Which octane is everyone using

Run premium I just came back from moab and I got best mpgs with premium and valley runner tune

 

Best post here

 

The Taco drinks regular. The other 2 only get Premium

 

In my neighborhood I know where they are, when I'm out and about I can punch it in my GPS or phone and I will go to the gas station of my choice. It's all about discipline...no big deal for me. I never settled for anything just for convenience if I have a choice !

 

If any of you guys follow Jay Leno, he's got a car collection that's preserved excellently. Quite often in his shows (Jay Leno Garage on YouTube) he talks about the poor quality of gasoline in California, and yes because of ethanol!...Toyota or any other manufacturer would love to sell you replacement parts or another vehicle

 

I have to wonder about those that have to run premium. They must have a completely different tune in their truck then i do to get better mpg. I can see it possible with an aftermarket tune, otherwise i thought all these v6 3.5's were tuned alike from toyota.

 

91 with KD Tune.

 

Maybe. There is no more power regardless of octane, however, if the timing curve, compression/cylinder pressure, or A/F ratio need the octane to keep from detonating, you are getting the most you can out of the design/tune. Some vehicles have knock sensors and will dial timing back which will dial power or efficiency back depending on how the engine was designed to run. My last truck had more power and far better efficiency on the tune that required 91. The tune made the engine run better, but required the knock resistance to run without detonation. One thing to remember about detonation is you cannot always hear it, but it is always doing damage. I have only used 89 in the Tacoma. If I were towing, I would use 91. Pushing the engine harder, it's more likely to knock. The higher octane offers more resistance to this. The difference in fill-up cost was about two dollars between 89 and 91. Here 87 is usually low balled and there is a 20 cent jump to 89 than a 10 cent jump to 91. The cost factor is minimal, even more so when gas costs 3-4 dollars per gallon as the difference becomes a smaller percentage of the total cost of a fill up.

The only area it might make a difference outside of engine parameters is ethanol content. Some 91 doesn't contain ethanol. I've seen the pump posted as such. ethanol produces less heat than gasoline, so the more you dilute a gallon of gas with ethanol, the less power is available from each gallon. You can make a lot of power with ethanol, but it requires more of it. Stoichiometry for gas, in general for highway cruise is about 14:1. For Ethanol it's about 9:1. The more ethanol a gallon of gas contains, the more fuel it will consume for the same amount of work. Ever notice your mileage decreasing after the blend has been changed to the higher ethanol content? Mine does. Not as much in this truck, but I saw more of a change in the old one and my wife's Jeep.

Just one guy's thoughts, your mileage may vary.

 

To go a step further, ethanol uses mostly RON to increase AKI. In real world operation, engines favor MON.

 

I run 87, which in Colorado is mid-grade.

 

you know what they say, different strokes for different folks.....

sorry, couldn't help myself

That's very interesting. I wonder how the old rotary engines would handle ethanol.

 

There are often reasons to run 91 octane in a car that can run 87. One is if you don't drive often and the car can sit with a single tank of gasoline for 3 months or more. The gas loses octane pts over time and can easily drop to low 80's in a short amount of time and I have actually seen cars not start due to gasoline that had been sitting for a long time. Ethanol based fuels can loose octane points even faster than gasoline. Small insurance to run premium in conditions of low usage

 

Those old RX7's were great little track cars. Literally disposable motors. But lots of power to displacement

 

87

And non-Ethanol whenever possible.

 

87 Costco Gas

 

There’s a gas station with 100 near me, I’m tempted to try but $10 plus a gallon is stopping me

 

87, for the most part. I'm one of those nuts who rarely lets the tank get below 1/2 so sometimes I'll top it off with 93, if the station isn't gouging on the price hike too much, but have never really noticed much difference. When I had a flex-fuel, 5.7 Tundra, I would put E-85 in, from time to time, and really liked the way in ran but the mileage would go down about 2 MPG. We still have a '05 Sequoia (4.7) and when I drove it as my DD, I would almost always run 93 because it tended to knock, under load on 87.

 

87 but they're introducing 88 octane in MN now. 15% ethanol, 85% gas supposedly burns cleaner and is cheaper. I'll probably give it a try if I see it at the pump up north. Right now I think just the city slickers get it.

 

Its the lower grade here in connecticut. In fact every grade contains at least 10% ethanol. We have 89 mid grade which runs really well in my boat, sled, and the rest of my power equipment.

 

Doesn't the gas cap on our trucks say no E85?