What fuel for 5.7

[MannymanX]

When using Costco 91 i get no knock and very smooth power bend.
87 knocks pretty bad for some reason... It did since brand new...

 

[392DCGC]

I have never gotten much better than 19.5 mpg using 89 . My truck runs great on 89. 91 octane at COSTCO was 25 cents less than the cheapest 89 in my area. I was surpised what a difference it made considering the comments I read from people saying it makes no difference. It made a huge difference in my truck and I saved $7.00 on the tank over buying 89.

I love Costco and almost exclusively fill our vehicles with their fuel because it's cheap, good, and fresh... but there in no way increasing octane by 2 points raised your MPG that much. Other factors were at play.

Nice! Crusing down I-10? The best part about Costco is you get a 4% cash back on gas purchases. So if gas is $2 a gallon at the pump, you end up paying $1.92!

If you use their Citi Visa, indeed. Only downside is you get the cash back once per year and in a paper voucher to take to Costco... bit ridiculous.

 

[LakesAZ]

I love Costco and almost exclusively fill our vehicles with their fuel because it's cheap, good, and fresh... but there in no way increasing octane by 2 points raised your MPG that much. Other factors were at play.

If you use their Citi Visa, indeed. Only downside is you get the cash back once per year and in a paper voucher to take to Costco... bit ridiculous.

True about the paper voucher, but if you take it to the area where they get product out of the cage and tell them you want to cash it, they will give you cash. This works as that's what I did a few weeks ago with mine.

 

[Lake Ram]

I love Costco and almost exclusively fill our vehicles with their fuel because it's cheap, good, and fresh... but there in no way increasing octane by 2 points raised your MPG that much. Other factors were at play.

If you use their Citi Visa, indeed. Only downside is you get the cash back once per year and in a paper voucher to take to Costco... bit ridiculous.

Other factors were at play? Such as? Same freeway, same route, same speed. Numbers don't lie. Not gonna argue, but I am going to stick with COSTCO 91.

 

[MannymanX]

87-89-91 changes a lot.
91 does give you better MPG, it's a fact...
My truck is not running smooth with Costco 87 as it runs with Costco 91.
MPG is not a thing to be considered because it cost more to use 91 and the difference in MPG is not high enough.

 

[Lake Ram]

87-89-91 changes a lot.
91 does give you better MPG, it's a fact...
My truck is not running smooth with Costco 87 as it runs with Costco 91.
MPG is not a thing to be considered because it cost more to use 91 and the difference in MPG is not high enough.

Agreed. If COSTCO offered 89 octane I would use it. My post was more about my surprise at the increased mpg using 91 and how much cheaper it is than 89 in my area. I just want the best performance my truck can offer, I didn't buy my Ram for its great gas mileage. More like in spite of it.

 

[392DCGC]

Agreed. If COSTCO offered 89 octane I would use it. My post was more about my surprise at the increased mpg using 91 and how much cheaper it is than 89 in my area. I just want the best performance my truck can offer, I didn't buy my Ram for its great gas mileage. More like in spite of it.

Make your own (if you have the patience). Guesstimate how many gallons you need to fill the tank, then fill half with 91 and half with 87... takes a minute longer to do, but saves a bit of money vs pure 91 and gets you to 89. Always fill with 91 first though... otherwise you lose some 91 leftover in the fuel pump hose that you paid for but never made it into the tank (unless the guy before you was also pumping 91).

 

[silver billet]

Make your own (if you have the patience). Guesstimate how many gallons you need to fill the tank, then fill half with 91 and half with 87... takes a minute longer to do, but saves a bit of money vs pure 91 and gets you to 89. Always fill with 91 first though... otherwise you lose some 91 leftover in the fuel pump hose that you paid for but never made it into the tank (unless the guy before you was also pumping 91).

If the guy before you was pumping 87/89 and you start with 91, then you're still getting junk gas in the hose you didn't pay for.

 

[gHiDoRa]

If the guy before you was pumping 87/89 and you start with 91, then you're still getting junk gas in the hose you didn't pay for.

man, that definitely hurt my engine....lol.

 

[LakesAZ]

Make your own (if you have the patience). Guesstimate how many gallons you need to fill the tank, then fill half with 91 and half with 87... takes a minute longer to do, but saves a bit of money vs pure 91 and gets you to 89. Always fill with 91 first though... otherwise you lose some 91 leftover in the fuel pump hose that you paid for but never made it into the tank (unless the guy before you was also pumping 91).

