40 MPG!

[Chibana]

 

This was the first chance I've had to fill up the car and immediately get on the expressway to see what the car will do at steady cruise at 65 mph. It dropped a couple of MPG by the time I had gotten onto I-75S and had to deal with late rush hour traffic (this photo was taken with only I-69E traffic, which is practically non-existent compared to I-75S between Flint and Auburn Hills). The final average, according to the car, when I pulled into work was 38.2 mpg. I have a 2012 Focus Titanium hatchback with Titanium Handling Package (big, fat, summer-only tires), and I had the automatic climate control set to 71 degrees. When I ordered this car, I was hoping I could hit 40 MPG on a quiet, flat, expressway. My own calculations for fuel efficiency would seem to back up the data I get from the trip computer, which seems to indicate high-30s on the expressway and 27 to 30 MPG in around-town driving. It's the city efficiency numbers that really blow me away. I often drive like a bat out of hell in around town driving (especially when I'm in a manual transmission car), so I've never gotten anywhere near 30 mpg in city driving in any of my cars.

[GaryG]

That's very good but that vehicle has much more to give. I got my Son a '12 SEL Focus Sedan and took him out for a short lesson in Hypermiling. Now he is getting 36mpg tanks in mostly short City driving. Mainly taught him about using the Ford aggresive fuel-cut (DFSO) feature and gave him a Scangauge II (SGII) to monitor Instant MPG and Open Loop which indicates 9,999mpg and Open Loop during fuel-cut. Reading the Instant MPG also allows him to get the best mileage at the best steady state speeds. Just a simple SGII can help anyone increase their MPG in City or Highway driving.

 

The '12 Focus has a small door covering the OBD II connection that the SGII plugs into to get data from the PCM and other modules on the Focus. In order to plug the SGII in, that door has to remain open or removed. Here is some Info on the SGII: http://www.scangauge.com/ If interested, you can get a big discount by joining http://www.cleanmpg.com/

[Chibana]

Thanks for the suggestion. I actually have an OBDII-to-Bluetooth adapter and Torque on my Android phone. I use it with my RX-8 almost every time I drive it for monitoring several areas, most importantly coolant temperature (of the things I can read without additional hardware). I can't use it in the Focus because of that stupid little door over the OBD-II port, and I don't want to remove it particularly.

 

However, I doubt I'll be getting anything higher than 40 mpg in steady-state expressway driving. That 40.3 MPG reading was just long enough for it to settle out to an average at 65 MPH on a flat expressway (it actually got to 40.5 MPG before I got to I-75, where it went downhill due to greatly increased traffic). I don't see how I'm going to do better than that with this sporty (and heavy) version of the Focus without driving even slower, which I won't do. I won't drive slower than semis, causing traffic problems for other drivers. However, I am impressed at how the car does around town. It's quite impressive considering I am no hypermiler, and won't be--I enjoy driving too much, and blasting through corners and expressway ramps causes a pretty big drop in that average fuel economy display.

 

40 MPG on the expressway is pretty darned impressive for a 3000 lb. car with 235mm wide ultra-high performance summer tires and 160+ hp. It was also on 93 octane gas (don't know that that matters much in this case).

[GaryG]

The new Focus and Explorer shine at highway speeds with their 6 speed transmissions and aero ability. The engine FE is great also.

 

I recently took a short vacation in my '11 Explorer to Fort Smith and got into a hurry to get to a family reunion. I was able to rip through the Ozark mountains maintaining 28mpg and having the fun of a lifetime. These new Ford vehicles are something else and I was totally impressed at how fast I could go and still use fuel-cut to maintain my mileage. Forget about slow driving and practice smart driving.

 

An example, my Son was accelerating up to speed too slow in his Focus thinking he could save more gas that way. That's not how it works! Accelerating too slow is almost as bad as jack rabbit starts. By the time it took him accelerating to a steady state speed at say a 15mpg Instant MPG, he could have accelerated at 10MPG Instant MPG and got to speed much faster and started cruising at 48mpg at a steady state speed saving much more gas. Kyle is now learning how to hypermile his Focus with the tools and knowledge I got him to try. It's not only going to save him gas, but he gets to drive what others consider normal and get 30% better mileage than the other Focus drivers.

