best fuel option for my gas boat?

[Ryan Lipgens]

When I tested Coleman a couple years back it was way higher than 55 Octane. My results with Coleman Fuel and 7oz. of HP2 oil using a Shatox Octane Meter was approx. 90, that was RON/MON/2. I can't remember the exact number as the info was lost on another forum board.

Just my results. Run what makes your engine happy. I love Coleman fuel and have had zero issues with it from stock to modified Zenoah engines.

 

[lohring]

The gold standard for octane testing is running in a variable compression engine under specified conditions to find the compression ratio when knocking begins. See https://en.wikipedia.org/wiki/Octane_rating Meters need to be calibrated for the type of fuel. I doubt that a calibration for pump gasoline would be correct for a naptha based fuel. In any case, Coleman fuel won't run well in a high compression engine. Quickdraws need 100 octane or higher fuel. Low compression engines do fine. That's as close to the engine based octane rating system as hobbyists come.

Lojring Miller

 

[JimZaremski]

Here's a thought fill up with what ever you want in gass 2/3 to 3/4 of a tank and add 50% nitro to the other 1/3 to 1/4 tell full and open your needle up about a full turn on the top end needle and about a half on the lower end and watch it come alive.

Got bored with my gass boat and did some testing and had fantastic results . Pass ya later Charlie

Nitromethane doesn't mix well with gasoline. However, ethanol is a mutual solvent and we tested a mixture of nitro and gasoline in an M&D Zenoah. The results are below. Again the problem is the engine is running a pipe designed for gasoline with a fixed ignition timing and head volume. The results are at the best needle setting.
Lohring Miller

Nitro Tests.JPG

the thing is you've got to take great care once you introduce nitromethane into the mix. Methanol only has an effective octane rating of about 98, but nitro is hilariously prone to detonation and can drastically lower the gasoline's knock resistance. I'd bet you'd have to run it so rich to prevent detonation that it'd cancel out any potential power gains from the nitro.

 

[Todd]

Quickdraws need 100 octane or higher fuel.

Lojring Miller

The old hi rev motors with the hi compression head need this. The Pioneers and the HT style motors all run 87 pump gas as the recommended fuel.

Todd

Quickdraw

 

[lohring]

Here's a thought fill up with what ever you want in gass 2/3 to 3/4 of a tank and add 50% nitro to the other 1/3 to 1/4 tell full and open your needle up about a full turn on the top end needle and about a half on the lower end and watch it come alive.

Got bored with my gass boat and did some testing and had fantastic results . Pass ya later Charlie

Nitromethane doesn't mix well with gasoline. However, ethanol is a mutual solvent and we tested a mixture of nitro and gasoline in an M&D Zenoah. The results are below. Again the problem is the engine is running a pipe designed for gasoline with a fixed ignition timing and head volume. The results are at the best needle setting.
Lohring Miller

Nitro Tests.JPG

the thing is you've got to take great care once you introduce nitromethane into the mix. Methanol only has an effective octane rating of about 98, but nitro is hilariously prone to detonation and can drastically lower the gasoline's knock resistance. I'd bet you'd have to run it so rich to prevent detonation that it'd cancel out any potential power gains from the nitro.

We never saw signs of detonation in any Zenoah or clones no matter what fuel we ran. I have no experience with the newer Quickdraws, but we did see signs of detonation in our early engines on 87 octane fuel. They had 1.8 cc or smaller head volume. Zenoahs have around 2.4 cc head volume.

Lohring Miller