Or just fill up at the half tank level and get 87 one time and the next get 91. It’s not a perfect solution but it gets the job done.

 

[awpratt79]

that is why I ussually try to find a station that has seperate hose for each grade of fuel, only premium non-ethenol fuel for me. Unfortunately when traveling that's not always possible so try to fill the tank with as much fuel as possible, it takes about 2 gallons or so to get the previous grade out of the single hose pumps that way it dillutes the ethenol blend as much as I can. Every vehicle I have had since wisconsin implemented the ethanol mandate has benefitted in MPG's with using non-ethanol fuel also etanol fuel leaves more carbon deposits inside the engine and on injectors resulting in more maint. cost down the road. My son is a tech at my local RAM dealership and tells me the stories of what he sees inside of some of these engines or clogged injectors with low miles. So either pay at the pump or pay in the shop.

 

[Timeless]

Make your own (if you have the patience). Guesstimate how many gallons you need to fill the tank, then fill half with 91 and half with 87... takes a minute longer to do, but saves a bit of money vs pure 91 and gets you to 89. Always fill with 91 first though... otherwise you lose some 91 leftover in the fuel pump hose that you paid for but never made it into the tank (unless the guy before you was also pumping 91).

This is what I do with Costco/Sams. It is either 93 or 87 and I basically swap at each fill up. It averages out to at least 89.

If the guy before you was pumping 87/89 and you start with 91, then you're still getting junk gas in the hose you didn't pay for.

that is why I ussually try to find a station that has seperate hose for each grade of fuel, only premium non-ethenol fuel for me. Unfortunately when traveling that's not always possible so try to fill the tank with as much fuel as possible, it takes about 2 gallons or so to get the previous grade out of the single hose pumps that way it dillutes the ethenol blend as much as I can. Every vehicle I have had since wisconsin implemented the ethanol mandate has benefitted in MPG's with using non-ethanol fuel also etanol fuel leaves more carbon deposits inside the engine and on injectors resulting in more maint. cost down the road. My son is a tech at my local RAM dealership and tells me the stories of what he sees inside of some of these engines or clogged injectors with low miles. So either pay at the pump or pay in the shop.

The residual amount left over from the previous user is going to hurt you as much as the residual amount left over from a 93 premium user is going to help the next person.

 

[LakesAZ]

This is what I do with Costco/Sams. It is either 93 or 87 and I basically swap at each fill up. It averages out to at least 89.





The residual amount left over from the previous user is going to hurt you as much as the residual amount left over from a 93 premium user is going to help the next person.

What he said above me

 

[silver billet]

This is what I do with Costco/Sams. It is either 93 or 87 and I basically swap at each fill up. It averages out to at least 89.





The residual amount left over from the previous user is going to hurt you as much as the residual amount left over from a 93 premium user is going to help the next person.

I wasn't suggesting that the amount in the hose is a large issue; just that it makes no difference which octane you start/end from.

 

[RunsWithBeer]

If the guy before you was pumping 87/89 and you start with 91, then you're still getting junk gas in the hose you didn't pay for.

According to the American Petroleum Institute the gas-pump hose typically retains about one third of a gallon of fuel.

 

[sppb32]

What's the 5.7 compression ratio?
What makes it require high octane fuel?

Sent from my SM-G977U using Tapatalk

 

[RunsWithBeer]

What's the 5.7 compression ratio?
What makes it require high octane fuel?

Sent from my SM-G977U using Tapatalk

Lemme google that for you...

Modern Mopar / Chrysler / Dodge 5.7 Hemi Magnum V8 Engines

www.allpar.com

 

[Timeless]

I wasn't suggesting that the amount in the hose is a large issue; just that it makes no difference which octane you start/end from.

Well you did suggest not going to pumps that have one hose with multiple octane options....so I was responding to that.

 

[silver billet]

Well you did suggest not going to pumps that have one hose with multiple octane options....so I was responding to that.

Where exactly did I suggest that?

 

[Timeless]

Where exactly did I suggest that?

So apparently you and I both did not see where I was originally responding to @awpratt79

If you scroll up you will see. Apologies for the confusion.