 

Why are you using 93 octane? Did you know additives are used in higher octane fuels to slow down combustion? Higher octane fuels have reduce BTU's than 87 octane fuels. The more BTU's, the more energy you have in every drop of fuel. If you need to slow down combustion to prevent pre-ignition due to higher combustion ratios, that's different because the higher combustion ratios will provide more HP. The 93 or higher octane than 87 will reduce your MPG because it has less energy and burns slower. If Ford says your engine is designed to run on 87 octane, run on the gas it was designed for. I would never purchase a vehicle that requires a higher octane fuel than 87 octane unless it was for something like a Shelby GT 500 with higher compression that I wanted performance out of. Your Focus will have less performance and MPG on 93 octane than 87 octane.

 

Now that you've used 93 octane, the long term fuel maps have adjusted in the Keep Alive Memory (KAM) to store your Air/Fuel ratios in the PCM. Your Long term fuel/air ratios are stored so that the PCM does not need to keep relearning air/fuel mixtures at certain engine loads and RPM's. When you change to the correct octane fuel, the Long term air/fuel ratios in KAM will take about a half tank to readjust those ratios for better MPG and performance. Even if you change from using straight 87octane gas to E10, your air/fuel maps in KAM need to adjust to the change in fuel types. E10 of course, has less BTU's than straight gas.

[akirby]

Higher octane fuels have reduce BTU's than 87 octane fuels. The more BTU's, the more energy you have in every drop of fuel. If you need to slow down combustion to prevent pre-ignition due to higher combustion ratios, that's different because the higher combustion ratios will provide more HP. The 93 or higher octane than 87 will reduce your MPG because it has less energy and burns slower.

 

This isn't true. Regular and premium fuel has the same energy content - premium is just harder to ignite. But once ignited they produce the same power. Premium allows higher compression which makes more power.

[GaryG]

This isn't true. Regular and premium fuel has the same energy content - premium is just harder to ignite. But once ignited they produce the same power. Premium allows higher compression which makes more power.

 

Just a response from a jackwagon that I would have expected! What good are those BTU's burning after the exhaust valve has closed? Those slow burning premium fuels are of no use in the exhaust system that has closed! The fast burning lower octane uses most of its BTU's where it is needed to give you the best MPG and performance as I explained. Akirby would never want me to prove my point in a money challenge for MPG for what we are talking about. Instead, he takes a chicken statement confusing everyone about content energy. The energy may or may not be in higher octane fuels, but my point in the '12 Focus he has no clue. Don't select things jackwagon in my statements if your not ready to challenge me into a MPG Challenge in the same vehicle.

[akirby]

Just a response from a jackwagon that I would have expected! What good are those BTU's burning after the exhaust valve has closed? Those slow burning premium fuels are of no use in the exhaust system that has closed! The fast burning lower octane uses most of its BTU's where it is needed to give you the best MPG and performance as I explained. Akirby would never want me to prove my point in a money challenge for MPG for what we are talking about. Instead, he takes a chicken statement confusing everyone about content energy. The energy may or may not be in higher octane fuels, but my point in the '12 Focus he has no clue. Don't select things jackwagon in my statements if your not ready to challenge me into a MPG Challenge in the same vehicle.

 

This has nothing to do with hypermiling and mpg. It only has to do with physics.

 

93 octane fuel is harder to ignite than 87 octane fuel. Once ignited, it burns the same (not slower) and produces the same amount of energy. I didn't create the laws of physics so don't hold it against me if you don't understand them. Jackwagon.

[Chibana]

I already stated why I'm using 93 octane fuel: Ford's Source Book states that the car will adjust timing to make more power on higher octane gasoline. I just wish I could find out how much. I have a pretty good idea how much an aftermarket tuner can get out of 6 octane, but I don't know how much Ford gets from this much increase in octane.

