silentbob
Full Member
Karma: +30/-1
 Offline
Posts: 141
|
 |
« Reply #15 on: May 29, 2011, 04:33:32 AM »
|
|
|
Thank you silentbob. Please let me know if I am understanding this correctly. In order to recover from ignition retard faster, then I want to decrease the values in the maps KRVFN, KRLVFN, and KRVFSN. Also, increasing KRDWSA will increase the amount it is advanced and setting KRDWA to zero will allow it to fully recover. Should all three maps be lowered? If so, anyone have the address for KRLVFN? 0x19662 KRVFN - number of ignitions/cylinders, or time indication of an early adjustment to early adjustment (step-width KR) 0x?  ? KRLVFN - number of ignitions/cylinders, time indication of an early adjustment to early adjustment (slow early adjustment) 0x19672 KRVFSN - number of ignitions/cylinders, or time for quick adjustment of the early KR I am thinking of cutting all values in these maps in half, changing KRDWSA from 1.5 to 3, and KRDWA from 2.25 to 0. Am I on the right track? Has anyone done this? Is this idea and my values safe? Is there anything I am missing? Thanks again guys. You understood this right and you could do this, but it wouldn't make physical sense. Look at the calibration hints at KRRA in the Funktionsrahmen. l KRDWSA l <= l KRDWA l - l KRDWKLA l. To adapt the knock threshold you should use a combination of KRDWA = KRDWSA and KRDWKLA = 0. Using a value KRDWSA (3) > KRDWA (0) doesn't make sense because if you have adapted a value of say 6 degrees and advance the ignition by 3 degrees if your current ignition retard is say 5.5 degrees you will make things worse. How fast you can phase the ignition retard back in is dependent on how fast the combustion chamber thermically regenerates from the increased temperature due to knocking cycles. If you phase it in to fast you will straight be into knock again. I don t know. Everybody here is so obsessed squeezing out the last bit of ignition angle. With 20psi + boost we are running resulting in ridiculously high peak cylinder pressures my strategy is to keep the engine out of the knock area. Even if kock doesn't f... up your engine instantly, your pistons will look like this over time (This is all assuming that knock detection is working 100% correct)  |
|
|
|
« Last Edit: May 29, 2011, 04:53:26 AM by silentbob »
|
Logged
|
|
|
|
|
nyet
|
|
« Reply #16 on: May 29, 2011, 02:51:12 PM »
|
|
|
Excellent post. I strongly favor not messing with the knock control (in particular, knock detection) very much. Everybody here is so obsessed squeezing out the last bit of ignition angle.
Agreed. And IMO there are better ways of getting more timing than dicking with KR... (race gas, lowering compression, water/meth etc).... |
|
|
|
|
Logged
|
|
|
|
|
Rick
|
|
« Reply #17 on: May 29, 2011, 04:33:49 PM »
|
|
|
My thoughts are a little different. IMO, people are overly scared of knock. What are peoples experience with tuning turbo engines? ME7 is the first I have tuned with such proper knock control, and If i'm honest so far it is hampering progress.
The piston pictured has been subjected to some serious det, I would think that is impossible with a correctly working tune. I have run many engines with very light audiable knock, i.e. detectable with a trained bare ear. Never have i seen that level of damage. Big boost engines often make their best power with slight knock, and can do this for 100k+ without effecting the engine life.
Have you seen most timing logs for S4's? the ignition curve undulates like crazy - this is not optimum! I am pro ignition timing - it extracts the most efficiency from the engine, and runs the lowest temp.
Rick
|
|
|
|
|
Logged
|
|
|
|
|
nyet
|
|
« Reply #18 on: May 29, 2011, 04:43:02 PM »
|
|
|
Have you seen most timing logs for S4's? the ignition curve undulates like crazy
I have not seen this in any properly tuned s4 with bone stock KR... what are you referring to? For very very fast S4s (including aggressively lightened cars) i've seen rate-of-load-increase related timing problems, but those are unrelated to KR. |
|
|
|
|
Logged
|
|
|
|
|
phila_dot
|
|
« Reply #19 on: May 29, 2011, 04:44:08 PM »
|
|
|
Thanks for putting that into perspective, that approach may be a little aggressive.
