What's the difference between ST knock retard, LT knock retard, and Total knock retard? Sometimes I'll see on my logs ST knock as 2 and LT knock as 0 and the total knock retard would be -2.
What's the difference between ST knock retard, LT knock retard, and Total knock retard? Sometimes I'll see on my logs ST knock as 2 and LT knock as 0 and the total knock retard would be -2.
ST is the instantaneous correction to ignition timing caused by knock. LT is a constant correction to ignition timing that is applied when the pcm always sees knock. For example you get a ST of 2deg @ 4500 rpm and spark should be 25, because of the 2deg. of knock it is now 23deg. If this consitantly occurs the pcm will always take the 2deg away. So in effect it becomes 23deg even if there is no sensed knock anymore. This is why it is important to reset the pcm if you ever have any LT knock retard because it is always taking away timing.
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so when i get a st retard of 2 that means its pulling 2 degrees of timing to prevent knock?
Yes. If it happens enough then it will transfer over to LT and always pull 2 degrees regardless of knock being present or not. And it is cumulative also. So if you have 2deg short term and 2 deg long term the pcm will pull 4 degrees total.
should i pull back timing myself with the diablosport and bring the ST to 0 or just leave it as is? ive never seen any value come up on the LT side, only the ST side.
should i pull back timing myself with the diablosport and bring the ST to 0 or just leave it as is? ive never seen any value come up on the LT side, only the ST side.
Depending on where the knock sets in, I would yank a degree out there, and then log again. Maybe add some fuel if you can.
But as mentioned before, ST is how much timing is being at that point in time. LT, is what the computer has seen (cumulative), and doesn't like.
-Will.
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Stage 1 ECM (NOT stock), Diablosport Predator, 3 bar map and tip, Interceptor Scangauge, AEM wideband, 750's (no return-line), MPX BFMIC, Walbro 255, DCR top end modifier, AGP WGA, 3 in O2 housing, QTP 3in downpipe with E-cutout stock catback, Nitrous Oxide Systems 65 HP shot, motor mount inserts.
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I want to add that we have seen the timing come back if your not seeing any ST knock. You don't have to reset the PCM, just pull timing with the DSP and it will come back over time (3 WOT pulls with no ST knock will adjust the LT knock). I have been doing a lot of testing with LT and ST knock over the past month and this looks to be the case with most of our tune and datalogs.
I want to add that we have seen the timing come back if your not seeing any ST knock. You don't have to reset the PCM, just pull timing with the DSP and it will come back over time (3 WOT pulls with no ST knock will adjust the LT knock). I have been doing a lot of testing with LT and ST knock over the past month and this looks to be the case with most of our tune and datalogs.
I would have to agree with you. I have seen the same thing in the past. I cant say for sure how many "pulls" it takes to clean itself up, but it does.
I noticed the mostly during my E85 trials. Its pretty amazing how aggressive you can get with the stuff, and still run the car a bit leaner than on strait pump. (AFR's) not fuel settings.
On E85, my commanded AFR is probably pig freakin rich! lol But its at 12.0 at the hit, creeps up to about 12.5, and then drops back down. I don't know what kind of numbers its putting down.. but the torque is, well.. violent on e85! lol
This is why it is important to reset the pcm if you ever have any LT knock retard because it is always taking away timing.
Would this explain why in past at the track I have disconnected my battery and many times again I have recorded my best ¼ mile track time right after I reset the battery.
I would also notice a initial higher boost spike when I reset battery and make a run at the track.
My gauge only shows KR, I see an ST b1 and LT b1 but those looks like fuel trims to me on my gauge. Because when I set ST to display it is showing data at idle. So where is the ST and LT knock shown on the gauge?
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i believe you have to go into logging and create a new log layout and then that will allow you to add the gauges you desire. go to add a gauge and then add whatever gauge style you want then add new parameter and it'll give you a listing of categories and knock control is one of them. then save the layout under a name you want. then you can open the layout in the monitoring mode.
i believe you have to go into logging and create a new log layout and then that will allow you to add the gauges you desire. go to add a gauge and then add whatever gauge style you want then add new parameter and it'll give you a listing of categories and knock control is one of them. then save the layout under a name you want. then you can open the layout in the monitoring mode.
Disregard, I did a search on knock retard and saw this post. Now after looking at the section it is in, this is the DS I have a scan gauge. Sorry disregard my previous posts.
Disregard, I did a search on knock retard and saw this post. Now after looking at the section it is in, this is the DS I have a scan gauge. Sorry disregard my previous posts.
Sounds like you may have an older firmware version of the scangauge like me. I only show KR. no ST or LT KR. You can send your scangauge back to Aeroforce and they can upgrade the firmware for about $30 i was told.
Now, back to the DS questions
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what is difference between ST LT Knock Retard
Linear Mode
