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3.6 - For Those Running Premium Fuel

Kreepin1

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You say you are prepared with data - ok then, show me REAL WORLD results. Show me a dyno graph, 1/4 mile times, fuel logs, SOMETHING that proves that running premium actually does offer significant real world gains. Your degrees and percentages are all relevant to "normal" and as a result, very deceiving. Going from 1 to 2 is a 100% increase, but on a scale of 100, it's a change that won't even be noticed. So "put up or shut up" as they say - lets see the goods.

Again, i've been through this countless times with countless vehicles, and i've never seen real world gains in performance or fuel mileage from running premium over regular, JL included. I just got my Tahoe tuned this spring, and I gained 1.5mpg and smoother shifts...MAYBE a tiny bit of power but it's really tough to call. That's on premium with a tune. Given, the Tahoe and JL are different vehicles but the limitation is still the N/A motor. You just aren't going to gain much without FI or other modifications to get more air and fuel into the motor, and you sure as hell aren't going to gain just by changing fuel grades.
From my seat it looks like @Livernois Motorsports has posted real world dyno results, logs, and taken the time to explain how they are getting the gains they have. You on the other hand are throwing around a lot of baseless claims and generally chitting in this thread.

Your degrees and percentages are all relevant to "normal" and as a result, very deceiving. Going from 1 to 2 is a 100% increase, but on a scale of 100, it's a change that won't even be noticed.
To anyone that knows engines you prove right there that you don't know what you're talking about. No gasoline engine on this planet needs 100 degrees of total advance. Most engines like 35 degrees plus or minus 5. Pulling 8 out of optimum is certainly going to cost power and efficiency. If you will go back and read what was posted with an open mind you might learn something.

The fact is, for a given air/fuel ratio each engine will have an optimum timing curve that requires a certain octane to run smoothly. Using fuel with a higher octane is a waste. Using fuel with a lower octane will require less ignition timing and WILL cost power and efficiency.

Having browsed the last 120 of your posts, I get that octane is one of your hot button issues. I also get that you love these on-line bickering sessions and will come back with some smart-ass response. But I won't be sucked into one of your pointless arguments. I am planning to get my Jeep an E85 tune from Livernois this fall in part because of the great info in this thread. :rock:
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TheRaven

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From my seat it looks like @Livernois Motorsports has posted real world dyno results, logs
Where?

No gasoline engine on this planet needs 100 degrees of total advance. Most engines like 35 degrees plus or minus 5. Pulling 8 out of optimum is certainly going to cost power and efficiency. If you will go back and read what was posted with an open mind you might learn something.
You clearly didn't read what I posted.

The fact is, for a given air/fuel ratio each engine will have an optimum timing curve that requires a certain octane to run smoothly.
...and you can find the optimum octane for the 3.6l Wrangler in the instruction manual. That's why they put it there.

Having browsed the last 120 of your posts, I get that octane is one of your hot button issues. I also get that you love these on-line bickering sessions and will come back with some smart-ass response. But I won't be sucked into one of your pointless arguments. I am planning to get my Jeep an E85 tune from Livernois this fall in part because of the great info in this thread. :rock:
Complete BS. You just inserted yourself into this "pointless argument" because you like to hear yourself talk. We don't actually disagree on much, so your post was a complete waste of time for anything other than you pretending to be Mr. Big Boy who's gonna "put me in my place".

OH and BTW, I think a tune is a great idea. I'd get one except that i'm not doing a damn thing that might void my warranty. I'm going to need it.
 

Livernois Motorsports

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Where?



You clearly didn't read what I posted.



...and you can find the optimum octane for the 3.6l Wrangler in the instruction manual. That's why they put it there.



Complete BS. You just inserted yourself into this "pointless argument" because you like to hear yourself talk. We don't actually disagree on much, so your post was a complete waste of time for anything other than you pretending to be Mr. Big Boy who's gonna "put me in my place".

OH and BTW, I think a tune is a great idea. I'd get one except that i'm not doing a damn thing that might void my warranty. I'm going to need it.
They're mentioning we posted logs, the videos already have been posted in the past, as well as the dyno graphs have been, as well as explanation of the baselines and how we choose the ones we post.