Unfortunately, I am having problems with the basics now.
How are you guys determining what changes to make to KFZW and KFZW2 based on ECUx logs? RPM, load, and timing angle are not matching up between the logs and maps. Obviously, there are other factors effecting timing angle, but I am trying to make changes scientifically rather than on a whim. How do you determine if KFZW or KFZW2 needs to be changed?
I am trying to work my CFs down after adjusting target AFR.
|
|
|
|
|
Logged
|
|
|
|
|
Rick
|
|
« Reply #20 on: May 29, 2011, 05:58:23 PM »
|
|
|
Have you seen most timing logs for S4's? the ignition curve undulates like crazy
I have not seen this in any properly tuned s4 with bone stock KR... what are you referring to? For very very fast S4s (including aggressively lightened cars) i've seen rate-of-load-increase related timing problems, but those are unrelated to KR. Nyet, i will dig some out. But, a stock car has very very conservative timing so there is no knock intervention. Phil - how would you tune ignition on a car without knock control? Rick |
|
|
|
|
Logged
|
|
|
|
|
phila_dot
|
|
« Reply #21 on: May 29, 2011, 06:17:31 PM »
|
|
|
Phil - how would you tune ignition on a car without knock control?
Rick, I don't follow. I haven't touched KR. |
|
|
|
|
Logged
|
|
|
|
NOTORIOUS VR
Administrator
Hero Member
Karma: +58/-7
Offline
Posts: 1056
|
|
« Reply #22 on: May 29, 2011, 07:46:20 PM »
|
|
|
The piston pictured has been subjected to some serious det,
I'm going to say that wasn't even detonation that made the piston look like that... it looks like a foreign object made it into the CC and bounced around a while in there. |
|
|
|
|
Logged
|
|
|
|
silentbob
Full Member
Karma: +30/-1
Offline
Posts: 141
|
|
« Reply #23 on: May 30, 2011, 01:39:46 AM »
|
|
|
 This is not a piston out of a random engine, but a RS4 with our oversensitive knock control posted by someone on audizine. That damage is most definately caused by knock. I can post some pictures of pistons from engines which were forced to knock in order to calibrate knock control if anyone wants to see it. I think nobody will argue that big boost engines will make best power on slight knock as they are obviously knock limited, but my thoughts are that with cylinder pressures easily exceeding 120bar I don't want to stress the engine hardware more than necessary and rather give up 10 hp.
|
|
|
|
|
Logged
|
|
|
|
NOTORIOUS VR
Administrator
Hero Member
Karma: +58/-7
Offline
Posts: 1056
|
|
« Reply #24 on: May 30, 2011, 08:25:57 AM »
|
|
|
This is not a piston out of a random engine, but a RS4 with our oversensitive knock control posted by someone on audizine. That damage is most definately caused by knock. I can post some pictures of pistons from engines which were forced to knock in order to calibrate knock control if anyone wants to see it. I think nobody will argue that big boost engines will make best power on slight knock as they are obviously knock limited, but my thoughts are that with cylinder pressures easily exceeding 120bar I don't want to stress the engine hardware more than necessary and rather give up 10 hp. When ever you have a chance, I'd like to see the pics  |
|
|
|
|
Logged
|
|
|
|
|
phila_dot
|
|
« Reply #25 on: May 31, 2011, 12:32:42 AM »
|
|
|
The only thing that still confuses me is KFZW vs KFZW2. The tuned files that I have seen modified KFZW and copied it into KFZW2. Is this the best approach? I would think that if it were optimal for them to be identical they would match from the factory or there would be no need for KFZW2 at all. The only thing I could find on this is a post by Tony, but I am still unsure how to balance the two maps. One map is when the intake cam is at minimum advance, and the other map is when the intake cam is at maximum advance. The ECU interpolates the values based on the theoretical intake cam advance as it switches between the two.
