Premium vs regular gas

[turkeybird56]

What do you notice?

Slightly less performance, ie., which a lot describe as pinging. The only time I put in 91 is if towing. Just took a 10 mile round trip into town and back for some Milk, buns, and a battery for lawn mower. Dang, even the mower batteries getting expensive, LOL.

All my gas cans have 89 in, since my lil generator runs on 89, chain saw, all other stuff need 89, so just a lot easier.
(of course now got a lil bigger generator, which has not been hooked up to fuel yet or activated, that be end of next week, pic in Senior Citizen thread).

But as U know, 1,000 different opinions, this is what works for dis BOIRD.

 

[Rayzaa]

I use 87 pretty much exclusively with an occasional 89 here and there. Never had any knocks. MPG is the same with both so i go the cheaper route.

 

[Mb7640]

I have always used what the Manual says unless I have a tune which requires 91. Better be safe then sorry

 

[Rayzaa]

Actually it's built to run on 89. But 87 works.

Actually its built for either or it wouldnt state so.

 

[HEMIMANN]

It says 89 octane is 'preferred'. Not that they are both the same performance.

 

[CheechDogg.0n37s]

I use 87 pretty much exclusively with an occasional 89 here and there. Never had any knocks. MPG is the same with both so i go the cheaper route.

Trust me, your truck is knocking with 87 ... unless you can prove it with data logs that it's not, your truck is definitely knocking ...

 

[Rayzaa]

Trust me, your truck is knocking with 87 ... unless you can prove it with data logs that it's not, your truck is definitely knocking ...

No it isn't. I've never heard one knock and it runs very well. Mine is a 07 and i don't recall if it mentions 89 in the manual, it's been a while. I'd have to look. It might.


My 2018 Challenger does.

 

[Dirt_Dobber]

If you are running 87 octane - you are getting a knock whether you can hear it or not!
The owners manual correct octane is 89 for Ram 1500 with 5.7 Hemi
go to 3:16 of this point YouTube Link and forward...

When you're using the correct octane fuel the spark ignites the fuel and the flame starts at the spark and travels outwards. This is a smooth and even burn that creates pressure to push the piston Downwards and then the exhaust gasses are forced out of the cylinder and the process repeats.

Now, let's take a look at the combustion process when you use a fuel with a lower octane than the manufacturer requires so the fuel and air mixture is pulled into the combustion chamber and the spark plug ignites it just like normal. But as the flame moves outwards the pressure inside the cylinder increases and causes pockets of fuel to ignite unevenly and this creates an explosion rather than a smooth burn and that metallic naki here is the uneven explosion which could damage the piston piston rings
valves head gasket and even the block so higher octane fuel prevents detonation in forced induction and higher compression engines.

 

[Wild one]

If you are running 87 octane - you are getting a knock whether you can hear it or not!
The owners manual correct octane is 89 for Ram 1500 with 5.7 Hemi
go to 3:16 of this point YouTube Link and forward...

When you're using the correct octane fuel the spark ignites the fuel and the flame starts at the spark and travels outwards. This is a smooth and even burn that creates pressure to push the piston Downwards and then the exhaust gasses are forced out of the cylinder and the process repeats.

Now, let's take a look at the combustion process when you use a fuel with a lower octane than the manufacturer requires so the fuel and air mixture is pulled into the combustion chamber and the spark plug ignites it just like normal. But as the flame moves outwards the pressure inside the cylinder increases and causes pockets of fuel to ignite unevenly and this creates an explosion rather than a smooth burn and that metallic naki here is the uneven explosion which could damage the piston piston rings
valves head gasket and even the block so higher octane fuel prevents detonation in forced induction and higher compression engines.

The better part of the video is at at the 12:05 mark,where he talks about reconmended and required fuels.I'd hazard a guess the majority of owners use regular gas in their stock Hemi's,especially when fuel prices are high,and i've never heard of one of them knocking a piston or cylinder wall out from detonation. Under boost they'll close up the ring gap and break the top ring land,but the majority of 5.7's aren't boosted or tuned

What is the BEST Fuel to Use in Your Car or Truck and WHY

Ever wonder what grade gasoline should you use in your car (what octane)? Are you paying for premium gas when you can just use regular? Are you using regular...

www.youtube.com

 

[Rayzaa]

If you are running 87 octane - you are getting a knock whether you can hear it or not!
The owners manual correct octane is 89 for Ram 1500 with 5.7 Hemi
go to 3:16 of this point YouTube Link and forward...

When you're using the correct octane fuel the spark ignites the fuel and the flame starts at the spark and travels outwards. This is a smooth and even burn that creates pressure to push the piston Downwards and then the exhaust gasses are forced out of the cylinder and the process repeats.

Now, let's take a look at the combustion process when you use a fuel with a lower octane than the manufacturer requires so the fuel and air mixture is pulled into the combustion chamber and the spark plug ignites it just like normal. But as the flame moves outwards the pressure inside the cylinder increases and causes pockets of fuel to ignite unevenly and this creates an explosion rather than a smooth burn and that metallic naki here is the uneven explosion which could damage the piston piston rings
valves head gasket and even the block so higher octane fuel prevents detonation in forced induction and higher compression engines.

I'd say that video confirms it's ok to run 87. And the manual says it's ok as well so contrary to the guys saying my engine knocks, sorry to disappoint but it doesn't.

I've also seen many here and other places state a higher octane gives them a little better mileage which I've also said isn't true and that video dispells that as well.

87 and 89 you won't notice a difference but some want to believe it.

 

[KoboldTaco]

Octane discussions are the new oil threads

Glad I bought a Diesel so I also no longer worry about octane…now I get to read about low sulfur, CET, DPF, DEF, bio-D etc…LOL.

