For the guys who think they get more power with 91 octane fuel

[Wild one]

Some of you guys with stock trucks need to watch this video

Does the Fuel You Choose Matter? | Engine Masters | MotorTrend

Does fuel really matter for your engine? Watch as the Engine Masters team takes a scientific look at just how much power and performance are produced by diff...

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[CheechDogg.0n37s]

I watched this video when it first came out ... I personally am not looking for more power from 91, what I am looking for is the denial of knock on our HEMIs which from how "MY" truck performs on 91 is much better than when I was using 89 the last year ... my MPGs have gone up by almost 2 mpg in town and the smooth acceleration is very noticeable especially when driving on the open highway ...

Just like I said in the octane thread, these engines are already built to make a certain amount of power "stock", unless you have modded the whole system then the 87-85 is going to give you more power vs the 91.

My opinion is that 91 has been marketed to a) get you to spend more money at the pump and b) get our vehicles to break down faster than the old engines without all the computer dependency ...

Most people today with the new cars will notice their vehicles running "better" with 91 especially since most sports cars are calling for 91 for optimal performance and the HEMI is no exception which is why I feel there are so many HEMIs with lifted and cam issues because people feel and decide to use 85, 87 and even 89 in these trucks ...

Regardless of which octane the normal HEMI owner uses, these engines will make the same power period but the risks of damaging the engine are much higher running 85-89 in my opinion .... so that is my reason for running 91 again in my truck, not for the power but for the prevention of damage down the road ...

 

[Sillygoose]

I watched this video when it first came out ... I personally am not looking for more power from 91, what I am looking for is the denial of knock on our HEMIs which from how "MY" truck performs on 91 is much better than when I was using 89 the last year ... my MPGs have gone up by almost 2 mpg in town and the smooth acceleration is very noticeable especially when driving on the open highway ...

Just like I said in the octane thread, these engines are already built to make a certain amount of power "stock", unless you have modded the whole system then the 87-85 is going to give you more power vs the 91.

My opinion is that 91 has been marketed to a) get you to spend more money at the pump and b) get our vehicles to break down faster than the old engines without all the computer dependency ...

Most people today with the new cars will notice their vehicles running "better" with 91 especially since most sports cars are calling for 91 for optimal performance and the HEMI is no exception which is why I feel there are so many HEMIs with lifted and cam issues because people feel and decide to use 85, 87 and even 89 in these trucks ...

Regardless of which octane the normal HEMI owner uses, these engines will make the same power period but the risks of damaging the engine are much higher running 85-89 in my opinion .... so that is my reason for running 91 again in my truck, not for the power but for the prevention of damage down the road ...

You're on some stuff man....

 

[Burla]

I can only say this, in my engine which the rumor is that it is tuned for 89, my truck sputters on 87 and runs like a ***** ape on 91, I am super cheap, if it ran good on 87 I would run 87, but the re-**** knock is noticeable to anyone in the truck. The only reason I use 91 instead of 89 is because costco only carries 91 and 87. When fuel is 7 bucks, I still run 87, but I miss my 91 on every trip. I must admit, I don't really know the science, I just know my eye sight can still tell the difference between night and day, and I can tell the difference between 87 and 91, and it isnt even close.

 

[Docwagon1776]

I wonder what their results would be if they heat soaked the engine prior to the pull and had a computer control for knock...

 

[CheechDogg.0n37s]

You're on some stuff man....

You tell yourself that homie ...but it's a fact that my truck runs like a [email protected]@$$ on 91, again, not that it makes any more power, but it uses every bit of power it has the potential to use on 91. Using 89 will retard it and 87 will really make "Dumb & Dumber" ... but the stuff I am on is just too much for you

 

[CheechDogg.0n37s]

I can only say this, in my engine which the rumor is that it is tuned for 89, my truck sputters on 87 and runs like a ***** ape on 91, I am super cheap, if it ran good on 87 I would run 87, but the re-**** knock is noticeable to anyone in the truck. The only reason I use 91 instead of 89 is because costco only carries 91 and 87. When fuel is 7 bucks, I still run 87, but I miss my 91 on every trip. I must admit, I don't really know the science, I just know my eye sight can still tell the difference between night and day, and I can tell the difference between 87 and 91, and it isnt even close.

Same here ... my truck is like like Scarlett Johansson in Lucy, the average HEMI on 89 and 87 uses 10% of it's brain capacity, with 91 it's like Lucy using 100% of it !!!

 

[CheechDogg.0n37s]

I wonder what their results would be if they heat soaked the engine prior to the pull and had a computer control for knock...

Those tests are a little vague if you think about it, there are so many other factors that go and affect power ... while these tests are still good and cool to see, I don't really feel they are the tell all ...

 

[HEMIMANN]

I can only say this, in my engine which the rumor is that it is tuned for 89, my truck sputters on 87 and runs like a ***** ape on 91, I am super cheap, if it ran good on 87 I would run 87, but the re-**** knock is noticeable to anyone in the truck. The only reason I use 91 instead of 89 is because costco only carries 91 and 87. When fuel is 7 bucks, I still run 87, but I miss my 91 on every trip. I must admit, I don't really know the science, I just know my eye sight can still tell the difference between night and day, and I can tell the difference between 87 and 91, and it isnt even close.

Thought you found an 89 to test against 91?

 

[HEMIMANN]

@Wild one - still educating, eh?

I've returned to 89 octane after my brief foray into 87 during the great inflation hype.

Learning the PCM algorithm for spark timing advance made my decision for me. I didn't like the knock sensing setup. Yes, it does run better on 89, no sputtering, I've always noticed that. I just wasn't towing much this summer when gas was $5+ / gal for 87.