What oil is best? and what ratio?

[Keith Gandy]

Cutting cookies id put my money on about 94 to 98 octane mixed with k2

 

[Keith Gandy]

I have the pin in on my 661 and its cranked all the wayup ...........
I have an 066r with the oiler all the way up, its the wettest of the 3
I have an 066 with the oiler modified

The two 066's have new oil lines and weighted pickups

I have no problem with 36" and .404 on any of the 3 90 cc saws

The biggest helper for keeping cool is to use wedges to keep the stump off the chain

Ah ha! Technique and experience!! Nice

 

[Keith Gandy]

High octane = slower combusting and unable to burn the whole mix intoduced completely in a short 2 stroke
High index/film oil= less combustible and slower combusting
tuned rich= worsens the effect of both which is leaving alota unburned oil and fuel that washes the piston clean. Go opposite on every account and u have faster igniting fuel and oil with more efficient complete burn resulting in more energy and a byproduct left behind thats visible

The timing advanced or retarded along with whatever octane used and whichever oil u use would have to be a balance. Get thoso 3 out of balance working against each other and all u have is a mess

 

[mdavlee]

Cutting cookies id put my money on about 94 to 98 octane mixed with k2

Think a stock 346 would show the most difference in this? I can get pump gas and 94 to mix a pint of each with K2, HP2, and super. I have 2 8x8 pine cants I can slide together to make it work longer than a couple 3 seconds.

 

[Keith Gandy]

Mike what im getting at is say for instance my 241 is rich at wot. Id choose 87 octane , timing advanced, and r2 or k2. Does that make sense?

 

[Moparmyway]

But ...........IMHO, you have to tune the saw for the most power in the cut with each mix to get a feel for any differences. Keeping the tune the same throughout could be playing into one of the mixxes hands and going against the others strengths

 

[mdavlee]

Mike what im getting at is say for instance my 241 is rich at wot. Id choose 87 octane , timing advanced, and r2 or k2. Does that make sense?

Yeah I get what you're saying. I just don't think 94 will show the fastest cut times. I could turn the 346 up to about 15k if it's just 1 cant or 14.5k in 2. The smaller the saw the pickier they seem to be on mix.

 

[Keith Gandy]

Yeah I get what you're saying. I just don't think 94 will show the fastest cut times. I could turn the 346 up to about 15k if it's just 1 cant or 14.5k in 2. The smaller the saw the pickier they seem to be on mix.

Id say test 87 vs 110 with super techniplate and r2

 

[Keith Gandy]

Im seeing in my mind the shorter the stroke the lower the octane can be used and the longer the stroke the higher octance to a point can be used?

 

[mdavlee]

Id say test 87 vs 110 with super techniplate and r2

I've already done the 93 to 110. Big difference in the 550. Plus the race gas is probably pretty stale this time of year. I figured 87 and VP 94 would be about all I can come up with this time of year. Only one pump within 30 miles for the 110.

 

[Ron660]

That's about 50% slower though. Never noticed that much difference before. Im going to try the HP2 in pump gas. Might only get to try it in the oak log cutting cookies but I'm going to compare somehow. I've not noticed more than 10% difference in fuel and that was with 110 and 93.

That was about exactly my difference with 110 and 93....10%.

 

[mdavlee]

That was about exactly my difference with 110 and 93....10%.

Mine was 110 10% slower. It slowed down the 550 and the 7900 I had ported.

 

[Ron660]

I have the pin in on my 661 and its cranked all the wayup ...........
I have an 066r with the oiler all the way up, its the wettest of the 3
I have an 066 with the oiler modified

The two 066's have new oil lines and weighted pickups

I have no problem with 36" and .404 on any of the 3 90 cc saws

The biggest helper for keeping cool is to use wedges to keep the stump off the chain

I think you solved my problem. Keep wedges in the stump to keep it off my chain....builds heat and probably hinders oil flow.
When you use a tank of fuel how much oil do you have left?

 

[Keith Gandy]

Mike on the 346 how would u tune one fuel from another? Identical rpm or each off 4 stroke?

 

[Ron660]

Think I need to go 404 and 063 on my 660. I have 3/8 and 050 now. Maybe that 063 might help oil a little better. Plus 063 might be faster....oh no another test with disputes.

 

[Moparmyway]

I think you solved my problem. Keep wedges in the stump to keep it off my chain....builds heat and probably hinders oil flow.
When you use a tank of fuel how much oil do you have left?

The 066r runs out of oil first, so I only fill it 3/4 with fuel
The 661r barely has enough to coat the bottom
The 066 has a little more than the 661

Think I need to go 404 and 063 on my 660. I have 3/8 and 050 now. Maybe that 063 might help oil a little better. Plus 063 might be faster....oh no another test with disputes.

.063 will oil better
.404 will be .063 as well, but it will last longer and also oil better than .050 3/8

 

[Redbull661]

ok guys I emailed andrew for his point of view on this octane debate...

ME -

Big debate right now is how different gas will work with different 2t oils and thus affect the test results.

So let's take si 7 and h1r.

Si-7 low visc, low flash, in it.

H1r maybe double the visc or close to it, and more than twice flash pt.

So I'm thinking it's fair to say pretty different ends of the spectrum.


QUESTION #1-

How would
87 oct, eth free run different with each of these?
91 octane eth free same thing
94VP same thing

Question #2
What if anything would change if ratio changed? Say from 32:1 to 40:1 ?

