Premium vs Regular gas?

[velorandy]

My new F250 (6.2L gas) has an owners manual recommendation (not a requirement) to use 91 octane gas or higher. The first 2K miles I did use premium, but the last couple of tanks (not towing) I’ve run regular with no noticeable change in MPG or engine performance.

Curious to know if other owners have a similar situation, and if you’ve towed using regular and/or premium and what kind of results have you had.

Thanks!

[rsdata]

same recommendation on my 2014 RAM 1500 truck. When I tow I bump up to premium, but when I don't I use regular.

[5picker]

Nothing but 87 in mine (2017 F-250) since new.
10 MPG towing.

[mopwr4me2003]

The main reason for a use with premium gas is to avoid a engine “ping” when under load. It feels almost like a misfire but it’s not. Higher octane burns slower and more efficiently than lower octane. With the cars nowadays you probably will never notice a difference because the computer will adjust for any issues that it sees, like to rich or lean and so on. When towing I would bump up to the higher octane or if you plan on driving in higher altitudes otherwise you should be ok.

[velorandy]

Originally Posted by mopwr4me2003

The main reason for a use with premium gas is to avoid a engine “ping” when under load. It feels almost like a misfire but it’s not. Higher octane burns slower and more efficiently than lower octane. With the cars nowadays you probably will never notice a difference because the computer will adjust for any issues that it sees, like to rich or lean and so on. When towing I would bump up to the higher octane or if you plan on driving in higher altitudes otherwise you should be ok.

Thank you, that’s the first indicator I was looking for, engine ping, thus far none. But for towing, I was thinking of trying a mid grade and if the results were undesirable bumping it up to premium.

My F250 has a max tow of 12,500, my TT fully loaded is at 7000 and I’m about 1500 shy of my payload max. So I’m not pushing the engine super hard.

[2Evil4U]

Yep. Running the recommended lower octane will be fine. These late model engines are so instrumented they have knock sensors and will pull timing at the slightest start of detonation. You won't even notice it unless you monitor engine timing. Using them loaded heavy won't hurt them but I want all the available power when I'm towing heavy so the higher octane will reduce the likelihood that the computer bumps the power down under heavy load.

[CedarCreekWoody]

I run 87 octane for daily use in my 2017 Ram, but kick it up to 89 for towing. Pinging can ruin an engine.

[Retired JSO]

Nothing but regular, what the manual calls for. ECM takes care of the ping on modern engines.

[CedarCreekWoody]

The manual on some engines, such as my Ram, calls for higher octane.

[babock]

Originally Posted by CedarCreekWoody

I run 87 octane for daily use in my 2017 Ram, but kick it up to 89 for towing. Pinging can ruin an engine.

Your engine has sensors that would prevent that from happening by adjusting the timing.

[jimmoore13]

Echoing others...

Most modern engine management systems will adjust for fuel octane. The adjustments may be imperceptible, but to get maximum performance under demanding conditions, use 91 octane. In day-to-day driving, especially unloaded, the loss of performance is unlikely to justify the increased price of gas for 91 octane.

But proper fuel octane protects your engine when it's working its hardest.
This is especially true with a small-displacement turbocharged engine operating with heavy loads at high ambient temperatures...perhaps also at altitude.

Knock (ping) sensors in a properly functioning engine will adjust timing and may even reduce boost, so it's unlikely that 87 octane will cause engine knock, but, if you are towing up long grades at high temperatures (say in the Arizona mountains during the summer), and you are operating near your vehicle's max GCVWR you'd be wise to adhere to the manufacturer's recommendations. If you hole out a piston and warranty repair discovers 87 octane in your tank (as they will when they investigate to save themselves the $4000 or so it may cost to replace the engine), they will void your warranty.

[babock]

Originally Posted by jimmoore13

If you hole out a piston and warranty repair discovers 87 octane in your tank (as they will when they investigate to save themselves the $4000 or so it may cost to replace the engine), they will void your warranty.

I would love to know how a dealer would be able to test for the octane number. My friend is a chemical engineer for Chevron and they have special engines they run to test for octane.

Gasoline with ethanol will lose octane all by itself by the ethanol evaporating.

Good thing about driving up mountains... the octane requirement is actually lower due to altitude. That's the reason octane number of fuel that you buy at high altitude locations is actually lower by a couple points on purpose.

[jimmoore13]

Originally Posted by babock

I would love to know how a dealer would be able to test for the octane number. <<snip>>.

Perhaps take a sample and send it to a lab, or ask for a fuel receipt?
Or perhaps the dealer would just drop in a new Eco-Boost no questions asked...even on a vehicle that shows evidence of towing and was rescued from along side the road with a trailer attached. Hard to know.

[DouglasReid]

The octane required for a specific engine is usually based on the compression ratio. Back in the day the majority of cars ran on "Regular" most of the rest used "ethyl" a higher octane fuel. Some of the Muscle cars needed even higher Octane which was available only at Chevron stations as "Custom".

Today the only cars which require premium that i know of are those with Turbochargers, again, because the Turbo creates such high compression ratio by forcing air into the cylinder.

If the owner's manual called for Premium for towing that is precisely what I would do, but otherwise Id run regular exclusively, towing or otherwise.

[babock]

Originally Posted by jimmoore13

Perhaps take a sample and send it to a lab, or ask for a fuel receipt?
Or perhaps the dealer would just drop in a new Eco-Boost no questions asked...even on a vehicle that shows evidence of towing and was rescued from along side the road with a trailer attached. Hard to know.

My bet is they would drop in a new engine. Let's say they could test the fuel(doubtful), the station he bought the last fuel could even be the culprit if the octane was low. Bottom line, the ping sensors in the engine should retard the timing until pinging stopped or reduce the turbo boost by controlling the waste gate.

[Martsing]

I use high octane when towing and regular when not towing.

Seems to be the best combination for me.

Marty

[RubyDually]

Originally Posted by babock

I would love to know how a dealer would be able to test for the octane number.

They don't....

When they find the damage is a result of detonation it would certainly be helpful if you had the fuel receipt to prove the fuel the manufacturer recommends is in it.

Same goes with oil.... Harley Davidson dealer mentioned this to me to hang onto my receipts to cover thy ass.

I do my own oil changes so it's needless to say I hang onto them until the next oil change.

[mopwr4me2003]

The key word in the manual is Recommended vs. Required. They are giving their recommendations based on test in the perfect world conditions. Yes they test these vehicles on tracks and regular driving but it’s still recommended. When you see service intervals at say 30,000 miles there will be required “ fluid flushes” but other recommendations for service. After almost 20 years of being a mechanic I never saw someone get a claim denied for a engine issue over the gas they put in unless it was diesel or E85 in a regular engine. I have on the other hand seen a claim denied for lack of oil change intervals. I’m not saying it doesn’t happen just saying I never saw it. Either way you should be fine with what you are doing. I know I would do the same thing.

[brannon]

I am in the premium camp for towing. The computer will retard the timing to prevent ping. Retarded timing raises exhaust gas temperature. No hard data to tell if this hurts anything. Peace of mind for me.

[DouglasReid]

The people who built your vehicle and engine spent Millions of dollars in R&D to try and provide a good product. They are not recommending something just for the heck of it. They have a vested interest in seeing you get the best performance and longest life out of their vehicle. If it lasts a long time and serves you well you will tell others and more sales will result.

They recommended it for a reason, why do anything else?