Robwatford

I just got back from a 1800 mile round trip to Smoky Mountain National Park in my 2018 Screw 3.5 EB towing our 4000lb camper.

Both ways I ran about 65Mph in tow/haul, but ran premium on the way down and regular on the return. In general premium was about 60cents more expensive.

On the way down I got 9.6mpg and 9.4 on the return. So no gas savings and as far as power goes there may have been a difference but I had plenty of power running on 87.

So 87 for me from now on.

Robwatford

Thanks I haven't seen that. Could have saved myself a few $$$.

Mike Up

Surprising as you should feel the extra 35 lbs torque and 13 Horsepower addition that the 93 octane has as seen here.

Robwatford

It did have more power, but I wasn't lacking power on 87, at least not enough to justify the cost.

chimmike

I get 2-3mpg better running 93 while towing, reason being is it can maintain gear better due to the additional torque thanks to advanced ignition timing on the 93. Should be virtually the same on the '18s. Lot of other variables apply but in the mountains, if the route was different in any way or more uphill than not, that could definitely affect your results.

Ryan_2020

I also find regardless of fuel / driving conditions / etc I always get worse fuel mileage on the way home......something about 'getting home' makes me drive more aggressively lol

smokeywren

I did a similar test a few years ago when my 3.5L EcoBoost was newer. My MPG improved enough using premium that I just about broke even on the cost of gas. My EcoBoost seems to be happier running premium when towing. Less downshifting for grades, slightly less coolant temp. So for long towing trips with my TT or cargo trailer, because it doesn't cost me more I run premium.

untraceable

You may have noticed more if the outside air temps where hotter.

The performance gain may be sight anyways. Most people are not towing at acceleration rates/speeds that tax the motors that hard anyways.

chimmike

it makes more power in all conditions with higher octane fuel. At cruise under load, it'll make more torque in gear at rpm, which may be enough torque to prevent what would otherwise require a downshift on lower octane fuel.

mass-hole

Was that study while towing? I imagine under load the higher octane fuel may have a larger effect since just cruising around town isnt putting the engine under a whole lot of stress.

For the last few months there has only been a $0.10 split between 87 octane and 91 octane here, so I have been running 91. Its like a 3% increase in cost.