Fuel octane requirements when premium isn't available.

[Jeepnutz]

Will the 392 compensate for lower octane when premium isn't available? Considering ordering a 2022 but there are quite a few times that premium fuel just isn't available in the back country on some of our trips.

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[RELBUS]

Why not pack octane booster?

 

[Jeepnutz]

Why not pack octane booster?

Lots of crap out there in octane booster land though not to mention the chance of the wife or I forgetting. FCA didn't add programming to retard timing a bit like what Ford does on the Raptor and mustang?

 

[asuperheat]

Rating is 91 required ( We have 93 here locally). Personally I would not run less unless its a situation where you have no choice then only what you need until you can top off with premium.

 

[Boatbuilder88]

What? No knock sensors on these these?

 

[Jeepnutz]

Rating is 91 required ( We have 93 here locally). Personally I would not run less unless its a situation where you have no choice them only what you need until you can top off with premium.

Well that's disappointing. Still waiting on a call back to verify but if that's the case the 392 is off my radar.

 

[Outrun]

Food for thought. Over in the Power Wagon forums and other 6.4L forums there seems to be quite a few using regular octane gas for thousands of miles with no issues.

 

[asuperheat]

The knock sensor should pull enough timing to protect the motor but it is pretty much designed and built for performance so the compression and base tune of the motor probably dictates 91.

 

[JJMalone]

If forced to use a lower octane fuel drive to prevent detonation. Detonation or pinging can be controlled by the way you drive. Pinging happens mostly when loading the engine at low rpm (lugging). Use light throttle and hold the engine in lower gears longer. If pulling a grade down shift and let the engine spin a little faster. The torque required to pull a grade is less in a lower gear. Pulling a grade at a given speed will take a certain amount of power. Using a lower gear will take less throttle. Remember HP=Torque X RPM/5252 so the higher the rpm the less torque needed. The knock sensors can only do so much. In the 60s when I was a mechanic in a different life I was at a seminar on octane requirements on high performance engines and the lecturer stated that once the engine was well up to speed in its power band it would run without detonation on much lower octane fuel. Over the years I have experienced detonation with hp engines and it always occurred at lower revs pulling up to the power band.

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