cobb ap knock retard ?
Is the knock count supposed to be for just one redline pull to measure a lot of knock ? For the past two weeks I have been noticing daily driving total knock around 4.6x this would be for the total drive to work or whereever not just one pull. I started getting knock past 2 when I changed to the blue fuel pump relay so I hope that is not causing an issue.
Evolving Member
Joined: Sep 2008
Posts: 318
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From: Czech rep.
This is my log, each pull at 4th gear is simillar. Is that necessary to tune the knock out?
I am running Stage 2 car Stage 2-93 Cobb map(a bit modified at low load)
Thanks,
Martin.
I am running Stage 2 car Stage 2-93 Cobb map(a bit modified at low load)
Thanks,
Martin.
Last edited by xhomm02; Mar 9, 2010 at 02:09 PM.
Cobb Knock Retard / .35 = Knock count
So .7 = 2 counts and .35 = 1 count
You should be fine, the 1's and 2's are almost impossible to tune out.
Here is his log for the lazy:
So .7 = 2 counts and .35 = 1 count
You should be fine, the 1's and 2's are almost impossible to tune out.
Here is his log for the lazy:
Code:
RPM IPW LTFT STFT Knock TP Boost Load 3330 11.52 3.12 0 0 34.43 11.31 150.94 2632 11.01 3.12 0 0 86.86 10.88 154.38 2753 12.8 3.12 0 0 86.86 15.23 179.38 2878 16.13 3.12 0 0 86.86 20.09 211.25 3041 18.94 3.12 0 0.7 86.47 22.99 214.06 3242 18.43 3.12 0 0.7 86.47 24.15 226.25 3453 19.2 3.12 0 0.35 86.86 24 225 3635 19.2 3.12 0 0.35 86.86 24.37 232.5 3848 19.97 3.12 0 0 86.47 24.95 238.75 4023 20.74 3.12 0 0.35 86.86 25.16 246.56 4247 21.5 3.12 0 0 86.86 25.74 250.62 4445 21.5 3.12 0 0 86.47 25.31 241.88 4632 20.48 3.12 0 0 86.47 24.58 236.88 4826 19.97 3.12 0 0 86.47 24 233.44 4979 19.97 3.12 0 0 86.47 24 230.31 5137 19.71 3.12 0 0 86.47 24 227.19 5304 19.46 3.12 0 0 86.47 23.79 223.75 5466 19.2 3.12 0 0 86.47 23.57 221.56 5618 18.94 3.12 0 0.35 86.47 23.57 219.38 5760 18.94 3.12 0 0.35 86.47 23.42 216.88 5891 18.69 3.12 0 0 86.47 22.84 215.94 6028 18.69 3.12 0 0 86.47 22.63 214.69 6162 18.43 3.12 0 0 86.47 22.04 210 6334 17.92 3.12 0 0 86.47 21.61 207.19 6426 17.66 3.12 0 0 86.47 21.25 204.38 6493 17.66 3.12 0 0 86.47 21.03 202.5 6590 17.41 3.12 0 0 86.47 20.88 200.31 6690 17.15 3.12 0 0 86.47 20.45 196.25
Former Sponsor
Joined: Oct 2008
Posts: 539
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From: USA
Some knock correction at WOT is ok, however, it isn't ideal. If you are seeing more and more knock correction, you might check your fuel pump relay as these do go bad and fuel delivery becomes more and more of an issue. That said, knock correction at low-load, low rpm and cruising is nothing to be concerned about. The engine will try to run as close to stoich/MBT as possible for best economy. We have noted this behaviour across all ranges of vehicles. Keep in mind that the knock sensor is an imperfect microphone that listens for noise, this noise is then processed by the ECU which looks for a specific pattern which is then interpolated as "knock." Very low knock readings may or may not be knock. Very high readings are something to be worried about.
Travis
COBB Tuning
Travis
COBB Tuning
Evolving Member
Joined: Jul 2008
Posts: 250
Likes: 1
From: Calgary, Alberta, Canada
Some knock correction at WOT is ok, however, it isn't ideal. If you are seeing more and more knock correction, you might check your fuel pump relay as these do go bad and fuel delivery becomes more and more of an issue. That said, knock correction at low-load, low rpm and cruising is nothing to be concerned about. The engine will try to run as close to stoich/MBT as possible for best economy. We have noted this behaviour across all ranges of vehicles. Keep in mind that the knock sensor is an imperfect microphone that listens for noise, this noise is then processed by the ECU which looks for a specific pattern which is then interpolated as "knock." Very low knock readings may or may not be knock. Very high readings are something to be worried about.
