Gasoline question

[Aspen03]

I guess the 5.4L Expy can run on E85, although I don't recall seeing the Flex fuel badge anywhere on the vehicle. I think it has the yellow band around the gas cap. I've never done it and don't think I will. You get a big reduction in gas mileage and probably power?

https://www.fueleconomy.gov/feg/noframes/34325.shtml

It depends w E85. I used to run it on a track car and it made absurd power, however with forced induction, might as well have considered it a liquid intercooler as it allowed similar gains. In an otherwise stock, NA motor you're likely not to gain much if any unless the pcm has the ability to adjust timing to take advantage of the higher octane E85. The time of year is alap going to play a role as blends of E85 change seasonally and be as low as E50 at times. That's why it's usually uncommon to see much of a gain without some tuning work. If you run it make it a completely full tank of E85 and allow trims and the pcm to adjust to it before making any solid judgements. The economy of it can be offset by price, sometimes here in indy E85 is over $1 a gallon less than premium, depending on where you shop. In my experience I've lost about 20% in mpg under normal driving conditions, $1 spread in price is closer to 40% savings. Under heavy foot...in boost it's more like 35% more fuel consumed...confirmed with data logs from HPT.

Does it depend on what engine you have and if you're towing? I thought the EcoBoost advised high octane in the mountains while towing? I might be conflating things here and applying something across the board that is case specific.

Ok ... I think I've learned something new here , that you can get away with lower octane gas in higher elevations. That's what discussion with other people is all about. Not winning an argument but education.

I'm thinking you can get away with lower octane at elevation, but you will have less power so the EcoBoost advises to run higher octane since it can adjust engine parameters and make up for that loss.

Like you said, the turbos make up for that altitude, you likely don't see much difference in air density in the cylinder. They're plenty capable of cramming in what the engine was designed for and I'd probably stick to recommended fuel in the ecoboost regardless of altitude. I'm not nearly as familiar with that platform but having friends w turbo builds that live at extreme altitudes compared to my own they stick to 93 and E85 and dont dare run lower or pre-ignition occurs. As far as towing in mountains that's the heaviest load a motor will likely ever see, the sustained rpm creates tremendous heat, plus you're usually giving it a fair amount of throttle which is prime season for pre-ignition to occur, thus the recommendation of high octane. E85 has a fringe benefit of colling the intake charge in the cylinder and reduces pre-ignition even better than some high octane race fuels.

 

[Adieu]

E85:

You lose about 20% MPG, and actually gain + several % power... WITH AN ECU THAT DETECTS AND ADJUSTS FOR IT (the Flex Fuel badge). Or the appropriate tune to do the same.

It might also help clean out some gunk along the way.

Otoh, if an engine was never designed to run with any % alcohol, it might eat away at certain fuel system components (seals, hoses, whatever wasn't spec'd with ethanol content in mind)

PS it runs hotter, which might not be so good for turbo trucks

 

[joethefordguy]

The owners manual says minimum octane rating of 87 is required for the 5.4 3V engine and to exclude use of gasoline with any octane rating lower.

I’m sure the ECM can retard the timing to prevent pinging but it’s also robbing power at that point.

View attachment 32093

I do not agree. If the manufacturer is requiring a minimum octane, my assumption would be that among other things, the ECM has a lower limit for retarding the timing. maybe it can, maybe there's something else. but I would not simply assume the engine components will handle less than required fuel octane.

 

[JExpedition07]

It depends w E85. I used to run it on a track car and it made absurd power, however with forced induction, might as well have considered it a liquid intercooler as it allowed similar gains. In an otherwise stock, NA motor you're likely not to gain much if any unless the pcm has the ability to adjust timing to take advantage of the higher octane E85. The time of year is alap going to play a role as blends of E85 change seasonally and be as low as E50 at times. That's why it's usually uncommon to see much of a gain without some tuning work. If you run it make it a completely full tank of E85 and allow trims and the pcm to adjust to it before making any solid judgements. The economy of it can be offset by price, sometimes here in indy E85 is over $1 a gallon less than premium, depending on where you shop. In my experience I've lost about 20% in mpg under normal driving conditions, $1 spread in price is closer to 40% savings. Under heavy foot...in boost it's more like 35% more fuel consumed...confirmed with data logs from HPT.



Like you said, the turbos make up for that altitude, you likely don't see much difference in air density in the cylinder. They're plenty capable of cramming in what the engine was designed for and I'd probably stick to recommended fuel in the ecoboost regardless of altitude. I'm not nearly as familiar with that platform but having friends w turbo builds that live at extreme altitudes compared to my own they stick to 93 and E85 and dont dare run lower or pre-ignition occurs. As far as towing in mountains that's the heaviest load a motor will likely ever see, the sustained rpm creates tremendous heat, plus you're usually giving it a fair amount of throttle which is prime season for pre-ignition to occur, thus the recommendation of high octane. E85 has a fringe benefit of colling the intake charge in the cylinder and reduces pre-ignition even better than some high octane race fuels.

Only the Naturally Aspirated FFV engines can run on and gain power from E-85 in stock form. They have Injectors with proper flow rating plus an FFV ECM that the senses the fuel type and adjusting timing/ flow to it. The 5.4L 3V engine has variable cam timing and can also alter ignition timing much better than the predecessors to it. With the Flex Fuel option it gets different injectors, lines to handle the increased ethanol content.

 

[igneous]

cheap gas is not good if US is buying from US

 

[Blksmk]

Only the Naturally Aspirated FFV engines can run on and gain power from E-85 in stock form. They have Injectors with proper flow rating plus an FFV ECM that the senses the fuel type and adjusting timing/ flow to it. The 5.4L 3V engine has variable cam timing and can also alter ignition timing much better than the predecessors to it. With the Flex Fuel option it gets different injectors, lines to handle the increased ethanol content.

Odd, my 98 Mitsubishi eclipse gsx and 89 skyline gtr saw both huge benefits. Both are high powered huge boost.

My friends Eb escape runs better and more smoother on e85 then on 93