[GaryG]

This has nothing to do with hypermiling and mpg. It only has to do with physics.

 

93 octane fuel is harder to ignite than 87 octane fuel. Once ignited, it burns the same (not slower) and produces the same amount of energy. I didn't create the laws of physics so don't hold it against me if you don't understand them. Jackwagon.

 

When I was in high school, my shop teacher did a demonstration with regular gas and high test gas. He took a ~3 foot glass tube and a tennis ball and mixed the regular gas in the glass tube and put a match to one end. The tube exploded with a quick boom. Then he took the premium fuel and mixed it the same way and put a match to the same end. The flame slowly burned from that end to the other end slowly and didn't explode. Once the premium gas was ignited, we saw it burn slowly down the tube and it didn't explode like the regular gas did. That is physics and it has everything to do with MPG when designing the compression and valve timing of an engine.

 

Once 93 octane is ignited, it burns slower and can continue burning in the exhaust system where the energy is not used in the combustion process. That is a waste of BTU and energy I was talking about. If the compression and valve timing was designed to better use this wasted BTU, that is a different story.

 

This thread is about 40 MPG and not physics, but if you want to say I posted something that was not true, address the subject please.

[akirby]

When I was in high school, my shop teacher did a demonstration with regular gas and high test gas. He took a ~3 foot glass tube and a tennis ball and mixed the regular gas in the glass tube and put a match to one end. The tube exploded with a quick boom. Then he took the premium fuel and mixed it the same way and put a match to the same end. The flame slowly burned from that end to the other end slowly and didn't explode. Once the premium gas was ignited, we saw it burn slowly down the tube and it didn't explode like the regular gas did. That is physics and it has everything to do with MPG when designing the compression and valve timing of an engine.

 

Once 93 octane is ignited, it burns slower and can continue burning in the exhaust system where the energy is not used in the combustion process. That is a waste of BTU and energy I was talking about. If the compression and valve timing was designed to better use this wasted BTU, that is a different story.

 

This thread is about 40 MPG and not physics, but if you want to say I posted something that was not true, address the subject please.

 

I'm addressing an inaccurate statement. I don't know what your shop teacher did, but whatever caused the different burn rate was NOT the octane level. And if gasoline in a car engine burned that slowly it would never run. There is no waste of BTUs from using premium - just a waste of money in most cases where the engine wasn't designed for higher compression and advanced timing.

 

The burn rate of a fuel is a measurement of the time required for

complete combustion of the airfuel mixture. The notion that octane

ratings affect the burn rate of fuel is about 180-degrees from

reality. Burn rate is a function of several variables, and the two

are completely independent, although there is generally a

correlation between octane ratings and burn rates.

 

To give you a good example of this, we contacted Jim Wurth from

Sunoco Race Fuels. He explains, A perfect example is Sunoco

Maximal, which is our fastest burning fuel, and coincidentally one

of Sunoco's highest octane fuels at 116 (R+M)2. A lot of Pro Stock

teams rely on Maximal for those sub-seven second runs. When they

are turning 9,000rpm or more, the fuel has to burn pretty quickly

to achieve complete combustion.

 

http://smokeriders.com/articles/Technical/High-Performance%20Gasolines.txt

[GaryG]

I already stated why I'm using 93 octane fuel: Ford's Source Book states that the car will adjust timing to make more power on higher octane gasoline. I just wish I could find out how much. I have a pretty good idea how much an aftermarket tuner can get out of 6 octane, but I don't know how much Ford gets from this much increase in octane.

 

The manual also says the engine is designed to use 87 octane. The manual does not say your mileage will improve with premium fuel, but at higher RPM's, common sense says performance may be better than 87 octane. Who needs to run a fuel efficient vehicle at a less fuel efficient higher RPM? Sure, the PCM can advance the timing and fire the spark plug to start burning the fuel earlier in the compression stroke for higher RPM's, but is that what you really want?

