Octane for 7.3 Godzilla

Forester Fred

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What are you running for gas in your 7.3 Godzilla? I’ve only made two trips with mine and ran 85 octane and it seems to run fine. But, I made a mistake and actually read my owner’s manual the other day and Ford recommends 87 octane and 91 octane in hot weather. Am I making a mistake or potentially damaging my engine by running lower octane fuel?
 
What are you running for gas in your 7.3 Godzilla? I’ve only made two trips with mine and ran 85 octane and it seems to run fine. But, I made a mistake and actually read my owner’s manual the other day and Ford recommends 87 octane and 91 octane in hot weather. Am I making a mistake or potentially damaging my engine by running lower octane fuel?


What does the owner's manual say? 87 AND 91 for hot weather. Pretty clear in my mind, so go with that since the factory says to do that. You can run higher if you want, that will hurt nothing but your wallet.
 
If you have 85 in it now, I would refill it with 91 and when the tank is low again go back to 87. ~CA

Sounds like a good idea. I filled the tank when I winterized it and I always refill at half a tank so I’ll fill with 91 when I get gas. We’re heading out next week so at least I won’t be running in hot weather.
 
I've said it before, if Non-Ethanol gas is available in your area your engine will love you for using it. Ethanol is a killer on your mileage. It would be more beneficial to use Non-Ethanol gas, rather than a higher octane Ethanol gas.
 
I've said it before, if Non-Ethanol gas is available in your area your engine will love you for using it. Ethanol is a killer on your mileage. It would be more beneficial to use Non-Ethanol gas, rather than a higher octane Ethanol gas.

I haven’t seen non ethanol gas around my area. I’ll have to keep an eye out for it when I’m on the road.
 
OK, probably overkill but that’s my middle name. Stopped at Oreilly’s this morning and picked up 4 bottles of octane booster. I have a full tank, 55 gallons, so the 4 bottles should raise the octane in the tank to at or above 87….in theory. Figured it’s a stopgap until I use enough gas to stop and refill at the half tank mark. May not do anything but it makes me feel better.
 
wow! 3MPG??? I'll have to try that!

It really is a dramatic difference. IDK about the mileage, but you can literally feel it in the seat of your pants. The engine sounds better, gets better economy, produces more power...

And it's not a placebo effect either. I burned through a half tank of non-E gas, wondered why the rig was running so much better, then realized I had entered an area where ethanol blend was actually the "exception"; non-E was plentiful, and was the "normal" fuel to be pumped. Not like home where it's the other way around, and the non-E pumps are the odd one out and advertised pretty heavily.
 
If your in a area where non-ethanol gas is available and your not using it shame on you.....

The ~$1/gal premium is a little tough to swallow sometimes. 55-gal tank on the Motorhome, 55-gal tank on the boat. Those are the vehicles I own that would see the most benefit from non-E. And that's not even considering the benefits to the on-board generator... But I use e-gas in my Jeep (daily driver), and I don't feel terrible about it...

There's only one station in my area that offers non-E, and it's a bear to navigate the pumps in the camper, or the truck towing the boat...

My closest Buccees is about 20 miles down the Interstate, and I've pondered going out there for fuel in the camper and/or towing the boat. I go there for diesel in DW's Yukon anyway so I can get plenty of highway to keep the filters happy and get the engine nice and hot. It's a nice, easy drive, but it's still 40 miles round-trip.

I sure wish it was more convenient around here...
 
If memory serves me right the lower grade non-ethanol gas at buc-cees was 25 cent a gallon higher. I'm heading south in a week, I'll post back on the exact price difference.
 
If memory serves me right the lower grade non-ethanol gas at buc-cees was 25 cent a gallon higher. I'm heading south in a week, I'll post back on the exact price difference.

That is what I have seen as well here in North Texas, 25~30 cents more per gallon. However, prior to a local gas station chain (they are not only local) named Valeros selling it nearby, the only gas stations that had non-e used to be found exclusively around the local lakes and marinas where it was common that they would charge about 1$ or more per gallon for non-e. ~CA
 
Buc-ees (sp) has non -ethanol in two different grades. I always get the lower grade. With it I get at least 3 m.p.g. better milage.

I use non-ethanol, but I do not see any increase in the MPG. I use it for its longer "shelf life" (truck sits a lot) and the reduction in corrosion. I have easy access to 90 octane non-ethanol. The manufacturer recommends 89 octane for our truck. I think the 90 is close enough.
 
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If memory serves me right the lower grade non-ethanol gas at buc-cees was 25 cent a gallon higher. I'm heading south in a week, I'll post back on the exact price difference.

Its a LOT more that $0.25 a gallon here.
So I'll just stay shamed, I guess. ;)
 
My V8 requires 89 octane. Lower octane reduces mileage, especially when towing and may cause problems over time.
Costco has premium of 91 or 93 octane for a maybe 50 cents a gallon more than regular plus it is Top Tier gas. Top Tier gas includes high quality additives to keep the engine clean inside. If I have a half tank of premium when I can top up mixing 87 with 91 results close enough to 89 to protect my engine plus saves a few bucks.

Top Tier gas is a real thing that actually does improve engine life and efficiency. ( I worked in the oil industry for 40 years.)
 

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