Fuel Economy?

[Boose]

Toby don't you know theirs always that one guy that says his car or truck gets phenomenal mileage. I remember my brother in law used to say his big ole 1970's Cadillac got 18 mpg. When I pumped him for more info, that was on a long Freeway trip, and driving at 55mph. His in town was 10! It's human nature to one up the other guy. My cars faster, my girls prettier, etc,etc. Everyone wants to be an Elvis, or a George Clooney when they walk into a room. Ever notice how all heads turn to the door at a bar, when someone comes through the door? Must be from watching those old westerns! When I drove a cab years back, I never saw more liars in one building in my life. I'd average $250.00 in fares, $100.00 to $120.00 in my pocket, but others would brag about $400.00 to $500.00 days. Yeah right!

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Moose, you're pretty knowledgeable on here... surprised you're taking that route...

 

[TobyU]

Have you tried it?

Yes, but not in a late model forced induction vehicle so my results were less than stellar.
Tested Cadillac 4.9, Grand Am 2.4 "quad 4", various 4.6s (non vvt) in town cars, 6.8 in Excursion. Had a friend that first brought it up using V-power (shell prem) in large navigator limo with 5.4 32 valve.
It was only .10-.20 a gallon more for each grade upgrade then so only. 20-.40 not
.60 like now. We have only seen an increase of no more than 3-4 mpg ever.
Where are you located? I bet altitude and humidity could also affect results.

 

[Boose]

Yes, but not in a late model forced induction vehicle so my results were less than stellar.
Tested Cadillac 4.9, Grand Am 2.4 "quad 4", various 4.6s (non vvt) in town cars, 6.8 in Excursion. Had a friend that first brought it up using V-power (shell prem) in large navigator limo with 5.4 32 valve.
It was only .10-.20 a gallon more for each grade upgrade then so only. 20-.40 not
.60 like now. We have only seen an increase of no more than 3-4 mpg ever.
Where are you located? I bet altitude and humidity could also affect results.

Absolutely, apples to oranges I agree. I'm in NJ at the shore... lots of oxygen down here at sea level

 

[1955moose]

Boose, I'm a skeptic. I just can't figure how only you get the phenomenal mileage, and the other 300,000 Expeditions with the same setup get noticably less. Did you do something special to yours that your not fessing up to? And if you know me by now, almost 5 years here, I like to joke. Don't take it personally. I've had to send PMs to apologize more than once. It's just your mileage figures are breaking all the rules of science and physics. If they are true, and I'm not doubting you, you may be a blessed individual, or the luckiest booger I've ever known! Either way, keep it safe.

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[JExpedition07]

I was averaging 20.3 MPG yesterday with my 5.4L on a good highway run, 87 octane. Had a tailwind.

 

[Boose]

Boose, I'm a skeptic. I just can't figure how only you get the phenomenal mileage, and the other 300,000 Expeditions with the same setup get noticably less. Did you do something special to yours that your not fessing up to? And if you know me by now, almost 5 years here, I like to joke. Don't take it personally. I've had to send PMs to apologize more than once. It's just your mileage figures are breaking all the rules of science and physics. If they are true, and I'm not doubting you, you may be a blessed individual, or the luckiest booger I've ever known! Either way, keep it safe.

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No worries, I just know you to be very open to the physics involved and an expert level knowledge of the internal combustion process.

I didn't do anything to it yet she's bone stock!
Granted, when I did the comparison between reg, plus & premium I made sure to accelerate easily and used the trip computer to gauge current MPG. Numbers were validated by math at the fill up. It was a deliberate exercise in "let's see how good I can get it". I used cruise control on flat road never going over 65 mph. Not something that I can normally replicate during my typical driving habits by any means. The good old Garden State Parkway will get you killed trying that during the morning commute. I have a big road trip coming up this summer. You can guarantee that I'll be trying this again as the schedule will allow. Cheers!

 

[Boose]

I was averaging 20.3 MPG yesterday with my 5.4L on a good highway run, 87 octane. Had a tailwind.

That's gold for that mill!

 

[JExpedition07]

That's gold for that mill!

The 6-speed and the 5.4L make a good pair, just loafs along on the highway sipping gas. Certain variations of expys like a 5.4L/ 3.31s and 4x2 were rated for 21 MPG highway, I’ve seen members list upwards of 22 mpg. I’ve also seen extreme lows of like 15 lol. MPGs vary that for sure.

 

[Boose]

The 6-speed and the 5.4L make a good pair, just loafs along on the highway sipping gas. Certain variations of expys like a 5.4L/ 3.31s and 4x2 were rated for 21 MPG highway, I’ve seen members list upwards of 22 mpg.

truth! My 05 with the 4 spd never saw 20 lol

 

[Paddler]

My math may be off ever so slightly but not by that much... You don't have to believe me, or try it if you don't want to. Just my own personal experience. I've built my share of performance motors and have a pretty good understanding of what makes these tick...