 

The DI engine in the new Focus has more than enough performance and power with 87 octane where it is the most efficient. My experience in hypermiling is that higher octane fuels reduce MPG in vehicles designed to run on 87 octane. Any performance improvements I've seen in higher octane fuels have had a overall negative effect in vehicles designed for 87 octane.

 

I complained to a dealer years ago that my new Ford Explorer was getting worse MPG than my last Explorer. The Tech ask me what fuel I was using and I said I changed to premium. He said that was the problem and recommended I use 87 octane. I thought he was crazy but he turned out to be right. Later, I purchased a new '05 FEH and started learning to hypermile it. One day I filled it up and notice a drop in my MPG after. When I looked at my sales slip I noticed I had fill-up with 93 octane fuel by mistake. My mileage returned to normal after that tank of gas.

 

There are vehicles like the Highlander Hybrid that can run on 87 octane, but the manual states that mileage and performance will improve with higher octane gas. In this case I would run the higher octane fuel if I purchased one of those. The reason I didn't purchase it was because of that language.

 

akriby's quote:

 

"I'm addressing an inaccurate statement. I don't know what your shop teacher did, but whatever caused the different burn rate was NOT the octane level. And if gasoline in a car engine burned that slowly it would never run. There is no waste of BTUs from using premium - just a waste of money in most cases where the engine wasn't designed for higher compression and advanced timing."

 

The statement I made was regarding a engine designed to run on 87 octane. My statement was not meant for engines designed to run on higher octane fuels with higher compression ratios.

 

The demonstration my shop teacher did was effective in showing us why and how pre-ignition knock occurs with lower octane fuels. This was a course in small gasoline engines and the fuels demonstrated was with gas you purchase at a gas station with low and high octane gasoline. I didn't ever say the demonstration simulated ignition of a air/fuel mixture under various compression ratios.

 

You seem to want to spin the subject to prove me and other posters wrong whenever you want. The article you quoted is about racing fuels but even that article has this statement that gets to my point: "although there is generally a correlation between octane ratings and burn rates."

[akirby]

You seem to want to spin the subject to prove me and other posters wrong whenever you want. The article you quoted is about racing fuels but even that article has this statement that gets to my point: "although there is generally a correlation between octane ratings and burn rates."

 

I'm not spinning anything. If I see an inaccurate statement I correct it. The example given by Sunoco showed that their HIGHEST octane racing fuel was also the fastest burning which is directly opposite your theory.

 

Automobile gasoline has the same burn rate whether it's regular or premium because it's formulated that way. Higher octane is harder to ignite which prevents spontaneous combustion before the spark is applied. Once it ignites it burns at the same rate as regular.

 

Those are simple facts.

 

This is what you said:

The 93 or higher octane than 87 will reduce your MPG because it has less energy and burns slower.

 

If it has less energy it's so small as to be undetectable and it does not burn slower and it should never reduce your mpg in a properly functioning engine designed for regular fuel. It will only lighten your pocketbook.

 

Believe whatever you want. I made my point and I'm finished if you are.

[GaryG]

I'm not spinning anything. If I see an inaccurate statement I correct it. The example given by Sunoco showed that their HIGHEST octane racing fuel was also the fastest burning which is directly opposite your theory.

 

Automobile gasoline has the same burn rate whether it's regular or premium because it's formulated that way. Higher octane is harder to ignite which prevents spontaneous combustion before the spark is applied. Once it ignites it burns at the same rate as regular.

 

Those are simple facts.

 

This is what you said:

 

 

If it has less energy it's so small as to be undetectable and it does not burn slower and it should never reduce your mpg in a properly functioning engine designed for regular fuel. It will only lighten your pocketbook.

 

Believe whatever you want. I made my point and I'm finished if you are.

 

Gas pump fuels with 93 octane burn slower than gas pump fuels with 87 octane. Engines designed to run on 87 octane may not burn as high as a percentage of energy as 93 octane provides, so more of the unburned slower burning energy may be exhausted in an engine designed to burn 87 octane. In order to get higher compression for more power, the octane must be raised to prevent pinging and engine knock. Engines designed with higher compression are also designed to run premium fuels. Running premium fuels in a vehicle's engine designed to run on 87 octane will not improve performance or MPG and in my personal experience will reduce MPG.

