying the fuel, poring it into one of these and adding a bottle of oil (depends on engine etc). What you don’t use comes home with you.
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Oh ok that makes more sense. So when adding fuel, I hear that I to make sure that 4% of it is spec oil. I looked online and saw the 1 gallon is 3785cc, so 5 gallons would be 18927.1. which would mean I should add around 757 cc of oil and around 18170 cc of fuel in the tank. So I can buy two 5 gallon drums of fuel then.

I’m making this so bloody complicated :joy:

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I think you might. It will become less confusing once you get going.

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Yeah I think so too, sorry for the silly question lol

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One more question: gearing. I’m trying to learn how rear gear sprockets work and am beginning to understand how they affect corner speed or top end speed. My question is should I worry about changing my gear ratio at the local/regional level or is that just a national thing. And if I should invest in different gear sprockets, what different setups should I get? All tracks around me have a straightaway with hairpins and turns. Will a medium ratio work for the majority of them?

If you want to look up the tracks they are Ocala Gran Prix, Orlando Kart Center, and Andersen RacePark.

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Well, gearing is typically different at each track. Presumably you will be driving/racing at a couple tracks only. You’ll likely ask what gearing is used and you’ll go buy those sprockets.

I don’t think my etown gearing ever changed. Maybe plus or minus a tooth.

You just need a few rear sprockets for the tracks you always run. Even though you might always run the same gearing, the sprocket itself wears out and needs replacing.

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You could literally call them and ask, what gearing for x engine is typical at your track?

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For fuel, step 1 is to see what the spec gas and oil mix is for the series/track you plan on running. Depending on what the rules say, you’ll likely end up needing to mix 6-8oz of oil per gallon of fuel. It might not hurt to just ask someone directly at the track just to be sure.

For sprockets, I always just bought them as I needed them. Pretty much every event I’ve ever been to has had some sort of parts support available trackside, so if you find yourself wanting to try a different gear you’ll likely be able to find one to buy right then and there. You’ll end up accumulating more over time as you travel around to different tracks. To start it’s probably best to just ask around while at the track for a good starting gear and then go up or down from there. You can also call whatever track you plan to run and ask for a good starting point for your class.

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For future reference…

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What do the numbers from 53-100 mean? Is the gear ratio calculated by finding the amount of teeth in the rear sprocket divided by the amount of teeth in the front sprocket?

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53-100 is the rear sprocket size. If you have a local shop just ask and they will give you a 3-4 tooth range to be in.

I went to a new track last weekend and the locals all said they were running 77-80. We ended up at an 81, being heavier (senior vs jr weights) and willing to turn a much higher rpm.

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Did you have to buy different sprockets to try them or do they let you try different ones before you purchase?

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I have a small selection that I have purchased a couple at a time over the last year . I think I currently have 77, 78, 79, 81, 83, 84, 85, 87. When I started with my KA I guessed and got the 79,81,83 then added the 84, 85, 87 when I got my sons micro swift, and purchased the 77 and 78 for this last weekend.

I wouldn’t suggest going out and getting a full set of 65-90 as you likely wont use that many at 3 tracks.

Good news is your planning on doing 206 first which means you will be at all the tracks and can ask the guys what they are running and make your list.

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Well I’m still unsure if I’m going to do LO206 first or go straight for Rok, depends on my parents and money, probably going to rent lo206 for a couple of racing while renting a X30 kart to practice. But the same concept apples