Using the "owner's manual" as justification for anything is irrelevant. Chrysler gets all kinds of information and practices wrong, as does any oem, I am not singling them out, but using that as the Gospel Truth is not advised.

here are some issues showing that they get stuff wrong:

Can't design a clutch the doesn't fail
Produced incorrect oil fill data to their dealer system
released over 60 calibration revisions since Job 1 in 2018

This is where understanding the engineering side of things matters. 11.3:1 static compression ratio would struggle to be 87 friendly even with Direct injection. These still use Port injection, which has less control over knock than DI. Then add in the EGR, the low lift cam system that increases dynamic compression, and the curb weight/load these see and it goes against anything that we have seen out of any engine design in the history of engines.

Some things you just can't engineer around and change in practical situations.

attached are 3 more baseline logs from 1 GM, 1 Ford, 1 Chrysler product. note, there is no knock retard happening on any of them and just as mentioned before, the Mustang is adding in timing. It even has a parameter in the log itself for potential low side and high side octane window. It says the lowest it could be is 91, and the highest it could be is 95. and it was 93.

Still waiting for proof that "every vehicle knocks no matter what" because it's completely contradictory to decades of first hand experience.

so, here is more proof that what we are saying is correct, and that knock is not "normal" to experience.
 

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We only have 95 unleaded octane available. No issues at all using it in my previous 3.6 JK and now in my 3.6 JL.
 

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We only have 95 unleaded octane available. No issues at all using it in my previous 3.6 JK and now in my 3.6 JL.
Your 95 is our 91. we in the USA use an average of Research octane and Motor octane, most other countries use Research octane which is always the higher of the 2. So 91=87, 95=91, 98=93.
 

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TheRaven

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They're mentioning we posted logs, the videos already have been posted in the past, as well as the dyno graphs have been, as well as explanation of the baselines and how we choose the ones we post.
Ok i'm going restate for like a fifth time what i'm actually saying, to keep this discussion on track.

I AM NOT SAYING THAT YOU ARE WRONG ABOUT TIMING RETARD/ADVANCE.

I AM NOT SAYING THAT YOU HAVE NOT POSTED DATA ON YOUR TUNES OR TUNES IN GENERAL.

WHAT I AM SAYING IS THAT YOU HAVE NOT PROVIDED JUSTIFICATION FOR YOUR STATEMENT THAT JL OWNERS SHOULD ALWAYS RUN PREMIUM IN THE 3.6L.

Your timing data and logs provide no real world proof of power or efficiency gains realized by the owner. That's what i'm asking for. I'm asking for you to prove your claim that if I run premium in my JL, I will see improved power and fuel mileage. I ask this because you are telling me something that I have already proven wrong. I already did the testing.
 

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I don't care about power or mpg. I am happy to hear the reasons my jeep knocks (especially in summer) and how running 93 octane mitigates it. I care about long term engine health. I would gladly give up mpg or even a little power to keep the engine from knocking. The last car I drove that knocked was a 1987 Kcar.
 

TheRaven

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I don't care about power or mpg. I am happy to hear the reasons my jeep knocks (especially in summer) and how running 93 octane mitigates it. I care about long term engine health. I would gladly give up mpg or even a little power to keep the engine from knocking. The last car I drove that knocked was a 1987 Kcar.
If you are experiencing knock that is not mitigated by the ecm, you have a problem with your engine and you need to get it looked at. Running premium is not a fix, it just masks the problem. You are not preventing any long term damage.

I have no problem knock in my 3.6l JL. It runs as smoothly and as knock/ping free as any other modern engine i've owned.
 

Livernois Motorsports

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Ok i'm going restate for like a fifth time what i'm actually saying, to keep this discussion on track.

I AM NOT SAYING THAT YOU ARE WRONG ABOUT TIMING RETARD/ADVANCE.

I AM NOT SAYING THAT YOU HAVE NOT POSTED DATA ON YOUR TUNES OR TUNES IN GENERAL.

WHAT I AM SAYING IS THAT YOU HAVE NOT PROVIDED JUSTIFICATION FOR YOUR STATEMENT THAT JL OWNERS SHOULD ALWAYS RUN PREMIUM IN THE 3.6L.

