I run Sunoco 91 oct. all the time with a Gumout fuel injector cleaner for $3 every two tanks and that saves gas and keeps the pinging away 245,000 k

 

I switched to 89 a few weeks ago and now get about 1.5-2 mpg better and have no pinging anymore so yes I'd have to say it works well. It was about 20ish when I first switched now I average 19mpg, I think its one of those things you have to try it on your vehicle and if it works it works and on some it wont make a difference.

 

These engines were tuned to run on regular, if you're pinging, you have other issues. Higher octane does not increase power, it just increases detonation resistance, necessary for higher cylinder pressures and aggressive timing.

 

Thank you, finaly someone with a brain. It just kills me how so many people cling to that old idea that premium gas is just better gas, it is just higher octane which means it takes an engine that is designed to burn higher octane for it to ignite the higher octane completly.
When you put high octane gas in an engine that is designed for regular you don't burn all the gas and your milage goes down, that a fact.

 

In a perfect world, your theory is 100% correct but for whatever reason, sometimes these things work a little different. I've been getting very consistent gas mileage so my next tank I will fill up on 89 and see if there is a difference...

 

Here in the UK, I use 99octane. Milage is 10 to 13.5 around town and 21 at a steady 60mph. Sounds bad, but I have the biggest smile you've ever seen.

 

I filled up with 89 octane about an hour ago, drove around a few miles, I was on a test drive checking out the new fan clutch I had just installed. It really seems about the same, no real discernable power differences either way. GF and I are about to leave and head out to dinner, will see how it does I guess. I need to drive it further, run out this tank and see how I do on MPG. Before today I always used 87, never had any trouble with it. I will post back when I have more info.

Jimmy

 

I think with how old my motor is and the superchips on fuel economy mode, when it was really bogged down it would do it...trust me I thought the same thing but consistently got 1-2 mpg better after switching and this is with putting every fill up in my phone since October.

 

After driving it further it does seem to have more power on mid-grade gas. It seemed to be a little easier to gun the throttle up a hill or to pass someone. The truck feels like it runs a bit faster, the throttle response is a little better but I don't know if it's the gas or the new fan clutch making the difference. I will keep monitoring this tank and see how it does as far as power, and check the MPG when I fill up again. Thanks for all the info here.

Jimmy

 

with all respect i thought you guys were full of it. i have always put 89 and have averaged 12.5-14 city and 16-19 with a mix of road but mainly highway .... my tank was half way full so i filled her up with 91 and after a few days of city driving i can honestly say that i notice a major difference....ill find out how much i averaged in my next fill up but im sure it wont be near 12.5 .... power wise i havent really notice a huge difference