Better Gas mileage with Premium?

I consistently get 20 the same type of driving with 10% ethanol and 87 what do you think I'm going to use. Mileage has every thing to do with driving habits and little to do with fuel. Maine's emissions standards are very close to CA's so we have had the same type of fuel for years.

 

Octane ratings are just a measurement of gasoline's anti-knock properties so I don't see how premium gives better MPG than regular. My 2010 owners manual only warns against using fuel with a octane rating lower that 87, nothing about increased performance with premium fuel. The stations on base have 10% ethanol in all three grades like it or not. My 2.7L doesn't knock on regular and gets 24 to 26 MPG so I use it. I admit I haven't put the truck on a dynamometer to see if I'm really getting all 159 HP.

 

and unlike you I drive an older Tacoma with 150k miles.

My driving habits are not that different but the gas I have used was. I find if I use chevron or shell only and use 89-91 I get better performance and mileage. over say am/pm and 87..

To each their own on outcomes, but this has been mine.

 

I'd like to ask everyone a question. What do you mean by "better performance" with premium fuel. Faster 1/4 mile times at the track? Increased horsepower at the rear wheel on the dynamometer? What?
I believe, but could be wrong, that the 2.7L (2TR-FE) and the 4.0L (1GR-FE) engines both produce their maximum rated horsepower on regular (87 octane rating) fuel? Is this incorrect?
Since octane is only a rating of gasoline's anti-knock property, where is the "performance increase" and more MPG claimed by some members coming from? I'm really talking about apples to apples here. Using the same brand of gasoline in regular and premium grades and the same level, or lack of, ethanol mixture.
Please show your work and neatness counts.

 

for me *better performance* is smoother acceleration and idle.

 

The engine can produce more horsepower and torque if it is not retarding the timing to compensate for knocking.

The way I understand it the regulations require the manufacturer to advertise the power produced by the lowest advertised fuel it's compatible with... so in this case it's rated to produce 239hp w/ 87 octane fuel and I'm told it's rated produce 149hp w/ 91. I don't remember the source for the second rating so someone can correct me if I'm wrong.

When the ECU detects knocking it retards the ignition timing, which reduces the power output of the engine. It's not that octane produces more power... it's that the lack of knocking allows the engine to operate to it's full potential.

 

I got better mileage with 91 for sure. I calculated the cost difference and it came out to 0.6 cents per mile more to use 91, or roughly $1.50 per tank. Between the extra power, cleaner burn and peace of mind, it's worth it to me.

 

+1000

those who think they're getting better mpg with higher octane are just fooling yourself.

our trucks are designed to run 87... you put 91-93 etc in it... you actually will get worse mpg and less hp since it wont burn off most of the gas.

 

Driving habits are the key to better mileage. Quick anecdote: Just got back from driving my Tundra Crew Max to and from North Carolina. On the way to NC, I drove between 65-70 and never once gunned the engine. I was in no hurry and wanted to see what I could get out of the 26 gallon tank. Normally, I get about 360 miles out of each fill-up around town. On this trip, I averaged 435 (~17mpg), although I was being very cautious about my driving... but I still had a fully loaded and slightly lifted full-size truck.

I'm not a big believer in high octane fuel unless the manufacturer calls for it. Seems like a waste of money if you can just adjust your driving habits a bit. However, when I was a bit younger, I never gave a shit and gunned my engine at every green light! Of course, gas was only $0.90/gal when I started driving.

 

Again, I absolutely get better mileage with 91. It's probably largely due to the fact than sub-91 octane HAS to have ethanol in my state. I buy eth-free 91 and get a full 2 mpg better than 89 with eth in it. Probably where some folks get confused. I don't know how many states are like MO, but here at least, it's 91 if you want eth-free, and only at a few select stations. I'm loving my 20.5 mpg avg in my dc 4x4 w/265/75/r16 Hankooks.

 

The v6 ecu's map for premium adds 3hp and 12 ft/lbs of torque. Published ratings are for the minimum acceptable octane level, as for most manufacturers. People who get better mileage on premium are probably benefiting from some combination of less ethanol and a leaner mixture allowed by the ecu.

 

I'll report back after a few tanks but I'm getting 2-3 mpg better than before....same driving habits and same routes. Was getting 15-16 before and now 18. That's with the AC on in 100+ weather and 3" lift and 33's. I also notice no lag when I mash the pedal.

 

With 91 right? What stations are you guys using around town? I've been sticking to QT.. read that they are a "top tier"

any other recommendations?

 

I'm thinking about running 109 or 112 octane for a few weeks and see if there is much differance in performance or mileage.

 

WOuld the 91 also have the affect on a 3.4l?

 

Im sure thats leaded and will kill the O2 sensors in short order.