Premium vs regular gas

[Dan Topp]

My 19 is stuck with 93 because of mods but from what I’ve seen the gas mileage is no different then before,if I drive normal even though it has larger injectors plugs maf and tune.

 

[2012RAM1500RT]

Actually I seldom reply but playing the victim card about fuel costs then claiming it’s a conspiracy to force EV sales is such an absurd claim I wanted to poke the hive to see if there is something worthy of consideration.

Well thanks to you my post got "edited" because I guess " higher ups" is considered "political". You and elon have fun, I'm out of here! To all the ones on here that could read mine or any other post on here that you disagree with and was able to move on, thanks. Lot of great folks on here and I'm gonna miss you. To the one's like this one, well I hope the next hive you poke you get stung many times! Last thing before I go, members like this one, "MIND YOUR OWN D A M N BUSINESS". If you don't like what someone else says put your big girl p a n t I e s on and move on. To the good people in here I enjoyed having grown up talk with, thank you.

 

[duc1100]

I reread our exchange and it seems to me you’re getting all worked up about being challenged on your fuel cost EV conspiracy theory. Obviously we live in different worlds. In mine people are expected to justify their words and actions instead of crying foul. I guess if we don’t have that in common you’re right about not challenging what gets posted.

 

[sburford]

I am no expert or chemical engineer, but you need to read up on what differences in octane does. Higher octane fuel can be compressed to a greater degree before igniting. Changing octane fuel can change when your fuel ignites in the cylinder. Newer vehicles manage this with the computer mostly. If your vehicle calls for higher octane and you use lower octane you can get some knocking due to early fuel ignition. Bottom line, if your truck calls for regular, use regular. The engine is timed for it. I drive a diesel that knocks so what do I know?

 

[flinkpoyd01]

I live in Utah and use 85 octane in every engine I own to include my BMWk1600gte motorcycle. Yes, occasionally the motor will ping and I simply use less throttle. I refuse to pay additional for fuel except in the fall (before storing for the winter) when I use "blue gas" for a few tanks to get the ethanol out of the system before the motorcycle sits for a few months.

Same. Utah and 85, except in my vintage mustang which gets ethanol free 88 or higher.

 

[ScubaSteve178]

What made you think premium would "be better"? An ad on tv? Use what the manual calls for which is 87 or 89 "for best performance". If anything overuse of premium can call for depositing, especially in the high pressure direct injection systems of the hemis and any engine using such. Go back to 87 and you will save at least 15% on fuel costs and lose zero performance or drivability.

Hemis, at this period in time, are not direct injected.

Also, the theory behind the use of higher octane vs lower is valid.

The 6.4 is capable of running 87 minimum, but the manual even states it is not uncommon to hear ignition knock at idle as a result. As a rule, that is not a good thing. Between compression ratio, load expectations, tuning for power, economy, and emissions from the factory, it is better to run the recommended octane due to the simple fact that the PCM will retard timing and increase injector duty cycle to minimize knock.

Climate and elevation will make your mileage vary, but over prolonged use, people have reported gains of a mpg or two better using just 89 over 87, and slightly better performance. I did not experience any mpg gain myself when I switched, but I did experience noticeably smoother idle, especially when the A/C was on, on hot days. Which is important, because an engine that is experiencing ignition knock is generating excess heat.

87 works. Perhaps well enough that reliability will never be a problem, but I would not say it is a waste to run the recommended fuel.

 

[RaminitinFL]

93 is actually NOT good for the motor, never was, gets worse mileage, runs not as well as either 89 or 87. Have three RAMS with 5.7, all of them get Top Ter 87 gas and they are great. Meet or beat EPA mileage estimates all the time, change oil every 5K with good Mobile on oil, and have between 42K and 128K over the three and not a problem with any of them.

 

[chows]

Here in kansas there are a few stations that when you put your credit card in 87-89-93 are all the same price figure that one out. so I use 89.

 

[duc1100]

I am no expert or chemical engineer, but you need to read up on what differences in octane does. Higher octane fuel can be compressed to a greater degree before igniting. Changing octane fuel can change when your fuel ignites in the cylinder. Newer vehicles manage this with the computer mostly. If your vehicle calls for higher octane and you use lower octane you can get some knocking due to early fuel ignition. Bottom line, if your truck calls for regular, use regular. The engine is timed for it. I drive a diesel that knocks so what do I know?

I suspect modern motors with anti-knock electronics stop engine knocking so the lower octane affects performance which may reduce MPG but that’s probably more than offset by the lower cost. I did see the post regarding engine buildup but I’m inclined to roll the dice and save at the pump.

 

[MontanaHandyman]

And speaking of fuel prices, some friends are traveling in Switzerland...gas there is $10 per LITER...equates to about $38 per gallon!!!

 

[RaminitinFL]

I haven't read all pages of this thread, but I have not seen a lot of scientific analysis for why a higher octane fuel is in general better. The reality is, that engines are designed to use a specific octane, primarily based on their compression ratio. Lower octane fuels burn faster, so their use in an engine designed to run on higher octane can cause knock, which is simply the result of the fuel burning quickly enough to create enough pressure to cause the intake valve to "ping" against the valve seat before it is fully closed. Knock sensors sense pressure timing and retard the spark timing so that this is eliminated or at least minimized. Use of higher octane fuel in engines designed for lower octane can have the opposite effect, although knock sensors can also compensate for this to some degree. In this scenario, the fuel burns too slowly and can actually result in lower performance and excess unburned fuel which then needs to be processed in the catalytic converter. This can cause failure of the converter. The bottom line here is that the quality of the fuel is far more important than the octane rating if you're looking for performance and engine health. The best bet, unless you have modified your engine, is to follow the manufacturer's recommendations. They are there for a reason. If your manual says that a higher octane fuel is preferred, use of that octane can and usually will result in slightly better performance and potentially better fuel economy. Use of the lower, acceptable octane rating will simply have a slight effect on performance and fuel economy in the other direction. Personal experience and opinion cannot trump the science. Read this article if you want to better understand this .....

