In Closed Loop Logged Duty Cycle below Commanded in WGDC table when under-boost

[Hookey]

Hi there, I have tuned 8 of these cars so far, all fg models and 1 ba. Contrary to popular techniques I always tune in closed loop then back fill the wgdc table from the logged wgdc. This takes longer, but I have had good success with it so far. Until now lol.

This is my personal car fg mk1 F6 525 pump id1050x pirotta flex fuel, GTX3582, 45mm external gate off housing. 3.5 xforce. I haven't done springs yet which is why I have the boost tapering off at high rpm. 

 

The issue I am having is I have a boost error of 1 to 1.5 psi. I am currently commanding 20psi. (boost by gear). This error was worse (2.5psi) I then upped the wgdc from 0.55 to 0.7 which is in the file now. This helped a lot but I noticed in the log that the closed loop is only commanding 0.4 wgdc roughly. I made the hysteresis smaller so it tryed harder to get to 20psi which didn't help. I have upped the gain 30 percent which didn't help so I put it back. 

I thought about putting 0.72 in the lower wgdc cells to see if it would get to 20psi but I would like to know why the logged dc is way below my initial DC in WGDC table. I  made sure I did both petrol and E85 tables as well so it wasn't an interpolation issue. 

I can put this in Open Loop and do it that way but I thought id see what you guys think. Thanks Mark

05-08-2022 11-50-44 AM Log.teclog FRF560_fan&dc.tec

[hjtrbo]

I'll check your logs later but off the top of my head, what gear are you putting the new wg values into? Boost by gear only works up to 4th in a ZF FG. 5th and 6th use the values from 4th. 

If not that, then you'll have an adder at play. I can look at all that later when I get a chance if no one else gets back to you in the meantime. 

As a side note, I find open loop first and get boost perfect, then back fill desired boost from the histogram. Similar but opposite to how you do it. 

[Hookey]

1 hour ago, hjtrbo said:

I'll check your logs later but off the top of my head, what gear are you putting the new wg values into? Boost by gear only works up to 4th in a ZF FG. 5th and 6th use the values from 4th. 

If not that, then you'll have an adder at play. I can look at all that later when I get a chance if no one else gets back to you in the meantime. 

As a side note, I find open loop first and get boost perfect, then back fill desired boost from the histogram. Similar but opposite to how you do it. 

 

Hey thanks for replying. I read your thread on when you went to closed loop. I have 0.7 WGDC I think it is in the cells for gears 2nd to 6th. I think from 3000rpm to 5000ish.  but the logged WGDC is only 0.4 to 0.5 and it is under boost by around 1.5psi. This is the first time I have seen this.

I was just going to go Open loop to sort it but thought someone like you might have an idea about why the logged DC is low. I think I have zeroed all the adders but may have missed something.

[hjtrbo]

Quite possibly. Your ect has a big influence over desired boost and wastegate dc. When I can get to your logs I'm sure we'll be able to sort it out. 

[Hookey]

3 hours ago, hjtrbo said:

Quite possibly. Your ect has a big influence over desired boost and wastegate dc. When I can get to your logs I'm sure we'll be able to sort it out. 

 

I noticed you are a kiwi. I'm down in Invercargill. 

I am wondering if it is the settings I have in auf3002. If the Change in spark is more than 5 degrees it will reduce WGDC by up to -0.3. I did this to reduce spike on gear change but may have overdone it

[hjtrbo]

Once upon a time kiwi, moved here in 2007. Still fly the flag though. 

Invercargill aye, fucken gets cold down there bro! What's your ect get to on a normal day? Anything below 74 or something close to that going from memory it will reduce boost. 

auf3002 won't be in play during normal WOT runs unless you have torque management or knock freaking out in the background. I had mine set to -1.0 for a while. Did not cause any dramas.

Still can't look over your logs but I'm keen to get to them.

Cheers

[Hookey]

1 hour ago, hjtrbo said:

Once upon a time kiwi, moved here in 2007. Still fly the flag though. 

Invercargill aye, fucken gets cold down there bro! What's your ect get to on a normal day? Anything below 74 or something close to that going from memory it will reduce boost. 

auf3002 won't be in play during normal WOT runs unless you have torque management or knock freaking out in the background. I had mine set to -1.0 for a while. Did not cause any dramas.

Still can't look over your logs but I'm keen to get to them.

Cheers

Hey thanks for your help. It ended up being auf3002. I had-0.3 in the cells from 5 up. I zeroed the table and then lowered the WGDC to 0.58 from 0.70 and it pulled 21psi. Got the old boost sensor pegged DTC upped that voltage limit to 5.1 to fix it. Ill lower the DC a bit more to get rid of the error but at least its following now. 

Anyone that is using Auf3002 for lowering your boost spike on gear change beware this may drastically alter your WGDC all the time. I have some false knock changing the spark I need to get rid of which is where it could be coming from.

11-08-2022 07-29-43 PM Log.teclog FRF560_DCfixed.tec

[hjtrbo]

Yeah, you're only supposed to hit the high deltas in 3002. That way it's exclusively for a gear change or other major torque management event. 

[hjtrbo]

Shout yourself some tuner nerd knock ears for father's day. 

[hjtrbo]

For comparison purposes. Your original settings vs what I run now.

 

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I also zero out the in built gear based multiplier and adder 0319 & 0326 

 

Along with a small tweak to the ECT table I don't generally see any adders in play on OL WG or CL Desired boost. 

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