Your timing data and logs provide no real world proof of power or efficiency gains realized by the owner. That's what i'm asking for. I'm asking for you to prove your claim that if I run premium in my JL, I will see improved power and fuel mileage. I ask this because you are telling me something that I have already proven wrong. I already did the testing.
Here is what I have posted:

proof that these have no "short term knock" when using 93 octane, which means it's only "learned knock which disappears after resetting the ECM, or eventually after driving it and reaching enough load cells that it learns it back out

I told you even in Chrysler's own logic there is a torque calculation input specifically for retard from MBT and it's percentage of impact on torque, posted what that math equates to in detail.

If I have to argue that 8.5* of spark retard will absolutely cause engine damage over time, and absolutely has a major impact in performance, then you are simply showing you know nothing about how engines work in this regard and are negating any validity to your statements.

But, since I have to prove to you something that is well established fact about how engines function, even though it's part of internal combustion 101, I will attach 2 logs and 2 graphs showing how much impact timing has. Mind you, this is a VERY short blip in timing that we were chasing during calibration development on a Camaro back in 2016, but it shows up clear as day on the log, and the graph. This is fractions of a second long vs nearly 8-10 seconds long on the JL/JT. If I have to argue that 20-30hp worth of loss is going to translate to reduced performance, again, you're showing that you don't understand how engines work. In and of itself that's no issue, but touting how you are right when real, hard data continues to show you are wrong is just silly.

So far, when we post proof, you deflect and talk about how we are just incorrect, with no proof on your part.

Plus, the whole thing of you testing "every vehicle you have ever owned" to see it's impact with and without premium on power and efficiency, bring us your data. Actual hard information. weather for the day, drive cycle information, throttle input, accessory load information, etc.

I don't care about power or mpg. I am happy to hear the reasons my jeep knocks (especially in summer) and how running 93 octane mitigates it. I care about long term engine health. I would gladly give up mpg or even a little power to keep the engine from knocking. The last car I drove that knocked was a 1987 Kcar.
Exactly the point. It's knocking so bad on 87 that you hear it. I have seat time in countless JL's, and everyone I have driving have shown this to be true.

If you are experiencing knock that is not mitigated by the ecm, you have a problem with your engine and you need to get it looked at. Running premium is not a fix, it just masks the problem. You are not preventing any long term damage.

I have no problem knock in my 3.6l JL. It runs as smoothly and as knock/ping free as any other modern engine i've owned.
Not at all true. Again, you're just regurgitating the info from the owners manual.

And, since your Jeep is knock free, post your datalogs and dyno runs showing no knock please. Or are you saying just because you can't hear it means it's not happening? Because those aren't the same thing.

Knock retard is reactive. It has to knock, and then the computer pulls timing. Meaning the knock event already happened. This in and of itself can cause damage over time, especially for those that are aggressive on the throttle. Then, let's say timing does learn and it stops actively knocking, but still has timing being pulled, again, this increases EGT, which increases catalyst temp, which will prematurely wear the catalyst out, and cause failure. On the headifold design on the pentastar, the catyalyst is so close to the port that it has reversion and sucks the substrate back into the engine if it fails and damages it internally.

2016_camaro_SS_impact_of_timing_drop.png
 

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Reseg

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Let me get this correct (without the fluff), Livernois Motorsports is claiming FCA is either lying, or incorrect in their official statement that anything higher than 87 octane in the 3.6L provides no benefit? And Livernois Motorsports claims to have proof that using 87 in a stock 3.6L JL is a bad idea, leading to less performance, lower MPGs, and early engine failure due to the type of detonation/knock they've documented?

Did I read that right?

Oooooooh boy. There are some lawyers somewhere that'd love this, in one way or another. FCA is extremely liable for those claims in the owners manual, just as Livernois Motorsports is liable for these claims they're making here to an audience of FCA's customer base...

Everyone get their popcorn while I screenshot this and send it to FCA corporate so they can clarify their position on 87 octane in the 3.6L lol.
 

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Livernois Motorsports

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Let me get this correct (without the fluff), Livernois Motorsports is claiming FCA is either lying, or incorrect in their official statement that anything higher than 87 octane in the 3.6L provides no benefit? And Livernois Motorsports claims to have proof that using 87 in a stock 3.6L JL is a bad idea, leading to less performance, lower MPGs, and early engine failure due to the type of detonation/knock they've documented?

Did I read that right?

Oooooooh boy. There are some lawyers somewhere that'd love this, in one way or another. FCA is extremely liable for those claims in the owners manual, just as Livernois Motorsports is liable for these claims they're making here to an audience of FCA's customer base...

