ECU boost control mods
hehe
Aug 16, 2007, 09:56 PM
#32
I was able to try out some new settings today:
load variable used: 6B42
update interval: 5 units (about 0.4-0.5 sec)
TBEC: "today's setting" in picture below
Results:
- Note that the maximum load error possible is +/- 20. At the start of the run, the load error sat at -20 for a while, and because of my TBEC settings and update interval, the WGDC got ramped up by about 4%. This worked ok with my BWGDC settings until about 4500 rpm, and then it caused the load to shoot up about 10 past the target load and cause a bit of knock.
- After that, the WGDCC algorithm caught up with the overshoot and lowered the load back down to the target load.
- In the last part of the run, the WGDCC algorithm had to pull the WGDC down to keep the load in-check with the target load.
This is the first time I've seen the boost/load control system provide positive and negative feedback control as expected, so its a step in the right direction. The main problem I see right now is that under low rpm WOT spool up conditions or during part throttle acceleration, the WGDCC can get cranked up quite a bit and can potentially cause significan boost overshoot when going WOT. My near term attempt at preventing this from happening will be to zero-out the top right side of the TBEC table so that when the load error is more negative than -10, the WGDCC will be zero. See the "tomorrow's settings" table.
load variable used: 6B42
update interval: 5 units (about 0.4-0.5 sec)
TBEC: "today's setting" in picture below
Results:
- Note that the maximum load error possible is +/- 20. At the start of the run, the load error sat at -20 for a while, and because of my TBEC settings and update interval, the WGDC got ramped up by about 4%. This worked ok with my BWGDC settings until about 4500 rpm, and then it caused the load to shoot up about 10 past the target load and cause a bit of knock.
- After that, the WGDCC algorithm caught up with the overshoot and lowered the load back down to the target load.
- In the last part of the run, the WGDCC algorithm had to pull the WGDC down to keep the load in-check with the target load.
This is the first time I've seen the boost/load control system provide positive and negative feedback control as expected, so its a step in the right direction. The main problem I see right now is that under low rpm WOT spool up conditions or during part throttle acceleration, the WGDCC can get cranked up quite a bit and can potentially cause significan boost overshoot when going WOT. My near term attempt at preventing this from happening will be to zero-out the top right side of the TBEC table so that when the load error is more negative than -10, the WGDCC will be zero. See the "tomorrow's settings" table.
Aug 16, 2007, 11:15 PM
#33
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wicked man this is awesome.any chance of getting 98640014 ROM mods?that would be primo since there isnt much info floating round in New Zealand bout this kinda stuff
Aug 16, 2007, 11:26 PM
#34
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wicked man this is awesome.any chance of getting 98640014 ROM mods?that would be primo since there isnt much info floating round in New Zealand bout this kinda stuff
Aug 17, 2007, 05:48 AM
#35
Good call on the overboost fix. I'll have to implement that as well.
So, 6B42 is working for you. I guess my situation is a little odd. I haven't been able to do any more logs yet, but I'll report back if I find anything else. It was ~98* ambient here yesterday which may have caused the load overshoot issue. If the problem persists, I'll simply dial in my boost exactly where it needs to be for the 260% load and then dial back the load offset by 10 to compensate.
So, 6B42 is working for you. I guess my situation is a little odd. I haven't been able to do any more logs yet, but I'll report back if I find anything else. It was ~98* ambient here yesterday which may have caused the load overshoot issue. If the problem persists, I'll simply dial in my boost exactly where it needs to be for the 260% load and then dial back the load offset by 10 to compensate.
Aug 17, 2007, 11:09 AM
#38
I found a couple of things today ...
First off, the issue with my loads not matching ... I had no negative correction set for +5 and below, so the TBEC table was allowing my boost to be off by +7.5 before correcting for it. I've added a -.5 correction to the +5 error and it seems to be working correctly. It was just a slight overlook on my part.
Secondly, I've found that the logged WGDCC% value seems to be at a base 64 scale. I simply changed the EvoScan data.xml file to subtract that 64 and the WGDCC% follows the correction to the BWGDC% curve. This was only after one short test. I used the formula "x/2-64."
First off, the issue with my loads not matching ... I had no negative correction set for +5 and below, so the TBEC table was allowing my boost to be off by +7.5 before correcting for it. I've added a -.5 correction to the +5 error and it seems to be working correctly. It was just a slight overlook on my part.
Secondly, I've found that the logged WGDCC% value seems to be at a base 64 scale. I simply changed the EvoScan data.xml file to subtract that 64 and the WGDCC% follows the correction to the BWGDC% curve. This was only after one short test. I used the formula "x/2-64."
Aug 17, 2007, 11:51 AM
#42
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Hi Mrfred
superb job
- i'm impatient to get the offset info for the EDM 88840016 - with my mods i'm peaking at 25psi so some better control is required !
(and also to load '2byteload' !)
Any chance to get it soon ? Can I help ? (like searching for patterns in the 512K file or other stuff - posting ROM/xml ?)
Alain
superb job
- i'm impatient to get the offset info for the EDM 88840016 - with my mods i'm peaking at 25psi so some better control is required !(and also to load '2byteload' !)
Any chance to get it soon ? Can I help ? (like searching for patterns in the 512K file or other stuff - posting ROM/xml ?)
Alain
