93 Octane ok?

[KrazyDidact]

Ever since purchase I've been using 93 octane. I just saw that the Manual says to use premium (92). Do you guys notice a difference? My car is also bone stock.

[SuperSound]

You'll notice it says minimum octane. So 93 is fine, but at least 92 is required.

Thought it was 91 though. Never seen 92.

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[KrazyDidact]

You'll notice it says minimum octane. So 93 is fine, but at least 92 is required.

Thought it was 91 though. Never seen 92.

Sent from my SM-G975U1 using Tapatalk

It sure does lol. Thank!


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[Hemissary]

By-far the majority are simply wasting money with zero PWR gains - using 93RON.

[jdm7]

Use what the owner's manual says, only go up in octane if you are hearing knock. Chrysler's engine controls can't add in spark for higher octane fuel, it starts with the max spark (calibrated to the octane level in the manual) and then reduces spark if knock is detected by the knock sensors. (I believe Ford has a system that can add spark if the sensors are quiet, up until some calibrated amount or the sensors start picking up knock.)

[Hemissary]

If you wish to get maximum performance, use the recommended RON rating. Do not(!) use the highest with the mistaken belief - you're actually getting better performance. There has to be existing knock first before a raise in RON value "might" be warranted.

If you want best fuel mileage, use 81RON. Absolutely zero damage or harm occurs by doing so.

Actually "hearing" knock from these engines is very unlikely cause the PCM instantly detects it and compensates.

[Prange]

On a stock car, I'll use what the manufacturer recommends.

[BillB1]

The manual recommends 87 which is not available. They have 91, 95 only.
I use 95, they claim 95 has better additives for cleaner injectors, smoother running engine.

The question:
What effects 95 has on engine performance when manual calls for 87?

In particular on RPM dropping from this: 620?

630.jpg


to this: 500? never 700 !

500.jpg

[MopaR/T]

I would use what manual says. But I did find one station in town where I work that has ZERO “corn” in it. In other words, none of the 10% ethanol additive that other stations use. I notice nothing as far as performance but the engine doesn’t seem to be suffering from the 90 octane unleaded gasoline I’m using now, compared to the 93 octane with 10% ethanol added.

From just memory of an article I read about fuels before, a lot of the stations get their octane ratings from the added ethanol? Basically they get the bump up in octane from only 90% dead dinosaurs and 10% corn... (or sugar cane? Can’t remember which?!)


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[jdm7]

Using higher octane than called for won't hurt the engine, it just isn't going to help performance. Some higher octane blends might not behave as well on cold starts due to the chemical changes for higher octane effecting the DI (distillation index or driveability index) and making it not like to "light off" on a cold chamber. If you want the cleaning content of the fuel, look for "top tier" fuels - these fuels have higher detergent content than mandated and are approved by OEMs as better for the fuel system. TOP TIER™ Gasoline Brands

[Hemissary]

The manual recommends 87 which is not available. They have 91, 95 only.
I use 95, they claim 95 has better additives for cleaner injectors, smoother running engine.

The question:
What effects 95 has on engine performance when manual calls for 87?

In particular on RPM dropping from this: 620?

630.jpg


to this: 500? never 700 !

500.jpg

Modern injector design function extremely well and rarely develop problems. Its a marketing ploy. You'll notice no difference using 95RON; it will run the same (engine won't know the difference).

[BillB1]

Modern injector design function extremely well and rarely develop problems. Its a marketing ploy. You'll notice no difference using 95RON; it will run the same (engine won't know the difference).

Good to know.
That means there is/are different reason/s for the drop in RPM.
I don't want to hijack the thread here,
I'll post a new topic for discussion.

Many thanks

[Hemissary]

Good to know.
That means there is/are different reason/s for the drop in RPM.
I don't want to hijack the thread here,
I'll post a new topic for discussion.

Many thanks

If you're referring to the idle hunting, its normal (as long as there are not huge swings >100rpm on a regular basis). Our machines use what is called a speed / density system to control rpm (lots of PIDs that contribute to multiple algorithms).

[CE9311]

The manual recommends 87 which is not available. They have 91, 95 only.
I use 95, they claim 95 has better additives for cleaner injectors, smoother running engine.

The question:
What effects 95 has on engine performance when manual calls for 87?

In particular on RPM dropping from this: 620?

630.jpg


to this: 500? never 700 !

500.jpg

So, these two photos. Are we going to ignore that one is in park and one is in drive?

[BillB1]

CE9311,

So, these two photos. Are we going to ignore that one is in park and one is in drive?

Thanks, excellent question.
I'll say yes please ignore it, at least for now, until you see these same pics posted on a separate threads here:
Diagnostics: LX Doctors

Note:
I did not want to hijack this thread,
It turned out to be a much of a serious problem than what I'd initially thought.

Regards
Bill