Gasoline explained - octane in depth - U.S. Energy Information Administration (EIA)

An introduction to gasoline octane, why octane is important, and how it is measured.

www.eia.gov

 

[duc1100]

And speaking of fuel prices, some friends are traveling in Switzerland...gas there is $10 per LITER...equates to about $38 per gallon!!!

Wow. Probably why you don’t see a lot of full size trucks and SUVs in Europe. It’s definitely nice to live in a country with oil reserves and be able to afford to drive a full size truck.

 

[SuesLaramie]

I had a 2007 Laramie for 10 years and sold it with 210,000 miles—-loved it and should have kept it. Anyway, mechanic told me that the EGR valve went, TWICE because I was using 87 octane. Can this be accurate? Currently have another Laramie—2018. Worried about having same issue. Gas is expensive enough without this happening again. Anyone have the same experience?

 

[IDSandman]

And speaking of fuel prices, some friends are traveling in Switzerland...gas there is $10 per LITER...equates to about $38 per gallon!!!

Switzerland has some of the best, if not the best public train system I’ve ever been on. Very little reason to not use train travel there if visiting or even if living there. Have friends that live there and they do own cars but rarely drive them due to the low cost and ease of the train system.

 

[Wild one]

I had a 2007 Laramie for 10 years and sold it with 210,000 miles—-loved it and should have kept it. Anyway, mechanic told me that the EGR valve went, TWICE because I was using 87 octane. Can this be accurate? Currently have another Laramie—2018. Worried about having same issue. Gas is expensive enough without this happening again. Anyone have the same experience?

Your 2018 doesn't have EGR. When they went to VVT (variable valve timing) they did away with the EGR system.

 

[Hemi395]

I tried a tank of 87 last week for the first time since I bought my truck in 2013. I have my Trinity set to flash the LEDs when it pulls more than 3⁰ of timing. On 89 it would only flash here and there under certain conditions and on 93 it hardly flashed at all. On 87 it was lit up almost the entire way to work. I started watching it and it was pulling 5-6⁰ every time it was in MDS or lugging at a lower RPM on the highway.

I also lost about .5mpg. Now obviously the cost of 93 vs 87 right now isn't worth .5mpg to me, but the fact that detonation is happening that much does matter to me. So it's getting at least 89 from now on.

Just my .02.

 

[Maui Time]

I have a 2022 6.4. Been running 87 in it since I purchased it. 8,000 miles. No knocks. No issues.

 

[AlexC2350]

So your opinion is the EV industry has more influence than the petroleum and internal combustion auto industries and me calling you out on that makes me part of the EV industry. I’m definitely interested in the reasoning behind your opinion.

I think he was referring to the governments green agenda. They’re fine with high energy costs, doesn’t mean **** for them. They can’t just force green on us but if people get sick of high prices and move to EVs and such it fits what they ultimately want. They’re getting us used to having nothing and liking it.

 

[Dusty]

Hemis, at this period in time, are not direct injected.

Also, the theory behind the use of higher octane vs lower is valid.

The 6.4 is capable of running 87 minimum, but the manual even states it is not uncommon to hear ignition knock at idle as a result. As a rule, that is not a good thing. Between compression ratio, load expectations, tuning for power, economy, and emissions from the factory, it is better to run the recommended octane due to the simple fact that the PCM will retard timing and increase injector duty cycle to minimize knock.

Climate and elevation will make your mileage vary, but over prolonged use, people have reported gains of a mpg or two better using just 89 over 87, and slightly better performance. I did not experience any mpg gain myself when I switched, but I did experience noticeably smoother idle, especially when the A/C was on, on hot days. Which is important, because an engine that is experiencing ignition knock is generating excess heat.

87 works. Perhaps well enough that reliability will never be a problem, but I would not say it is a waste to run the recommended fuel.

As stated in an earlier post my mileage records would indicate a very slight increase in MPG, but the difference could well be within the noise of the variables, such as driving cycle, ambient temperature, weather, and me.

However, when I switched back to 87 recently I, too, noticed a slight difference in idle quality that apparently only I could detect. That was Kwik-Fil and Speedway gas. The Sunoco seems to be okay.

Regards,
Dusty
2019 Ram 1500 Billet Silver Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, factory dual exhaust, 18” wheels. Build date: 3 June 2018. Now at 71822 miles

 

[duc1100]

I think he was referring to the governments green agenda. They’re fine with high energy costs, doesn’t mean **** for them. They can’t just force green on us but if people get sick of high prices and move to EVs and such it fits what they ultimately want. They’re getting us used to having nothing and liking it.

The fundamental error in this logic is money drives policy and the petroleum industry and internal combustion automotive industry has orders of magnitude more financial resources than any green agenda. The reality is a petroleum based society like ours doesn’t scale with ours and the world’s increasing populations and economies. Simple cost vs demand. Also high gas prices hurt the party in office so the Democrats have more to loose and everyone knows all politician’s first concern is staying in office so any left green agenda will take a backseat to the economy. The current spike in fuel cost is a combination of world demand, refining capacity and commodity prices influenced by a war.