Higher Octane of any benefit for towing?

davido

Super Active Member
Jul 17, 2014
1,407
This is really dependent on the vehicle.

With a 2015 Ford Explorer Sport, premium is recommended anytime, and required for towing.

With my 1995 Ford Bronco 5.8L XLT regular is recommended. Premium isn't even discussed in its manual. However, I find that the vehicle is prone to knocking under load pulling up grades, and that problem becomes non-existent if I use premium while towing. It also runs cooler with premium. Who knows; these are old cars, and it's quite possible a previous owner got the timing advanced a little more than it should be, making premium advisable when towing.

Modern vehicles have a knock sensor. That sensor will retard timing a touch if it begins "hearing" knock. Retarding timing decreases power somewhat. On the other hand, a modern vehicle designed for towing should already state in its manual if premium is recommended for towing. If it doesn't say it, it's probably not needed, and is only a waste of money.
 

davido

Super Active Member
Jul 17, 2014
1,407
Does a Sport have a different engine than the ones listed in this 2015 manual?

View attachment 87383
The Sport has the 3.5L EcoBoost engine.

I live in Utah. In my area, the elevation is between 4200 and 5200 feet. The regular unleaded is 85 octane here. 87 is an upgrade. Also note for that engine it says, "Premium fuel will provide improved performance and is recommended for severe duty usage such as trailer tow."

So in re-reading that, I would probably use mid-grade (which is 87 in my area) for daily driving, and full premium (89 or 91 in my area, depending on the station) for towing. I don't have that vehicle anymore, though. My ex-DW has it. ;) I get to tow with my '95 Bronco 5.8L v8 XLT, which doesn't even recommend premium at all, but benefits greatly from it when I tow the popup.
 

Sharpie

Member
Nov 2, 2009
63
Ontario Canada
I use premium all the time. I get better gas mileage and not power. All those people that say just run regular or you will damage your engine are wrong. How would running a cleaner gas damage your engine. Also I have done a lot of research on this topic and have found out that the added ethonal they now put in gas causes more problems then they tell you. Over the last 20 years of driving and towing I have done mileage tests on regular gas towing and not towing. And then filled up with premium and done the same tests. I have noticed increased mileage and better performance with premium over regular. And not a little increase over 100 km on the highway when towing the popup. Here's a little information about regular with ethonal added the don't tell you. First ethonal is corrosive to aluminum and rubber parts. It also attracts moisture so it's not good in boats. Ethonal separates if left in the gas tanks so not good for classic cars that sit all winter. Ethonal is like water and does not burn so you get no useful power from burning in a gas engine. And ethonal plugs up the small jets in injectors. And if you state does not add ethonal to their gas watch the car in front of you when you leave at stop sign see how much water comes out of the exhaust. That's what is in regular gas also. Water the stuff the makes exhausts rust out and causes you to repair them. Like I said I have done many years of research on gas. I do know that if you have one of those flex fuel trucks you have to do you own tests because a friend of mine can only run regular gas in is crappy flex fuel truck. Because the computer is totally set up to run gas and E-85 gas. Which is worse the regular gas.
 

Tonya Harding

Super Active Member
Gold Supporting Member
Jun 15, 2018
1,913
Virginia
That's why they make additives for ethanol gas such as Startron/Sta-bil etc; been running 87 w/ additives in my Tacoma (manual recommendation) for over 12 years w/ no probs, no rust, not concerned about a few more mpg...
 

JimmyM

Super Active Member
Gold Supporting Member
Jun 5, 2014
3,333
Franklin, MA
My 2001 GMC Denali had a very light engine rattle (pinging) under acceleration when towing. It felt weak. The weather was very hot as well. I put a tank of 93 in just to see what happened. The rattle went away and my power returned.
If you're getting light knock, the computer will pull spark back to try to prevent the knocking. That will reduce power. You may not hear the knock.
Try a tank of super and see what happens.
 

xxxapache

Super Active Member
Jul 30, 2008
4,558
That's why they make additives for ethanol gas such as Startron/Sta-bil etc; been running 87 w/ additives in my Tacoma (manual recommendation) for over 12 years w/ no probs, no rust, not concerned about a few more mpg...
On the other hand, I have been running ethanol gas with no additives in my Toyota pickup 28 years and have had no fuel related issues. I have several vehicles older than that, also. Never had fuel related issues with any of them.
 

