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Octane Booster Advice


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I've put a new head on my 250R and the bike will no longer run on 93 pump gas. I've experimented with some inexpensive octane booster, and the detonation seems to be completely gone, but I haven't worked the bike hard in a 5 lap moto yet. Got a race coming up this weekend and I'm a little concerned.

Any of you folks have any advice about octane boosters--or some other solution to a high compression head? I don't plan on buying a 5 gallon drum of race fuel between now and Sunday.

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heard nothing but bad things about octane booster, personally wouldnt put it in my bike. just go with V. P. racing fuel. octane booster dosent really raise it that much. ive also heard it messes with the float, deterioration etc etc. wouldnt do it. my two cents

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You can try some VP StreetBlaze 100; cheaper by a long shot vs. MX race gas.

In a pinch, you can pick up a gallon of Toluene at Home Depot and add 12 oz/gallon of pump gas. to get an extra (real) point or two. Probably better to just buy some VP100 if you can find it locally.

Some octane boosters are Ethanol or Methanol-based. If your pump gas is also E10 (or thereabouts), you can cause a phase separation (which will cause alcohol/water/gas to form 2 or 3 different layers) by adding an alcohol-based octane booster. Just something to be aware of.

In general, petroleum-based octane boosters won't hurt. Neither will alcohol-based booster if used in moderation and if you don't get the dreaded phase-separation. Both types have less BTUs than fuel, so neither one will help you make HP. Only an oxygenated race fuel and a richer mix will do that.

Edited by davidl9999
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Octane boosters are more of a snake oil than anything. On the back of some of the bottles, it even tells you how little they actually increase your octane. For the most part, for every point they raise your octane, your octane is actually only increasing by .1. So, if you added 3 points to your 93 pump gas, it would still only be a 93.3 octane rating.

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Octane boosters are more of a snake oil than anything. On the back of some of the bottles, it even tells you how little they actually increase your octane. For the most part, for every point they raise your octane, your octane is actually only increasing by .1. So, if you added 3 points to your 93 pump gas, it would still only be a 93.3 octane rating.

No, and yes.

Torco and NOS brand octane boosters actually raise the octane rating 6+ numbers depending on the amount put into the fuel.

I run pump 91+ Torco octane booster in my Kenne Bell SRT8 (recommended by them @ my boost level on my "street" tune. On higher boost I have to run true race gas). Now those other cheaper brands only up the rating by a couple POINTS, not numbers. And those are the useless ones.

I tried running torco + 91 pump on my CR250 back when I first got it, and blah. It sucked on the stock head lol, killed throttle response (kind of like running AV gas on a stock head...) but with the modified head / increased compression I'm sure it'll do just fine as I do with AV gas and my modified head.

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Thanks everyone!

I have currently got some cheap petroleum based booster in the mix. As said before, it stopped the detonation riding around here in the yard in 95* Arkansas summertime, but that's not the same thing as running it on the track for 5 laps. Quite honestly, I don't trust the stuff for race day.

I'll probably pick up some Torco or NOS brand booster for the weekend based on your comments. I've also got a gallon of nitromethane in the garage for rc airplanes--but that'd probably get me in trouble at this state series race!

The new head and VForce3 reeds have got the bike running like a beast. Will give a race report Monday!

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I've also got a gallon of nitromethane in the garage for rc airplanes--but that'd probably get me in trouble at this state series race!

If you don't place, they won't test your fuel. Just sayin'... ๐Ÿ˜

Good luck for the win! ๐Ÿ˜

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Heck, I plan on placing! I guess I've got too much time on my hands, because I did do some research on mixing nitro with gasoline, and I found out that is a good way to blow the engine--forget that.

I have changed plans though, because I found a local supplier of Sunoco racing fuels. He's getting me a 5-gallon drum of MO2X for this weekend. I should be fine, and the bike ought to run very strong. If I get beat, it won't be because the engine is underpowered. I'm sure my (lack of) skill and the (lack of) handling on the 97 250r chassis will be enough to get me beat though.๐Ÿ˜

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Heck, I plan on placing! I guess I've got too much time on my hands, because I did do some research on mixing nitro with gasoline, and I found out that is a good way to blow the engine--forget that.

I have changed plans though, because I found a local supplier of Sunoco racing fuels. He's getting me a 5-gallon drum of MO2X for this weekend. I should be fine, and the bike ought to run very strong. If I get beat, it won't be because the engine is underpowered. I'm sure my (lack of) skill and the (lack of) handling on the 97 250r chassis will be enough to get me beat though.๐Ÿ˜

Nah, you only get 2x the combustion BTU output with nitro vs. gas, properly tuned. Won't harm a thing... ๐Ÿ˜

MO2X is a lot of octane (112 pump) and is oxygenated; not sure what your pump gas is. Just making a point that you might need to rejet for the fuel vs. what you've been running. Again, good luck on the win!

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Got the jets to go up 1 or 2 sizes on the main on both my bike and my son's YZ85 (we share the fuel jug). The specs tell me to expect 5-6% hp increase on either bike. That's cheap horsepower if it really works as advertised. Can't wait to see my 11 year old's reaction after his first lap or two.

I read an article that said that mixing nitro with gasoline actually lowered the effective octane rating. I know it's counter intuitive, given that dragsters run it with huge boost numbers. Whatever, it was enough to scare me away from that thought. I'm feeling lots safer with the load of fuel I've got coming.

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