Chief1851

I know the fuel management systems are pretty smart, but the fuel suggested is (Premium) which most manufacturers consider 91 octane.

93 octane probably works great under boost, but I'm curious when your trying to cruz if it's just not getting a really efficient burn.

I work at a manufacturer where a lot of our product is mapped for 87 (E10) fuels and when you run higher octane fuels your fuel consumption is poor. Granted our systems are mostly open loop.

FLSTFI Dave

If I remember right the Ford Manual says premium for the 3.5 EB.

I know my wife's Range Rover has a Ford designed 4 cylinder twin turbo, and the fuel door say 92 or better. So does the owners manual.

I was thinking that Premium with the Ford truck meant 92 or better, like the Range Rover.

I know my Stingray is real clear on what to burn, 93 and Top Tier gas.

I guess I will run a couple tanks in a row of the 91

Napalm

It depends alot on where you are - in the country and elevation wise.

you won't find 93 octane in Colorado most likely - or parts of wyoming. but you will find 91. I notice this mostly with foreign cars here - they don't often account for this.

but if you're in Denver say - 91 is like 93 for those of us nearer flatter land.

Out in East TN I Know I can find 93 most places but I don't go out there often. Usually once a year to flog the tail of the dragon - and I do that in a 4 door family car today.

(pontiac g8 Gt- modified)

But yes when you see your stickers and your power numbers - if you have an ecoboost anything - those were all done running 91 octane - E0 gasoline.

Unsure about the "flex fuel" capable devices but I think they were tested using E10 and 87 or such octane gas.

Chief1851

Let us know how it worked. I'm curious.

I run 87 E10 and feel I get a better bang *pun intended* for my buck. I ran 2 tanks of 91 non-oxy and saw no change in power or mpg.

gregsfc

Wow. Thread started about the 2018s. That's what I thought the discussion was supposed to be about. Not yet another thread about how some people can't believe others can get at or near rated mpg; especially regarding the EBs.

For the record, my 2015 F150, 2wd, short bed with 3.31 gears and 2.7 liter EB gets better versus the EPA estimate than any of the F150s I've driven or owned over a period of 19 years. My calculations are hand calculated. My record is trip meter error adjusted, which comes out at 1.8% pessimistic, yet I calculate it at 1.5% pessimistic just so I know I'm reporting conservative numbers. Yes the FE on-board computer way over estimates mpg in my truck; the data figure that is miscalculated is the "gallons used" figure, however, it's not consistent, but in my truck, it will average 1.5 mpg higher than actuality. My lifetime average over almost 2 years and 25,000 miles is 24.1. Like most vehicles, it does better in the summer than winter, but this truck does not lose very much in cold weather as compared to others I've owned. Also, unlike previous F150s I've owned or driven at work, this 2.7 in a light and very basic form, letting torque drive the truck, does very well in city driving. I measure only tank-to-tank, but I think if I drove only city miles, as long as they weren't super urban with a bunch of park-and-go situations, that it'd beat the city rating; probably more like 20. The highway rating is hard to meet, but I usually run 65 and in warm and calm weather, nowadays since the engine is well worn, I can achieve about 26.5 in a round trip, but that's only in ideal conditions. I've got a bed cover, but I get virtually no gain from it, as I've operated plenty without it with about the same result. My best guess for a highway estimate at speed limit in average weather, is more like 25.5 against an estimate of 26. So it's still not bad at all, and is absolutely real in some truck configurations and with some drivers. I've tried only a higher octane only once. I just can't convince myself to spend all that extra money just to see if I get a gain in performance and/or mpg. I've never got myself to put in pure gas. It's the most expensive fuel to buy around my home these days. I used to put it in my motorcycle, but my motorcycle seems to love E10, because I don't get a gain from it and it's about 80 cents per gallon more than regular E10. I do use it in my small-engine equipment. This octane talk is overrated.

Now back to the thread...There is news to talk about regarding the 2018-changed power trains regarding 3.3, 2.7, and 5.0. They all went up; they all had increased peak numbers; one or the other or both. I'm personally glad they didn't try to up the hp in the 2.7. Running hp is one huge enemy of fuel economy, and with turbo charging, it would be hard to up the peak without upping the running hp for highway cruising. And the first tier upgrade engine in a half-ton is plenty at 325 hp in a truck that starts and just over 4100 pounds.

