Premium Gas vs Regular.

Depends on where you are at, because not all areas are scaled the same. Where I am 85 is regular, 87 is mid, and 91 is premium. I have to use midgrade or above.

 

Did you continue to fill up with premium instead of putting the pump back in to finish the transaction and starting a new one?

 

My mistake, meant to say 87 with 10% ethanol. Had another brain fart when posting this.

 

Are you aware that the gen3 6 cylinder engine has a compression ration of 11.7? It is a high compression engine. The variable valve timing allows it to safely use gasoline with a minimum octane of 87. This doesn't mean that nothing changes when you put premium in the tank. The timing is then advanced until the knock sensors start to register potentially damaging knock. This does impact how the engine runs though likely not enough to show measurable improvements in power and mileage. However, my experience is that it runs smoother on premium. For me, that is worth the money.

 

i saw or felt no discernible difference with performance or fuel mileage between 87, 89 or 93 octane. i use 87. i have noticed a slight difference of where i purchase fuel and give a slight edge to chevron.

 

I have been running 87 octane since I bought my truck. For two weeks I switched to 89 octane just to see if it made any difference (other than to my wallet). No difference.

My previous ride, a JGC with the 5.7 HEMI, actually had a note in the Owner's Manual that the engine was designed and tuned to run on 89 octane. You could run it with lower octane, but power and mileage would decrease slightly. They actually stated that you could run it with higher octane but it was a waste of money, as the engine wouldn't create any more power or improve mileage. Always thought that was an interesting thing to include; refreshing transparency.

 

I drive a manual. How the engine is running is very apparent as vibrations through the shifter, which the driver is in frequent (obviously) contact. Maybe that's why it feels so good with premium gas?

 

People in this topic should look heavily into 'self deception'.

 

i do not know. i drive a manual too (but i eat meat and do not do cross fit) and as stated, i saw and felt no discernible difference among grades of fuel. my truck idles smooth and is very quiet, and i average about 22ish MPG. but that probably has more to do with the toyota brand oil i use and change every 5K miles.

 

"...You swear you've heard it before as it slowly rambles on and on..."

 

Maaaaybe

 

Based on prior threads related to this very topic, you should alternate 87 and 91 octane every other fill up, then change your oil after 5000 mi, before waiting 10k mi to change it again.

After that, please provide a pic, so we can determine if it’s totaled. Good luck!

 

A few things:

The owner's manual doesn't say "use 87 octane fuel". It says, "use at least 87 octane fuel". This means that if you live at higher altitudes where 85 octane fuel is sold as regular you still need to use at least 87 octane.

You need to fill up at least 3 times with higher octane fuel to see the most benefits. For one thing there is still some 87-octane fuel in the tank that is mixed with the higher-octane fuel. It will be the 3rd fill up before you have nothing but high-octane fuel in the tank. Plus, the computer needs time to adjust to the change in fuel. Almost none of the "tests" take this into account. They fill up one time and reach the wrong conclusions. It needs to be long term commitment to see results.

Fuel mileage won't change. But you may see better performance and the engine will run a little cooler when towing. Unloaded the difference is very small. This is also highly dependent on the individual vehicle.

Newer vehicles and vehicles with higher engine compression ratio's see the most benefit. Some vehicles specifically do recommend higher octane fuel, but only when towing. But even those that don't recommend it can see some benefit.

In 2021 I pulled a smallish travel trailer from GA to CO and back with my 2014 F150/5.0 engine. I switched to 91 octane after I got above 5000' and the difference in power was dramatic. I was struggling with 87 octane even though the owner's manual doesn't say I have to use 91 when towing it made a noticeable difference. I continued to use high octane for the rest of the trip, even at lower altitude, and started using it in all of my vehicles including my 2007 Tacoma and 2020 Explorer after I got home.

At the time I could find 91 octane for only 20-30 cents a gallon more than 87 if I shopped carefully. That was a price difference I was willing to pay. It made the least difference in my older Tacoma, but there was a definite difference in how often it downshifted on hills. In theory the newer 3.5 engine should see more benefit from 91 octane and I'm betting the new turbo engine coming out in 2024 will really benefit from it.

After about a year the gap between 87 and 91 octane became 70-90 cents per gallon. At that price point the I didn't feel the slight increase in performance was worth the cost and I went back to 87 octane gas other than when towing.

 

I'll throw some on to the pile, but from a bit different perspective (hopefully not to totally hijack...) I use premium for the fact that it is the only available grade around here that is ethanol free. I can use anywhere from over two tanks a month, or down to a 1/4 tank for a month. Depends on what time of year, who's vehicle we use more, etc. If I don't drive enough, and don't feel like filling the tank, I could go 3 - 4 months without refilling if I wanted to.

So, let's say I'd have a truck sitting there with half a tank. How long would it take the e10 gas to absorb a quantity of water / deteriorate to a point where it could start being detrimental to either performance or mechanics? We go through some big temperature swings here, which I assume can contribute to condensation. Does the octane rating also come into play in such a time frame? How long do you go between fillups..... if octane or e-free helps, I would lean towards using what's best.... for me I try to stay e-free; nothing to do with octane or performance.

 

Unleaded to Premium is an .80 swing here, so only my V gets the good stuff.

 

Did you include our sales tax that can be as high as 10% in some cities?

 

I run 91 for the same reason. It's the only gas without corn in it around here. If you're going to let it sit for a while, it is best to let it sit with a full tank of non-ethanol fuel. Any empty space in the tank could have condensation, so with it half empty you are providing a lot of surface area for that condensation to occur. Fill it up before you let it sit.

 

The only way to really prove it is to have somebody else fill up your tank and then you try to figure out which grade you are using. And you need to do that a few times to be able to average out your impressions. Too much work. Just go by the manual. Saves money too.

P.S. I am not sure if has been noted above... If your state has 85 then make sure to fill up with a higher grade if you are going to drive down to sea level.

 

Not true. "Computer" starts adjusting the timing as soon as the engine reaches ops temperatures - Knock feedback sensor comes to life.

 

Pfffft 110. Child’s play. When I get home come by Langley AFB. I’ll hook you up with some real octane. Truck might smell like an F-35 on the flight line though.