Knock but No Negative Corrections (Data Logs) Opinions

[2006ser]

Ing correction on all cylinders I see + 6 all I remember positive is good lol

 

[twolf]

Okay, so the post about Cobb updating their strategy. Does that only apply to OTS maps?

I changed nothing on my car (did update my AP). Went from seeing zero knock, ever, to seeing 1 or 2 knocks occasionally on full gear pulls. But the problem is, sometimes I will see negative corrections (from -1 up to -2.3 or so in some cases) with only 1 knock.

Haven't changed my tune, it's not bad gas, I notice that sometimes it will happen on a pull and sometimes on a downshift.

I'm ASSUMING it's false knock from my exhaust.

I'm getting dyno/street tuned as soon as I get my FMIC/crash bar installed, but until then I'll be running this tune. I've tried to get data logs for my tuner, but I can't get it to happen on a highway pull. Only when I'm hooning around, which makes me think it's false knock from my exhaust moving around.

 

[Lizzardmax]

Okay, so the post about Cobb updating their strategy. Does that only apply to OTS maps?

I changed nothing on my car (did update my AP). Went from seeing zero knock, ever, to seeing 1 or 2 knocks occasionally on full gear pulls. But the problem is, sometimes I will see negative corrections (from -1 up to -2.3 or so in some cases) with only 1 knock.

Haven't changed my tune, it's not bad gas, I notice that sometimes it will happen on a pull and sometimes on a downshift.

I'm ASSUMING it's false knock from my exhaust.

I'm getting dyno/street tuned as soon as I get my FMIC/crash bar installed, but until then I'll be running this tune. I've tried to get data logs for my tuner, but I can't get it to happen on a highway pull. Only when I'm hooning around, which makes me think it's false knock from my exhaust moving around.

Based off of your username and profile pic I will tell you right now that we have the exact same person tuning our cars...lol

That information from Cobb is relevant to both OTS maps and Protune maps unless otherwise altered by the tuner, which in this case it has not been from my understanding.

In my opinion, research, and own personal experience these one or two counts you are seeing ARE related to the Major version change in v220. Prior to the version change ignition corrections would ramp up much slower using OEM (I think) standards. Then if "3" counts were encountered then a cyl would pull back some timing. Now timing is ramped-up more quickly (and smoothly) to try and keep the car as close to knocking as possible (so power early in pull is not wasted), and as soon as one count is encountered, timing is held back on that cyl while still advanced on others, and if a second knock is counted then timing will be reduced for that cyl (not necessarily so much as to go negative, but could). You can see this in the fourth log posted in my OP. Based off of what we are getting from Cobb as well as some of the previous comments in this thread what we are seeing is not necessarily bad, maybe a tad on the aggressive side. I would worry more about the sustained negative corrections though. I have been monitoring knock counts lately rather than corrections and running a log to see what is happening with corrections at any given time, I'll reverse that and see how often/sustained I get negative corrections.

What for me indicates that the counts I am seeing are not false is the conditions that they happen in. Consistently only in higher gear WOT freeway pulls and always right around 4K rpm. Also, if I do a WOT freeway pull (5th) and baby the throttle up then WOT only after 4k..rarely if ever knock count. I will get a random knock count on cyl 4 occasionally others when hooning low gear blasting, never been worried about that.

I can only imagine that your tune will be better for you after a revision/dyno/street tune, but I would not expect the knock counts to go fully away just because that is kinda how Cobb roll's. Never the less still on the fence about asking to have mine pulled back a bit more.

We need to meet up and have a compare-o.

 

[twolf]

Who are you? [MENTION=2537]Lizzardmax[/MENTION]

The thing is, my negative corrections aren't sustained. They're sporadic.

I do believe it's knocking, but I'm insinuating that the negative corrections are caused by the exhaust issue.

 

[Ryephile]

Who are you? [MENTION=2537]Lizzardmax[/MENTION]

The thing is, my negative corrections aren't sustained. They're sporadic.

I do believe it's knocking, but I'm insinuating that the negative corrections are caused by the exhaust issue.

Could one of you guys PM me who your tuner is please? Just curious. I think he's doing a good job based on [MENTION=2537]Lizzardmax[/MENTION]'s logs so I'm not looking to dig up dirt.

Regarding the sporadic negative corrections, that's exactly how it works. The knock algorithm is always observing and calculating, and it works quick. Also keep in mind that everything is adding or multiplying with that ignition algorithm; temperatures, actual load, pressure ratios, the works. Long story short, I wouldn't stress about it. Additional tuning by your tuner will be incremental at best, and definitely not perceptible by your butt-dyno.


Your exhaust movement theory is easy to test. Change the hangers and/or add shaft collars to limit hangar and tubing movement. This is especially relevant if your exhaust is actually banging against the bodywork.

 

[twolf]

Could one of you guys PM me who your tuner is please? Just curious. I think he's doing a good job based on [MENTION=2537]Lizzardmax[/MENTION]'s logs so I'm not looking to dig up dirt.

