ITT: MS3X VVT settings and tuning - Page 6 - Miata Turbo Forum - Boost cars, acquire cats.

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Old 11-11-2014, 11:14 PM   #101
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ALRIGHT, here you go. logs and screen shots attached

the weirdest part about all of this, is the difference between perfect VVT operation and crazy sporadic jigsaw looking jerkiness is....................NOTHING

Absolutely nothing is changed between the different runs, yet sometimes it works perfect as you can see, and sometimes it looks like its having a seizure.

Can the cam PHYSICALLY advance and retard that fast and hard? I doubt it. Y'all think its a cam sensor going out or something? I dunno. I'm totally open for suggestions .


PS: oh and 1 last thing - sometimes it doesn't show as working at all. Like the gauge will show 0 no matter what. Then it works. Then it doesn't. Then it works sometimes.

Its so weird
Attached Thumbnails
ITT: MS3X VVT settings and tuning-vvt-weirdness.png   ITT: MS3X VVT settings and tuning-vvt-weirdness-1.png   ITT: MS3X VVT settings and tuning-throttle-lift-afr-dip-2-vvt-normal.png   ITT: MS3X VVT settings and tuning-throttle-lift-afr-dip-vvt-normal.png  
Attached Files
File Type: msl vvt weirdness.msl (313.5 KB, 68 views)
File Type: msl vvt weirdness 1.msl (115.8 KB, 53 views)
File Type: msl throttle lift afr dip, vvt normal.msl (132.2 KB, 47 views)
File Type: msl throttle lift afr dip 2, vvt normal.msl (226.7 KB, 75 views)
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Old 11-11-2014, 11:54 PM   #102
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Quote:
Originally Posted by 18psi View Post
ALRIGHT, here you go. logs and screen shots attached

the weirdest part about all of this, is the difference between perfect VVT operation and crazy sporadic jigsaw looking jerkiness is....................NOTHING

Absolutely nothing is changed between the different runs, yet sometimes it works perfect as you can see, and sometimes it looks like its having a seizure.

Can the cam PHYSICALLY advance and retard that fast and hard? I doubt it. Y'all think its a cam sensor going out or something? I dunno. I'm totally open for suggestions .


PS: oh and 1 last thing - sometimes it doesn't show as working at all. Like the gauge will show 0 no matter what. Then it works. Then it doesn't. Then it works sometimes.

Its so weird
Can you repost with "VVT angle 1" and "VVT target 1" on the same Graph? I found that I needed to set min/max values for each to be in the same range, so that the lines can be directly compared. I get some angles like "285" on engine start that will throw off the scale for "VVT angle 1", making it harder to compare visually.

Example of my VVT data attached.
Attached Thumbnails
ITT: MS3X VVT settings and tuning-screen-shot-2014-11-11-9.52.35-pm.png  
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Old 11-12-2014, 09:55 AM   #103
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Have you logged the VVT data to see how closely it is following the table?

That looks like the VVT table from DIYPNP? I tried that type of table but ended up with small changes in MAP while in steady state cruise causing the targeted VVT angle to start oscillating. It then would cause a noticeable on/off sensation that I could feel in the drive train.

I ended up varying angle only by RPM under about 65Kpa and over 20Kpa. That made for a more steady angle at cruise.

I have similar settings for the PID parameters. They are working okay, but I do start to get some oscillations after it idles for more than a few minutes. Any hints on tuning that out would be great.
I have not logged VVT data.

It works great on the street, dyno was great, so I have no reason to really question the settings.

It is the table from the VVT tuner, just interpolated to the smaller 8x8 table on rev's MS3.

On the dyno we took the 7000rpm column down to nearly nothing, as suggested by the operator who's tuned lots of VVT engines, so I didn't argue.

Our next tuning session will include working on the idle, so I'll let y'all know if the 2x2 section in the bottom left gives us any headaches.
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Old 11-12-2014, 10:27 AM   #104
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Any reason why you didn't use the VVT map that was included with the basemap?
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Old 11-12-2014, 10:34 AM   #105
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I'm using the VVT map that was included in the basemap
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Old 11-12-2014, 11:22 AM   #106
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I was referring to curly's comment.
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Old 11-12-2014, 11:38 AM   #107
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Oh, my bad.

Any ideas about why mine is going berzerk randomly?
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Old 11-12-2014, 12:02 PM   #108
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Just curious, are the vvt angle readings from what the controller is trying to do or what is measured off of the cam sensor?

