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post #1 of (permalink) Old 08-03-2015 Thread Starter
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KR logging on 3.6L LFX engines

I was just wondering if anyone has logged the amount of KR (Knock Retard) that they are getting on their 3.6L LFX engines. I'm always reading how these engines are tuned from the factory with lots of KR, so I recently started paying more attention to the KR levels in my HPTuners logs. I was kinda startled by the amount of KR that I seen in the logs! I've seen up to 9 degrees of KR, but that was rare - what really caught my attention was how *often* there was KR (not really the number of degrees of KR).

I always run 93 octane gas, so I really wasn't expecting to see KR so often. The hotter it is outside, the worse he KR seems to be. Also, certain RPMs seem to consistently produce KR - for example, between 1200 and 1300 RPM at light throttle, KR was particularly bad. I seem to be at 1200-1300 RPM a lot while just cruising at a constant speed and I would see KR until I either let off of gas a little or applied a little more gas.

Just yesterday, I removed a degree or two of timing at certain places in my high octane table, paying special attention to the 1200-1300 RPM range and sure enough, it seemed to help significantly, so I don't believe that this was false knock or anything like that. Currently, my timing tables are from the Overkill 91 octane tune, but KR was even worse with the stock tune (mainly because the stock tune is a LOT more cautious about removing KR, so you generally see it more often as it slowly restores the timing - the Overkill tune restores timing MUCH faster than the stock tune when it encounters knock).

Anyway, I was just curious if anyone else has logged and/or monitored their KR levels in the 3.6L LFX engine - and what their results were. Not just at WOT (where I rarely see KR), but at part-throttle as well.

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post #2 of (permalink) Old 08-03-2015
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No, but I watch the KR closely on the Lincoln. No issues, but I watch it. As you know, KR is the worst under lugging conditions (ie. struggling in a high gear when you should really be in a lower gear).

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post #3 of (permalink) Old 08-06-2015
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Are you buying your gas at the same place all the time ? Perhaps a longer term study with different fuel suppliers and see what/if any the difference is? I would have suggested 20.00 at a time from each but cross contamination may affect the outcome.

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I do usually buy my gas from a small, family-owned Mobil station (93 octane top-tier fuel). It's near work and the only Mobil station I know of, to be honest. Sometimes, I do have to get gas around my house at Sunoco (which is all that is around me) - I still do get 93 octane, but it's not top-tier "certified" and I just don't trust these places - they're always owned by foreigners and I have no idea if they just buy the cheapest gas possible or what. I just trust the Mobile station more for some reason, mainly since I know that Mobile uses Top-Tier gas.

I do monitor the ethanol content and it's usually around 7% or 8%.

However, with the advice of some others on the HPTuners forums and a little more logging, I have actually got rid of the majority of my KR just by skimming a degree or two of timing off here and there in the main problem areas - and by using the previously un-used IAT (Intake Air Temp) spark modifier tables to remove a degree or two from certain areas when the IAT's are over 95F. So right now, I am getting VERY little KR, even when very hot out. I'm going to keep monitoring and go from there.

I know I've said it a million times now, but having an HPTuners device has really opened my eyes and I've learned SO much about how these cars work. It's been a great experience and would recommend it to anyone interested in this kind of stuff!

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General Motors, along with six other top automakers, have established the TOP TIER Detergent Gasoline Standard. This is the premier standard for gasoline performance, and is designed to ensure optimum engine performance.
https://fastlane.gm.com/2014/10/13/5...tier-gasoline/

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You may not have read my last post, but I do in fact use Top Tier fuel. Just an FYI (wasn't quite sure what the goal of your post was).

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What's the ethanol content of your 93 gas.
Y'all have different requirements there than we'all do.
Our "premium" gas (shell) has no methanol.
Just wondering if it's the same for you. ?

Some things are better left unsaid, which I generally realize right after I have said them.
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Quote:
Originally Posted by jtrosky View Post
I do monitor the ethanol content and it's usually around 7% or 8%.
From my post above. :-)

Generally, I believe that most gas here has "up to 10%" ethanol.

EDIT: Also, my understanding (which may be wrong) is that ethanol is more resistant to knock than regular gas, so if anything, ethanol-laced gas would cause less knock, not more.

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The 87 octane I've been running is 12% ethanol. They do have ethanol free premium at one location about 15 miles north of me for $.40 more then the ethanol premium. How much does ethanol effect the gas?


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I was thinking more of phase separation in the storage tanks at the dealer.
I pick up about 7% in mpg (L/100 km) if I use ethanol free fuel ( premium)
As to whether it knocks more or less I dunno.

Edit
Do I understand you that you can watch this happen real time as your driving ?

Some things are better left unsaid, which I generally realize right after I have said them.

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Quote:
Originally Posted by KG2014 View Post
The 87 octane I've been running is 12% ethanol. They do have ethanol free premium at one location about 15 miles north of me for $.40 more then the ethanol premium. How much does ethanol effect the gas?


