Boost by Gear
#21
SADFab Destructive Testing Engineer
iTrader: (5)
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 18,642
Total Cats: 1,866
Start with a 20kpa delta. Once your tuning gets good you can lower it. The delta is basically just a holdoff that keeps the wastegate closed until you are close to your target.
Theoretically you don't need those rows of 100, because the algorithm will be keeping it closed anyways. I use those rows to get more resolution in my rpm.
Theoretically you don't need those rows of 100, because the algorithm will be keeping it closed anyways. I use those rows to get more resolution in my rpm.
#22
delta
Start with a 20kpa delta. Once your tuning gets good you can lower it. The delta is basically just a holdoff that keeps the wastegate closed until you are close to your target.
Theoretically you don't need those rows of 100, because the algorithm will be keeping it closed anyways. I use those rows to get more resolution in my rpm.
Theoretically you don't need those rows of 100, because the algorithm will be keeping it closed anyways. I use those rows to get more resolution in my rpm.
#23
SADFab Destructive Testing Engineer
iTrader: (5)
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 18,642
Total Cats: 1,866
Originally Posted by Help bubble
(Closed-loop) Boost pressure must be within this many kPa of the target boost before closed-loop control will activate.
Outside of this range the valve is held wide open (keeping the wastegate shut) for fastest spooling.
Outside of this range the valve is held wide open (keeping the wastegate shut) for fastest spooling.
#24
Oh, wow, OK, that is set to 100, so it currently only holds the wastegate closed until I am within 100 kpa of the target!? Ok, I didn't understand that setting at all, wow. I thought that was just setting the whole table to see 100kps as atmospheric, good grief. OK, 20% sounds much better, now that I understand it. How close (small) can you get that delta without having boost spikes, I wonder?
#25
SADFab Destructive Testing Engineer
iTrader: (5)
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 18,642
Total Cats: 1,866
Depends a lot on your setup and tuning. As I said before, mine is set to 20kpa (not %, stop saying percent). I also have a really fucky wastegate and boost control is very hard. My bias table looks ridiculous.
#26
Yes, 20kpa, not %, sorry. I set it to 20kpa just now. I think I've got this map ready to test, but I need my driver, I can get so much more done when I have someone to drive and do what I tell them instead of datalogging and pulling over all over town. Trying to get him to come and drive this afternoon so I can try this.
#27
Weird
Ok, that was disappointing, I went from having a tune that was hitting really solid boost when tuning it wrong, to one that doesn't hit the targets anymore, and has also developed way more oscillation in the boost. I tried lowering the duty numbers a little and raising them a little, but that didn't help. Raising the delta to 30 kpa seemed to diminish the oscillations a little, but it's really rough. When I look at the log file, it doesn't make much sense to me, it never really meets the targets, and takes a long time to get close. Any chance you could look at the log and tell me what you think I'm doing wrong?
#28
SADFab Destructive Testing Engineer
iTrader: (5)
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 18,642
Total Cats: 1,866
Well you brought your duty table down a bunch. It went from 30 to 23? It worked before? Why did you change it.
Never mind. Your 190kpa looks the same. I'll look tonight.
Never mind. Your 190kpa looks the same. I'll look tonight.
#29
Hmmmm
Ok, I notice in the log, that the boost duty never went below 33 through the pull, so it is ignoring my duty numbers to try to reach the boost target. I guess it needs a little more duty cycle to reach the targets. I'll try that. Are the oscillations because it's trying to reach the targets without enough duty cycle perhaps?
#30
best yet
Ok, I think I got it by copying the 33 duty that it never went below in that last log I posted. It isn't oscillating wildly anymore, just a little bump past right at the beginning then it settles at 190 kpa. Please look at the current log and tune and tell me what I could do better. Boost by gear is working now.
Thread
Thread Starter
Forum
Replies
Last Post
sickmiatabra
MEGAsquirt
0
04-13-2016 09:54 PM