TSQ

Active Member
Mar 28, 2021
377
Niagara Region, ON
32.0 MJ/l - energy content of 100% gasoline
31.2 MJ/l - energy content of 10% ethanol, 90% gasoline

So fuel containing 10% ethanol (E10) has 2.5% less energy. 100% gas (without ethanol) should yield a ~2.5% increase in fuel economy.

Premium fuel is not cleaner, although it may contain additional detergents. The benefits of additional detergents will depend on the engine itself. As the fuel in modern direct injection engines does not pass through any throttle bodies, intake plenums/manifolds, or over any intake valves, there is less benefit to having additional detergents in the fuel than there used to be.

 

Sharpie

Member
Nov 2, 2009
63
Ontario Canada
This is utterly false. Ethanol is Ethyl alcohol. It burns. Quite well.
The issue, as a fuel, is that Ethanol has a lower BTU content than straight gasoline. So it produces less energy per gallon.
Sorry but it separates from the real gas and causes more fuel problems. It is also a attraction to water. Take a look sometime at that gas can in your shop that very rarely get used. Pour it into a clean Paul and see how bad it has separated and how much water is in it. I have been repairing engines for years both automotive and small engines. (Lawnmowers and snowblowers) I have seen the crap separate and cause many problems.
 

JimmyM

Super Active Member
Gold Supporting Member
Jun 5, 2014
3,333
Franklin, MA
Sorry but it separates from the real gas and causes more fuel problems. It is also a attraction to water. Take a look sometime at that gas can in your shop that very rarely get used. Pour it into a clean Paul and see how bad it has separated and how much water is in it. I have been repairing engines for years both automotive and small engines. (Lawnmowers and snowblowers) I have seen the crap separate and cause many problems.
YMMV. I've been using ethanol gasoline in every car, generator, mower etc I've owned since ethanol in gasoline has been a thing. Never any issues.
 

Patrick w

Active Member
Aug 13, 2021
652
2
The only time I run mid grade is when towing in the mountain states (Colorado, Wyoming, Utah and Montana) that only have 85 octane regular (their mid grade is 87). Although there is active controversy whether this is necessary with modern computerized engine management systems, auto manufacturers do not seem to "qualify" their octane rating requirements based on altitude. The "light" pinging that comes with lower octane is usually not audible over engine and tire noise, but the corresponding retarding of the engine timing would result in reduced power. I towed a Coleman Cobalt over the continental divide twice with a 2010 Subaru Forester, once with regular gas, and once with mid grade, and felt a difference (mainly, did not have to drop the 4 speed auto into second gear while grinding up to the Eisenhower tunnel).
Coulda swore the 2010 Forester was either the 5eat or the cvt depending on model...
 

Dave2514g

Active Member
Sep 2, 2019
274
Ontario, Canada
Then you have been lucky.
Agreed. Ethanol is a small engine killer.

Around here the 93 octane is all ethanol free and most 91 is as well. I use either for my small engines. If you run the engine regularly it's not an issue to have ethanol in the fuel. But if the fuel sits in the bowl of the carb for any time (even a month or two) it can turn into essentially a varnish and really gum things up. Small engine mechanics make most of their money around here from the people that let ethanol gas sit in their lawn mower over the winter
 

Paul E

New Member
Oct 15, 2022
7
Try towing with a ford ranger with a v6 3.slow….. everyone,Everyone passes you on upgrades.
Lol. By 3.slow I’m guessing you have the old 145 hp Vulcan V6.

Had the same engine in my 98 Taurus. Reliable and easy to work on but a little power challenged.
 

Bowman3d

Super Active Member
Apr 13, 2015
1,033
LaLa land (SoCal)
Lol. By 3.slow I’m guessing you have the old 145 hp Vulcan V6.

Had the same engine in my 98 Taurus. Reliable and easy to work on but a little power challenged.
yes it’s the same engine that’s in the Mazda pick up. It’s an 03 and only has 65k on it. But I’ve been throwing around the idea of dumping a 3.8L in it.
 




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