Everyone get their popcorn while I screenshot this and send it to FCA corporate so they can clarify their position on 87 octane in the 3.6L lol.
Lawyers never need facts to start a litigation, however, yes, it is our stance that this engine should NOT be ran on 87 unless absolutely necessary and driven gently as such. The liability is never on someone erring on the side of caution.

And everyone told me that the 2.0 was supposed fail early...

Seriously though, how early could this start to be a problem? Just out of warranty or 250,000 instead of 300,000?
There is no hard number, as it depends on how someone drives and maintains it. Sort of like the rocker arm issues, it depends on too many factors. However, as these age, there likely will start to be detonation related failures of some sort crop up. So you're likely to see a mix of both.

This is big reason why these gain so much power from tuning, as they are past the limits of 87 already. Just another reinforcement into these.

Again, manufacturers make these kind of mistakes all the time.

Ford, gen1 coyote engines are notorious for knocking the ring lands off of pistons (not to mention countless EcoBoost engines)

GM 2.4 SIDI engines, plus 1.4, 1.5, and 2.0 Turbo engines have piston cracking issues

As more and more manufacturers move to try to get the most efficiency and power out of their product, these situations increase in frequency.
 

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it is our stance that this engine should NOT be ran on 87 unless absolutely necessary and driven gently as such.
Do you have any experience with elevation and how it impacts a modern engine such as the 3.6L? Here in CO my "regular" grade fuel is 85 octane (using (R + M) / 2 method which I believe is the standard in the US). Mid grade is 87, premium is 91. I don't have the best ear or feel for engines but I was convinced my 3.6 was knocking while in Denver on our regular 85 at just call it 5,280 ft of elevation. So I started running 87. To my ear I am not noticing knocking now, but I'm wondering if you have an opinion on the matter. Basically; Is it still true for a modern NA engine like the 3.6 that as we increase elevation we can (should?) reduce octane? Or would me switching to 91 octance likely be a waste of cash? I have ran the odd tank of 91 here and there, I can't tell a difference from the 87 but again I by no mean have an ear for this.
 

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Not at all true. Again, you're just regurgitating the info from the owners manual.
So basically what you're saying is "the timing data I have posted along with truths that everyone already knows proves that the people who designed this machine and the experiences of hundreds of thousands of JL owners are all wrong". Got it.

You have completely failed to connect your data to real world results. Even the dyno graph you posted shows there is little to no difference. Again, I BELIEVE YOU when you say that the handful of JLs you have tested have shown higher degree of spark retard than you are used to. What i'm telling you is that it's not a big problem, and all you have come back with is "if you don't think it's a big problem, then you don't know engines". You sound like a typical fanboy.

I don't need to prove anything. I'm not the one claiming that the people who created the machine are wrong. If you make the claim that the sky isn't blue, I don't need to provide proof that it is. The burden of proof is on you. This subject has been beaten to death. FCA spoke, they were questioned, they spoke again, they were questioned again, and they spoke again. There is no ambiguity on where they stand on the proper octane for the 3.6l. So what it comes down to is - do I trust the designers of the machine, who lose money when the machine fails? Or do I trust a small tuning outfit who's profit comes from fixing "defects" in said machine? I'd have to be a moron to not see the obvious choice here...especially when it mirrors my own real-world experience.
 

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Do you have any experience with elevation and how it impacts a modern engine such as the 3.6L? Here in CO my "regular" grade fuel is 85 octane (using (R + M) / 2 method which I believe is the standard in the US). Mid grade is 87, premium is 91. I don't have the best ear or feel for engines but I was convinced my 3.6 was knocking while in Denver on our regular 85 at just call it 5,280 ft of elevation. So I started running 87. To my ear I am not noticing knocking now, but I'm wondering if you have an opinion on the matter. Basically; Is it still true for a modern NA engine like the 3.6 that as we increase elevation we can (should?) reduce octane? Or would me switching to 91 octance likely be a waste of cash? I have ran the odd tank of 91 here and there, I can't tell a difference from the 87 but again I by no mean have an ear for this.
Modern control systems adjust the calibration for altitude, so it measures BARO almost continuously and adjusts the calibration, both fueling and spark (as well as other items) so they add power in because the less dense air typically allows for more timing, because of that though the octane requirements don't change nearly as much as older vehicles used to.
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