What grade of gas?

[Gale Hawkins]

Not only are you spending money for nothing, you're actually getting less than nothing. Higher-octane fuel has less energy in it, so your motor will produce less power AND get worse gas mileage.

JayC

JayC I do not want you talking around my MH because it does not know your version of the truth and makes more power and MPG on 93 than 87. :laughing:

 

[MacLawn]

I already posted this non-ethanol gas link, but here it is again:

Ethanol-free gas stations in the U.S. and Canada

If you know of a non-ethanol station in your area, you can add it, or delete a station that no longer carries non-ethanol gasoline. I have about three in my area of east central Georgia, and non-ethanol is all I have been buying for my small engines since I learned about it.

 

[ModMech]

JayC I do not want you talking around my MH because it does not know your version of the truth and makes more power and MPG on 93 than 87. :laughing:

That's called being "knock constrained" and is the rare exception rather than the general rule.

Using higher octane fuel is not necessarily "bad" but also provides no real advantage unless you are dealing with a knock or convience issue.

FWIW, I use 89/91 (midgrade) for our 2-stroke fuel and mower to meet the highest minimum standard of 89 for the products we own. I *could* use 87, but that would fall below the minimum requirement for two engines, but would be OK on the other 4.

 

[DarkBlack]

knock, ping, peng, pang or whatever. Timing advance gives increased power with a higher octane fuel to a point on low compression engines, be it manually or by cpu controlled knock sensors or other management systems, thus millions of motorists who get better performance and mileage with higher than manufacture's minimum recommended octane fuel.

 

[JDL538]

I drive a 400 HP Corvette the book says use premium gas or regular, I use regular it never pings and is fast as lightning, so untill I here a ping that's what I will use.

 

[ModMech]

knock, ping, peng, pang or whatever. Timing advance gives increased power with a higher octane fuel to a point on low compression engines, be it manually or by cpu controlled knock sensors or other management systems, thus millions of motorists who get better performance and mileage with higher than manufacture's minimum recommended octane fuel.

That is true but only until no additional advance is available and in the vast majority of vehicles, there is only a degree or two of adaptive advance available to the ECM for this. Once you have more octane than can beneficially advance timing, more actually reduces power output due to the lower BTU/gal.

To say it another way, as long as the ECM can advance timing more to take advantage and more importantly not knock, more octane can be an advantage in power and economy.

For MOST vehicles, a step from 87 (knocking) to 89 will be enough. There are also significant differences to how any particular engine responds to Research vs Motor octane. These octane measurements are not the same method so the results are different as well.

 

[DarkBlack]

That is true but only until no additional advance is available and in the vast majority of vehicles, there is only a degree or two of adaptive advance available to the ECM for this. Once you have more octane than can beneficially advance timing, more actually reduces power output due to the lower BTU/gal.

To say it another way, as long as the ECM can advance timing more to take advantage and more importantly not knock, more octane can be an advantage in power and economy.

For MOST vehicles, a step from 87 (knocking) to 89 will be enough. There are also significant differences to how any particular engine responds to Research vs Motor octane. These octane measurements are not the same method so the results are different as well.

I agree on 89 being enough for most. Some engines can develop a just a single cylinder that has a hot spot due to an obstructed passege way or bad casting from the factory. In those cases that one cylinder can trigger the sensor, and cause the whole 6 or 8 cylinders to be ignition retarded, and with theses engines the 93 fuel can in cases allow the ignition to run back at full advance, and the power and economy is restored.

 

[travis potter]

A freind gave me this hint If you have a v engin with the carb in the center in your small air coled tractor when you stop opene the hood and let it cool down if you don't the gas we now have can expand in the fuel bowl and jam the nedel into the seat which will require a carb re build. Just a hint.

 

[Just Bill]

A freind gave me this hint If you have a v engin with the carb in the center in your small air coled tractor when you stop opene the hood and let it cool down if you don't the gas we now have can expand in the fuel bowl and jam the nedel into the seat which will require a carb re build. Just a hint.

Your friend may be sniffing gas.
Don't let him scare you.
Carbs are vented and will not build pressure in the bowl.
The heat can cause the fuel to evaporate and leave a varnish in the carb
that can cause sticking.
Using a carb/injector cleaner will help with that.