Octane question

[ACTION JACKSON]

My motor is set to use 100 I believe is the octane. Can I run 110 without any negative effects like pre ignition, or causing motor to heat up in excess.
I do have a airport down the road I think I can get 100, just might be easier access going to gas station for the 110. Thanks for any info.

 

[Mike Unger]

No negative effects. However best power output happens when you run the lowest octane you can without experiencing detonation or knock.

so for absolute best output try to find 100. But higher won’t at all hurt.

 

[LohringMiller]

What motor are you talking about? Zenoahs and their clones run fine on Coleman fuel which is around 50 octane.

Lohring Miller

 

[Grimracer]

Coleman is 70 octain.
Its all about flame timing on a two stroke. What good does a long burn do you when the port opens before the flame is done propagating.

Coleman every time!

Grim

 

[SayMikey]

Coleman every time here. These motors are primitive. If your running a QD thats different

 

[Hydro Junkie]

The only motor I know of that require anything over 100 is the CMB 27. According to Stu, he had to run that high to get the engine to run correctly in his rigger

 

[Rich Jones]

When I had Matthew Waldron at M&D build me a 26 Zenoah a year or so ago, he told me not to worry about running anything more than 87 but to buy the best grade of 87 you can. The age old debate, Shell vs. BP vs whoever. If my memory serves me correctly, he mentioned Shell and Marathon as a couple he would recommend. Now with that said, I ran 92 all year with good results but I’m betting not MUCH better than it would have been with 87. As far as the av gas, what are the benefits? What performance enhancement could I expect with higher octane?

 

[Hydro Junkie]

I know it's used in full sized aircraft to prevent detonating when you get up to altitude and are running leaner so I would assume that detonating was a problem that Stu was working at solving. You would have to ask Stu to get more information on that one

 

[Daniel's Racing]

When I had Matthew Waldron at M&D build me a 26 Zenoah a year or so ago, he told me not to worry about running anything more than 87 but to buy the best grade of 87 you can. The age old debate, Shell vs. BP vs whoever. If my memory serves me correctly, he mentioned Shell and Marathon as a couple he would recommend. Now with that said, I ran 92 all year with good results but I’m betting not MUCH better than it would have been with 87. As far as the av gas, what are the benefits? What performance enhancement could I expect with higher octane?

Clean consistent fuel without ethanol that will stay fresh and not attack the soft parts. If you run a filter in your pump line you would not believe the crap that is in pump gas.

Having more octane than is needed will not be detrimental to our tiny engines in any measurable amount. It won't be measurably faster either but never even give a consideration to it.

100LL is not what people think.

First the Low Lead part. It isn't really Low lead at all. It has less than previous AV gas had but even today the lead content is much higher than regular leaded fuel from 70's. Lead is good. It is another lubricant and 2 strokes love it.

Second is the octane. It is only 95-96 octane. It is not 100 octane in the RM/2 method we use in USA.

Don't get caught up in high octane burns slow BS.
Higher octane fuel does not necessarily mean it burns slower. There is no correlation between octane rating and the speed at which the fuel burns. Some of the highest octane race fuel made burns considerably faster than others with far less octane.

I burn through 25 gallons of 100LL every two months in my offroad toys and never have fuel issues and they all run incredibly well.

 

[Rich Jones]

Clean consistent fuel without ethanol that will stay fresh and not attack the soft parts. If you run a filter in your pump line you would not believe the crap that is in pump gas.

Having more octane than is needed will not be detrimental to our tiny engines in any measurable amount. It won't be measurably faster either but never even give a consideration to it.

100LL is not what people think.

First the Low Lead part. It isn't really Low lead at all. It has less than previous AV gas had but even today the lead content is much higher than regular leaded fuel from 70's. Lead is good. It is another lubricant and 2 strokes love it.

Second is the octane. It is only 95-96 octane. It is not 100 octane in the RM/2 method we use in USA.

Don't get caught up in high octane burns slow BS.
Higher octane fuel does not necessarily mean it burns slower. There is no correlation between octane rating and the speed at which the fuel burns. Some of the highest octane race fuel made burns considerably faster than others with far less octane.

I burn through 25 gallons of 100LL every two months in my offroad toys and never have fuel issues and they all run incredibly well.

Good stuff Daniel!

 

[Hydro Junkie]

I have to agree with Daniel, octane has nothing to do with fuel burn speed. It has everything to do with fuel's RESISTANCE to burning. What needs to be remembered is that detonation is nothing more than fuel starting to burn while the piston is still coming up the cylinder. I know, some are going to say that a car's ignition system fires the plug somewhere around 6* BTDC, and that would be true. That is offset by the speed the crank is turning at since, by the time the fuel really gets into it's burn, the piston is already headed back down. The idea is to really keep the fuel in a compressed area as long as possible so that the expanding pressure can actually push the piston down, something best done within the top inch or so of the downstroke, Beyond that, the volume of the cylinder gets to be too large to really use the energy created by the burning fuel

 

[Rich Jones]

Coleman every time here. These motors are primitive. If your running a QD thats different

So straight up Coleman lantern fuel/white gas?

 

[SayMikey]

Yes no stink boat can ride in the car. No funky additives. Good power

 

[Rich Jones]

Yes no stink boat can ride in the car. No funky additives. Good power

Anything weird with needle settings?

 

[SayMikey]

No not at all

 

[Daniel's Racing]

Aviation fuel is relatively low odor and compared to pump fuel these days it is odorless. It does not have that nasty stench.

Coleman fuel is up to like $15 a gallon. Av gas is $4.50 a gallon.

 

[ACTION JACKSON]

What motor are you talking about? Zenoahs and their clones run fine on Coleman fuel which is around 50 octane.

Lohring Miller

The bzm thanks lohring

 

[ACTION JACKSON]

Thanks for all the great information everybody. I will try & get the av gas Before trying the 110 gas.

 

[Daniel's Racing]

Thanks for all the great information everybody. I will try & get the av gas Before trying the 110 gas.

Av fuel is lighter than some other fuels and as such it will not mix with some oils. Maxima 927 is one of those oils. It mixed fine for 6 years I was using that exact mix.

Mixed up 100's of gallons of 100LL and Maxima 927 all of a sudden would not mix and still as far as I know will still not mix with it.

No matter what fuel and oil you should always do a clear jar test first to be sure oil mixes properly and stays mixed.

Not just 100LL and Maxima but every fuel and oil combo each and every time you make up a new batch.

Klotz Supertechniplate is the answer as it has always blended perfectly and is a similar synthetic 20% castor blend to the Maxima 927

 

[Grimracer]

great test!.. good into for sure!

Grim