Autotune saws and fuel quality

[NorthcentralYooper]

Just wondering on the autotune saws if you get more performance out of higher octane fuel then say mid grade?
I know a higher octane on a 4 cycle engine can allow more timing and a leaner mixture.
Not sure how advanced the autotune saws are when it comes to this.

Thanks

 

[Mastermind]

I never use high octane fuels. Even in the saws I build with higher compression.

 

[NorthcentralYooper]

I never use high octane fuels. Even in the saws I build with higher compression.

I guess what I'm calling high octane is 95.
So do you use 87 octane? I know the canned husqvarna fuel is 95.

 

[Mastermind]

All I can get here is 87 in non E fuel.

 

[NorthcentralYooper]

All I can get here is 87 in non E fuel.

Oh ok we get 91 octane non E , I think being Snowmobiling is so big here. Most sleds require 91 or higher and if you run ethanol then you have to run a resistor if fuel injected or rejet 1 size richer

 

[cgraham1]

93 non-Ethanol here.

 

[cgraham1]

93 non-Ethanol here.

It works fine.

 

[Terence Hill]

Are US octane ratings MON or RON?
or:
(MON + RON)/2

 

[NorthcentralYooper]

Are US octane ratings MON or RON?
or:
(MON + RON)/2

Our numbers are mostly posted as AKI 87 or anti knock index this is a average between Europe's RON and the other MON.

Roughly in Europe the common number is 95 Ron , this is around 91 AKI for the U.S.

 

[NorthcentralYooper]

It works fine.

I am really wanting to know more how Autotune works , it says based on fuel quality as one of the features. .though it doesn't have a knok sensor or o2 sensor. I'm assuming it reads purely off Rpms. I like the higher octane fuel because the ability to keep knock at bay. It also has a cooling effect as well. When I did fuel map tuning on Subarus you could advance the timing and actually run leaner with higher octane.

 

[Mastermind]

I wish we had better grades of non E fuel here, 87 is the highest I've found.

 

[jrsdws]

Lucky enough to have non E 89 octane up town. I use it in all small engines.

 

[Terence Hill]

I mostly run our BP 95RON non E in my chainsaws, motorcycles and car.
Seems to give no problems and doesn't go off (go stale) like the lower octane (91 RON) fuel that we have here.

 

[Mastermind]

The short stroke in a saw engine seems to do fine on lower octane fuel, but I've not been able to really test middle octane fuels like 93. I have tested 101, and it slowed my saws down.

 

[NorthcentralYooper]

The short stroke in a saw engine seems to do fine on lower octane fuel, but I've not been able to really test middle octane fuels like 93. I have tested 101, and it slowed my saws down.

I agree the 101 octane would probably slow them down . I'm guessing to get max benefits out of higher octane you'd have to advance the timing even more . I know on the Subaru tuning the timing could be advanced ALOT with higher octane and in return really increased the power . Otherwise no increase in power but it would keep the cylinder head temps lower .

 

[Mastermind]

I drag raced for many years, and of course since I came into saw modding from that background, I went straight to race fuel.

These saw engines are a different breed.....

 

[NorthcentralYooper]

Yea I suppose , i'll still take a 93 non E fuel anyday.

 

[mdavlee]

87 is fastest. Lowest e free for me.

 

[Stihlvarna]

I can't get non E fuels or have never seen it around here. Wish I could. Do they have it at the pumps?

 

[mdavlee]

Yes everywhere here. 2 stations in 5 miles and 8-10 in 15 miles.