Had the truck two weeks , it runs better on 89 octane

I was near a boat landing once and was able to fill my truck with E-0, that tankful was the best MPG my truck ever got.

 

All fuel grades here are 10% ethanol. If i run a more than a tank of 92 octane shell my tacoma 3.5 begins to feel lazy with less power and a lot of transmission hunting when going up any hills. My fuel mileage drops below 20 mpg. Even the exhaust tailpipe tip changes color to a thick sooty black. With 87 its got nearly the same throttle response as the 4.7 tundra i had with way more top end. I just got back from a 70 mile round errand this morning...truck fly's on 87.

 

I feel like my truck runs better after I wash it. Does it really? I doubt it. It really seems like the difference is in my head more than in the way the truck runs. Intellectually at least.

I run 87 and pat my dash to make my truck feel better. I'm absolutely sure it appreciates my attention and performs better because of it.

 

I can't say about all gasoline in different parts of the country, i know fuel in parts of the midwest suck vs what i get here. Our gas is pretty fresh. Maybe it is more mental for some that think premium grades are better in these trucks, but i've yet to experience it.

 

Shell gas has a tendency to leave soot. Also, it's kind of expected when the direct injection kicks in, as that's also known to create a lot of soot, so I would say that's a non-issue. Regardless, running premium should advance your ignition timing further and/or knock less (which in theory would still allow your timing to be more advanced in areas regular octane did knock) depending on what tune you're on. It's odd you seem to have the opposite effect.

 

so what do they add ethanol to make 93?

 

you want LOWER octane at altitude, not higher....

 

For sure E-0 will preform better than any ethanol mix. There are a few stations around here that off it, but I'm not one to take a lunch along just to go get gas. I use only top tier gas which I personally feel is more important than jumping up in octane. No real performance issues with quality grade 87.

 

my distance to empty went from 291 miles to 396 miles going from 87e10 to 91e10. took a long time for it to adjust (6 or 7 tanks). this is with the 2.7 though.

truck seems to run better with less downshifting and slightly more power. timing is less retarded. I think it's worth the increased fuel costs.

 

Yeah, corn provides worse fuel economy. That's pretty common knowledge. I go for ethanol free whenever possible, and locally that's only 91 Octane. When traveling I can find it in 87 and I'll run that. Better fuel economy, less water attraction, and less corrosion/seal wear are all benefits of not putting corn in your tank.

 

All I know if my Lightning will have a CEL if I put ethanol anything in it. Taco don’t give two shits apparently.

 

So, fuel octane rating deals greatly with its ability to resist knock. That's its main purpose. Higher compression engines typically benefit more from higher octane fuel. They can run on lower octane without suffering from knock thanks to the computer systems we have today. A higher octane fuel will basically burn slower so to say. Not having to compensate for a low octane fuel (running 89, 91, etc) could allow the engine to run with its optimal timing etc in place and maybe just make slightly better performance. can you feel it. Maybe, maybe not

 

I find it highly doubtful that you observed an over 30% increase in fuel economy, that would be roughly going from 17mpg to 23mpg in the exact same conditions.

 

I don't know about your neck of the woods, but Sheetz are popping up around me in Columbus like weeds and they have E0, 90 Octane I believe. Before Sheetz came to town, the only place near me with E0 was the marina lol.

 

I wouldn’t really go by the computer “distance to empty” calculation, it’s pretty inaccurate IMHO.

 

I'll add this to the octane talk.
MON+RON/2 = Octane
MON = motor octane / RON = research octane
For obvious reasons, MON value is more important - due to the engine running at a more "real world" scenario (rpm/load you can lookup exact specs)
** This doesn't take into account RVP rating = summer/winter blend. That's a whole other topic but can also effect drivability due to fuel volatility.

MON=80 / RON = 100 = Octane = 90.
MON=70 / RON = 110 = Octane = 90.

So, you get the point. Not ALL 87/89/93 are the same. Also, some companies add detergents that can change some factors. So theoretically, no difference. But due to the differences between stations/companies, you actually can experience differences. Not all 87 octanes are the same. Also note - ALL manufactures get the oil through the same pipeline - and they don't get the oil "they" specifically drilled for. They get the next batch inline.

So, to an extent, both sides of the argument can be true in different circumstances.

 

Have folks here verified if it's accurate or not? I question it but I'm much too lazy to do the math lol.

 

I live in Colorado and run 85. My fuel mileage is not great (17-18mpg). I know octane shouldn't affect gas mileage but I decided on my last tank to try 87 just to see what would happen. I got 14 effing mpg out of that tank...

 

Mine is accurate to within 2 mpg

 

“Distance to empty”?