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ECMlink Knock Readings Seem High - Would like some timing map input

llxkevinxll

Proven Member
435
196
Jan 29, 2012
Cleveland, Ohio
1). No boost, vac, or exhaust leaks.
None
2). Verify mechanical timing.
Timed
3). Verify base timing
5deg factory spec
4). Ignition system
NGK BR7ES @ 0.020", new MSD wires, ~1500 miles on new OEM PTU/Coil pack.
5). Motor health
~1500 miles on build, have not taken measurements
6). Basic throttle body adjustments.
BISS is slightly out of adjustment, base TPS voltage is set
7). Compression ratio
8.5:1 JEs, unsure on calculated CR (unknown HG thickness or chamber volume)
8). Wiring and sensors
Harness was rebuilt with all new Sheridan Engineering connects ~4k miles ago.
9). No DTC/CEL codes
None
10). Electrical system
ACDelco GM Alternator, rewired. ~50 miles on new alternator. Optima Red Top in trunk.
11). Base fuel pressure and injector values
43.5 psi with car on and vac line attached (so a bit higher than factory). FIC 1650s with dead times from data sheet set.
12). Properly calibrated and configured wideband sensor
Innovate MTX-L, recal ~500 miles ago
13). Type of fuel
Marathon/Citgo 93. ~9.8% on the GM flex sensor

Hey guys, I was hoping to have some second opinions on my timing map and the knock readings I am seeing. Just want to know if I am seeing some sensor oddities or if the knock I am registering is likely real. I have attached a log snippet of a pull. Pardon the throttle position, the not particularly smooth country road isn't the best tuning surface. Am I mistaken thinking 1.1 deg of total timing at 6500 rpm is odd? That seems exceedingly low but I really haven't tuned other DSMs. Most of my experience is N/A SBC stuff which doesn't quite translate for this particular question. Any comments/opinions welcome. Just want to get a better grasp on what I am seeing.
 

Attachments

  • Edited WOT log.elg
    17.3 KB · Views: 21

1990TSIAWDTALON

Moderator
9,128
4,964
Nov 14, 2013
Independence, Kansas
When my 9:1 or 10:1 4g motors are on GASOLINE, they are very finicky about how much timing I can get into them before my knock sensor starts going bazerk. About 5* max is all I could do. I switched to E85 and could put 15* in, no problem and the car loved it. I have used Meth/Water injection to try and help but I could only get another 2-3*, if that.
I'm sorry I hadn't looked at your log sooner. I am a SBC guy also, so the DSM thing was a learning (and still is) curve.
Try lowering boost and see if the knock goes down or away.
Marty
 

ec17pse

Freelancer
5,449
2,744
Nov 1, 2008
London, UK, Europe
im zero expert currently LOL but does seem very odd. its showing cell as 9 so how its jumped to 1.1 and a bit before that -0.3 i dont know.

only thing my eyes see is it happens in higher boost only so past around 18psi, once past that your getting knock, so could it be fueling is off.

please dont take my advice precisely here, im seeing this as a result so to me that shows something is off and i would start with fueling as possibly the start or the issue.
 

llxkevinxll

Proven Member
435
196
Jan 29, 2012
Cleveland, Ohio
When my 9:1 or 10:1 4g motors are on GASOLINE, they are very finicky about how much timing I can get into them before my knock sensor starts going bazerk. About 5* max is all I could do. I switched to E85 and could put 15* in, no problem and the car loved it. I have used Meth/Water injection to try and help but I could only get another 2-3*, if that.
I'm sorry I hadn't looked at your log sooner. I am a SBC guy also, so the DSM thing was a learning (and still is) curve.
Try lowering boost and see if the knock goes down or away.
Marty

Between that post and now I did lower boost and it made little to no difference. I tried taking timing out of it as well and it pulled basically the same amount as this. When Ricky tuned this car on the previous engine combo he had some issues with knock similar to this. Like you say, it disappeared as soon as the E content in the fuel went up. For now I'll just leave the timing soft on pump and let the Max Oct map do the work. Just feels so odd to see knock at 3 degrees or whatever when the SBC stuff takes 40+ LOL.
 

1990TSIAWDTALON

Moderator
9,128
4,964
Nov 14, 2013
Independence, Kansas
We were at 40*+ on the 6.6L SBC, currently going EFI and we'll report how that all turns out. :)
If lowering the boost didnt help, the only test left is add E and report back. If you richen the mix, do you think it would help quelch the knock?
 

llxkevinxll

Proven Member
435
196
Jan 29, 2012
Cleveland, Ohio
We were at 40*+ on the 6.6L SBC, currently going EFI and we'll report how that all turns out. :)
If lowering the boost didnt help, the only test left is add E and report back. If you richen the mix, do you think it would help quelch the knock?

