Premium gas

The new Stihl 4 mix engines on the pole pruners and blowers all call for synthetic mix and a minimum of 91 octane. Not sure about the stratocharged motors.
 
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  • #52
Reading up on it, the way octane is measured depends on what country you live in, there are two methods. Europe and Japan are different from the states and Canada. What I buy as 100 octane premium would be 95-96 in the states, still pretty high.
 
woodworkingboy said:
Reading up on it, the way octane is measured depends on what country you live in, there are two methods. Europe and Japan are different from the states and Canada. What I buy as 100 octane premium would be 95-96 in the states, still pretty high.
Click to expand...

I think it is pretty universal as far as I can tell.
Europe, North America all use Ron scale to measure Octane, as far as I can tell.
We have 92, 95 and 98 as standard here.
 
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  • #55
Magnus, the states and Canada use what is called an AKI index, it is an average between RON and MON. The octane rating would be lower than the same gas rated in Europe and Japan.
 
As I understand it the way to test Octane is done in one of two way's, Ron or Mon. It is two different tests.
What index, marketing name or combination each use is up to them I guess.
Here, the octane value is set and described by Ron standard according to the sellers etc
In US I think they have as you say a average between the two, often state both and if not they state the Ron value when asked.
 
Really strange to look over this again. I did it in 2008.
Lots less actual facts and info today and more marketing.

Last time I asked for the Ron octane rating and got it from most.

I also asked for content specified and that was harder...
 
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  • #58
Magnus, the states and Canada use what is called an AKI index, listed on the pumps, it is an average between RON and MON. Talking to people maybe is different? I think your country uses RON, like over here. Who knows why they don't standardize it?
 
It is standard to use Ron.

I am not sure why it is written this or that but I do know the two types of meassuring Octane is RON and MON.
I doubt anyone uses Mon as it is a more unrelieble way to test as well as more expencive, if I am not mis informed.

If I ask for a product description from Mobile, Shell, BP, Gulf, Statoil or any other sold I get the octane rate in Ron regardless of manufacturer.
If I get it in Mon I can estimate by charts what it could be in Ron, but it is not very accurate and better is if they test in Ron.
I believe they are forced to do so to follow standards set. If not I doubt they would...

http://www-static.shell.com/static/...y/fuels/shell_blyfri_95_commercial_jun_10.pdf

Last I did this it was much easier to find this info...
 
It is like taking a temp reading in Farenhight and one in Celcius then mixing the two and say you have a new index called xxx.
 
Every pump I've ever seen had (R + M / 2) under the octane rating. Sounds like the average of Ron and Mon to me.
 
Yes.

And if everyone was showing the average between C and F in temp, that would be the way to tell.
But they have to measure it some how to get the numbers to divide by two. As they need both to get the average it is not to hard to get one or the other.

One system would work just as well...
 
lumberjack said:
Trucks have EFI and electronic ignition which can advance the timing and take advantage of the higher octane, saws do not.
Click to expand...
Actually there is one saw that can , the Husqvarna 576XP AutoTune. I still am amazed how its computer setup makes this saw run so well and the fuel economy it delivers. I am waiting for the new 562XP AT and the T540XP to fill the bill also.
I always run Esso premium gas with Stihl full synthetic 50:1 oil.

Willard
 
HolmenTree said:
Actually there is one saw that can , the Husqvarna 576XP AutoTune. I still am amazed how its computer setup makes this saw run so well and the fuel economy it delivers. I am waiting for the new 562XP AT and the T540XP to fill the bill also.
I always run Esso premium gas with Stihl full synthetic 50:1 oil.

Willard
Click to expand...

Willard...
It has no knock sensor, no way to read exoust values, no temp indicator either, so it has no info to correct from other than rpm.
I can't see how the timing can be altered either as the two systems (fuel and ignition) is completely separate and it has no way of telling what go in it, or out other than RPM.
This type of carb have been run on other types of engines before (electronically controlled carburetor) with mixed results.
 
Magnus said:
Willard...
It has no knock sensor, no way to read exoust values, no temp indicator either, so it has no info to correct from other than rpm.
I can't see how the timing can be altered either as the two systems (fuel and ignition) is completely separate and it has no way of telling what go in it, or out other than RPM.
This type of carb have been run on other types of engines before (electronically controlled carburetor) with mixed results.
Click to expand...
Thankyou for the information Magnus.... I take it as correct. There is not very much information on the Husqvarna AutoTune out there, still a "new technology" for chainsaws from what I have found.
I'm only certain is will get even more advanced.

Willard.
 
Non-ethanol for sure. Hard to find here in the South, but I have my sources. It is only about 10 cents more per gallon, but I will not chance burning up my favorite little Husky 242 again. Yes, it has been rebuilt because it is the fastest thing for topping and pruning. I have a small stock of "50 fuel" that I bought up from an auto parts outlet that I keep for emergencies. It is premium fuel with a stabilizer added. Still doesn't justify the $4/quart pricetag. Runs great, though. Our ethanol here is seldom more than 10% by law, but the advent of 15% ethanol scares us treemen and boaters. Anyone that prizes their small 2 cycle engines should not even think of using that krap!
 
In my opinion this is a half step...
I don't see why they go all the way and have a controlled fuel system.
If it is emissions and fuel efficiency they are after there is no other way to go...
That way we still could have power in the saws with even less weight and better emissions.
 
They just put the MS241 on the market about a week ago.
That one has it as well.
 
Magnus said:
Willard...
It has no knock sensor, no way to read exoust values, no temp indicator either, so it has no info to correct from other than rpm.
I can't see how the timing can be altered either as the two systems (fuel and ignition) is completely separate and it has no way of telling what go in it, or out other than RPM.
This type of carb have been run on other types of engines before (electronically controlled carburetor) with mixed results.
Click to expand...
I should have asked this in my last post.. The husqvarna 576XP Auto Tune I use has a computer that can set it self to run in different outside temperatures, altitude, different mixes of fuel. Sensors?
I do understand temperature, altitude and fuel quality do effect rpm so from that base the computer or micro processor would have to correct the rpm by adjusting the fuel/ air mixture, but how much more does the igntion process other then just rev limiting? This 576 Auto Tune technology is already several years old and Stihl now has it .

Willard
 
HolmenTree said:
I should have asked this in my last post.. The husqvarna 576XP Auto Tune I use has a computer that can set it self to run in different outside temperatures, altitude, different mixes of fuel. Sensors?
I do understand temperature, altitude and fuel quality do effect rpm so from that base the computer or micro processor would have to correct the rpm by adjusting the fuel/ air mixture, but how much more does the igntion process other then just rev limiting? This 576 Auto Tune technology is already several years old and Stihl now has it .

Willard
Click to expand...
Only things that it has to work with is the flow of impulses (rpm) and fuel pressure.
It is like a electronic intelly carb in my opinion. Better, but just barely.
The little computer register the rpm, then compensate the fuel, like we do on the needles conventionally.
It has no contact with ignition system, that compensate timing after rpm too and limit rpm.

It has no information to know what running temp it has or how well the fumes are burnt.
 
CurSedVoyce said:
Guess I have to check my tuning on all my 2 strokes now... I just switched over to 100LL avgas. No ethanol.
Running it a little rich with mix too. :/:
Click to expand...
There are other qualety's with AV fuel that is good. Not so agressive and with a good oil it is a good fuel.

Make sure the saws have no carbon build up that could get you in trouble.
 
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