Started using Premium gas for my 2006 SR5 Sport, 160K miles

Ask and you shall receive. Base timing tables are identical. Between an 06 and 13 are essentially same. Only real difference is a change in how they went about dealing with knock from 2011- and 2012+. 2011- they started high and worked down to an optimal timing advance, but complaints of a knocking motor made them in 2012+ start low and work up to an optimal timing. The only other change is on the 2012+ trucks with the ECU TSB applied where they reduced timing by a smidge 1-3* in the 1600rpm area 40-80% load of the "Low Octane" timing table. But really that table isnt referenced much at all.

Needless to say the tune between 06-15 is nearly identical. The major difference one will feel between a 2011- and 2012+ truck is the throttle pedal mapping. There is a reason the 2011- trucks feel sportier and its because the throttle pedal to throttle blade opening is more linear than the 2012+ trucks that are much more downward curved (meaning you have to push on the gas pedal more to open the throttle the same)

 

Good explanation. I was researching and found a few links in regards to racing with E85, so tuning, higher compressions can get better performance it appears
https://www.google.com/amp/s/carfro...e/why-does-e85-make-more-power-than-gasoline/
But your engine has to be tuned for it it seems:
https://performancebyie.com/blogs/ie-auto-blog/make-power-safely-ethanol-blends
Edmunds did a test back in 2009 on a car designed to run different fuels and E85 provided significantly less mpg than gasoline but the cost was lower. Not sure this applies to modern day engines if they are designed to run either E85 or gasoline but interesting:
https://www.edmunds.com/fuel-economy/e85-vs-gasoline-comparison-test.html
From what I’ve read so far ethanol provides more oxygen and cooling and can improve performance IF a cars tuning can take advantage of that but at lesser mpg as you say. I’ve always wanted to test the % ethanol in the gas I buy, would be interesting to see how my stock engine runs and mpg difference for no ethanol vs 10% ethanol. Maybe some day.

 

Still the same for this day. again stoich and load AFR's for E85 are MUCH lower than gas, meaning much more fuel is needed to maintain a proper air fuel ratio on E85. But like stated, because of the extra fuel, and its composition you get a cooling effect which also allows for more timing on top of the higher octane . E85 has tons of benefits as far as racing applications but a daily driver not so much.

 

Makes sense. Just found this article showing the composition of gasoline and ethanol, showing ethanol is highly oxygenated and why the air/fuel ratio has to be adjusted.
https://extension.psu.edu/fuel-ethanol-hero-or-villain
So I’m learning a bit here, thanks.

 

I like beef jerky. I click on these threads because they are a garunteed dumpster fire.

Here's something to blow the higher is bigger crowds mind, what altitude are you driving at? Us folks that live in the mountains can run 85 all day long (actually decades in my case). The higher altitude effectively reduces the compression ratio making 91 or even 87 a waste. If the engine timing can run fully advanced higher octane is expensive and pointless. A far more interesting test would be to run your tank empty and then send a friend to fill it up with 91 or 87 or 85 and not tell you which one they used. Without knowing what you're running can you REALLY tell what's in the tank. Then get out the calculator and see how much more it cost in terms of dollars / mile to drive.

 

Haha this thread is a match strike compare to the real dumpster fire on a thread I participated on over the benefits you get in engine additives In various brands and with regular vs. mid grade or premium octane fuels, I don’t want to start that again here so will look for a link
Here’s the link, thread started out talking about milage until I brought up why I like using Shell 89 mid grade for the engine cleaning additives:
https://www.tacomaworld.com/threads/how-is-your-fuel-millage.642958/page-4#post-22262805
Fun thread haha

 

E10 is the max on the Taco

 

It’s because your wallet is lighter, so less weight in the truck = less drag

 

Interesting. How does the ECU decide to use the "Low Octane" table? A Knock or timing threshold? Is there a "High Octane" table? Are these Toyota nomenclatures or just the given names from tuning communities? Why are they called "Horse shoes?" Are there "Horse socks?" Sorry about all the questions.

Yeah, the throttle pedal/plate mapping is... something on 2012+. I'm sure there is a reason, I just cant figure it. Less driveline shock? It certainly isn't going to help sell trucks on test drives.

 

When you buy gas at the pump you don't really know what you're getting. I have always run 87 octane in all of my vehicles and sometimes I'll get a tankful that just seems have more power. Sometimes for no explainable reason I'll see 1-2 mpg better than expected, sometimes 1-2 mpg worse than expected. The quality of the gas can vary significantly even within the same octane rating.

Old gas is less efficient than fresh gas. And since they sell a lot more regular there is a better chance the guys buying premium and mid grade gas are getting old gas. That may explain why there is conflicting data. While the higher octane might potentially be beneficial, if you get old gas it could be cancelling out the benefits.

Ford recommends 87 octane for normal driving, but 91 or higher for towing with the 3.5 turbo engine. Not with the V8. Depending on the vehicle I can see improved performance, and even minor fuel mileage gains. But never enough gain in fuel mileage to offset the added costs.

100% ethanol free gas isn't common here, and it is expensive when it is available. Two years ago I was on a long road trip and found gas dirt cheap in Tupelo MS. I had a chance to try a tank of ethanol free gas at about the same price as I normally paid for 10% ethanol. That was the worst fuel mileage, and worst running tank of gas for the trip. I was finally able to fill up with better gas in Oklahoma and got my normal performance and fuel mileage back,

 

To what data are you referring? Most everything in this thread is anecdotal which is useless.

 

91 octane makes mine idle much smoother. At 89k, perhaps I need new spark plugs.

 

I notice a positive difference in my 15.