Regarding the sporadic negative corrections, that's exactly how it works. The knock algorithm is always observing and calculating, and it works quick. Also keep in mind that everything is adding or multiplying with that ignition algorithm; temperatures, actual load, pressure ratios, the works. Long story short, I wouldn't stress about it. Additional tuning by your tuner will be incremental at best, and definitely not perceptible by your butt-dyno.


Your exhaust movement theory is easy to test. Change the hangers and/or add shaft collars to limit hangar and tubing movement. This is especially relevant if your exhaust is actually banging against the bodywork.

I have the MBRP exhaust, the slip joints love to "slip" out of place, I have to readjust it every couple of months. It is hitting up against the midship brace.


My tuner is JST Performance. I have no qualms with him, he's offered to give me revisions if I get him logs, but I'm getting dyno tuned by him in about a week or so when I get my FMIC on. His customer service is great, and I'm 100% sure when I go down there he'll solve my issue...

Keep in mind that whatever is going on is likely nothing to do with his tune. It was literally flawless for several months, way after I got my final revision locked down. Whether winter fuel mix was the change, or it's false knock, or new strategies, I do not know.

 

[frankiefiesta]

I have the MBRP exhaust, the slip joints love to "slip" out of place, I have to readjust it every couple of months. It is hitting up against the midship brace.


My tuner is JST Performance. I have no qualms with him, he's offered to give me revisions if I get him logs, but I'm getting dyno tuned by him in about a week or so when I get my FMIC on. His customer service is great, and I'm 100% sure when I go down there he'll solve my issue...

Keep in mind that whatever is going on is likely nothing to do with his tune. It was literally flawless for several months, way after I got my final revision locked down. Whether winter fuel mix was the change, or it's false knock, or new strategies, I do not know.

Add some spacers to the mid brace to clear the exhaust. Had to do this with my 3" injen catback

 

[Ryephile]

...

In my opinion, research, and own personal experience these one or two counts you are seeing ARE related to the Major version change in v220. Prior to the version change ignition corrections would ramp up much slower using OEM (I think) standards. Then if "3" counts were encountered then a cyl would pull back some timing. Now timing is ramped-up more quickly (and smoothly) to try and keep the car as close to knocking as possible (so power early in pull is not wasted), and as soon as one count is encountered, timing is held back on that cyl while still advanced on others, and if a second knock is counted then timing will be reduced for that cyl (not necessarily so much as to go negative, but could). You can see this in the fourth log posted in my OP. Based off of what we are getting from Cobb as well as some of the previous comments in this thread what we are seeing is not necessarily bad, maybe a tad on the aggressive side. I would worry more about the sustained negative corrections though. I have been monitoring knock counts lately rather than corrections and running a log to see what is happening with corrections at any given time, I'll reverse that and see how often/sustained I get negative corrections.

What for me indicates that the counts I am seeing are not false is the conditions that they happen in. Consistently only in higher gear WOT freeway pulls and always right around 4K rpm. Also, if I do a WOT freeway pull (5th) and baby the throttle up then WOT only after 4k..rarely if ever knock count. I will get a random knock count on cyl 4 occasionally others when hooning low gear blasting, never been worried about that.
....

Very good reasoning, you definitely have a good picture of what's happening.

Knock is always contextual, and there are so many variables it can be daunting. Fuel temperature, air charge temperature, cylinder head temp, more obscure things like humidity are all going to affect combustion stability. The transient into full boost at lower RPMs near the torque peak *may* induce a slight combustion instability, and as such that may induce a knock count or two. That, combined with the significant BMEP tapering as RPMs rise, would strongly imply that knock is less prevalent at higher RPM. On top of that, engine noise in general is fairly exponential with RPM, so many knock filters taper their listening to zero or nearly zero near redline, because the sensor and DSP cannot discern between knock and noise at high RPM. Obviously the specifics are very engine dependent, I'm just giving an overview. Of course it's important to keep it in perspective; the BMEP we're seeing on this engine is hugely impressive for premium unleaded. Here's some perspective:

Honda S2000 AP1 = 189 PSI
Lotus Exige S w/ECU tune [300 HP] = 251 PSI
Fiat 500 Abarth = 307 PSI
MINI "F56" John Cooper Works = 319 PSI
My 1992 Miata with 260 HP Megasquirt 3 GT2554R turbo setup, an arms length away from bending all the con-rods = 354 PSI
2016 Ford Focus RS = 377 PSI
VW Golf R w/APR Stage 2 ECU tune = 481 PSI
FiST w/Stage 3 tune [est. 325 LbFt crank] = 505 PSI

 

[2006ser]

So exhaust movement can cause negative ign corrections?

 

[Ryephile]

So exhaust movement can cause negative ign corrections?

It's possible. The knock sensor is "just" a transducer, a microphone, that's bolted to the engine. The DSP in the ECU has been tuned to listen with greater sensitivity at certain frequency ranges [it's actually a Hz vs. sensitivity curve]. If there are things on the car making noise in the frequency bands the knock system is tuned for, it could register a false positive.

 

[twolf]

Add some spacers to the mid brace to clear the exhaust. Had to do this with my 3" injen catback

I've been meaning to, or I'll likely end up buying the tubular brace for more clearance.

