104 Octane?

[PES+]

So your hi speed needle is at 2 turns out you say.......

Glad it is working out for you...

 

[OilHead]

So your hi speed needle is at 2 turns out you say.......

Glad it is working out for you...

Yep could'nt beleive it at 1 & 1/2 turns out the thing was still sittin at 13,400. At 1 3/4 the idle would'nt controll itself fast enough to stop the chain even going after the idle speed screw. It has a good amount of grunt & the 8 pin makes up for what little bit of rpm its missing. Dont see it having any problem running a 9 pin in soft wood , it does require adding 1 extra link to do it then you cant run a 7 pin. You probably could run a 18" or 20 " bar with the 9 pin if you used skip chain. & that being around 110 " per second instead of 90' with the 7 pin.
:greenchainsaw:

 

[z4lunch]

Jd

Steve here... I ran it(race car gas) in my John Deere 425 garden tractor... 2cyl watercooled Kawi. The engine missed from time to time. Put regular in it and it was fine again...
Steve

several years ago I returned home from work late and wanted to get the yard mowed b4 dark. out of mower gas and no time to run to town and still mow b4 dark.

filled up with race gas as it was all I had at the moment( don't remember the exact octane but it was Unacal racing gas )

noticed the mower didn't bog down as much in the thicker parts of the lawn as usual

normally used a tank and a half to do the whole lawn, this time mowed all on just under one tank full

I really don't think my 5.5 hp briggs is a "high compression" engine

now maybe I'm just looking at this all wrong but it sure seemed to me that I completed the same task on less fuel and the mower did not work as hard in the taller grass

but I guess this would have nothing to do with how a chainsaw would run on better fuel huh?

You run whatever you wish...I'll stick to the good stuff

 

[super3]

Steve here... I ran it(race car gas) in my John Deere 425 garden tractor... 2cyl watercooled Kawi. The engine missed from time to time. Put regular in it and it was fine again...
Steve

Whatever

 

[056kid]

the point of higher octane gas is to prevent detonanion. As long as there is no detonanion run the lowest octane you can for the most power. diesel oil will not work in in a low compression gas motor cause of its high flash point. pretty much the same idea with the high octane and low compression. I have 210lbs of compression and run 110.

 

[OilHead]

I highly doubt your saw has 210 lb. psi of compression . What kind of saw is it & what's been done to it ?

 

[BlueRidgeMark]

the point of higher octane gas is to prevent detonanion.

Exactly. Higher octane does NOT mean more power. It's needed in higher compression engines to prevent detonation, that's IT.

Those engines have higher power because of the higher compression (and usually other modifications), NOT because they run high octane gas.


In electronically controlled engines, you CAN see more power from higher octane fuel, NOT because the fuel has more energy, but because the timing is adjusted to the earliest possible point before detonation. If you use higher octane gas, there will be less detonation, therefore the timing will be further advanced, which (within limits) provides more power.

Use high octane fuel in an engine with standard mechanical timing, and you won't be able to measure any increase in horsepower.

And a 'test' done by mowing a lawn one time isn't exactly what you'd call a valid test.

 

[Hugenpoet]

As I tell most people on all these pointless subjects... You use what you want and I'll use what I want. Some people have run 104 and had a saw last for 20 years! And I've used pump gas and had the same. Point of the whole thing is... At least use some good 89+ octane fuel and good quality oil from whatever maker you want and you'll have some great fun use of your saws or whatever. 89 octane doesn't cost an arm and a leg so no problem with that. Enjoy.

+1 IMHO just good plain practical advice, take it or disregard it as one wishes. Rep'ed you for that.

 

[wireedm]

Just a little advice.............Do NOT put that 105 methanol stuff in it. It burns WAY slower than regular gas. Cars that use it automatically adjust their ignition timing to accept it.

 

[OilHead]

Changes In Gasoline 3 - 1996 Update.

There must be higher octane than 89 at the pump. We use to have 92 but they have scaled it back to 91. Anyway check out page # 4 from "The Auto Technicians Gasoline Quality Guide " 1996 Update - Changes In Gasoline 3. You'll notice that the best fuel you can purchase at the pump is low in octane for the compression ratios that saws are running at. You'll also notice thruout the read they are recommending a jet change up one size on carburated engines for areas that have implimenated 10% methonal blend. So what to do ,just run more of it. Check out my "Pop Off Pressure" thread it is designed to be a work around rather than changing the jet. Still more to go over there .

 

[Outlaw5.0]

I mixed up a gallon of 100 octane GT leaded, my 2 cycles never ran better. The bogging cold is nearly 100 percent gone, once warm, the throttle response is awesome. I was using unleaded premium before, all the pumps now say 10 percent eth. Now my lawnmower is not totally happy on straight 100 octane, but mix it 50/50 with 87 octane, it runs great.

 

[ShoerFast]

Just a question,,,,if I may ask?

Just a question, as there seems a lot of differant ideas on why and when a saw/engine needs higher test fuel.

Let's just for the say, say a mostly stock MS-310....

What would need a higher octane fuel, the 310 with a 16" bar running hi-RPM's in the cut , more used limbing A)?

Or the same saw, 24" bar running lower RPM's in the wood, more for blocking?

 

[056kid]

It's a 250cc water cooler with some BIG
ports

 

[Andyshine77]

104 Octane will work fine in a stock saw, but your not going to gain anything from running it. I just started running 110 Sunoco mixed 50/50 with 93 octane and my saws are running really well on it, plus it smells better.

 

[OilHead]

If you really want to raise the octane the best way to do it is to replace 1 quart of the stuff you get at the pump with a quart of toluene to equal the gallon. Or 25% . $ 5.00 worth . Probably wont find it for much less. So to batch up a gallon of it your talkin around $ 3.10 for 3 quarts of fuel + the 5 & $ 2.00 for the oil or $10.10 . On a really hot day sure just for fun but worth less below 70 degrees. Blown modify'd is a whole nother breed of cat. Think you know. You can accomplish the same thing by delivering more fuel thus reducing the cylinder head tempature & reducing spark knock so pump grade is no longer a problem.