Not all motors will get the benefit. I completely agree that anyone who puts premium in their Honda Civic is a knuckle head, it does nothing. ANY motor with a turbo or blower and a modern ECM that recognizes the increased octane will perform better with premium over regular.
Engines produce more power when the timing is advanced. The higher octane allows the ECM to advance the timing more while preventing detonation (knocking). A forced induction motor is more susceptible to this based on the increase in combustion temperature generated by the turbos (Ideal gas law). Sure these motors "run fine" on regular because the ECM adjusts for this. There is a noticeable increase in power when I run premium as the tune is sharpened up. The 3.5 in the Raptor & F150 Limited requires premium as the tune is always sharp, hence the higher output of those motors over our 3.5's.

It's a tank of gas... try it, drive it for 100 miles and then we can see.

Sorry, when anecdotal evidence conflicts with science, I'll take the science. It's literally impossible for any of us to do a scientific study that holds all other factors constant except for octane. Besides, engineers have already done it. Higher octane fuel can provide higher performance because it allows higher compression, etc, but it contains the same amount energy. That's about 114,000 BTU/gal, but varies a couple of percent seasonally, E10, etc. So, if you run regular in a newer engine designed to run on premium, you likely will not achieve the actual rated HP and torque, because as you say the engine has anti-knock sensors and compensates. But your mileage will be very similar. I'm very confident you will not see a significant increase in mileage by running premium. The only real difference is cost.

 

[Paddler]

The 6-speed and the 5.4L make a good pair, just loafs along on the highway sipping gas. Certain variations of expys like a 5.4L/ 3.31s and 4x2 were rated for 21 MPG highway, I’ve seen members list upwards of 22 mpg. I’ve also seen extreme lows of like 15 lol. MPGs vary that for sure.

I might have seen 17MPG a couple of times in my '08, but average was 15MPG. I'm seeing at least 25% improvement with my 2018, even though it's a Max 4WD.

 

[Boose]

Sorry, when anecdotal evidence conflicts with science, I'll take the science. It's literally impossible for any of us to do a scientific study that holds all other factors constant except for octane. Besides, engineers have already done it. Higher octane fuel can provide higher performance because it allows higher compression, etc, but it contains the same amount energy. That's about 114,000 BTU/gal, but varies a couple of percent seasonally, E10, etc. So, if you run regular in a newer engine designed to run on premium, you likely will not achieve the actual rated HP and torque, because as you say the engine has anti-knock sensors and compensates. But your mileage will be very similar. I'm very confident you will not see a significant increase in mileage by running premium. The only real difference is cost.

I disagree... A motor making more power due to the tune is therefor more efficient when compared to the same motor with a more conservative tune. The presence of more power means the driving characteristics are inherently different. Lower revs, less throttle input required to accelerate to the same given speed etc. Injector curves do not change much based on octane. The spark timing is the biggest variable.

You are looking at the "science" in a vacuum. The science of the ECM programing and laws of thermodynamics cannot be ignored to favor an article that does not take all aspects into consideration. your cited article speaks to putting premium in a car that was unable to take advantage of it.

If you want to play armchair physicist have at it. I don't need to justify to you why I experienced what I experienced. Until you try it on this motor, you have no dog in the fight. It's your wallet.

 

[TobyU]

We also forgot to consider that the premium fuel you bought could have been 100% gas and the regular fuel you bought could have been at least 10% ethanol. That alone is claimed by many people to give two to three miles per gallon more I just having pure gas with no ethanol.
That could have been the only reason you saw an increase but the possibility of computer maxing out timing because no detonation sensed and the pure fuel could have amounted to Greater gains.
I am more of a facts, or that's not possible person myself but I am always sit don't ever say things are impossible because if you do things long enough will eventually see something that just doesn't make sense but it is fact because you witness it personally.
For instance I used to run around and a 1996 town Car limousine that weighed about 7100 pounds empty. It always peeing on 87 gas and most all the pain was gone eight or nine so that's usually what I ran. I decided to try to pull the octane adjust shunt one-time which retards the timing 3 degrees. I fully assumed it would get poorer mileage after I did this.. to my surprise my mileage increased. This was on 87 gas and it no longer pinged.
I'm of the old school that the more timing until you get to the point of detonation and quite a bit of it gives you more power and more fuel mileage.
I was actually getting 14.1 miles to the gallon around town with the air on. That was the first time that vehicle ever cracked 14 around town. It would get 22 to 23 on the highway.
It had the 308 opener in. Now I had another vehicle that was the same weight and size but our older model 1992. It had the 3. 27 limited slip rear end in it and had only the aod instead of the 4 R 70 w which has a lower first gear ratio.
This car always got more fuel mileage than the newer car. This one would see 23 to high 24s on the highway. Maybe even occasionally cracking 25.
It's just like gearing and stuff and Towing. We say that a higher rear end turns higher RPMs so you lose fuel mileage but sometimes if you're pulling something you're able to give it less gas and not strain the engine as much because you're at a different spot in the horsepower and torque curve so you can actually get better mileage and have more power.
Sometimes just have to test it for yourself to see what results you get. You also can't go by what other tests have done and manufacturers and the industry. Their conditions are different than yours.