 

I can't believe you have not found this information on the internet! Here is just a sample of my findings:

 

"Octane Facts

• Knock occurs when cylinder pressures are high. It is normal for an engine to ping a little at full throttle

because cylinder pressures are very high at full throttle. Engine knock, however, should not be ignored

since it can result in serious damage to the engine.

• High octane gasoline burns slower than low octane gasoline. The slow burn prevents engine knock when

cylinder pressures are high.

• If your engine runs well and does not knock or ping on low octane gasoline, there is no advantage in

switching to higher octane gasoline.

• If your engine knocks or pings, it does not necessarily mean something is wrong with the gasoline. It could

be a problem with the engine’s electronic control systems, ignition timing or exhaust gas recirculation. On a

high mileage engine, a carbon build-up in the cylinders can increase cylinder pressures and cause knock."

 

"Octane Myths

• High octane gasoline improves mileage.

In general, if your car is designed to run on 87 octane gasoline, high octane gasoline will not improve

mileage. If switching to high octane gasoline does improve mileage, you might find that your engine, or its

control systems, need repair.

• High octane gasoline gives quicker starting.

No, it doesn’t.

• High octane gasoline increases power.

If your car is designed to run on 87 octane gasoline, you shouldn’t notice any more power on high octane

gasoline. Again, if it does make a noticeable difference, your engine, or the engine’s electronic control

systems, may need repair.

• High octane gasoline has been refined more – it is just a better product.

Additional refining steps are used to increase the octane; however, these additional steps do not necessarily

make the gasoline a “better” product for all engines. They just yield a different blend of hydrocarbons that

burn more slowly. The additional steps also increase the price."

http://www.state.mn.us/mn/externalDocs/Commerce/Gasoline_Octane_Facts_102902052227_OctaneFacts.pdf

[akirby]

• High octane gasoline burns slower than low octane gasoline. The slow burn prevents engine knock when

cylinder pressures are high.

 

This is a common mistake on numerous websites. They say "slower to burn" when they really mean "harder to ignite". It's an easy mistake in terminology. They are all wrong.

 

Do you understand the difference between "harder to ignite" and "burns slower"? Those are 2 different things. Higher octane resists spontaneous detonation.

It does not burn slower. The Sunoco example showed their highest octane fuel was also the fastest burning because they are 2 different things.

 

I'm not arguing about the benefits or non benefits of using premium vs. regular, only that your statement about premium burning too slow and wasting energy down the exhaust is wrong. Once the fuel mixture ignites there is no difference between regular and premium.

 

I can't believe you haven't found THIS information on the internet:

 

Gasoline faq part 3

 

Simply put, the octane rating of the fuel reflects the ability of the

unburnt end gases to resist spontaneous autoignition under the engine test

conditions used.

 

The antiknock ability is related to the "autoignition temperature" of the

hydrocarbons. Antiknock ability is _not_ substantially related to:-

1. The energy content of fuel, this should be obvious, as oxygenates have

lower energy contents, but high octanes.

2. The flame speed of the conventionally ignited mixture, this should be

evident from the similarities of the two reference hydrocarbons.

Although flame speed does play a minor part, there are many other factors

that are far more important. ( such as compression ratio, stoichiometry,

combustion chamber shape, chemical structure of the fuel, presence of

antiknock additives, number and position of spark plugs, turbulence etc.)

Flame speed does not correlate with octane.

[GaryG]

This is a common mistake on numerous websites. They say "slower to burn" when they really mean "harder to ignite". It's an easy mistake in terminology. They are all wrong.

 

Do you understand the difference between "harder to ignite" and "burns slower"? Those are 2 different things. Higher octane resists spontaneous detonation.

It does not burn slower. The Sunoco example showed their highest octane fuel was also the fastest burning because they are 2 different things.