From a general pid tuning view it looks like you're hitting unstable operation and need to back off your proportional value and probably tinker with your integral value. What kind of pid tuning technique did you use?
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Old 11-12-2014, 12:07 PM   #109
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I'm pretty sure it's measured, because VVT target is what the controller is trying to do, and that's super duper smooth. And half the time, when it works correctly, it matches what the controller is trying to do perfectly, as it should. The other half, not so much.

As discussed earlier in this thread, I started with P at 100, I at 0, and D at 0, slowly worked P down til targets were met, then started increasing I to hold targets to redline, and then added D to stabilize the transients.

HOWEVER,
I have tried LITERALLY every single setting for VVT PID and nothing prevents it from oscillating from time to time like it does.

I think I'm going to start a new thread about it, might be an issue with my MS unit or my wiring or my VVT valve? I dunno
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Old 11-12-2014, 12:23 PM   #110
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Cool yeah if backing off P doesn't change the unstable operation then it certainly could be noise on the lines... If you send a signal to the actuator and it doesn't get there the system will freak out. If you send a signal to the actuator and it gets there, but the resulting feedback measurement doesn't make it to the controller, the system will freak out.

Sorry did you say that you're not getting any sync errors? I'm not certain how the ms handles the crank/cam signals, but they're probably running on interrupts and the measured time between crank and cam events are probably fairly accurate. So if you don't see any sync issues then I'd say something sounds scratchy on the actuator.
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Old 11-12-2014, 12:27 PM   #111
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No sync errors at all. I was actually expecting to get some, but no.
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Old 11-12-2014, 12:36 PM   #112
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I've only been rocking the ms3 for a month or so and haven't really looked at the timing capture capability.
Can you accurately capture the time between crank and cam events? That would at least let you test vvt setpoints for certain. As in set a vvt offset and observe the time shift between crank and cam events.
Not sure if I can be of much more help, but I'll see if I can answer these questions tonight. Unfortunately my vvt engine is still in pieces so I can't check that end quite yet.
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Old 11-12-2014, 04:27 PM   #113
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Rev, we tried yours for a bit, then tried the interpolated DIY's vvt tuner map. We ended up dyno'ing with the DIY map and I didn't want to change back after dyno'ing. Shoulda done a back to back, but it slipped my mind.
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Old 11-12-2014, 05:01 PM   #114
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Mostly wondering "why", more than anything.
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Old 11-12-2014, 06:21 PM   #115
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I've heard a lot of dyno tuning had gone into the vvt tuner map, and wasn't sure about yours. I had bugged you about a dozen times when I was checking over things, so I just threw on theirs to be sure it was a good map for the dyno time, and again forgot to switch back and see the difference.
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Old 11-12-2014, 07:07 PM   #116
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I have found that I need to set a value in neutral hold duty even though I run the engine with NHD disabled. It requires a power cycle. In theory at least, with NHD disabled it should not have any effect on VVT function regardless of what is the grayed box, yet it does.

Also, I enable adjust inj timing relative to VVT table.
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Old 11-12-2014, 08:00 PM   #117
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what value do you run in neutral hold?
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Old 11-12-2014, 10:29 PM   #118
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Quote:
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what value do you run in neutral hold?
Whatever stabilizes idle target vs actual. Usually between 20-50 I think.
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Old 11-13-2014, 10:46 AM   #119
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What kind of differences do you do on the VVT table with a boosted application - I am especially interested if 949racing could chime in on this - as my Trisha project is in the near future running a VVT (already in the car) with a C30-74 Rotrex (just missing some small bits). So - something you guys already have done - watching your Mental project with interest. Although my engine is nowhere as sophisticated as the engine in Mental... ;-)



Thanks!
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Old 11-13-2014, 12:43 PM   #120
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What kind of differences do you do on the VVT table with a boosted application - I am especially interested if 949racing could chime in on this - as my Trisha project is in the near future running a VVT (already in the car) with a C30-74 Rotrex (just missing some small bits). So - something you guys already have done - watching your Mental project with interest. Although my engine is nowhere as sophisticated as the engine in Mental... ;-)



Thanks!
Mental is an OEM rebuild with Manley rods. Deviate OTOH, has a $10k race engine, maybe thats the one you are thinking of. Tables don't change much from S/C to N/A, all else being equal. I have not tuned a turbo NB2 engine yet so I can't comment on that. I'm guessing not much would change. A few here have and posted their tables. I don't share tables though, sorry. They need to be tuned on a dyno by a pro or experienced tuner who knows what to look and listen for. Otherwise stay very conservative.
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