 

[arlisscm]

I've been meaning to, or I'll likely end up buying the tubular brace for more clearance.

I had that problem with my injen exhaust, every now and again it would bonk the brace. I got a Pierce Motorsports brace and no more bonk. Real nice piece and easy to do.

 

[2006ser]

It's always cylender 4 that's -2.50 sometimes it's -1.90 just depends

 

[Lizzardmax]

Ahh yes good ol' cylinder 4. It is also the first to knock for me.

Very good reasoning, you definitely have a good picture of what's happening.

Honda S2000 AP1 = 189 PSI
Lotus Exige S w/ECU tune [300 HP] = 251 PSI
Fiat 500 Abarth = 307 PSI
MINI "F56" John Cooper Works = 319 PSI
My 1992 Miata with 260 HP Megasquirt 3 GT2554R turbo setup, an arms length away from bending all the con-rods = 354 PSI
2016 Ford Focus RS = 377 PSI
VW Golf R w/APR Stage 2 ECU tune = 481 PSI
FiST w/Stage 3 tune [est. 325 LbFt crank] = 505 PSI

"The definition of BMEP is: the average (mean) pressure which, if imposed on the pistons uniformly from the top to the bottom of each power stroke, would produce the measured (brake) power output."

HEAAAAVY! Wonder how long the thing will deal with that. Good thing conn. rods are sinter forged.

 

[dyn085]

Interesting conversation.

Monitoring knock counts and ignition correction is redundant so there's no need to waste the PID space logging both for each cylinder. Just because you see knock is irrelevant, what matters is the frequency and correction. Any reduction of timing is a 'negative' correction, whether you go into negatives or not, because removing half-a-degree of timing is the same at zero as it as at +6-it's just half-a-degree of reduced timing.

Having a negative correction is normal and I wouldn't even worry about it. If I was getting a negative correction followed by a negative correction immediately after a negative correction then that would not be good, but a negative correction that is followed by no timing correction (negative or positive) or followed by increases in timing is perfectly normal and fine.

 

[dyn085]

It's always cylender 4 that's -2.50 sometimes it's -1.90 just depends

Your tune is too aggressive and you should step it down.

 

[Lizzardmax]

Interesting conversation.

Monitoring knock counts and ignition correction is redundant so there's no need to waste the PID space logging both for each cylinder. Just because you see knock is irrelevant, what matters is the frequency and correction. Any reduction of timing is a 'negative' correction, whether you go into negatives or not, because removing half-a-degree of timing is the same at zero as it as at +6-it's just half-a-degree of reduced timing.

Having a negative correction is normal and I wouldn't even worry about it. If I was getting a negative correction followed by a negative correction immediately after a negative correction then that would not be good, but a negative correction that is followed by no timing correction (negative or positive) or followed by increases in timing is perfectly normal and fine.

Very good information. So basically these few knock occurrences are not necessarily of major concern. However, saying as I can re-create the circumstances in which they occur reliably and often (Passing on freeway) I could stand to take measures to reduce or eliminate those consistent events.

For reference I have just taken a log on a similar E30 blend tune (that I just tested and love and always want to run). It is much more Tidy. [MENTION=4567]Ryephile[/MENTION] You may want to see this one:

E30 5th gear WOT:
http://datazap.me/u/lizzardmax/fiestaststage2rev0?log=1&data=7-10-11-12-15

93 5th gear WOT:
http://http://datazap.me/u/lizzardmax/rev1slot393oct24psi-target?log=0&data=7-10-11-12-13
http://datazap.me/u/lizzardmax/rev1slot393oct24psi-target?log=1&data=7-10-11-12-13

 

[twolf]

[MENTION=2537]Lizzardmax[/MENTION] what gear are you passing in? I usually drop to 4th to pass...

 

[Lizzardmax]

[MENTION=2537]Lizzardmax[/MENTION] what gear are you passing in? I usually drop to 4th to pass...

If I am in 6th doing 80@3k rpm I will drop to 5th and go WOT (start out at about 3.5k rpm). Not sure what the rpm would be If I downshifted from 6th@3k to 4th, Im sure close to 4.5K? Seems like it would be a bit high, but not right @ redline.

All I know is 3K in 6th, down to 5th WOT, then back to 6th when I hit about 5K, is effing moving. Haha

 

[frankiefiesta]

If I am in 6th doing 80@3k rpm I will drop to 5th and go WOT (start out at about 3.5k rpm). Not sure what the rpm would be If I downshifted from 6th@3k to 4th, Im sure close to 4.5K? Seems like it would be a bit high, but not right @ redline.

All I know is 3K in 6th, down to 5th WOT, then back to 6th when I hit about 5K, is effing moving. Haha

Damn boy, passing higher than 80mph? Lol driving like a psycho out there! Haha

I too usually just drop to 5th for a quick pass but never need to go WOT. If I need to go WOT to pass someone I usually just slow down and let that person do their thing. Not worth the ticket, risking an accident, or racing a commuter in their Camry/sonata