 

I'm not arguing about the benefits or non benefits of using premium vs. regular, only that your statement about premium burning too slow and wasting energy down the exhaust is wrong. Once the fuel mixture ignites there is no difference between regular and premium.

 

I can't believe you haven't found THIS information on the internet:

 

Gasoline faq part 3

 

There were two things I have personally experienced myself about higher octane fuels.

 

1. The demonstration my teacher did where I witnessed with my own eyes the difference of the burn rate as the flame started at one end and I watch the flame burned down to the other end in the test of glass tube with the high octane fuel. The 87 octane just exploded with a pop.

 

2. The drop in MPG when I added 93 octane to the tank in my '05 FEH vs 87 octane.

 

I was incorrect in this thread when I said the BTU of 93 octane was lower than 87 octane. What I have said for years is that 87 octane straight gas has a higher BTU than 87 octane E10. You are correct that the BTU is about the same in 87 and 93 octane. One thing I don't like anyone doing including myself is saying something incorrect. My apologies!

 

We both agree I think, that the use of a higher octane is only to prevent pre-ignition due to higher compression ratios. The only thing we disagree here I think, is that you don't agree 93 octane has a slower burn rate than 87 octane. I've read a lot in the last few days about this and I still stand by that statement. One article goes into detail with an example of gasoline with two different densities:

 

"A gallon of gasoline will usually contain from 115,000 to 125,000 BTUs. Most enthusiasts want the gasoline

with the most BTUs, and that can be misleading. The BTU content is of little value if some of the gasoline is

still burning when the exhaust valve opens and all of that energy escapes out the exhaust as heat and unburned

hydrocarbons. Most engines that exceed 7,000 RPM can benefit from a 115,000 BTU per gallon gasoline than

a heavier gasoline that may contain 125,000 BTUs per gallon, but does not have time to completely burn in the

combustion chamber. Think about this: One gasoline has 115,000 BTUs and is 95% burned before the exhaust

valve opens; the other contains 125,000 BTUs but is only 85% burned before the exhaust valve opens. Simple

math tells us that the first gasoline gave up 109,250 BTUs. The other gave up 106,250 BTUs. Which would you

prefer? I would take the 109,250 BTUs from the 115,000 BTU per gallon gasoline.

http://www.rockettbrand.com/techsupport/documents/TechBulletins/BtuContentOfGasoline.pdf

 

This article just repeats the other article:

http://www.whitfieldoil.com/www/docs/171.286/racing-gasoline-.html

 

This article addresses what I seen in my teacher's demonstration where the higher octane burned in a controlled manner instead of exploding like I saw the lower octane do:

 

"Octane rating does not relate to the energy content of the fuel (see heating value). It is only a measure of the fuel's tendency to burn in a controlled manner, rather than exploding in an uncontrolled manner. Where the octane number is raised by blending in ethanol, energy content per volume is reduced."

http://en.wikipedia.org/wiki/Octane_rating

 

BTW, in my earlier days I built and ran race engines such as a 427 Medium Riser I put in my '67 Shelby GT 500. With the pop-up pistons I had 13.5:1 compression and had to use octane boost and Sunoco 260, so I know a little about octane. I sold the Shelby because gas went unleaded and I got an offer I couldn't refuse.

[akirby]

So how do you explain Sunoco's highest octane fuel is also their fastest burning? Your article doesn't say it's the octane that affects burn rate - it says:

 

In testing conducted using a 740 horsepower 358 cubic inch racing engine with 14:1 compression

ratio, the engine made 5 more horsepower on a 100 octane unleaded RFG than on 110 octane

leaded racing gasoline. “How so” you ask? It is because the RFG contains an oxygenate that

allows for more complete combustion and the fact that the gasolines have similar vaporization

characteristics.

 

It's the oxygenate that decreases the burn rate, not the octane level. It may very well be that the fuel your teacher used did burn differently but it wasn't just because of the difference in octane.

 

Since we agree that you shouldn't use Premium unless the engine was designed for it, let's call it a draw and move on.

