slimcubby

iTrader: (1)

Hey guys,

I am thinking of switching from 87 octane to 91 octane. Are there any pros and cons to doing this? I am stock with no tunes and wondering if I'd get better performance or gas mileage and if its worth the switch.

EricTheOracle

Only if you're working the engine hard or if your 91 octane fuel has less or no ethanol. Ethanol is used as a filler and you'll get an increase in mpg with non-oxy fuel.

slimcubby

iTrader: (1)

Our 87 and 91 both contain up to 10% ethanol.

aeford09

you'll get tons of answers... both for and against it being better... i personally ran one tank though of premium and i think it got better mileage. i ran to empty my first full tank of 87. filled up with 93. it seemed to last a bit longer than the 87. as for performance, i don't know... seems about the same. i have 5.0.. that's just my seat of the pants opinion. i filled up using giant eagle fuel perks so i only paid $1.59 for 93 octane. probably wouldn't do it paying full price

13Harleyfan

Stay with the 87, you won't notice the difference.

EricTheOracle

In my neck of the woods where we are mandated 10% ethanol, we also have at some stations 91 non-oxy for boat motor snow machines and small engines. My MPG jumped from 19 to 21 on the non-oxy fuel.

boy_welder2000

I have not ran 91 in my truck yet, but I did try it in my motorcycle once (manual says no less then 86) and I got worse mileage and it didn't run any better. I have been reluctant to try it in the truck based on that. On the other hand though, I only run 93 in all my small engines. It seems to help them start and run better. Sonoco stations around here have 87, 89, 91, and 93. All the rest have 87, 89, and 91 but all grades have 10% corn in them. Around here also, the price difference between grades is usually 10 cents. Based on that, I use 87.

Wanted33

I've tried it in several different vehicles I've owned. The only difference I noticed is the 91 octane cost more. These engines are tuned to run on 87, so that's all I run.

Ssls6

If you have good records of your mpg before, then try it for a while and you be the judge. I keep pretty good records on my 6.2l and didn't expect much difference but was a bit surprised. I only tried it based on a footnote in the f150 brochure. I can honestly say in my truck that 93 octane almost pays for itself….almost.

Azuri

Save your money the slight throttle response you may gain isn't worth the cash you spend. Your 6000 pound truck won't thank you for it. All the top tier petroleum suppliers provide cleaning additives in the gas. In other words 87 won't gunk up your engine if that's your concern. The trucks straight out of the factory are tuned for 87 as your manual will confirm.