 

[Paddler]

Yep, my wallet. I tend to keep a firm grip on it. My XLT calls for regular so that's what I run. I rarely use all the available 375HP as it is. Anybody who says his mileage increases by 40% by running premium over regular is employing faulty methodology. I'll believe what the experts tell me.

 

[Boose]

We also forgot to consider that the premium fuel you bought could have been 100% gas and the regular fuel you bought could have been at least 10% ethanol. That alone is claimed by many people to give two to three miles per gallon more I just having pure gas with no ethanol.
That could have been the only reason you saw an increase but the possibility of computer maxing out timing because no detonation sensed and the pure fuel could have amounted to Greater gains.
I am more of a facts, or that's not possible person myself but I am always sit don't ever say things are impossible because if you do things long enough will eventually see something that just doesn't make sense but it is fact because you witness it personally.
For instance I used to run around and a 1996 town Car limousine that weighed about 7100 pounds empty. It always peeing on 87 gas and most all the pain was gone eight or nine so that's usually what I ran. I decided to try to pull the octane adjust shunt one-time which retards the timing 3 degrees. I fully assumed it would get poorer mileage after I did this.. to my surprise my mileage increased. This was on 87 gas and it no longer pinged.
I'm of the old school that the more timing until you get to the point of detonation and quite a bit of it gives you more power and more fuel mileage.
I was actually getting 14.1 miles to the gallon around town with the air on. That was the first time that vehicle ever cracked 14 around town. It would get 22 to 23 on the highway.
It had the 308 opener in. Now I had another vehicle that was the same weight and size but our older model 1992. It had the 3. 27 limited slip rear end in it and had only the aod instead of the 4 R 70 w which has a lower first gear ratio.
This car always got more fuel mileage than the newer car. This one would see 23 to high 24s on the highway. Maybe even occasionally cracking 25.
It's just like gearing and stuff and Towing. We say that a higher rear end turns higher RPMs so you lose fuel mileage but sometimes if you're pulling something you're able to give it less gas and not strain the engine as much because you're at a different spot in the horsepower and torque curve so you can actually get better mileage and have more power.
Sometimes just have to test it for yourself to see what results you get. You also can't go by what other tests have done and manufacturers and the industry. Their conditions are different than yours.

Same station I always use with no more than 10% Ethanol Tier 1 Gas.
I had a 93 Bronco that would ping fierce with regular from any station other then Exxon. As that was running the old EEC IV, I just twisted the distributor until it stopped. Exxon is always the highest priced...
As long as you don't punch it with the lower gear ratio, it's a net lighter load and requires less throttle to do the same work and hence less fuel! The seat of the pats factor made that hard in my Mustang back in the day

 

[Boose]

Yep, my wallet. I tend to keep a firm grip on it. My XLT calls for regular so that's what I run. I rarely use all the available 375HP as it is. Anybody who says his mileage increases by 40% by running premium over regular is employing faulty methodology. I'll believe what the experts tell me.

Well good luck you you and your closed mindedness. Love the people that come on forums and either ask for advice and then bash anyone that doesn't say what they want to hear. Or those that provide little to know constructive input by being a cranky old fart stuck in the 1970's. Either way good day to sir.

 

[Paddler]

I'm not sure how you're measuring your MPG, but here are a few things to consider. First, you need to fill up at the same pump, parking in about the same spot. Top your tank off exactly the same each time. In order to minimize the error in filling up, you must drive the same exact route under the exact same conditions, and you need to drive until your tank is very low. In my case, that would be at least 500 miles. If you only drive 100 miles, your error will be five times as much as if you drive 500 miles each time. Chose a couple of days with a stable weather pattern, same temperature, wind conditions, humidity, etc. Drive at the same time of day, with the exact same technique. Cruise control, etc. These are the bare minimum requirements one must satisfy in order to draw any reliable conclusions. Or, you can read scientific reports published by experts who perform more exacting tests. Anecdotes are just that. I'm not bashing anyone, just saying that a 40% increase in fuel mileage is scientifically impossible. If you doubt this, just do what I outlined above and get back to us.

 

[1955moose]

Personally Boose, I'm stuck in 1965! I was 10, and I loved the Music/TV shows. How could you not like Hogan's Heroes. You got me to try an experiment tomorrow. I'm going to fill up my 2 valve gas hog with 91 premium, and see if I bump off my usual 10 mpg. I'll let you know next week when I top up again.

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[Paddler]

I filled up today, topped it off well. 447.6 miles, 25.5 gallons. Trip computer said 18.7, hand calculated at 17.55MPG. That's more of a discrepancy than I usually see, but I'm not sure I topped it off the time before. That's the lowest mileage I've seen since I bought it. After filling up, I got on the freeway and drove to work, then drove home. From the gas station to my house is about 8.5 miles, and my house is about 250' higher elevation. As I passed the gas station on my way home (63MPH on CC both ways), the mileage read ~25.8MPG. When I got home, it read 24.6MPH. I think I would see 24-25MPG at 65MPH on flat ground. Regular fuel was $1.90/gal, while premium was $2.19/gal. If I could get 40% better mileage with premium, that would be 34.4MPG. I wish that was the case.

 

[Garrett]

I’m consistently at 15 with tune for 93 and 24inch wheels