661 Oil Test 32:1 vs 40:1 vs 50:1 ?

[KG441c]

87 makes more power. The trapped compression ratio on saws is much to low to see any benefit from higher octane fuel.

Does that mean that the stroke is too short for the saw to burn high octane completely per stroke to be any benefit?

 

[cuttinties]

Does that mean that the stroke is too short for the saw to burn high octane completely per stroke to be any benefit?

It means a couple of things. The stroke isn't long enough with high enough compression, or the bore isn't large enough with enough compression. If a person were dealing with predetonation then they'd benefit from a higher octane. But to get that much compression in a saw would put it in a realm that wouldn't be a work saw. And even then you need to make use of the compression at that point. There's a reason your saws don't run 400 lbs of compression. This argument of high vs low octane is pretty feckless. The only real problem most need to concern themselves with is properly mixed ethanol free fuel and proper tuning. Then it's about making a sharp chain.

 

[SCHallenger]

Another vote for .404. And a big thanks for your testing!! This stuff provides very useful information.

 

[KenJax Tree]

Then why is the canned fuel like Motomix,Trufuel,SEF and such 93 octane or higher?

 

[KG441c]

Do u think higher octane will run alil cooler at the expense of some power?

 

[cuttinties]

The why is the canned fuel like Motomix,Trufuel,SEF and such 93 octane or higher?

Very simple. That's usually the octane which has the fewest additives.

 

[SCHallenger]

The why is the canned fuel like Motomix,Trufuel,SEF and such 93 octane or higher?

Motomix is 92, VP is 94, & Husqvarna premix is 95.

 

[KenJax Tree]

Lol i was just asking.... This stuff is way over my head[emoji1]

 

[cuttinties]

Lol i was just asking.... This stuff is way over my head[emoji1]

It's a good question really. Most places sell the "premium" ethanol free fuel which is usually 92 or 93 octane in the United States. In Europe the ethanol free fuel is anywhere from 94-97

 

[walexa07]

I think the canned fuel is higher octane for longer shelf life. Fuel octane degrades over time, so if you start off with 87, open the can and it sits several months or a year you could be in the low 80's by the time you get around to using it. Starting with 93, hopefully it won't degrade to the point of predetonation before it gets used up. Just my thoughts.

In the central southern US where I live/travel, ethanol is in all grades of gasoline. If you do find a place that has some ethanol-free fuel, it will likely be 87 or 89 octane. There is 1 store in my town that only sells ethanol-free gasoline, and in all grades. Very well may be different in different areas - this is just what I have seen local to me.

Waylan

 

[cuttinties]

I think the canned fuel is higher octane for longer shelf life. Fuel octane degrades over time, so if you start off with 87, open the can and it sits several months or a year you could be in the low 80's by the time you get around to using it. Starting with 93, hopefully it won't degrade to the point of predetonation before it gets used up. Just my thoughts.

In the central southern US where I live/travel, ethanol is in all grades of gasoline. If you do find a place that has some ethanol-free fuel, it will likely be 87 or 89 octane. There is 1 store in my town that only sells ethanol-free gasoline, and in all grades. Very well may be different in different areas - this is just what I have seen local to me.

Waylan

I've been to 29 states and my statement was based from a general standpoint. There's a couple of states that have a great variety of ethanol free options. But places like Iowa predominantly sell 89 with 10%.

 

[KG441c]

Im interested to see temp. Differences in the oil ratios!!

 

[Fishnuts2]

I'll jump in too, and speculate that you'll not see much if any temperature differences. There are only a couple of drops of oil differences between the ratios used anyway, considering you'll burn just a few ounces of mix for the tests.


Sent from my iPhone using Tapatalk

 

[Termite]

Redbull, you are the testingest guy I know.
And I like it.

 

[Outlaw5.0]

No such thing as pre detonation, now preignition yes. Detonation happens after the igntion of the air/fuel mixture

 

[Brentc]

I vote .404


Sent from my iPhone using Tapatalk

 

[cuttinties]

No such thing as pre detonation, now preignition yes. Detonation happens after the igntion of the air/fuel mixture

Detonation, or engine knock, occurs simply when fuel pre-ignites before the piston reaches scheduled spark ignition.

 

[Adirondackstihl]

I been running mine with motul 800 2t off road, at 40:1, Im not liking what I see on top the piston

I run VP w/ 800 2T @ 32:1 and I couldn't be any happier. No build up.
Nice film of oil on everything internal.
I was actually just inside one of my old 044's this weekend that I know I had personally ran a minimum of 5gal through. Top of the piston was almost as shiny as the day I installed it.
Little tiny bit of so called carbon at the exhaust side. I'll post a pic

The one on the right has seen approx 6-7 gallons of fuel. At least 5 of which was Motul & VP @ 32:1

 

[Outlaw5.0]

Detonation, or engine knock, occurs simply when fuel pre-ignites before the piston reaches scheduled spark ignition.

False, detonaton/knock happens after the spark ignition of the air/fuel mixture. Preignition is when the air/fuel mixture ignites before the timed spark resulting in peak pressure before TDC.

 

[HuskStihl]

It means a couple of things. The stroke isn't long enough with high enough compression, or the bore isn't large enough with enough compression. If a person were dealing with predetonation then they'd benefit from a higher octane. But to get that much compression in a saw would put it in a realm that wouldn't be a work saw. And even then you need to make use of the compression at that point. There's a reason your saws don't run 400 lbs of compression. This argument of high vs low octane is pretty feckless. The only real problem most need to concern themselves with is properly mixed ethanol free fuel and proper tuning. Then it's about making a sharp chain.

Guys, we've been over this 1000 times. There are two rules, and if you remember them, you'll always be right
1). Anything associated with a larger number will always be superior in every way to something associated with a smaller number, in any application. 93 is much better than 87. .063 is much better than .050. .404 is much better than .325.

2). If it is more expensive, it is going to be way awesomer. Feckless indeed