Reg vs mid vs premium Does it Matter

[mcdbirdman]

Does it really matter as long as my engine doesn’t knock?

 

[retired]

nope your engine runs best on whatever octane does not ping.if it does not ping on 87 run 87

 

[DILLIGAF]

Use whatever the Custom tune calls for.

 

[joesstripclub]

It will run fine on 87 and will pull timing accordingly to adjust for the reduced octane. If you had been running 89 and switched to 87, the engine would probably experience some slight knock and start to pull timing accordingly to adjust, so the difference would likely take some time and not be a drastic change. You may or may not even notice the difference depending how you drive.

I used to think "oh who cares its not a big difference", but my mom used to own a lexus gs soemthing that was rated for 91 octane recommended - 87 min. She was cheap and just ran the 87 all the time and it seemed like the car was running fine, but following her one day I noticed the car would puff out smoke every time she accelerated. I dont know if that was due to the lower octane fuel or if the car had a greater issue, but that always stuck with me seeing how that car ran on lower grade fuel.

 

[mikeru]

The manual says something to the effect that 89 octane is recommended for optimal performance and fuel economy, but 87 octane is acceptable. I run top tier 87 octane in my truck and have never noticed any knocking or pinging. I've listened for it at times, especially on hot days when climbing a decent grade. Some people claim they can hear pinging when they run 87, and I'm not disputing that. Just saying mine doesn't do that. Anything higher than 89 is a waste of money as far as I'm concerned. Especially at the prices we're seeing for gas now.

 

[mcarey]

I'm in UT, and run 85 (our regular) in my Power Wagon. I've never noticed any pinging. Highway MPG is mid 16s or so if I'm not climbing canyons, and with mixed driving (predominately shorter trips around town) I see 11-12.

 

[Irishthreeper]

‘21 2500 6.4 runs fine on 87, even pulling a 5W. Would 89 be better? Maybe. Am I willing to pay for it? Nope.

 

[SniperDroid]

I run 89 or 91, depending on the price of the fuel, when towing the trailer. Can I afford it? Sometimes. Can I afford problems down the road...
NO! I'm not an engineer, or a chemist, and never been a very good mechanic. I also turn off the 4 cylinder feature using Tow Haul mode when towing, and the Max Gear Lever when not towing. Never saw much use for a 4 cylinder truck.

 

[evolizzee]

You'll be good on regular unleaded. Premium unleaded is pretty much for the owners with power increasing tunes on their truck.

 

[2012RAM1500RT]

This is something I don't argue about I just go by my own experience. I have a Hemifever 87 octane and 93 octane tune. I haven't heard any pinging what so ever using 87 octane. I've had some tell me it pings, I just can't hear it. I've been a mechanic for 45 years and I know very well what pinging is. If it even pinged once I would use a higher octane. I know the timing is ******** with the computer to prevent it from pinging which hurts your power some but the truck runs a flat 14.1 second 1/4 mile bone stock with the exception of a Vararam CAI and a Diablo tuner with the Hemifever tune. Not a rocket but not bad for a 5000 lb brick with a 345 CI naturally aspirated engine either. I run 89 in it about 30% of the time just to check MPG and performance and there is not enough difference that I can tell. If I got 1 more MPG or it ran noticeably better I'd run 89 or 93 all the time. I'm all about performance more than I am about saving a few dollars. Do your own test, you're not going to hurt it. Don't let anyone tell you what it's going to do, you're own test will be more realistic.

 

[msedly]

I've driven a handful of 1500's w/ the 5.7 over the years and some definitely ping more than others. I currently drive a '21 w/o e-torque and it does ping a little on harder acceleration with 87. Anything under half throttle and it's not really noticeable. My previous Ram was a '19 w/ e-torque and it pinged a ton with 87.

I've noticed that it tends to ping the most when in MDS. If I drive around town at 35 mph or so with the windows down I can usually hear it. Mostly goes away running 89.

If I know I'm going to be towing more than a few thousand pounds I try to make sure I have 93 in the tank. I occasionally tow portable generators that are in the 7-8k lb. range and have noticed that 93 definitely makes a difference in power (with a small bump in fuel efficiency).

Assuming you're not flat out everywhere you go, 87 is normally fine for typical commuting.

 

[runamuck]

I run regular in mine and in the trucks I have owned before. seems to run fine. I have gotten over 20 a few times on the road. tried a few tanks of midgrade when towing in high heat but nearly always use regular whatever octane it is when I fuel up.

 

[star_deceiver]

The local stations have regular at $1.679/L….. Costco has Premium 91 for $1.699L… 89 at the local stations is around $1.80 to $1.90/L…
I always use Costco 91.

Shop around

Also, the Costco has a $150 limit on transactions… you should see the unhappy faces on the people waiting when I hang up the nozzle and pull out my cards for round 2 of filling… Patience boys… you’ll get your chance to drain your account, too….

 

[mikeru]

The local stations have regular at $1.679/L….. Costco has Premium 91 for $1.699L… 89 at the local stations is around $1.80 to $1.90/L…
I always use Costco 91.

Shop around

Also, the Costco has a $150 limit on transactions… you should see the unhappy faces on the people waiting when I hang up the nozzle and pull out my cards for round 2 of filling… Patience boys… you’ll get your chance to drain your account, too….

Not all Costco stores are created equal. I filled up yesterday at the only Costco in the area (next closest one is over 100 miles away). They have 87 and 91 only. 87 was $4.01/gallon and 91 was $4.46/gallon. Guess which one I went with.

 

[buckley888]

So the engine control module is supposed to retard the spark timing when it detects engine knock. I'm assuming the reverse is true, that timing will advance without knock signals (to some programmed max)? So 89 octane recommended and 87 acceptable makes sense. Can I monitor my timing live via AlfaOBD? Might be fun to see if there's a difference.

 

[star_deceiver]

Not all Costco stores are created equal. I filled up yesterday at the only Costco in the area (next closest one is over 100 miles away). They have 87 and 91 only. 87 was $4.01/gallon and 91 was $4.46/gallon. Guess which one I went with.

Costco only has 87 and 91, no mid-grade. Although there are 2 Costcos in Alberta that have Diesel as well. Was $1.59 and $1.71 this after noon. Still filled ‘er with 91.

 

[Dinky]

When i had my 2014 1500 hemi. i drove 50miles round trip to work everyday. i never saw a difference in fuel economy or performance. this could vary truck to truck as they are not all the same 100%

 

[Ramalanche]

Where you are matters, at high elevations you can use lower octane since there is less ambient air pressure which restricts maximum compression on a naturally aspirated engine.

 

[BWL]

I find I use 1-1.5 litres per 100km less when I run premium vs regular. I never buy mid grade so I don't know on that. I did this last drive to work on 1 tank of premium and managed 12.2l per 100 km. Over 900 km and change. Usually I'm 13-14 on regular. Not enough savings to offset the cost in the past, but it was only 20cents a litre more this time and when gas is close to 2 bucks a litre a fill being 220 instead of 200 isn't as noticeable as opposed to say 130 vs 150 at last year's prices.

 

[lipidboy]

I use ethanol free fuel when available, sometimes 87, sometimes 91. There is often a higher price due to taxpayers subsidizing ethanol, but I have many hundreds of thousands of trouble free miles and good mileage.