is higher octane really any better for the 4 cylinder?

i have run 91 since the day i bought the bitch, ill prolly keep doin it cuz a few extra buck a tank aint shit to a OG

 

I've been running 93 octane since I got it a couple of month ago. Reading this thread I'm going to try 87 for a while to see what it does.

 

i always used 93 octane and then i switched it 87, seamed like the truck did not respond as well. Then i tried 89 and the truck seamed to run just as good as 93 with edging out a tad bit better gas mileage.

so 89 from here on out with the fill ups

 

I tried high test for a few weeks & got 0 improvement. Happily back to the cheap stuff.

 

lol this looks like a job for that performance pruimer thread

 

Me too. After buying the truck, I tried various fuel grades: disconnected the battery overnight to reset the ECM and gave it several tankfuls to adjust to the different octane, etc etc. I found absolutely no benefit from using anything over 87 octane.

 

performance per octane levels is purely compression ratio dependant. study what your compression ratio's are and and put in proper octane grade accordingly.

 

Higher octane only helps prevent premature ignition on higher compression motors... which either results in knocking/lower performance or your computer adjusting timing etc to eliminate that knocking, also hurting performance.

Regarding previous posts about needing a controlled environment to test whether higher octane has any benefits: Your testing environments may be tainted by the fact that in many cases, you actually get high octane when purchasing lower octane fuels.

I wish I had asked more questions as to why, but a terminal operator on our fuel pipeline told me never to buy premium because they ship out a lot of premium even when the truck was supposed to be loading regular. I dont know if it is an excess of premium production at the refinery or the fact that unleaded gets drained so fast and they have to suppliment premium to meet their contracts.

 

I think my truck runs better on regular (87 I think) versus premium.

I heard that if you put premium in a vw jetta they blow up? random lol but wanted to say it

 

My truck seems to run better on 93 octaine especially during the winter months when the gas is that crappy winter blend. Gas milage possibly 1 mpg better. My driving is inconsistant so its hard to be accurate.

 

I used 91 because its a cleaner burn so cleaner engine. And only chevron or shell.

 

Very true. I use Sunoco it is one of the few gas companies that dont support enemies of USA

 

Guess mine isn't doing too bad based on what has been posted. I usually get 320 or so on 87 and that is right at 1/8th of a tank left driving 75 on frwy with 32x11 E load heavy ass tire/wheel combo and stock gearing with 5 speed. Tried plus and super a coupla times but it made no difference in mileage or performance so I just feed it regular from Shell.

 

LOL -- High octane is designed for high-compression engines and does not burn cleaner in a normal-compression engine. You are wasting your money and making fat cats even fatter.

That's good gas mileage for a prerunner 4-cyl with big ass tires. I bet you could do even better going 65!

 

not necessarily true i do have a different truck them him but with the same motor i usually average around 400+ miles per tank.

but when i did try and use premium there was absolutely no gain in performance and it could have been me but it seemed as though the truck idled a bit rougher.

 

Dunno bout that, it only turns 2500 rpm doing 70-75mph in 5th. Doing 65 would lug the shit out of it in 5th gear. Maybe 60-65 in 4th. Kinda interested in 4.56 gear change.......

 

If you're doing 2500rpm at 75mph it would be ~2167rpm at 65mph... hardly lugging.

 

Maybe not lugging but definitely no acceleration or torque for headwind especially with overhead rack items like this..........



Had to draft behind 18 wheeler on frwy to hold 70 mph like this due to 20-30 mph headwind.....or drive in 4th gear, lol. Thinking sweetspot for mpg with my setup would be closer to 3k rpm..........

 

i get much better performance with my 2TR-FE on 91. it runs on 87 but i get significantly less power and mpgs. It also gear hunts like crazy on 87 with no gear hunting on 91.

 

I ran 91 on my truck in the first few months after I got it, then switched to 87. My MPG went up with 87. Hardly scientific, but that's my experience. Even though the 3rd gen 2.7 has a higher compression ratio than older 2.7s, I'm not sure it's enough to take advantage of 91.