Question #3
Is the octane going to be changed more than 1/2 of a pt either way ie. 87 to 86.5 or 87.5 94 to 93.5 94.5 with any of the above?


***Not sure if this will play into your response but...
stroke on most saws is 34-40 mm with bore sizes 8-16mm larger than stroke. So they're not square.
-------------------------
His response -

re question #1 -

For all the octanes, the oils will work fine, changing the octane should not warrant a change in chemistries and whatnot, perhaps just volume of oil. The assumption that I’ll make is that with higher octane, you are running at higher compression since that’s the whole purpose of high octane fuel. If you are running at higher pressure, than the oil’s applicable flash point (the temperature it volatizes in the crankcase in this situation) will increase simply due to the gas pressure. So the oil will remain liquid, and thus unburned at higher temperatures than normal.


There is a flip side to this though. If the higher octane is warranted due to increased compression, then the engine is under higher load and the pressure factor is going to be negligible compared to the more important factors of increased heat and load. So for higher octanes, I would expect a higher content of oil to be needed.


This all comes back to tuning the engine properly and finding the right ratio for the tune. Fuel should remain constant for that process or else when it is changed, the tune should be revisited. The autotune system isn’t going to take the load into account as far as I know, so you may want to go heavier on the oil even if the autotune is working properly. You’ll probably see performance drops with different octanes, but again, that’s all part of the tune, finding the right octane as well.


Question 2
What if anything would change if ratio changed? Say from 32:1 to 40:1 ?


In terms of octane rating, nothing.



Question 3
Is the octane going to be changed more than 1/2 of a pt either way ie. 87 to 86.5 or 87.5 94 to 93.5 94.5 with any of the above?


H1-R is tested specifically according to CIK-FIA regulations for MON and RON which measure octane changes and the change is always less than 0.1 difference from reference. So, no H1-R will not change the octane of the fuel. I don’t have the same data for Si-7, but I doubt it would affect it 0.5 or more.

 

[mdavlee]

Mike on the 346 how would u tune one fuel from another? Identical rpm or each off 4 stroke?

I could tune for 4 stroke but it would probably be over 15k for that. It's got an unlimited coil on it so I can tune wherever it wants to be. If you tune to the same rpm first you can tell if it 4 strokes more or less with each mix. Then tune to a light 4 stroke and reference with a tach. Have to get a log over by my cant stand to warm it up in and play some before doing the cuts on the cant and maybe a few more chains. I may have enough new 60dl 3/8" to do the test with.

 

[Ron660]

ok guys I emailed andrew for his point of view on this octane debate...

ME -

Big debate right now is how different gas will work with different 2t oils and thus affect the test results.

So let's take si 7 and h1r.

Si-7 low visc, low flash, in it.

H1r maybe double the visc or close to it, and more than twice flash pt.

So I'm thinking it's fair to say pretty different ends of the spectrum.


QUESTION #1-

How would
87 oct, eth free run different with each of these?
91 octane eth free same thing
94VP same thing

Question #2
What if anything would change if ratio changed? Say from 32:1 to 40:1 ?

Question #3
Is the octane going to be changed more than 1/2 of a pt either way ie. 87 to 86.5 or 87.5 94 to 93.5 94.5 with any of the above?


***Not sure if this will play into your response but...
stroke on most saws is 34-40 mm with bore sizes 8-16mm larger than stroke. So they're not square.
-------------------------
His response -

re question #1 -

For all the octanes, the oils will work fine, changing the octane should not warrant a change in chemistries and whatnot, perhaps just volume of oil. The assumption that I’ll make is that with higher octane, you are running at higher compression since that’s the whole purpose of high octane fuel. If you are running at higher pressure, than the oil’s applicable flash point (the temperature it volatizes in the crankcase in this situation) will increase simply due to the gas pressure. So the oil will remain liquid, and thus unburned at higher temperatures than normal.


There is a flip side to this though. If the higher octane is warranted due to increased compression, then the engine is under higher load and the pressure factor is going to be negligible compared to the more important factors of increased heat and load. So for higher octanes, I would expect a higher content of oil to be needed.


This all comes back to tuning the engine properly and finding the right ratio for the tune. Fuel should remain constant for that process or else when it is changed, the tune should be revisited. The autotune system isn’t going to take the load into account as far as I know, so you may want to go heavier on the oil even if the autotune is working properly. You’ll probably see performance drops with different octanes, but again, that’s all part of the tune, finding the right octane as well.


Question 2
What if anything would change if ratio changed? Say from 32:1 to 40:1 ?


In terms of octane rating, nothing.



Question 3
Is the octane going to be changed more than 1/2 of a pt either way ie. 87 to 86.5 or 87.5 94 to 93.5 94.5 with any of the above?


H1-R is tested specifically according to CIK-FIA regulations for MON and RON which measure octane changes and the change is always less than 0.1 difference from reference. So, no H1-R will not change the octane of the fuel. I don’t have the same data for Si-7, but I doubt it would affect it 0.5 or more.

That's my thoughts also. Higher compression can benefit from higher octane....that's the purpose of achieving more performance. Also higher performance engines will require more oil. More engine power...more octane and more oil. The only way you'll know in your chainsaw is test. I've proved it in my saw but I'll do it again to see if I get the same results. Keith's 362 also proved it.

 

[laslabjohn]

Looks very strong!! John has a new 661r behind my back in the shop at all times that haunts me!!! He hasnt put fuel in her much less ported but knowin him he is reading/learning and comin up with a plan of attack on her!!! Lol!!

Yes sir! You would be correct! Lol