What Octane Do You Use?

[DOTCOM]

I've been putting 93 Premium in my 392. Curious if it's necessary?

 

[SmoothDriving479]

You can run 87 adequately, 89 minimum is recommended(for best performance), though.

91 octane is required, minimum.

 

[DOTCOM]

Thanks!!

 

[dgerb]

You can run 87 adequately, 89 minimum is recommended(for best performance), though.

What are the results of running 87...knocking or pinging?

 

[Meradin]

The engine has a knock sensor so it will just retard the timing to adjust for the poor gas. I believe that 91 is recommended. We don't have 91 around here so I run 93.

 

[SmoothDriving479]

The engine has a knock sensor so it will just retard the timing to adjust for the poor gas. I believe that 91 is recommended. We don't have 91 around here so I run 93.

Actually, you are right, don’t put 87 in there. 91 octane is mandatory for the 392. The 87 is for the Ram 6.4 not the SRT.

 

[Shortcut]

I've been putting 93 Premium in my 392. Curious if it's necessary?

If it is available I highly recommend it. My milage dropped from 20mpg highway to 15 -16 mpg highway and 12 - 13 MPG around town now that I only have access to 91 octane. P.S. use Top Tier fuel like Costco, 76, Valero, Cheveron, etc.

 

[cgr]

I also run 93. Does anyone have a true scale of quality rankings?

 

[jmwillia]

91 is all they have around here could you get some octane booster and add to fuel to boost it up a bit?

 

[Smess]

Normally if a vehicle requires higher octane it is listed. There is nothing at the fill or on the door, nothing on the visor, nothing on the dash by the fuel gauge.

Does anyone else have anything marked anywhere?

 

[Battle.Rattle]

Normally if a vehicle requires higher octane it is listed. There is nothing at the fill or on the door, nothing on the visor, nothing on the dash by the fuel gauge.

Does anyone else have anything marked anywhere?

I know I read it somewhere. Maybe the owners manual.

 

[BenLandry]

It’s on the Spec sheet: 91 or higher

https://s3.amazonaws.com/chryslermedia.iconicweb.com/mediasite/specs/2021_JP_Wrangler_Rubicon_392_Specsla6s2mf70hctfgb5q521eniaq4.pdf

 

[Farmer John]

This seems like something the dealership should have mentioned to me.

Yesterday, I picked up my 392 and no one said a word about it needing premium fuel.

I am so glad I stumbled across this thread.

I run AvGas in a couple of antique tractors because it is still considered leaded. It has an octane rating of 101.

I wonder what effect that would have in a 392

 

[guruman]

This seems like something the dealership should have mentioned to me.

Yesterday, I picked up my 392 and no one said a word about it needing premium fuel.

I am so glad I stumbled across this thread.

I run AvGas in a couple of antique tractors because it is still considered leaded. It has an octane rating of 101.

I wonder what effect that would have in a 392

If there is any lead in it, it will kill either the O2 sensor or the cats... I'm not sure which... maybe both. But if it's a "lead substitute" I'm not sure.

 

[Ted392]

Do not use avgas in an engine with catalytic converters. It will damage/ruin them. O2 sensors will also fail.

Follow the manual 91/93 octane.

 

[Bald Guy]

93 octane for me. : )

 

[Turboencabulator]

So as someone who buys a few thousand dollars of “AvGas” a year it’s important to know that there are 3-types of 100 AvGas. The most common is 100LL (Low Lead) which is blue and ubiquitous. There is actually a new AvGas called G100UL that is unleaded and starting to become available it’s yellow in color, and I think that would be fine in a 392. There is also the old school 100 AvGas (high lead) that’s green and uses Tetraethyllead to raise the octane to 100, and that stuff is near impossible to find and for good reason. I fly a Boeing Stearman and have a mod (STC) that lets me use regular non-ethanol auto gas that I get at my local Sheetz for $3/gal vs paying $7/gal for 100LL at the airport. I test it for ethanol content by adding water and seeing if any ethanol separates out using a little tester. I still need to run about 25% 100LL to help keep the valves seats lubricated and keep the engine happy. The low compression Continental R-670 (668 cu-in) radial engine only needs like 65 octane to prevent detonation (knocking) so it’s an easy engine to feed. Twice the displacement of a 392 but half the horsepower
So I wouldn’t use AvGas (G100UL) unless your just looking for a way to spend money quicker.

 

[ParadigmDawg]

In my drag racing days, I used 116 octane gas in my push mower. I did this because my sponsor paid for gas and I was too lazy to go fill another jug. I didn't figure it would start much less run and I assumed it would run the motor quickly. I sold that mower 10 years later...lol

 

[Jeepstin392]

91 is listed as the minimum due to that being the highest octane available at altitude. Just as regular at altitude is 85. This is not factoring in race fuels or special fuels. Just in general, the typical 3 grades are regular, mid grade and premium. typically, you won’t find anything higher than 91 at altitude. Many Rocky Mtn states have this.
they make the engine to optimally run at no less than 91, due to this fact of fuel availability anywhere you may travel in the country at any altitude.
Could you run less? Sure, compromising performance, and potential/eventual motor damage.
It’s also wise to carry a bottle of octane boost, depending your travels as at times, premium isn’t available. This is typically in more remote areas.

Personally, I’ve often pondered why spend $80k on a vehicle, and try to save just a couple hundred bucks a year on lesser octane fuel?

 

[ParadigmDawg]

91 is listed as the minimum due to that being the highest octane available at altitude. Just as regular at altitude is 85. This is not factoring in race fuels or special fuels. Just in general, the typical 3 grades are regular, mid grade and premium. typically, you won’t find anything higher than 91 at altitude. Many Rocky Mtn states have this.
they make the engine to optimally run at no less than 91, due to this fact of fuel availability anywhere you may travel in the country at any altitude.
Could you run less? Sure, compromising performance, and potential/eventual motor damage.
It’s also wise to carry a bottle of octane boost, depending your travels as at times, premium isn’t available. This is typically in more remote areas.

Personally, I’ve often pondered why spend $80k on a vehicle, and try to save just a couple hundred bucks a year on lesser octane fuel?

Octane boosters are notorious for eating o2 sensors. I would rather put lower octane in it when there was no other choice and top it off with higher octane gas as soon as I could find some. I am sure that is easier said than done but in my part of Texas, every station has 93 and I can drive 14 miles from my hoses and get pump 100 octane. They used to have pump gas up to 116 but now they only have 100 pump and the rest is can.