Car has ~35% E in the tank now and the knock is basically non-existent. 0.4 pulled in a couple small blips during a pull. Nothing I am concerned with. I could try to add fuel but it is at 10.5:1 where it is pulling 7*. Not sure how much more room there is to go on the rich side. Is there a point where you are doing more harm than good? Power numbers aside.
 

danl

Proven Member
670
77
Apr 8, 2002
Severn, Maryland
That's how real knock looks. I'd like to see what your AFR's are but can't see what you have the wideband tagged as. Regardless, looks like it is set up with an ethanol sensor. Add ethanol and if you see it disappear, that confirms it, you need more octane.

It looks like your combo won't take much more than 5 degree in boost. If you want to keep running that fuel, you need to reduce timing in the transition zone and over 2.0grams/rev at all RPM's. The knock starts at 2.5 grams/rev, so you need to catch it before that. I've added a table to show you what it should look like. You will need to smooth things out in the 1.5-2.0grams/rev area, but this should put you on a better path.

You must be logged in to view this image or video.
 

llxkevinxll

Proven Member
435
196
Jan 29, 2012
Cleveland, Ohio
That's how real knock looks. I'd like to see what your AFR's are but can't see what you have the wideband tagged as. Regardless, looks like it is set up with an ethanol sensor. Add ethanol and if you see it disappear, that confirms it, you need more octane.

It looks like your combo won't take much more than 5 degree in boost. If you want to keep running that fuel, you need to reduce timing in the transition zone and over 2.0grams/rev at all RPM's. The knock starts at 2.5 grams/rev, so you need to catch it before that. I've added a table to show you what it should look like. You will need to smooth things out in the 1.5-2.0grams/rev area, but this should put you on a better path.

You must be logged in to view this image or video.
Thanks for the reply! The wideband is listed as 'LC1WB'. It is an MTX-L with default 0-5V output scaling and uses the LC1WB preset in ECMLink.

I will take a look at my map and make adjustments as you suggest.
 

danl

Proven Member
670
77
Apr 8, 2002
Severn, Maryland
Car has ~35% E in the tank now and the knock is basically non-existent. 0.4 pulled in a couple small blips during a pull. Nothing I am concerned with. I could try to add fuel but it is at 10.5:1 where it is pulling 7*. Not sure how much more room there is to go on the rich side. Is there a point where you are doing more harm than good? Power numbers aside.
On gasoline based fuels you won't see much power difference between 11 and 12 AFR. Running closer to 11 helps protect a potentially lean cylinder due to an airflow distribution issue or a bad/dirty injector. E85 is more tolerant, you can run it half a point richer without it costing significant power.

Also you got me by 1 minute on your post. You will want to reduce the timing on the low octane map, like I suggested in my first reply, so that the car does not detonate on pump gas.
 

llxkevinxll

Proven Member
435
196
Jan 29, 2012
Cleveland, Ohio
On gasoline based fuels you won't see much power difference between 11 and 12 AFR. Running closer to 11 helps protect a potentially lean cylinder due to an airflow distribution issue or a bad/dirty injector. E85 is more tolerant, you can run it half a point richer without it costing significant power.

Also you got me by 1 minute on your post. You will want to reduce the timing on the low octane map, like I suggested in my first reply, so that the car does not detonate on pump gas.

Yep! I just adjusted that as you recommended. I was making adjustments in the rows AFTER knock was registering and really didn't consider making changes in the load lines above the ones where the knock occurred. "Catching" it before it happens as you phrased it. Thanks for the insight!
 

danl

Proven Member
670
77
Apr 8, 2002
Severn, Maryland
AFR's look fine enough for pump ass. I noticed it likes to go to 10.4's at 5250 then leans out to 11 out the top. Clean up the timing on pump ass first then if you want to hunt for the 5-10 hp on the table, maybe try to get those 10.4's to 11.0's.

If you have the same dip on E85, I think you will find that the Speed Density table is where you will make those edit's because it affects both maps. I hi lighted the cell where it dips to 10.4's, so you may want to edit the area around that. I think you will end up with 90-91% in most of the cells near where you have that rich dip. In general it just needs some light changes. If the ecu is targeting 11 in the fuel map, and the wideband says 10.4, then you need to drop 5-6% in VE to make everything whole with the world. Certainly though, half an AFR isn't a big deal.

