octane of gas in mix????????

[bump_r]

I know people that put premium gas in their normal run-of-the mill cars with the logic that it gives them more power. I never even try to convince them that its money down the drain with no added benefit. Now maybe I'm wrong and someone needs to straighten me out, but I'm a firm believer that this is the way it works.

Dan

It's my understanding that (some) cars have knock sensors that will allow the ECU to advance the spark timing up to where knock (detonation, preignition, whatever the term de joir) occurs, then retard it back to where it stops. In this dynamic spark timing situation, there is performace to be gained by using a gasoline (premium) that allows the ECU to advance the timing a bit more than crap 87 would allow. With fixed spark timing of my saws, this dynamic timing advance does not enter in to the equation, so unless the particular characteristics of a given 2-stroke (compression ratio, natural hot-spots, whatever) require premium, I'm with the others that performance would not be enhanced by the switch. Get into the arguments of better additives in premium gas versus "regular" for whatever benefits, and I'm out of the discussion. Yeah, may be improvements in other areas of fuel quality, but performance, I think not.

That said, my manual says use premium, I use premium.

 

[buck futter]

I'm with west texas 40:1 I think its a happy compromise of both sides of the argument. I've recently switch to premium gas because I only mix a gallon or so at a time and it is only another 30 cents or so. That is very cheap insurance, I also recently increased the compression on one of my saws and I guess it really needs it now.

Buck

 

[lesorubcheek]

Right on bump_r. And I don't mean to imply that if you have a new Corvette or a supercharged engine that premium gas is needed to take full advantage of the engines performance capabilities, even though with a knock sensor, it may not kill an engine like a Corvette from 1967. Only point is that driving an '87 Blazer with a 2.8 (yep I got one) there's no advantage in performance or otherwise running premium gas.

As for saws, I think it goes without saying that some are higher performance designs than others and that many would definitely benefit their longevity by running premium gas. Please understand that I never meant to imply that any given saw may not require premium. All I meant to say was that if you have a saw that was designed to operate on 87 octane gas, that using 92 is not going to add any performance. If however you have a saw that's designed to run on 92 and you're constantly running 87, you'll very likely shorten that saws life.

Dan

 

[RES]

I still have the question if anyone has experienced pre-ignition, knocking or whatever you want to call it on a 2-cycle engine of any sort. How would you know that it is occurring?

 

[WadePatton]

Right on bump_r. And I don't mean to imply that if you have a new Corvette or a supercharged engine that premium gas is needed to take full advantage of the engines performance capabilities, even though with a knock sensor, it may not kill an engine like a Corvette from 1967. Only point is that driving an '87 Blazer with a 2.8 (yep I got one) there's no advantage in performance or otherwise running premium gas.


Dan

On the cars with anti-knock. Even though the ECU can manipulate the timing to avoid detonation, I do believe that the engine will perform better when the timing is not compensated in that manner.

Nothing to do with saws.

 

[ol'homey]

I bet most gas stations sell 10x as much regular as they do premium. Doesn't this mean the premium gas might be 10x as old as the regular? If the premium has been sitting at the station for a couple of months when you put it in your can, wouldn't it go bad faster than the regular that just came off the truck? If so, wouldn't it be better to buy the regular to get the freshest gas and then add octane boost along with the oil to get the required mix?
Would you buy a bottle of octane boost/stabilizer/synthetic oil that when mixed with 87 will boost it to 95 octane at say 32:1 ? We could call it Arborist Ultra oil and sell it right here. We could rotate pics of popular fellers with their saws on the front like they do with Wheaties. What do you think?

 

[robert f]

I bet most gas stations sell 10x as much regular as they do premium. Doesn't this mean the premium gas might be 10x as old as the regular? If the premium has been sitting at the station for a couple of months when you put it in your can, wouldn't it go bad faster than the regular that just came off the truck? If so, wouldn't it be better to buy the regular to get the freshest gas and then add octane boost along with the oil to get the required mix?

I worked at a gas station for a bit and our premium tank was 1/8 the size of the regular tank. It was topped off everytime the regular one was so it was always fresh.

 

[madcummings]

50-1 for 20+

I Have a 028 that was bought new in 1979 that has run 50-1 it's whole life and is still running strong. I finally looked at the owners manual and it says to run 40-1. oops. Oh well I always run fresh gas and now where I live in se wi I always buy premium gas so I know that there is no ethanol in it. That will kill a two stroke quicker than anything. Have fun with your 026. I have run my dads 036 pro and that saw rocks. TODD

 

[WadePatton]

That bears repeating.:greenchainsaw:

 

[madmax]

always run 40:1, with regular but, :greenchainsaw:

 

[1953greg]

Anyone ever do timed cut comparisons with the same saw and wood, and only change the octane of the fuel?
Would it cut that much faster that it is worth the extra buck or two per can of gas?

mike, i havent done any timed cuts but i have milled w/ an 066 at nite and switched octane fuels. w/ 87 (500' elevation) the dual ported muffler would glow red inside. w/ 92 it would not. couldnt tell any difference n power. not sure just how much lower the temp was. i did try to check w/ a cooking thermometer but it only went to 500*. best i could tell the 92 was 50-75* cooler. both mixes 40:1. convinced me to never use reg n saws again.

good day 1953greg