What octane do you use?

[Ram]

I have been running "low-test" all this time since owing it. Now stumble across in my VIN report a "minor" option "With 91 Octane Level Gasoline"....

 

Ok, is anyone running 91 or above?

[corncobs]

I have used 89 for 2 tanks out of 56 tanks and it's not worth the extra expense. 87 is what the car wants that's what she gets. :)

[DeeCee]

Have used 87 since the car was new. Usually get my gas at Murphy's at Wall-Mart as you get a decent discount with the WM Discover card (15 cents per gallon right now). With 24k miles now the car's computer reports lifetime average is 47.4 mpg. Don' see any reason to try higher octane gas.

[acdii]

For the life of the car I have been using 89 Octane only because the gas station sold it as regular, but that station closed recently, so I have been running 87 now for a few tanks, and the MPG has been fine. In fact I just had my first 47 MPG tank.

[djminfll]

I've been running on 87 octane 100% of the time. No problems, runs great, no need to up the octane.

[murphy]

It's a computer controlled ICE. It can dynamically adjust the timing parameters to match the gasoline it has been fed. Regular gas, whatever its octane happens to be, works fine.

[Ram]

I totally understand computer control of the engine but the octane of an engine is determined by how much compression the engine has been manufactured with. I am very interested in why the minor option package states 91 octane. I don't run the high test gas and don't have the hearing any more to determine if the engine is pinging or having any other kind of detonation issues.

I do have some high performance engines and they do require high octane and they tell you when its not high octane. Its a lot easier to determine on my other vehicles, I just can't tell anything on this thing it way too quiet. And is the anti noise unit helping suppress any of these signs that the engine is not liking low octane.

 

This maybe to much into this, hopefully someone else with some design background of this engine can chime in some day and solve this?

[murphy]

The ICE has a detection system for "pinging" (pre-detonation) and can immediately adjust the parameters to eliminate it.

This is an Atkinson cycle engine that operates differently than a standard Otto cycle engine.

 

It has always intrigued me that high octane gas burns slower than low octane gas but is more expensive.

[hybridbear]

I totally understand computer control of the engine but the octane of an engine is determined by how much compression the engine has been manufactured with. I am very interested in why the minor option package states 91 octane. I don't run the high test gas and don't have the hearing any more to determine if the engine is pinging or having any other kind of detonation issues.

I do have some high performance engines and they do require high octane and they tell you when its not high octane. Its a lot easier to determine on my other vehicles, I just can't tell anything on this thing it way too quiet. And is the anti noise unit helping suppress any of these signs that the engine is not liking low octane.

 

This maybe to much into this, hopefully someone else with some design background of this engine can chime in some day and solve this?

I believe someone else asked about this previously and the suggested answer is that the cars are filled with 91 octane at the factory with 0% ethanol because it is unknown how long the cars will sit and that is done so that the gas won't deteriorate in the tank. But the cars come from the factory with only a little gas in the tank. The dealer then fills the car before selling it to you. The dealer likely only fills it with 87 because that's the cheapest for them.

[Easy Rider]

Now stumble across in my VIN report a "minor" option "With 91 Octane Level Gasoline"....

 

Could you explain that a bit please ?

What exactly is this "minor option package" you are talking about ??

 

There is NO advantage to be gained with most cars by using a higher octane than recommended. NONE.

 

Now some models say that 87 is "acceptable" but recommend higher. I don't think that any of the Fusion line is like that.

Edited June 15, 2014 by Easy Rider

[Easy Rider]

It's a computer controlled ICE. It can dynamically adjust the timing parameters to match the gasoline it has been fed.

 

That is only partly true.

There is no "gas detector" or "octane detector".......only a knock detector.

And for an engine where "regular" is the only recommended fuel, the maximum timing setting allowed is designed to work with that.

Or to put it another way, the timing can NOT be advanced enough to really take advantage of the higher octane fuel.

 

The "compression" that is designed into an engine is a mechanical function determined by the piston stroke and the valve timing.

The timing of the spark impacts the dynamic compression and if set too far advanced can make even a "low compression" engine ping and knock.

Edited June 15, 2014 by Easy Rider

[hybridbear]

Could you explain that a bit please ?

What exactly is this "minor option package" you are talking about ??

 

There is NO advantage to be gained with most cars by using a higher octane than recommended. NONE.

 

Now some models say that 87 is "acceptable" but recommend higher. I don't think that any of the Fusion line is like that.

Put you VIN into Etis and then click to expand all the "minor details".

[Easy Rider]

Put you VIN into Etis and then click to expand all the "minor details".

 

Not much help really.......for one who doesn't know what ETIS is either.

;)

[murphy]

 

Not much help really.......for one who doesn't know what ETIS is either.

;)

http://www.etis.ford.com/