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Author Topic: All things load/requested boost notch and NWS...  (Read 28914 times)
jibberjive
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« Reply #30 on: April 27, 2012, 02:42:26 AM »

Another random thing I noticed, in KFNWWL there seems to be a discontinuity in two of the higher load columns where it goes from active (1) at low RPM's, to 0, then back to 1 at mid RPM's.  See the 110% and 135% rows that I circled in the pic below. Is there a reason for this, or do you think it's just an oversight by the factory, and those 0's in the middle should be 1's? If you look at the rest of KFNW/WL, there's a pattern of solid blocks of staying on, then switching off, not this on-off-on.



« Last Edit: April 27, 2012, 04:07:09 AM by jibberjive » Logged
s5fourdoor
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« Reply #31 on: April 27, 2012, 10:34:08 AM »

honestly i think all of these tables in debate need to be stitched together to replicate what the ECU actually sees.  for instance, KFZW+KFZW2+KFNW = zwgru?  or whatever it is...     i asked this question before and there wasn't a very good answer.  how do the actual transistions occur?

is the 0-1 turned into a step function?  or is it a hard 0-state 1-state.   at what exact point does this transition occur relative to KFNW?
i think we need to take the s4 and rs4 zwgru and compare them.  all of the tables are vastly different.  i bet you'll see the timing reflects a physical change in the torque curve.  and now we're back to the torque model...

someone needs to take the tables we have and create an excel or matlab model of the expected torque curve, resultant horsepower curve, approximate fueling curves and optimal ignition curves.  this stuff is all linked and we are talking bout changing tables in isolation...
« Last Edit: April 27, 2012, 10:36:59 AM by nehalem » Logged
julex
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« Reply #32 on: April 27, 2012, 12:03:22 PM »

Physically the cam tensioners are only capable of two positions, "1" which expands the tensioner. It then presses on the chain and advances intake phase. Position "0" puts cam tensioner into default "retarded" position. AFAIK the ECU has no ability to modulate that into any intermediate phase. It is either, ON or OFF.

In the advanced "1" phase, the intake valve phase overlaps exhaust valve phase by a considerable amount.  Normally I believe it is only 2 deg as measured here http://www.audizine.com/forum/showthread.php/297064-Cam-profile-data-for-all-factory-cams. Add 18 deg of cam advance and suddenly you're overlapping 20 deg, which essentially leaves door open for either exhaust gas to back into intake or intake to exhaust. Due to air inertia though I believe that some clear air pushes exhaust gas out with some fresh air inevitably just escaping through that path. That's the secret behind improved economy and torque on cam advance.

The result though is that engine effectively consumes more air than it is really using for combustion, which would result in AFR inbalance if not corrected via these "helper" tables.

This would also explain notch in MAF readings. Engine is using more air with NWS active than with NWS inactive and when NWS inactivates you see the drop since the venting is not taking place anymore. The engine is using less air now per piston than before.

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TTQS
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« Reply #33 on: April 28, 2012, 05:18:34 AM »

Thanks for a good explanation julex. I'll update my tuning guide with discussion from this thread, so if I ever get Revision 2 out you might recognise some of the words.

TTQS
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jibberjive
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« Reply #34 on: July 26, 2012, 01:53:13 PM »

Here's a good quote from prj in another thread regarding this (reposting here for future reference of something to try):

jibberjive, to mostly remove the notch, the last column of KFPBRKNW and KFPBRK should be set to equal values.
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ddillenger
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« Reply #35 on: May 12, 2014, 12:20:39 AM »

I have a notch!

This is after setting KFPRG and KFPRGNW to like values. I've never gotten a notch before, so I wanted to post it Tongue

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userpike
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« Reply #36 on: May 12, 2014, 01:20:53 AM »

I have a notch!

This is after setting KFPRG and KFPRGNW to like values. I've never gotten a notch before, so I wanted to post it Tongue



Will you throw in WGDC to that chart please?
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ddillenger
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« Reply #37 on: May 12, 2014, 01:32:01 AM »

Kind of irrelevant as it's a notch in requested, not actual Tongue

But sure. I will a little later.
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userpike
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« Reply #38 on: May 12, 2014, 07:41:18 PM »

Kind of irrelevant as it's a notch in requested, not actual Tongue

But sure. I will a little later.

I'm interested in how much change in WGDC there was during the notch is all.
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ddillenger
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« Reply #39 on: May 12, 2014, 08:01:55 PM »

I'm interested in how much change in WGDC there was during the notch is all.

0 change.

The issue was in KFPRG fwiw.
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BlackT
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« Reply #40 on: June 15, 2021, 12:42:16 PM »

Fastes way to get rid of this boost req drop? But to keep NWS active

KFPBRK and KFPBRKNW  al to 1?
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NG Coupé
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« Reply #41 on: August 30, 2022, 11:30:53 AM »

Here's a good quote from prj in another thread regarding this (reposting here for future reference of something to try):

Quote from: prj on July 26, 2012, 01:16:30 PM
jibberjive, to mostly remove the notch, the last column of KFPBRKNW and KFPBRK should be set to equal values.


Had a notch in requested boost at 3880 rpm. That exactly solved the problem. Thank you for that!
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