[GaryG]

So how do you explain Sunoco's highest octane fuel is also their fastest burning? Your article doesn't say it's the octane that affects burn rate - it says:

 

 

 

It's the oxygenate that decreases the burn rate, not the octane level. It may very well be that the fuel your teacher used did burn differently but it wasn't just because of the difference in octane.

 

Since we agree that you shouldn't use Premium unless the engine was designed for it, let's call it a draw and move on.

 

Now that I've found the answer, I think we can call it a draw. My old teacher couldn't have used an oxygenate that decreased the burn rate. I'm 58 now and that was back in 1970. They do say that ethanol (an oxygenate) can be used to raise the pre-ignition threshold, but gasohol was not available in our area back then. The one thing that did slow the burn rate I witnessed back then is no longer allowed in gasoline for street vehicles. Remember what I said was one of the reasons I sold my Shelby? UNLEADED GAS! The LEAD is what slows the burn rate and you can speed up that burn rate by removing it. That also explains how Sunoco formulated a faster burning racing high octane fuel.

 

What do you think akirby?

[akirby]

Now that I've found the answer, I think we can call it a draw. My old teacher couldn't have used an oxygenate that decreased the burn rate. I'm 58 now and that was back in 1970. They do say that ethanol (an oxygenate) can be used to raise the pre-ignition threshold, but gasohol was not available in our area back then. The one thing that did slow the burn rate I witnessed back then is no longer allowed in gasoline for street vehicles. Remember what I said was one of the reasons I sold my Shelby? UNLEADED GAS! The LEAD is what slows the burn rate and you can speed up that burn rate by removing it. That also explains how Sunoco formulated a faster burning racing high octane fuel.

 

What do you think akirby?

 

I think we should leave it at that and move on.

[GaryG]

I think we should leave it at that and move on.

 

Maybe one last thing:

 

"Octane, as you can see, is not a measure of how much power - or, more correctly, specific energy - is contained in a fuel. And remember that leaded high-octane race fuels burn slower than most unleaded fuels, and may reduce performance in stock or lightly modified motorcycles. A high octane rating itself, however, does not mean that the fuel is slow burning. Hence, it has no direct bearing on the power characteristics of the fuel."

http://www.rxp.com/Octane.htm

[akirby]

Maybe one last thing:

 

"Octane, as you can see, is not a measure of how much power - or, more correctly, specific energy - is contained in a fuel. And remember that leaded high-octane race fuels burn slower than most unleaded fuels, and may reduce performance in stock or lightly modified motorcycles. A high octane rating itself, however, does not mean that the fuel is slow burning. Hence, it has no direct bearing on the power characteristics of the fuel."

http://www.rxp.com/Octane.htm

 

Thank you. Now we can move on.

[Chibana]

So now I have someone telling me that the power of my Focus is just fine as it is and good enough for anyone, so I should not use higher octane gas. ??? Thanks, but I'll decide that for myself. The Source Book clearly states that it is designed to take advantage of higher octane gas by advancing the timing and making more power. I never stated anywhere that I'm trying 93 octane gasoline for better fuel efficiency. I am trying it for better performance. I also plan to get a cat-back exhaust, intake, rear anti-roll bar, and possibly a reprogrammed ECU after the warranty is done. I value the extra power, and the changes I made to my 2005 Mazda3 significantly improved fuel efficiency as well as performance. I'm a driving enthusiast. I'm also a physicist, by education, so I don't need the high school physics lectures, thanks.

[akirby]

So now I have someone telling me that the power of my Focus is just fine as it is and good enough for anyone, so I should not use higher octane gas. ??? Thanks, but I'll decide that for myself. The Source Book clearly states that it is designed to take advantage of higher octane gas by advancing the timing and making more power. I never stated anywhere that I'm trying 93 octane gasoline for better fuel efficiency. I am trying it for better performance. I also plan to get a cat-back exhaust, intake, rear anti-roll bar, and possibly a reprogrammed ECU after the warranty is done. I value the extra power, and the changes I made to my 2005 Mazda3 significantly improved fuel efficiency as well as performance. I'm a driving enthusiast. I'm also a physicist, by education, so I don't need the high school physics lectures, thanks.

