Dont be fooled- Advertised octane rating of ethanol free canned fuels

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banditt007

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I just wanted to point this out. In the US when people refer to octane, we measure by the AVERAGE number of both the RON measurement and the MON measurement (RON+MON/2). If you look at the yellow square that shows the octane number at the gas pump, you will see it lists how the number is achieved.

I noticed that while true fuel advertises its "92 octane" thats the RON only measurement which cannot be directly compared to the standard US way of measuring. What it equates to in the U.S. measurement i'm not sure maybe someone else can chime in if there is some sort of conversion. I could not find a good enough image of the Stihl motomix to see if it is also rated using only the RON measurement...
 
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According to Octane rating - Wikipedia, the free encyclopedia MON is typically 8 to 10 points lower so the average would be half that from either one. The saw manual tells you to use that octane before adding pre mix oil which makes the mixture rating lower. Probably the octane posted on the cans is after the oil is added. It is unlikely I will get any of those products.

Rather amusing look at that wikipedia page and see that natural gas/methane gets the same number either way and propane gets a difference of 15. They are determined at 600 and 900 rpm in the lab.
 
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O.P I just started using some Stihl moto mix. Im not a Stihl salesman, and have all hukies saws now. Don't get me wrong I love Stihl saws too, but I want to put it out, that Im not just favoring Stihl when I say this. But they have world renowned engineering, and stay a step ahead with many things. With them knowing all the fuel issues, and knowing of the strong world of critics, guy's like many of us here, who will not be afraid regardless of brand, or whatever, to call it like we see it. I would say that there octane rating could be put to the test, and true, never heard one issue of it. But with all the fuel problems today it's definately a constantly evolving, and roll with the punches game. But the Moto mix I trust it with there name on it. True fuel, I have no experience with myself.
 
banditt007 said:
I just wanted to point this out. In the US when people refer to octane, we measure by the AVERAGE number of both the RON measurement and the MON measurement (RON+MON/2). If you look at the yellow square that shows the octane number at the gas pump, you will see it lists how the number is achieved.

I noticed that while true fuel advertises its "93 octane" thats the RON only measurement which cannot be directly compared to the standard US way of measuring. What it equates to in the U.S. measurement i'm not sure maybe someone else can chime in if there is some sort of conversion. I could not find a good enough image of the Stihl motomix to see if it is also rated using only the RON measurement...
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My Trufuel is advertised at minimum 92 octane, my SEF is 94, you say yours is 93, huh?
 
reindeer said:
I've used TrueFuel 50 in my heavily ported chainsaw running at 225PSI+ with absolutely no problems.
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Good point. Has your saw ever seen a hundred + degree day? Did you advance the timing from stock? Do you run long bars? Do you bog the saw down in the cut? What size wood are you cutting? What type of wood do you cut? Oh sorry ...
 
banditt007 said:
I just wanted to point this out. In the US when people refer to octane, we measure by the AVERAGE number of both the RON measurement and the MON measurement (RON+MON/2). If you look at the yellow square that shows the octane number at the gas pump, you will see it lists how the number is achieved.

I noticed that while true fuel advertises its "92 octane" thats the RON only measurement which cannot be directly compared to the standard US way of measuring. What it equates to in the U.S. measurement i'm not sure maybe someone else can chime in if there is some sort of conversion. I could not find a good enough image of the Stihl motomix to see if it is also rated using only the RON measurement...
Click to expand...

That's interesting. I recently have been running off a two gallon tank of gas that I had purchased from a gas station close buy. Supposedly it was non-ethanol and i got the 93. My saws seemed to have a low growl last time I was cutting and not the fast cutting whiiisp that I like to hear. So where am I supposed to go for the best gas?
 
I stopped using pump gas a year ago. I use true-fuel exclusively now and have never had a problem with my saw, most of which sit as "shelf queens". They all start with ease, even after sitting. My blower, hedge trimmer and weed whacker (echos), all get used more often and I keep a gallon of Stihl Ultra mixed with Chevron premium for them. No problems yet. The saws appear to love the canned stuff. Really pop well and start easily, not so if I try to use the stuff I mixed myself. Just my observations.
 
Naked Arborist said:
Good point. Has your saw ever seen a hundred + degree day? Did you advance the timing from stock? Do you run long bars? Do you bog the saw down in the cut? What size wood are you cutting? What type of wood do you cut? Oh sorry ...
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The timing is advanced 5*. It took 3, 10 second runs at 245 PSI+ in order to get it to detonate. It seems unlikely a stock saw will detonate on this stuff. If your saw detonates on this, you likely have other issues.
 
Since Stihl offers the warranty extension when using the Moto-mix I would figure they have a clue about its ability to resist knock.
 
Im sure they run fine on Moto-mix. Lets analyze the business, gimmick, side of this. Lets say Stihl sells a million saws and convinces everyone to buy a can of Moto-mix. At $8 plus a can there probably making a cool $4 profit maybe more. $4 million dollars will go a long way toward fixing warranty work especially when the fuel be used is top notch and likely not causing a warranty issue to begin with. Good insurance for the customer, great deal for the retailer. We've all heard the warranty horror storys about Echo and its 5 year warranty, you dont Stihl wouldnt pitch a fit even if you used Ultra and or Moto-mix and you tried to claim a foul on something fuel related?
 
Is Echo tough to deal with REJ2? I only had one saw issue, my pole saw when new, was under powered I though from day one, used it a year or more, and stopped running Took it to my saw shop, and they called echo, they warrantied everything, no questions, and it was a fault from the factory. Im just curious, why I ask this was my only experience with the warranty side, of saws ever.
 
NORMZILLA44 said:
Is Echo tough to deal with REJ2? I only had one saw issue, my pole saw when new, was under powered I though from day one, used it a year or more, and stopped running Took it to my saw shop, and they called echo, they warrantied everything, no questions, and it was a fault from the factory. Im just curious, why I ask this was my only experience with the warranty side, of saws ever.
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Im not sure, but i hope not, i was only parroting what ive heard here in a sarcastic kinda way.
 
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I was taking down a tree for a job my friend picked up. He was running hiss stihl 460 magnum and I was running my cs 530 (after I got the tree down on the ground) off that same gas. I felt pretty small. I told him about it and he gave me some 93 from a corporate gas station with some Stihl two stroke oil. the difference was totally obvious. I felt a little better about being a lowly Echo guy. That gas I got from this small business owner in the guetto with his supposed " 93 - non-ethonal ' - I want to empty it out in he's parking lot, and go get some sthil premix or at least something half less watered down.
 
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Husqvarnas fuel premix is advertised as 95octane, I'll have to check a can tomorrow to see how they calculate it. BTW for anyone who hasn't heard, Huskys extended warranty plan is in effect. Buy a 6 pack of oil or 3 cans of premix and double the warranty.
 
screamin350 said:
Husqvarnas fuel premix is advertised as 95octane, I'll have to check a can tomorrow to see how they calculate it. BTW for anyone who hasn't heard, Huskys extended warranty plan is in effect. Buy a 6 pack of oil or 3 cans of premix and double the warranty.
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I've never seen Husky canned fuel.
 

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