I always go by the owners manual. A generalization however is that 91 or higher is best reserved for high compression, performance orientated engines. Knocking is pre-detonation and timing is computer adjusted to minimize that condition when running lower octane fuel.

Let‘s say you are running 87 for the life of your truck. I’ve watched many a tear down and the odds of you causing engine damage due to the fact your truck adjusted timing between 87 to 89 is super, super low as in you’ll never put enough miles to ever cause an issue In your trucks lifetime of ownership.

Put in what makes you feel better - don’t waste your money on 91. you’ll never recoup the cost offset and any perceived benefit of mileage gain is simply that.

 

[Hemi395]

No it isn't. I've never heard one knock and it runs very well. Mine is a 07 and i don't recall if it mentions 89 in the manual, it's been a while. I'd have to look. It might.


My 2018 Challenger does.

Yes it is knocking on 87, its just not to the point you hear it. When you actually hear it the PCM is pulling 6+* of timing.

Hook a scantool up with 87 in it and look at ST Knock. Prove me wrong.

 

[ramffml]

I'd say that video confirms it's ok to run 87. And the manual says it's ok as well so contrary to the guys saying my engine knocks, sorry to disappoint but it doesn't.

I've also seen many here and other places state a higher octane gives them a little better mileage which I've also said isn't true and that video dispells that as well.

87 and 89 you won't notice a difference but some want to believe it.

Something ... something ... horse ... water ...

 

[Rayzaa]

Yes it is knocking on 87, its just not to the point you hear it. When you actually hear it the PCM is pulling 6+* of timing.

Hook a scantool up with 87 in it and look at ST Knock. Prove me wrong.

My 2007 Hemi has a lower compression ratio (9.6 to 1) than my 2018 Hemi (10.5 to 1) in my Challenger. I use 89 in the Challenger. 07 is a Gen III and the 18 is Gen 4 Eagle Hemi.

 

[Wild one]

My 2007 Hemi has a lower compression ratio (9.6 to 1) than my 2018 Hemi (10.5 to 1) in my Challenger. I use 89 in the Challenger. 07 is a Gen III and the 18 is Gen 4 Eagle Hemi.

The engines are all Gen 3 ,the truck bodies are the differant Generations. All Hemi's since 2003 are Gen 3 engines,the heads are differant with Apache and Eagle heads,but it's still called a Gen 3 engine

 

[Hemi395]

My 2007 Hemi has a lower compression ratio (9.6 to 1) than my 2018 Hemi (10.5 to 1) in my Challenger. I use 89 in the Challenger. 07 is a Gen III and the 18 is Gen 4 Eagle Hemi.

And......?

 

[Rayzaa]

The engines are all Gen 3 ,the truck bodies are the differant Generations. All Hemi's since 2003 are Gen 3 engines,the heads are differant with Apache and Eagle heads,but it's still called a Gen 3 engine

Nope, the Hemis have differences. Google it and you will see. I mean call it what you want but they are different.
https://youtu.be/U0w9Y21r8nc

 

[Wild one]

Nope, the Hemis have differences. Google it and you will see. I mean call it what you want but they are different.
https://youtu.be/U0w9Y21r8nc

I didn't say they weren't differant,all i'm correcting you on,is everything from 03+ is called the Gen 3 engine. Go find us a Gen 4 Hemi engine,not a Gen 4 truck body

 

[CheechDogg.0n37s]

I'd say that video confirms it's ok to run 87. And the manual says it's ok as well so contrary to the guys saying my engine knocks, sorry to disappoint but it doesn't.

I've also seen many here and other places state a higher octane gives them a little better mileage which I've also said isn't true and that video dispells that as well.

87 and 89 you won't notice a difference but some want to believe it.

Well my truck "DOES" get better MPGs on 91 .... yes it's "OK" to run 87 or 89 but that doesn't mean it's right ... when people, doctors anyone says its "OK" doesn't mean you should ....

Like most people know, only data logs can prove that there is knock, people think knock is always "audible" sound, no it doesn't always happen like that ... regardless it's your truck, it's his truck, it's everyone's own truck, but a year of running 89 and that was enough to convince "ME" that while 89 might be "OK" and recommended, on 91 "MY" truck runs bette and gets better MPGs

 

[toddmakesamove]

Knock is known as the silent enemy. Think of it like your BP out of wack. Shure you're fine and "OK," but when it rears its ugly head, you will not be.

When it comes to octane to knock on detuned naturally aspirated engines - it really isn't happening...if it is - it's very low (sub 20db). Commuter HEMIs are very detuned and don't need the best octane. If you're towing or going across the mountains where your RPMs are staying past 4.5K, shifting around under high load - then one should run higher octane. If you're going to Home Depot, grocery store, lawn supply, towing light loads, the park or etc. you don't need to run higher octane.

I'm sorry to say it to y'all, most HEMIs are commuter engines, with low HP & TQ, and are meant to be "putted around." My buddy just got the TRX RAM truck, and it's slow as Christmas on the STREET. Really cool truck, but it's slow when it comes to speed, and it's because it's a truck. As an example, that HEMI needs the best fuel but normal truck HEMI's do not. I think some of y'all believe you bought a high-performance vehicle that needs the best...normal truck HEMIs are no such thing - chill.

Another example is if regular unleaded is (today's prices in GA on AAA) $3.1 and mid is $3.6 you'd have to get 2.5 more miles per gallon to be competitive with regular unleaded. Never seen anyone's example out here show an extra 2.5 miles per gallon. Stop being so serious about things that don't really matter.

There is a time and place for higher octane in commuter vehicles, but I doubt most will ever actually need it in these trucks.