 

It's ok to use premium if the engine is designed for it which should yield slightly better power and fuel mileage from the advanced timing. If the engine isn't tuned to advance the timing to take advantage of premium then it's a waste of money.

 

From the financial side it's debatable whether the added mpg is worth the extra cost of premium but if you're doing it for performance it should be fine.

[GaryG]

So now I have someone telling me that the power of my Focus is just fine as it is and good enough for anyone, so I should not use higher octane gas. ??? Thanks, but I'll decide that for myself. The Source Book clearly states that it is designed to take advantage of higher octane gas by advancing the timing and making more power. I never stated anywhere that I'm trying 93 octane gasoline for better fuel efficiency. I am trying it for better performance. I also plan to get a cat-back exhaust, intake, rear anti-roll bar, and possibly a reprogrammed ECU after the warranty is done. I value the extra power, and the changes I made to my 2005 Mazda3 significantly improved fuel efficiency as well as performance. I'm a driving enthusiast. I'm also a physicist, by education, so I don't need the high school physics lectures, thanks.

 

I'm real impressed! You want to decrease the value of your new Focus by adding aftermarket crap years from now after the warranty. In the meantime, you think for one minute you will improve performance by paying more for gas? You are a physicist? I would fire you in a minute if you worked for me! Lets take a step back, I would never hire a person with your ideas. If you don't like the vehicle you purchased, why try to design changes you know nothing about? The Ford Engineers are smart, competitive and know what their doing. You don't know JACK!

[akirby]

In the meantime, you think for one minute you will improve performance by paying more for gas?

You don't know JACK!

 

Apparently you don't know JACK. The Ford engineers think you'll get better performance from premium which obviously means the PCM is programmed to advance the timing.

This is straight from the owner's manual:

 

Octane recommendations

Your vehicle is designed to use

“Regular” unleaded gasoline with a

pump (R+M)/2 octane rating of 87.

Some stations offer fuels posted as

“Regular” with an octane rating

below 87, particularly in high altitude areas. Fuels with octane levels

below 87 are not recommended. Premium fuel will provide improved

performance.

 

Jackwagon.

[GaryG]

Apparently you don't know JACK. The Ford engineers think you'll get better performance from premium which obviously means the PCM is programmed to advance the timing.

This is straight from the owner's manual:

 

Jackwagon.

 

At the top of that paragraph, it clearly states that the vehicle is designed for 87 octane. The paragraph then discusses stations that have a regular gas lower than 87 octane. In that case I read that premium gas at those stations will provide better performance. In other words, all regular gas is not 87 octane and a higher octane would be the next best choice. No where does it suggest a higher octane number for increasing performance and it does not state anything about advancing timing any different for premium fuels. The paragraph also does not mention the PCM as you are suggesting. This is the kind of spin I've grown to expect from you.

 

Now, the thought of someone thinking that bolt on aftermarket parts that may or may not fit or work will increase performance in this highly tuned engine package is just crazy to me. Ford is on the cutting edge in the design of their components in this day and age for the best efficiency and performance possible under just about every condition. Ford needs all the performance and efficiency it can get to compete in the auto industry today and you can bet their engineers are looking for any advances in design to improve their products.

 

Like I said earlier, I've built race engines and I know the limitations on letting well enough alone. One change in engine design can make a world of difference to the computer programming and performance in today's vehicles. I'm not getting world record mileage in my all stock '09 FEH because I don't understand performance. Performance and MPG have everything to do with one another. My '09 Ford Escape Hybrid has the highest Lifetime MPG Average over 30,000 miles of any other make gas/electric non plug-in Hybrid base on the combined EPA rating in the US. That includes but not limited to the Prius, Insight, Ford Fusion Hybrid, Civic Hybrid and Lexus Hybrids. I put Ford as having that distinction in the Hybrid Class, so tell them I don't know JACK.