Also, add VE in the high RPM cells. I know you might not go there, but say something unexpected happened, you want it to keep the fueling up.

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Stapl3

Proven Member
1,547
119
Oct 27, 2004
MI, Michigan
That's just the way it is with pump gas. When I was using a 60-1, to get 30psi I had my timing at 0* peak. With E85 on the other hand I could run whatever boost and timing I wanted. Stuff is like cheating. Jesus juice.

BTW that's one of the best logs I've ever gone through as far as being set up correctly calibration-wise and nothing sticking out as 'wrong'. Well done.
 

danl

Proven Member
670
77
Apr 8, 2002
Severn, Maryland
I agree on the ecu configuration. The poster also clearly took time putting together the post, making it easy to provide feedback. His grammar was also good. This helps when trying to figure out what is going on.

OP, I’m not sure what your power levels are, but you might want to consider BR8ES plugs. When you get them, do a pull on them and then take a picture of the ground strap. That will help tell you if the timing is correct.

 

llxkevinxll

Proven Member
435
196
Jan 29, 2012
Cleveland, Ohio
I agree on the ecu configuration. The poster also clearly took time putting together the post, making it easy to provide feedback. His grammar was also good. This helps when trying to figure out what is going on.

OP, I’m not sure what your power levels are, but you might want to consider BR8ES plugs. When you get them, do a pull on them and then take a picture of the ground strap. That will help tell you if the timing is correct.


When the car was tuned on the previous engine combo, Ricky at Rix Racing did the tuning and moved me to a 7 and mentioned 8s were a bit much for my power (448 peak on his Mustang dyno, though that was stock cams not the 272s). I imagine there is much debate over plug temps. I will pull the plugs (though they have cruise/idle time on them) and get some pictures posted.

I have attached a log from yesterday with ~35% E and timing changes based on your recommendations. I left the VE table alone for now.

Also note, I am avoiding WOT below 5kish on purpose for now as that has been recommended to me for drivetrain longevity (avoiding the torque spike). The T3 TS + HX35 was making a good bit of torque and early in the rev range on Ricky's dyno.

I also appreciate everyone's comments on the ecu calibration and post. I spent a lot of time and effort on this car might as well spend 5 minutes writing out a post haha.
 

Attachments

  • Clipped Log 2.elg
    11.1 KB · Views: 7

danl

Proven Member
670
77
Apr 8, 2002
Severn, Maryland
Plugs are a preference, I always run colder than required as a risk mitigation technique. On E85 you can run hotter plugs that you would on pump ass.

You are correct in stating that torque hits will kill the drivetrain. If BCS_gear is correct, this is a third gear pull, correct? It does not appear that you are doing boost by gear? The only reason I mention this is because one way to reduce the torque spikes is to run lower boost, then ramp it in as RPM's climb. Another method, which I usually use to compliment this is to reduce timing as well. This was a common technique on the Eve 8/9 to to keep the stock rods inside the block. Well, that was unless you were ******** known for magic 8s, bonus points if you get the reference.

The latest log looks great. It appears you cleaned up the SD table. You are at the threshold of knock, even with 35% ethanol. What happens if you do a second third and 4th gear pull? You may see that knock is higher each successive gear. If so, then you need to further reduce timing on your low octane map. You are only about 1 deg away. Remember, get behind the knock because once it sets in, the ecu can not recover. If you run 1 deg less to keep knock at bay, you keep the ecu from pulling orders of magnitude more trying to get it under control. Thus the car will be faster with low/no knock.

Once you get that sorted, up the ethanol content. It is clear your car requires octane, so give it what it wants.
 

llxkevinxll

Proven Member
435
196
Jan 29, 2012
Cleveland, Ohio
Plugs are a preference, I always run colder than required as a risk mitigation technique. On E85 you can run hotter plugs that you would on pump ass.

You are correct in stating that torque hits will kill the drivetrain. If BCS_gear is correct, this is a third gear pull, correct? It does not appear that you are doing boost by gear? The only reason I mention this is because one way to reduce the torque spikes is to run lower boost, then ramp it in as RPM's climb. Another method, which I usually use to compliment this is to reduce timing as well. This was a common technique on the Eve 8/9 to to keep the stock rods inside the block. Well, that was unless you were ******** known for magic 8s, bonus points if you get the reference.

