Simple Gasoline Grade Question

[blahargoue]

I recently traded my '17 EcoDiesel for a 2020 1500 Laramie 5.7 Hemi to gain nearly 4000 pounds of towing capacity. That is working out really well so far on my recent 3000 mile trip from CA to Wyoming towing my 8000 lb travel trailer. Big difference in stability with new chassis.

I was reading thru the manual a few days ago and noticed that they recommend 89 octane fuel but it also says 87 octane is acceptable. I've been running 87 octane for 5000 miles so far without issue. So for grins I started filling up with 89 octane. I frequently travel 300 miles each way (not towing) between my mountain home and a little place we have in the coast. I have not noticed any performance, drivability or fuel mileage difference between the 2 grades of fuel. The ECM seems to be doing a great job of mitigating any pinging and such. Frankly, I can't tell any difference and will go back to 87 octane unless I plan on doing some hard towing. Fuel mileage is still right at 19 mpg at 75 mph on both grades if fuel.

So, has anybody else noticed any difference in their stock truck on 87 v. 89 octane fuel?

 

[Graygoose]

The age old argument.

For me, I did 89 all the time. I don't want the computer to pull timing for a few dollars per fill up. Rather have all the Hemi power available when needed.

Daily around town, 87 would work, but passing, pulling, etc 89. So as cheap as gas is now, why not 89.

 

[retired]

I have a 6.4 and have used all 3 grades 87,89 and 91 and no difference in mpg or seat of the pants feel.

 

[Travelin Ram]

I wish someone would put one on a dyno and get some real world numbers. My opinion is it’s such a small difference that only a dyno or a timed quarter would know the difference.

 

[retired]

I wish someone would put one on a dyno and get some real world numbers. My opinion is it’s such a small difference that only a dyno or a timed quarter would know the difference.

yup

 

[Graygoose]

well in race cars, 1* of timing can be huge. Im sure in a street car is minimal, but pulling timing kills power.
I pay for 395hp, I want it all

 

[Overlander]

Isn't there lore regarding 89 and avoiding hemi tick... ?

 

[blahargoue]

I certainly can't see what 89 v 87 octane would have to do with the Hemi Tick.

 

[Burla]

Where I get gas they only have 91 or 87, I can say the truck's engine just runs perfect on 91 and is not so spiffy on 87. For my truck it is night and day difference.

Well explained here...

 

[bluebeast1562]

well in race cars, 1* of timing can be huge. Im sure in a street car is minimal, but pulling timing kills power.
I pay for 395hp, I want it all

Graygoose, I also like the idea of having 395hp but to be honest, where was that 395 number pulled from? Engine dyno at say, 6000rpm? Rear wheel dyno?
I do not believe that 395 is an attainable number in daily driving, tranny will not allow a consistent *** rpms. Just my 2 cents.

 

[Graygoose]

Graygoose, I also like the idea of having 395hp but to be honest, where was that 395 number pulled from? Engine dyno at say, 6000rpm? Rear wheel dyno?
I do not believe that 395 is an attainable number in daily driving, tranny will not allow a consistent *** rpms. Just my 2 cents.

Ask Ram where they got it.
It's all over their website and lit

 

[pacofortacos]

I run 87 normally and go to 89 when towing in hot summer weather. Heavy load I go 89 or above. Empty cruising 87 - even at high elevation I stick to 87 not the 85 - I don't live at high elevation, so I prefer to not put the 85 in the tank.

 

[msedly]

I've noticed a bit of spark knock on 87, especially with MDS active. I usually run 89 or 93 and don't notice any knock with either. Slight MPG increase but definitely not going to break even vs. using 87. Long term it's better for the engine if it's not knocking so I'll play it safe.

 

[bluebeast1562]

I too run 89 most of the time, sometimes I do fill up with 91 or 93 (pure gas) but she sure loves to drink that stuff up.

 

[yakalong]

I run 87, never an issue. Run what makes you happy

 

[ram1500rsm]

91 for me and the excuse is we don't have 93 available here in California. I only pump 87 on rentals where I don't care for such octane grade. Every rental I've had had pinged on 87 in the summer. . I bought a 395HP Hemi equipped truck and want all the 395hp so I not only disabled the 4 cyl crap but also did a massage on my Hemi timing map as well as several other changes in the tune to guarantee such power delivery. If I could run 93 I'll run it without any regrets.

 

[Amerinamese]

I get 93 at Costco because it's cheaper than 89 at any other station. It's even cheaper than 87 at normal stations. I've only filled up 4 times since owning the truck and haven't used anything other than 93. I've had no problems.

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