Travis
COBB Tuning
Travis
COBB Tuning
Also on another note, I'm looking at xhomm02's log, how do you get the AP to sample so frequently? I'm looking at my logs and it seems to log a sample every half a second. Do you just not log as many items?
Evolving Member
Joined: Sep 2008
Posts: 318
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From: Czech rep.
What amount of knock correction is okay under WOT? I did a couple pulls today and I saw my knock retard count go as high as 2.46. Number is a bit high, but only happened once outta 2 pulls.
Also on another note, I'm looking at xhomm02's log, how do you get the AP to sample so frequently? I'm looking at my logs and it seems to log a sample every half a second. Do you just not log as many items?
Also on another note, I'm looking at xhomm02's log, how do you get the AP to sample so frequently? I'm looking at my logs and it seems to log a sample every half a second. Do you just not log as many items?
2.46 knock retard is pretty high as I understand from what I have read so far. Can you post the log?
Evolving Member
Joined: Jul 2008
Posts: 250
Likes: 1
From: Calgary, Alberta, Canada
And as for logs here it is. I just did 2, 3 gear pulls (1'st, 2'nd, 3'rd). The first time I did there was 1 count of measured knock retard that was at 1.41, which isn't too too bad. But the second time I did it, there was a recorded count of 2.41, and 2.11. I noticed the LTFTs stayed at 0% throughout the data log. I thought that it would go up a few percent to prevent the car from leaning out.
Evolving Member
Joined: Sep 2008
Posts: 318
Likes: 0
From: Czech rep.
Yeah that's what I kinda thought, I had a lot of stuff being logged before, and I reduced the list a bit, but didn't seem to change the frequency. I'll take out some more things from the list next time I do any logging.
And as for logs here it is. I just did 2, 3 gear pulls (1'st, 2'nd, 3'rd). The first time I did there was 1 count of measured knock retard that was at 1.41, which isn't too too bad. But the second time I did it, there was a recorded count of 2.41, and 2.11. I noticed the LTFTs stayed at 0% throughout the data log. I thought that it would go up a few percent to prevent the car from leaning out.
And as for logs here it is. I just did 2, 3 gear pulls (1'st, 2'nd, 3'rd). The first time I did there was 1 count of measured knock retard that was at 1.41, which isn't too too bad. But the second time I did it, there was a recorded count of 2.41, and 2.11. I noticed the LTFTs stayed at 0% throughout the data log. I thought that it would go up a few percent to prevent the car from leaning out.
Also decrease logged items to about 5, then the freq. will increase. LTFT does not prevent from knock, it tries to keep the AFR as close as possible to the values set in the tables (in case of air filter dirty or things like that).
Evolving Member
Joined: Jul 2008
Posts: 250
Likes: 1
From: Calgary, Alberta, Canada
Yeah I'll try to do a 4'th gear pull and log that. But the cops are out on full force since it's kinda warm out here, so I'm kinda scared of getting pinched haha. I know of a street where I can probably do a 3'rd gear pull safely, so I might have to just work with that.
Former Sponsor
Joined: Oct 2008
Posts: 539
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From: USA
Please do your logs in a safe an controlled environment! If you are running the Harman intake, that could be part of the problem if you are using a calibration not made for that intake. These cars are very sensitive to changes in the intake. That said, I would take a look at your fuel pump relay and then think about a tune for your intake. I hate to tell you again to just get a tune, but it really is the best way to go for intakes that we don't have calibrations for. We are not currently working on further intake calibrations, however, that does not mean there won't be more in the future.
Travis
COBB Tuning
Travis
COBB Tuning
Evolving Member
Joined: Jul 2008
Posts: 250
Likes: 1
From: Calgary, Alberta, Canada
^^ Haha I know I know I totally understand! I'm thinking of getting a tune in about 2 months or so, just gonna use one of the OTS maps as a temporary solution before my tune. Just hoping that the OTS maps is safe enough for my car if I'm not ripping on my car... much.
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