Also regarding the 2.7. I don't know if others may know this but I did not. I always assumed that the combined rating was a rounded down mean or median of the city and highway rating; i.e. 19/26 = 22.5 = 22. But when I saw the numbers for the 2018 2.7-liter EB, I was confused. How do you get 22 mpg combined from 20/26? Why is it not 23? Was it error, or is calculated differently than what I thought? I went right to the source...the ORNL guys that run the site and do all the work and provide information about gov't estimated mpg for all on-road vehicles. I understand some of what they said. First of all; a manufacturer is allowed to round down their hwy estimate. They said that Ford obviously did, because their raw numbers came out 19.6319 and 26. Secondly, they don't just get the mean of those two number. They use a weighted average to the ten-thousandth of a full unit or 4 decimal places to the right, just as you see with that 19 figure above. The weight is 55% city and 45% highway. But it goes further than that "no pun intended". They don't just use rounding like we learned in sixth grade, they use ASTM rounding. The brainiac told me that it's similar to what banks use as a method of rounding. Anyway, if you use a simple weighted average, you get 22.49. You round down and get 22. But fueleconomy.gov told me that the actual number, using the ASTM method for the F150, 2wd with the 2.7, came out 22.2-something. Either way, it's still 22 combined.

The 5.0 was the most impressive of all to me regarding the newest engineering work Ford did. It's got 10 more peak horses and 13 more peak ft pounds torque, yet still went up one city and highway. I'm not as impressed with the 3.3, because I thought that the base engine FE for 2015-2017 were pretty measly; and with bringing in an all-new torque weasel with DFI and other changes to lower frictions and all that work, in a version of truck that was not very impressive to begin with and to increase mpg only 1 in each category and still fall under the 2.7, was not very impressive.

My interest is how all the torque curves changed with all this DFI work. If the 3.3 torque curve is a lot flatter than the outgoing 3.5, I might be a little more impressed with the work they did on the base engine. I was also surprised to see that Ford is now saying that the 2018 5.0 is not DFI, but simply DI. Did anyone else catch that? I thought that all five gas engines, including the Raptor version 3.5 were going to be DFI; not just PFI or DI?

It's also interesting that Ford not only upped the peak performance in all of these reworked engines, but added max payload and max towing for those who wanted or needed it. This increased capability did not come about due to improved performance; rather, they actually made the frame and suspension even stronger. So there is a configuration with the 5.0 that is the new payload champ in the segment, and a 3.5 version that is the new tow champ in the segment. So lots of good news here for pickup fanatics: higher performance in all but the carryover power trains, higher mpg in all but the carryover power trains, and a stronger truck for all power trains. The competition will have to "go further" to catch up now! Pun intended.

Chief1851

Sorry Greg, I was recommending Dave try a lower octane to try HELP him. I agree high octane fuel is overrated. Hell even if it gets you 2 MPG more, which it doesn't (Unless it's required for engine protection) premium fuel would cost an extra $28 dollars a fill on a 36 gallon tank.

The posts switch from 18s to prior model years way before we chimed in.

Perspective....
36 Gallons of $2.80/g fuel ($100) @ 20mpg = 720miles Costs $0.14 per mile
36 Gallons of $2.00/g fuel ($72) @ 18mpg = 648miles Costs $0.11 per mile

With that perspective, premium fuel does not gain 2mpg so the cost per mile is actually way more. Worse case would be it didn't help at all and you paid about $0.15 per mile for a placebo.

It's not cost effective when it comes down to fuel mileage.

With that being said, premium fuel has its place.

1. It works way better in a gas can that might not get used for 3-4 weeks.
2. It may be required for maximum performance and engine safety while under heavy load.

Napalm

what I have found in testing my other veichles is that it has much more to do with your driving conditions.

I notice you're in MN.

For me - when the OAT temps creep past 90 - I find I can get 2 or so mpg better using 93 octane. It worked out as 2.4 mpg better in our 2012 ford focus 2.0L 4 - it works out as about 1.9 mpg better in our 2016 ford exploder 3.5 TiVCT - worked out to 3 mpg better in my 2004 Pontiac GTO unmolested and that car didn't really want to use anything past 89 so I didn't push it.

In a 5.3 silverado using 93 octane nets about 2.5 mpg highway better also but again - when the temps are up at or past 90 F.

That's the bigger issue - stopping knock and pulling timing to prevent knock. Under 80degrees F - less of an issue - below 60 - not even on the table I suspect.

so I put 93 in when the temps are high in the summer like they have been the past few weeks. Also and I've said this before - I'm that crazy person that believe in running fuel injector cleaner right before an oil change - in my NON DI cars. With Direct Injection I don't bother.

I bet if you were to tow on 87E10 and then tow the same thing on 93 E10 you'd get a good bit better mpg - but again that's a guess based on the engine power ratings.

Chief1851

Yes from MN, we have had a hot summer. Love it here when the temps get into that 50-70°F range with low humidity, good power and great mpgs.

Warm weather does have an effect on octane requirements, but running the recommended octane the engine will manage to knock on its own (add more fuel, tweak timing). Sure using a little higher octane will prevent the EM from having to add more fuel to stop knock. Is it worth the cost?

gregsfc

Oh yeah. I know. Pages and pages ago. Right from the very beginning I think. That's what I was referring to. Also with respect to octane. Not your recent conversation. Your good and good perspective. Thanks.

The MuchMan