What gas octane???

Use what the manufacturer recommends.

Dennis12 wrote:
Use what the manufacturer recommends.

X2.
Some will tell you to use the cheap stuff but the effects of doing so will add up.

We have found that in the MH I must push hard on the throttle using the 85 octane. We stay with the 87 octane. We get a little better mileage with 87 over the 85 octane.

If you drive on steep grades, putting higher octane will make the engine working better.
Modern engines have anti-ping sensors, so they will adjust for lower octane if you use it, but lowering the performance will make for gear downshifting and in the result - higher fuel consumption.

I agree with the above comments, especially the cheap gas problem. Around here, the independent brands don't have their own refinery/distribution system so buy their gas from others. Basically, they get what's leftover after the refinery puts out its trucks for the day. So, I stick to major brands.

When I was a super-bike racer and rode my bikes between races, I learned from others which brands were the best. Back in 80s, Union76 and Texaco were best, Chevron was 2nd best (of what was available to me here). So, you might Google gas quality and see what you learn. Of course, on the road, you often have no choice! :)

Bill

The Ram 6.4 runs fine on 87 octane which is what is recommended by Ram.

ScottG wrote:

Dennis12 wrote:
Use what the manufacturer recommends.

X2.
Some will tell you to use the cheap stuff but the effects of doing so will add up.

X3, If you rig is OEM why ask for opinions when the manual tells you the MFG recommendations.

BTW 6.x engines are not large. They are low end of the v8's

I suppose it depends on your purpose. I've played around some with tuning of my Mustang that has custom tunes. 91 tune is more powerful, but I don't get much of a mpg payoff. So, I generally run the 87 tune.

I agree that the minimum should be what the mfg recommends, but add that if you can buy gasoline outside of the large cities with less ethanol you'll be better off as well.

My manual says 87. I use 87 or the next higher when available. I would only use 85 if that was all there was.

jimbow2 wrote:
Users of the big gassers: Dodge 6.4, GM 6.0, Ford 6.4....... Can the lower octane be used or do you need the higher octanes????? Colorado we have either 85, 87, or I think 91..

Word on the street is that do to our altitude in Colorado 85 octane is equivalent to 87.
As for me? I stick with manufacturer recommendation to keep it simple.