Car and Driver octane test

mich800 wrote:

Lynnmor wrote:

ShinerBock wrote:

Lynnmor wrote:


Name a few people that said that.

What do you use for a tow vehicle?

You were one of them that stated premium fuel is required when towing with an an Ecoboost truck.

I currently use a Ram 2500 CTD as a tow vehicle. What does that have to do with anything?

I did repeatedly copy & paste fuel information from the Ford owners manual without embellishment, you choose to disregard what it says, Here it is once again:

For best overall vehicle and engine performance, premium fuel with an octane rating of 91 or higher is recommended. The performance gained by using premium fuel is most noticeable in hot weather as well as other conditions, for example when towing a trailer.

You want comments from only those that own a Ecoboost while you use a Ram diesel and comment on a Ford. :S

This is actually the full quote:

"Your vehicle is designed to operate on regular unleaded gasoline with a minimum pump (R+M)/2 octane rating of 87.

Some fuel stations, particularly those in high altitude areas, offer fuels posted as regular unleaded gasoline with an octane rating below 87. The use of these fuels could result in engine damage that will not be covered by the vehicle warranty.

For best overall vehicle and engine performance, premium fuel with an octane rating of 91 or higher is recommended. The performance gained by using premium fuel is most noticeable in hot weather as well as other conditions, for example when towing a trailer. See Towing. "

So premium is recommended not required for full performance. I think everyone is wrapped up on being correct instead of accurate. The standard ecoboost was designed to operate on regular 87 octane.

I keep trying to tell him this, but he refuses to accept it.


There are engines that have their hard parts designed to run premium meaning things like cam profile is specifically design run on premium fuel, but they can adjust/turn the cam and alter ignition timing to run on regular fuel with lower performance and may run into knock issues depending on the main cam profile. Then there are engines with hard parts designed to run on regular fuel, but can adjust to run on premium fuel for more performance. These generally knock much less with regular fuel because their profile is specifically designed for regular fuel

However, engines can only adjust their timing to a certain point and some engines can adjust more than others depending on how they adjust their cam. I know the cam phasers on both the exhaust and intake valves on the over head cam Ecoboost engines has a large range of adjustment. Push rod engines generally have less adjustability due to only having one cam instead of 2-4 cams on OHC engines. Another thing that adds to their ability to adjust is direct injection which also cools the pistons as well.