|
|
|
|
|
Logged
|
|
|
|
silentbob
Full Member
Karma: +30/-1
Offline
Posts: 141
|
|
« Reply #26 on: May 31, 2011, 04:50:29 AM »
|
|
|
The only thing that still confuses me is KFZW vs KFZW2. The tuned files that I have seen modified KFZW and copied it into KFZW2. Is this the best approach? I would think that if it were optimal for them to be identical they would match from the factory or there would be no need for KFZW2 at all. The only thing I could find on this is a post by Tony, but I am still unsure how to balance the two maps. One map is when the intake cam is at minimum advance, and the other map is when the intake cam is at maximum advance. The ECU interpolates the values based on the theoretical intake cam advance as it switches between the two.
It's exactly how Tony discribed it. I have also seen this copy thing you discribed on many files from various tuners. I know why they do it, but it's complete bullshit (or lets say unprofessional) in my opinion. Usually when a calibration is done the engine is measured over the hole operating range with in our case two camshaft timings. Based on the measurements it's decided what cam phasing is used on which operating point. The two maps contain the values out of this measurements. So the ignition angles for both phasings are optimal even if you have a fault in the system and the cam is stuck in one position. What tuners usually do is put the car on the dyno with whatever cam phasing is calibrated and tune ignition angle. To make things easier they put the same calibration in both maps. Now if you have a fault in the cam switching system you will have wrong ignition angles in the area were the cam would have been in an other position. It's not that critical on our engines because the max difference in timing is "only" 20 degrees, but it can become on engines were you have up to 60 degrees. |
|
|
|
« Last Edit: May 31, 2011, 04:58:54 AM by silentbob »
|
Logged
|
|
|
|
|
s5fourdoor
|
|
« Reply #27 on: May 31, 2011, 03:36:32 PM »
|
|
|
So are we advocating running the same maps on KFZW and KFZW2 then?
The changeover map is KFNW, right? I can't find anything which shows how to "stitch" the maps together with respect to KFNW.
Could somebody possibly share their KFZW/KFZW2 maps with us? I like what Rick said regarding knock/tuning, but I'd personally rather avoid knock if possible...
|
|
|
|
|
Logged
|
|
|
|
|
julex
|
|
« Reply #28 on: May 31, 2011, 04:15:41 PM »
|
|
|
realistically you should only tune the last column for maximum load as this is where timing matters the most. Leave the rest at factory.
Since you also have changeover map that tells you when cam adjustment takes place, you should make adjustment to timing map 1 before and timing 2 after the cam shift leaving the other stuff alone.
This will leave the maps in their factory state should anything fail in cam timing mechanism.
If you want to be completely accurate you could probably increase the "dead" timing area in map 1 with delta change at the same rpm/load in map 2 and vice verse. This way, should your NWS fail, you will still get higher timing but not as much as just copying of the values.
that's my take on it.
|
|
|
|
|
Logged
|
|
|
|
|
phila_dot
|
|
« Reply #29 on: June 02, 2011, 11:06:15 PM »
|
|
|
I need a little help with understanding the schematic. What is the circle with the plus or minus next to it? Also, what is the asterisk in the box? These aren't explained in the beginning. I have included my general understanding below.  The output from KFZW is input into the partial function ZW_NWS as zw_local. fnwue = 1 is the maximum possible overlap of the inlet camshaft and determines whether KFZW or KFZW2 is used in ZW_NWS. I have not completely figured out the origin of fnwue, but I didn't see any relation to KFNW. If SY_NWS = 0, then zwnws = zw_local (does not apply). If SY_NWS = 1 and fnwue < 1, then zwnws = zw_local? If SY_NWS = 1 and fnwue = 1, then zwnws = the output from KFZW2? If SY_NWS = 2, then zwnws = the output from DZWNWSUE (does not qpply)? zwnws is effected by KFDZWKG, dzwoag, and dzwol (I believe all = 0) and is the output as zwgru - Basic ignition |
|
|
|
|
Logged
|
|
|
|
|
