Zaphod

Hi guys,

after I got my MS3(X) running nicely I took a ride yesterday and got the VE dialed in quite a bit.

As I cruised at the Autobahn I had one spot that I had a little problem...

Scenario is - light throttle cruise TP ~30%, speed is a t 180 kph (~ 111mph) and boost is around peak (170kPa). The boost control is working perfectly well when I give the throttle a nice stab, but at that low throttle the MAP is starting to oscillate...

See:


This is how my boost target table looks at the moment:


As you can see - at 30% TPS the boost is exactly between to different targets (I guess the MS interpolates them..?).
The oscillations can well be because of my rough VEtable - but could also be hunting between the two different boost targets. (?)

So I thought a bit about how a correct boost target map would look like...?!
How does yours look?

Thanks

Faeflora

iTrader: (2)

No see um pic.

Zaphod

Should be working now...

Braineack

iTrader: (62)

See if adding a little bit more D helps. What are you PID settings?

Zaphod

PID is at 22/22/70 now -
Control interval is at 10ms.

with higher TPS the boost control is near perfect.

Gets to target fast, holds target till redline, doesn't overshoot too much...

Braineack

iTrader: (62)

really close to what i have, but i think Im using 100D. Might want to try it?

Zaphod

I am going to try for sure - I am always a bit scared of this high D values, because I thought they would bring oscillations...

Ken seid in this thread (where some other member asked about bc tuning) at Msextra just some days ago:

Maybe 100 is sparingly... it all depends on point of view...

Edit:
I have noticed, that the PID values on all the Miata MS2/3 tunes I have seen tend to be very close...