So what are the opinions or experiences with fuel grades and ethanol versus non-ethanol?

Are there any results that indicate going higher than 87 octane provides a smoother, cleaner, more even and cooler burn or is this just an opinion or is there evidence to the contrary?

Also, is there a reason to seek out and run non-ethanol (or ethanol with an ethanol treatment) if you are burning through a tank of gas once every week or two and not letting it sit and get stale and eat up your rubber/plastic innards as ethanol seems to do?

If I change from 87 octane up to a higher grade just for giggles, should I anticipate having to adjust the air mix screw to accommodate for any differences in the performance of a different grade than what it was tuned with (87 octane)?

Thanks!

Well....this could become a very controversial subject.....almost as bad as an oil thead.

The stock engine doesn't benefit from or need any higher octane than 87.  There really won't be any power increase or loss from using higher octanes you can get at normal fuel pumps.  The higher octanes aren such a big increase that jetting or timing changes would be required - but you will not realize any performance increase by using them.  Some claim that the higher octanes can get stale at service stations that don't sell a lot of it.....and it may sit in the tanks for a while.  I imagine the higher octane tank is a bit smaller than the lower grade tank - but don't know how often it might get used and replaced.

For any vehicle that is driven regularly - there seems to be little problem from ethanol fuels.  Older motorcycles and boats with fiberglass fuel tanks are the exception as the ethanol can dissolve the resins.  I also had trouble on a 2009 Sherco trials bike and the ethanol made the nylon (plastic) fuel tank swell and become soft.

My own personal experience with ethanol suggests that equipment with carbs that sits for extended periods of down time can have problems.  Tillers, leaf blowers, snow blowers, chainsaws can all sit for long periods of time....and any fuel can go bad when left in this equipment.  Old pre-ethanol fuels would turn to varnish and gum everything up....while modern ethanol fuels dissolve rubber parts, rust steel parts and corrode aluminum when left too long.  Engines that have diaphragm carbs tend to store better than engines with float bowls and gravity systems that can keep delivering more fuel to the float bowl as the fuel evaporates and allows the float to drop.

Gee folks this is a 8.5 to 1 engine it shouldn't even need 87 but here in California thats the lowest we are allowed and it works great. Buying the higher priced stuff is just a waste of your money

A guy we dont see much of anymore who lives down around Galveston runs premium in the heat of summer.

Gyrobob wrote on 09/04/12 at 03:05:42:


Premium burns slower,thats like retarding the spark so engine runs slightly cooler with less power.Here it is I told you how it is.

bill67 wrote on 09/04/12 at 05:10:56:

No, it doesn't. Make your arguments about oil all you want but don't start spreading misinformation like that. Octane has nothing to do with how hot or fast a fuel burns.

arteacher wrote on 09/04/12 at 06:48:57:



   yep

During the HEAT  of the summer, IF my engine is feeling hotter than normal then I will run the higher octane fuel.  
Any engine with a high compression piston in it should also have a higher octane fuel to help prevent detonation.

bill67 wrote on 09/04/12 at 08:48:30:


I vote with Cave......Higher Octane fuels are more resistant to knocking (detonation) in higher compression engines.  They don't burn hotter, or slower, and there is going to be very little difference in the way 87, 89 and 92 octane pump gas runs in our Savage.  Racing fuels, leaded fuels, Avgas are all different types of fuel.....and they will react completely different than what you can buy at your local gas station.

You will not find any reliable source that documents a slower burn on 89 or 92 octane pump gas........only rumors from unreliable sources.