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Octane requirements for the 6.4 Hemi???

louisiana_dog said:
I wonder when they switched. Maybe the manufacturing date determined when they switched over to 87. Mine was made in July and recommends 89.
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Mine july 1 of 2020
 
Use 87 for everyday driving. If I were to push the engine (can't think of a reason to be thrashing a PW off the redline), I'd try to get the mix to be around the 89. Biggest thing is no codes and modern ECMs will keep the engine safe.
 
jadmt said:
my 2020 owners manual says 87 and no mention of 89. Page 471.

6.4L ENGINE
Do not use E-85 flex fuel or ethanol blends
greater than 15% in this engine.
This engine is designed to meet all emissions regulations and provide satisfactory fuel economy and performance when using high quality
unleaded gasoline having a posted octane number range of 87 as specified by the (R+M)/2 method.
While operating on gasoline with an octane number of 87, hearing a light knocking sound from the engine is not a cause for concern. However, if the engine is heard making a heavy knocking sound, see dealer immediately. Use of gasoline with an octane number lower than 87 can cause engine failure and may void or not be covered by the New Vehicle Limited Warranty.
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I have a 2020 with the 6.4 and the owners manual says 89 octane is recommended.
 
@JC said:
91 is ethanol free here so that's what it gets. No ethanol will touch my engines.
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I used to believe that too but after actually testing the fuel i have yet to find a local station that actually has 91 that tests how 91 should most endup testing at 89 octane and containing about 5% ethanol
 
H3LZSN1P3R said:
I used to believe that too but after actually testing the fuel i have yet to find a local station that actually has 91 that tests how 91 should most endup testing at 89 octane and containing about 5% ethanol
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And we get charged the premium for this so called special blend.

Sent from my moto z3 using Tapatalk
 
has anybody try add regular 85 and just add octane boost additive?
 
leshawn yazzie said:
has anybody try add regular 85 and just add octane boost additive?
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I mentioned it in your other post, but I run 85 all the time. Granted, I'm in Colorado so the altitude allegedly has some impact on how that performs, but I've had no issues following this approach through multiple Hemi's.
 
I’ve been running 87 in mine since I got it in November of 2019. Haven’t noticed any issues around town or pulling a 7k lb camper into the mountains of NH & VT. So weird that they have conflicting info online & in print manuals...

Somewhat on the same topic - how bad is Sam’s Club gas? I know top tier brands are the best stuff, but is Sam’s as bad as the El Cheapo stations I used to see in GA?
 
60_Driver said:
I’ve been running 87 in mine since I got it in November of 2019. Haven’t noticed any issues around town or pulling a 7k lb camper into the mountains of NH & VT. So weird that they have conflicting info online & in print manuals...

Somewhat on the same topic - how bad is Sam’s Club gas? I know top tier brands are the best stuff, but is Sam’s as bad as the El Cheapo stations I used to see in GA?
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Just about all gas comes from the same depo's these days. The only difference is the additive package that gets mixed in when it is pumped into the truck.

I use 100% Mobil gas in my Caddy because I have a fuel card for work, but aside from that, I always prefer the unbranded stations for the cost savings. Ive never noticed an issue with it. I wouldn't worry about using the Costco gas.
 
60_Driver said:
I’ve been running 87 in mine since I got it in November of 2019. Haven’t noticed any issues around town or pulling a 7k lb camper into the mountains of NH & VT. So weird that they have conflicting info online & in print manuals...

Somewhat on the same topic - how bad is Sam’s Club gas? I know top tier brands are the best stuff, but is Sam’s as bad as the El Cheapo stations I used to see in GA?
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Costco is part of the TopTier branded family.

www.toptiergas.com

Fuel Stations - TOP TIER™

TOP TIER™ Licensed Brands prominently display the TOP TIER™ logo on the pump, pump handle, canopy or in a station window.
www.toptiergas.com www.toptiergas.com
 
Not so worried about the top tier situation but I use 89 exclusively in my truck.

smaller companies get their gas from the same places that big companies do. I worked at Racetrac for years and they’re not a top tier brand but QuikTrip, their main competitor in this market, is. We got all our gas from marathon so we were selling top tier gas, we just didn’t have the logo
 
Have always ran premium, it runs way cleaner.
When I still had my 04 hemi last year I had to have the heads off for a cam follower swap, the tops of pistons were still as shiney as the day it left the factory.
 
Reviving this thread from the dead. I've been running 86 since I got the truck and have noted no performance issues while unloaded or towing. I'm at 7,300 ft in elevation. What are you guys that live at high altitude pumping?
 
The comment in the manual - if you hear knocking light knocking - don't worry about it. If you hear heavy knocking - increase the octane rating - crazy.

If you hear knocking, it is damaging your engine and long before you hear it.

The only reason they might suggest lower octane fuel is the same reason to recommend long duration between oil changes. Meet some kind of fleet cost accounting number. Same impact on engine life.
 
LeRamona said:
Reviving this thread from the dead. I've been running 86 since I got the truck and have noted no performance issues while unloaded or towing. I'm at 7,300 ft in elevation. What are you guys that live at high altitude pumping?
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86 Octane fuel isn't sold here in Western Colorado. I've been running 85 Octane in our 4.0 Gen 6.4L since 2016 with 130K miles on the odometer. Our nearest fuel station has one pump with a choice of diesel and 85 Octane gas, only. 87 and 91 Octane are available at the next fuel station which is 40 miles south on the highway, as well as 85 Octane. If our 4.5 Gen wasn't a diesel it would get 85 Octane because it has had zero engine issues at our altitude in the 52 years that I've been running it.
 
JohnandDonna said:
Getting ready to pull the trigger on ordering a 2020 2500 Mega Cab with the Hemi. I would like to know what the actual octane requirements are. Some websites say it uses premium gas. I have seen postings in this forum that say you can use regular but mid grade is preferred. Who has a 2019 with the Hemi and what do you use? What does the owner manual say should be used? Frustrating as I cant seem to get a straight answer from the dealer (they say they think its premium). HELP!
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My 25 2590 HD says 87 in the fuel cap contracts what I use
 
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