ThePass

iTrader: (3)

First, my mspnp9093 came with decent maps, so I ran those for a while out of boost, but soon wanted to get it tuned to use boost so I started messing with the VE and spark tables. I read the whole megasquirt extra manuals on tuning, and following instructions there, turned off Target AFR tables and set the Accel Enrich limit high enough that it wouldn't turn on, and then went on to adjust the VE table. After tweaking, datalogging, tweaking again, repeat, I got a decently acting VE table. Then I turned the target AFR and accel enrich back on and things got a lot richer all across the board. That got me thinking, you guys probably don't turn that stuff off every time you want to tweak your VE right? So since I was starting with an already working VE table, should I leave that stuff activated and tune VE according to datalogs with them on?

Second, at some points on my datalogs, at one steady rpm and MAP level, the AFR will 'bounce'. This also happens between about 3400 and 4200 rpm during acceleration. I want say, 12.8:1 in this area as boost builds, and in my datalog I'm seeing oscillations between 14:1 and 11:1 in this area. This confuses me because I have 'smooth' transitions between cells in my VE table. So I would expect a smooth change of AFR during acceleration, wether the VE tables were off too lean or too rich, I'd expect it to be a steady AFR, not so jumpy. Learn me a bit on this?

Thanks as always for putting up with 'rookie' questions.
-Ryan

Braineack

iTrader: (62)

look at the log for tpsaccel. I bet it's kicking in then.

if you really want to turn it off, change all the rates to 0.0ms

ThePass

iTrader: (3)

Hmmm you're right, it seems every dip is accompanied with the accel Y lighting up red in MLV.
What can I do to alleviate this problem? I should I make something in the accel wizard less sensitive?
I noticed in the Accel Deccl trigger dot window I can turn accel off when in boost - should I just do that or is that a bad idea?
I have not messed with any of the settings for accel enrich, they are as they came with the mspnp.
This is what my Acceleration Wizard window looks like (don't know how to get an actual screen shot of the window)

Map-based
Value (ms)...Rate (Kpa/s)
9.0.................300
7.0.................200
5.0.................130
2.0..................80

MAPdot threshold (Kpa/s): 50
Accel time (s): 0.4

Suggestions?
-Ryan

Braineack

iTrader: (62)

I had to dramatically alter the supplied table...DIY suggest you use the fpr vacuum line and an inline fuel filter to remove noise...

turn all the values to 0.0ms...that will effectively disable it for now. get your tune good, then go back in and start fine tuning the accel enrichments...fwiw, I'm only at 1.0ms at 300kPa. I still have a slight lean tip in, but it seems I don't need much more to get it right.

Although I'll be adding a TPS this weekend so I'll have to work on TPSdot instead.

ThePass

iTrader: (3)

Ok, I'm setting all the values to 0 m/s, setting accel enrich off when in boost, and I'm going to go datalog and see what happens.

samnavy

iTrader: (7)

Great discussion about ACCEL ENRICH starts at Post#96
https://www.miataturbo.net/forum/showthread.php?t=18648

ThePass

iTrader: (3)

excellent info there samnavy. thanks a lot.

ThePass

iTrader: (3)

Ok, I set my accel enrich values to much lower numbers - 1.8 max tapering down to 0.5, instead of the DIY supplied 9 max tapering to 0.5, and after a few datalogs I'm seeing GREAT results. My crazy dips and rises in AFR at WOT accompanied by dips/rises in the pulsewidth are gone, and accel Y doesn't flash on and off in MLV during a pull.

Now, it's developed a lean tip-in, which I'd assume is due to the accel wizard being 'weaker'.. what exactly should be altered in the accel enrich to try to minimize the lean tip in?

Thanks again
-Ryan

Braineack

iTrader: (62)

add more fuel. Most likely in the higher kPa rate cells. maybe change 300kPa to 2.2ms. work your way up...

ThePass

iTrader: (3)

Just so I have a clearer understanding of how this ae works... it seems like the rate is how quickly the kpa rises pers second yea? So... isn't it impossible for my car which right now barely peaks over 150 kpa max boost to ever be effected by the 300 kpa setting? Or is this more like... 300kpa/sec = 75 kpa/0.25sec? Which is something that I guess maybe I could achieve - a 75 kpa rise in a quarter second...
Am I on the right track here or lost?
-Ryan

Mach929

iTrader: (3)

yes it's the rate of change kpa/second, when you stab the throttle
higher numbers will add extra fuel when you hit the gas maybe too rich, lower numbers will add less maybe causing a lean tip in, you gotta find the right setting where it's just right

ThePass

iTrader: (3)

I changed the 300 to 250 and changed the value to 2.2. We'll see what happens.
on a side note, I just recently learned about using ve analyzing in mlv. This is cool