ethanol vs clear 7.3 MPG

[Red Forman]

I’ve run 87 and 93 octane with and without ethanol and have had 0 differences in mpgs.

 

[SparkyMike]

On a NA engine the octane rating above the recommended rating wont make a difference on mpg or horsepower. Our badass 7.3 takes 87 so no point in running 89 or higher. I am curious if the 0% ethanol will make a measurable / noticeable difference in power or mpg though.

On a related note, Engineering Explained on YouTube did an excellent video showing that the Ethanol blend on modern engines makes effectively no difference on wear. Link to that video ---->

 

[Jamie V]

On a NA engine the octane rating above the recommended rating wont make a difference on mpg or horsepower. Our badass 7.3 takes 87 so no point in running 89 or higher.

Not according to the owners manual.

 

[SparkyMike]

Not according to the owners manual.View attachment 55041

Didn't get that far in my manual yet! I stand corrected.

 

[Rooster]

In central FL we have 89 ethanol free at Wawa. It is normally close to the price of premium, and my 7.3s love it performance wise and mpg wise. Definitely worth the extra cost to me.

Just the performance increase with the tuner was worth it for me. I hated how the truck would drag from a stop. Now, it will pick up quite well. When I was running stock tires, I could easily get 14.5 on the lieometer. I was showing about 460 miles per tank of gas. I changed to wider mud tires and took at pretty big hit on the MPG. I can get 13-13.5 if I am not in city driving. City driving kills the MPG. I am happy that I got the tune. I am still running the ethanol free even though I am paying over $5 a gallon for it.

I’ll have to try a tank. I get 13 overalll. Going 65 the other day through some mountains I got a little over 14.5 on the dash. Kicked it iup to 80 for the last 100 miles and some mountains and it dropped that 240 mile trip to 13.4. Mine is all stock

80

 

[Rooster]

Not according to the owners manual.View attachment 55041

Had t seen that either

 

[SteveG75]

Damn, I got to try some of the pure gas. I have been running the usual E10 87 octane for 6k miles. But since WaWa has that 89 pure gas, may be worth a shot. Got 20 gals stored in garage for the generator but that is last year’s batch (gotta love Stabil).

 

[SparkyMike]

I am really curious how much a difference it makes 87 -> 91 octane. I've had forced induction vehicles that could run on 87 just fine, but 91 for optimum performance, and it made a really noticeable (see huge) difference. On a NA vehicle though, where it can only suck in so much air on its own? Yeah, it can compress a little further before ignition but is that really gonna be noticeable in daily driving scenarios? The part in the manual for hotter temps, high altitude, or heavy towing would make sense to prevent knock and protect the engine. I think I'll do a little research, see what I find from ppl smarter than me.

 

[Jamie V]

On my 2018 F150 the gen III 5.0 coyote had 11.5:1 compression and would detonate if I ran 87 octane E10. It mostly did it when it would skip gears from 1-3 & 3-5 when the load was greatest. When I would run 91 (E10) it would be fine and have more noticeable power on those skipped shifts. This new 7.3 with lower compression has no signs of detonation.

I know ford uses knock sensors to adjust how much timing goes to the tune so I’m assuming going to 91 or 93 octane would allow the computer to add more timing to give us more HP & TQ but I’m not sure if you would feel it.

 

[CRS250]

I had a Flex Fuel 5.7 Tundra, several years back, and it ran and sounded different on E85, in a good way, but the MPG was 1-2 less and once E85 cost the same as gas, there was no point in using it. I have not tried 91+ in the 7.3, yet, but might give it a try. Gas prices so high now, another $.50/gal isn't going to move the needle much.