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93 Octane is 93 octane regardless of the amount of ethanol...ethanol has a lower BTU rating than gasoline and basically lowers the 'potency' of gasoline. It can reduce gas mileage and power...not a lot but noticeable.
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Quote:
Originally Posted by jtrosky View Post
I was just wondering if anyone has logged the amount of KR (Knock Retard) that they are getting on their 3.6L LFX engines. I'm always reading how these engines are tuned from the factory with lots of KR, so I recently started paying more attention to the KR levels in my HPTuners logs. I was kinda startled by the amount of KR that I seen in the logs! I've seen up to 9 degrees of KR, but that was rare - what really caught my attention was how *often* there was KR (not really the number of degrees of KR).

I always run 93 octane gas, so I really wasn't expecting to see KR so often. The hotter it is outside, the worse he KR seems to be. Also, certain RPMs seem to consistently produce KR - for example, between 1200 and 1300 RPM at light throttle, KR was particularly bad. I seem to be at 1200-1300 RPM a lot while just cruising at a constant speed and I would see KR until I either let off of gas a little or applied a little more gas.

Just yesterday, I removed a degree or two of timing at certain places in my high octane table, paying special attention to the 1200-1300 RPM range and sure enough, it seemed to help significantly, so I don't believe that this was false knock or anything like that. Currently, my timing tables are from the Overkill 91 octane tune, but KR was even worse with the stock tune (mainly because the stock tune is a LOT more cautious about removing KR, so you generally see it more often as it slowly restores the timing - the Overkill tune restores timing MUCH faster than the stock tune when it encounters knock).

Anyway, I was just curious if anyone else has logged and/or monitored their KR levels in the 3.6L LFX engine - and what their results were. Not just at WOT (where I rarely see KR), but at part-throttle as well.

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Yea this car is designed to advance and retard timing at will. I also started running 93...I mostly worry about WOT...as long as no KR shows up there I don't worry too much about it. Temperature seems to have a lot to do with it. Once it gets below 70 degrees the KR starts to fade. As long as it's less than 10 degrees the computer can account for it and it's not doing any harm to the motor. If it's pulling timing at WOT you're losing power and nobody wants that!

I still have people argue with me about this car being able to take advantage of 93 Octane without a tune...and it sure can...the tables are already there and slowly but surely the computer will advance the timing if no knock is detected. Another thing I did was to decrease the rate and degrees the computer pulls timing...sometimes it will pull 4 or 5 degrees when it really only needs 1 or 1.5. Just be careful with those tables...because you still want it to retard timing when needed.
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Yeah, I probably shouldn't worry about it since it does it from the factory with the factory tune, but since I don't need to squeeze every last drop of power from the car, I decided to attack the problem a little. It's amazing how much the KR can be reduced/elminated by just removing a degree or two of timing here and there. Now, the most I ever see (so far) is 4 degrees - and even that is rare - it's usually 2 or less now. I've also started to tune the IAT (Intake Air Temp) spark modifier tables so that the hot weather (IAT's over 95F) don't affect it so much. Surprisingly, the IAT tables weren't used at all from the factory (or with the Overkill tune).

I've also settled on a compromise between the stock and Overkill tunes regarding how fast it restores timing when it does detect knock - the stock tune restores timing VERY slowly and the Overkill tune restores it VERY quickly. I decided to go with a "middle of the road" value so that it restores timing relatively quickly, but not as quickly as the Overkill tune. I've been doing a LOT of logging with HPTuners and I've learned so much about how these cars work - I mean I've really learned a LOT! :-) Very cool stuff...

I've found that the car defaults to the High Octane table and only moves towards the Low Octane table if and when it experiences knock. Since I saw KR so often with 93, I can only imagine how much timing gets pulled with 87 octane! There is no doubt in my mind that this car runs better with 93 octane fuel.

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Quote:
Originally Posted by TSS View Post
No, but I watch the KR closely on the Lincoln. No issues, but I watch it. As you know, KR is the worst under lugging conditions (ie. struggling in a high gear when you should really be in a lower gear).
These 3.6 cars (the 9th gen more so than the 8th) seem to be tuned to stay in a high gear as much as possible for economy, so tuning the transmission might help elminate some KR (by providing a quicker kickdown at less throttle %).

Quote:
Originally Posted by retiredpauly View Post
What's the ethanol content of your 93 gas.
Y'all have different requirements there than we'all do.
Our "premium" gas (shell) has no methanol.
Just wondering if it's the same for you. ?
No gasoline you buy (unless you're buying racing fuel) should have methanol! That stuff will eat your fuel system even at low concentrations, and should be considered a contaminant, not an additive. I'm assuming you meant ethanol (all pumps around here are labelled 10% or "up to" 10% ethanol).

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My mistake in my first posting I made. I did in fact say methanol.
The subsequent posting I referred to it as ethanol.
Maybe spell check got me or I didn't proof read it.
I dunno
But I meant ethanol.

Some things are better left unsaid, which I generally realize right after I have said them.
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