Higher MPG with Premium gas?

If a gas station has 87 octane on the pump, it must be at least 87. If that gas station buys 87 octane, the supplier has to guarantee they filled the tanks with 87. Busy station has nothing to do with it. How would the octane level vary? That makes no sense at all.

Now, with my motorcycle, I have to have minimum 91 octane. With a small tank (3 gal.) a blender pump can screw that up some, because there is always gas in the hose from the previous purchase (maybe as much as a half gal.), which will reduce the overall octane I'm getting through dilution. There has been a lot of discussion over the years from bike manufacturers and fuel suppliers about this. It's not a big issue with big tanks/ larger fillups.

 

Every engine that I have ever pulled the heads off of that had always used low octane cheap fuel had carbon buildup on valves and pistons and that can contribute to valve issues, potentially leading to them burning. Carbon deposits can disrupt airflow, create hotspots, and even ignite prematurely, causing pre-ignition or detonation, which can damage valves.

If you tear down an engine that has always had nothing but top tier premium fuel used in it the valves and pistons will have a nice clean grayish look to them.

 

Huh? Every engine built today uses knock sensors for just this reason. Knock sensors can fail, but you'll get a CEL light if it does.

edit: Pre-ignition generally does more damage to ring lands and piston edges than valves.

 

Knock sensors can’t prevent carbon buildup from low octane cheap fuel.

 

WTH does carbon buildup have to do with knock sensors? Carbon buildup can affect valve seating and can leas to pre-ignition (knock).

 

agree

 

NM, you don’t get it and you’re wasting my time.

 

It’s not exact, has margin of error. Blend could be a little off, and the equipment that measures the blend may also be off. I’m not gonna be convinced otherwise nothing is perfect.

 

You made the claim.

 

I don’t know about octane, but ethanol is known for creating deposits and led to valve issues in my wife’s car, years ago. The engine was a Chrysler 4 cylinder and it developed a miss at only 30k miles. The tech said that ethanol was the culprit, which made sense because it was a year or two into E10 being common in this area.

 

I run mid grade fuel … I feel like the truck runs better and I get more miles to the gallon when compared to the 87 .

 

You made the claim; not me. Preignition is going to damage the piston or rod before it burns a valve. I've never seen a single example of pre ignition damaging a 3.5... have one you can share?

 

Pre-ignition can absolutely lead to valve burning, particularly exhaust valves.

Any internal combustion engine can be damaged by pre-ignition 2gr-fks etc.

 

Most likely due to ambient temps. My taco in winter gets 17-18. Cold = lean = computer adds fuel = low milage. Summer i get 21-22 warm = rich = computer leans fuel= better mpg

 

Cpt fulll retard here I did this years ago I swapped my plugs out that another member recommended, done did the OTT tune and Anderson mani spacer with running 93 a lot and maybe 2 gallons topped off with e85 once in a while to massage my timings ego ahhhhhh Rawr

 

Consumer Reports actually did a test a few months ago with various vehicles that the manufacturer states runs on regular octane. They found VERY LITTLE difference in MPG or 0-60 time with all their vehicles, using 87 octane first and then 92 octane. Wont go into exact details, but you can review it if ya want.

 

Fuel trucks are reused, you cannot expect them to be completely depleted when they refill and remix at the supply point I stand by my claim that 87 octane is never pure. It is a target by some measurement by some machine by some mixing method there is no way it will be exactly 87. The machine calibrated at the export point may claim 87 but it’s not perfect never will be. There’s always a margin error. It will be close, maybe higher, but could be lower and could have sediment residue pollution in it just how it is it’s not a perfect number. The busier the station, the more remixing with different trucks, maybe similar supply points but the margin of error for a Pure 87 increases as the tanks are frequently used. I can’t prove it. I can state that I’ve gotten gas at a station and my truck ran terrible for a tank. As soon as I refilled, it ran fine. Thus I would say the original gas station had gas that was not pure and clean 87. I’ve also filled up with 91, and saw no noticeable difference in performance or MPG‘s so my experience tells me everything fluctuates at a gas station. What doesn’t fluctuate is the amount I’m willing to pay per gallon.

 

I knew an elderly man on a not exactly large fixed income who bought a particular gas company's marketing bullshit hook, line, and sinker. He only bought premium fuel from their stations. When I think of how much extra he spent for no reason whatsoever it just makes me shake my head. But it was his money and it gave him some kind of geriatric superiority boner so more power to him.

 

100% agree with you except that I could understand .25 or .50 or .75. But almost $2 more? and national prices have dropped and Hawaii hasn't. so you know, we getting ripped off.