The latest log looks great. It appears you cleaned up the SD table. You are at the threshold of knock, even with 35% ethanol. What happens if you do a second third and 4th gear pull? You may see that knock is higher each successive gear. If so, then you need to further reduce timing on your low octane map. You are only about 1 deg away. Remember, get behind the knock because once it sets in, the ecu can not recover. If you run 1 deg less to keep knock at bay, you keep the ecu from pulling orders of magnitude more trying to get it under control. Thus the car will be faster with low/no knock.

Once you get that sorted, up the ethanol content. It is clear your car requires octane, so give it what it wants.

I do have boost by gear setup and this was a 3rd gear pull. I am currently running open loop control in ECMLink with 1st gear having pretty low values and 2-5 using the same values across the rev range.

Between the OP and the second log I did continue tweaking and playing around in the VE table so that is likely the changes you saw. I did just make an adjustment for that super rich dip in the 5500-6000 range but left the rest alone between the most recent log posted and the "current" ecu calibration. WB Factor 3% or less on the rich side seems reasonable. That rich dip was closer to 10% so I will try to tune that out to be in line with the other RPM regions.

Timing table updated as you proposed. Will make another run at 35% E. The car felt really good on that last pull. The best it has since I put this engine combo in by far. Really appreciate the help. I will find some time to get the car out and get another log posted with these changes.
 

danl

Proven Member
670
77
Apr 8, 2002
Severn, Maryland
I'm glad it is cooperating. They don't always cooperate, you must have done a good job turning the wrenches. You logs looked really good. If your target and actual AFR within a handful of percent, everything is calibrated correctly and you can be confident that it will be consistent, giving you the maximum chance to get the most out of it.

If you move to higher ethanol %, you need to know that you can increase timing past mean brake torque without knock. What I mean is, you can actually run enough timing to lose power. It is also hard on the engine to make it eat more timing that it wants. You need to tune timing on the dyno. Andre explains it better than I can below. He also has other great videos, including others specific to E85.

You must be logged in to view this image or video.
 

llxkevinxll

Proven Member
435
196
Jan 29, 2012
Cleveland, Ohio
I'm glad it is cooperating. They don't always cooperate, you must have done a good job turning the wrenches. You logs looked really good. If your target and actual AFR within a handful of percent, everything is calibrated correctly and you can be confident that it will be consistent, giving you the maximum chance to get the most out of it.

If you move to higher ethanol %, you need to know that you can increase timing past mean brake torque without knock. What I mean is, you can actually run enough timing to lose power. It is also hard on the engine to make it eat more timing that it wants. You need to tune timing on the dyno. Andre explains it better than I can below. He also has other great videos, including others specific to E85.

You must be logged in to view this image or video.

That was going to be my next question. I have watched that video (and watch many of their videos). Right now my max oct table is the same curve Ricky built with -3 degrees in the boost region. Again, that was on the stock cams, 1G head, and 1G intake. This car is now on the Evo 3 + 2G Head + Crower 272s. With everything else basically the same. I am not looking to max out this setup, but without knock feedback to guide me, how do I make decisions on the Max Oct table?
 

danl

Proven Member
670
77
Apr 8, 2002
Severn, Maryland
It is really hard to give you advice on what the timing should look like on E85. You need to get it on a dyno to get all the power out of it. In the meantime, look at that link about reading the spark plugs ground strap to make sure the timing is safe. Another method is to go by trap speeds at the track. Reading plugs or trap speeds won't help you build a timing curve because you can not tune in 500 RPM increments like you would on a dyno. However reading plugs will tell you if you have too much timing in it, which is useful in making sure it is safe.
 

curt-s

Proven Member
1,515
286
Dec 21, 2008
Winterville, MB_Canada
That's how real knock looks. I'd like to see what your AFR's are but can't see what you have the wideband tagged as. Regardless, looks like it is set up with an ethanol sensor. Add ethanol and if you see it disappear, that confirms it, you need more octane.

It looks like your combo won't take much more than 5 degree in boost. If you want to keep running that fuel, you need to reduce timing in the transition zone and over 2.0grams/rev at all RPM's. The knock starts at 2.5 grams/rev, so you need to catch it before that. I've added a table to show you what it should look like. You will need to smooth things out in the 1.5-2.0grams/rev area, but this should put you on a better path.

You must be logged in to view this image or video.

I don't want to be that guy but just so it's clear to everyone newer to link that may be reading this, the rows he's referring to are not g/rev but load factor tracked from the log. For instance, at a point where it's at 2.76g/rev, the load factor is only 2.45.

I thought you were referring to the rows as g/rev and it took a couple re-reads to realize you were instead looking at the log for those airflow numbers and then tracking the table as load factor from each sample.
 
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