Tuners Rejoice! Free Tuning For M4.4!

[Boxman 102]

Good to know, thanks for that one, seems more logical! Any idea about "K+L" by any chance?

Edited October 14, 2017 by Boxman

[rkam 39]

Kurtz und Lang

Short term and Long term

KFBAKL is part of function UKSEFI Ubergangskompensation fur SEFI - Wandfilmmodell along with a bunch of other parameters according to damos file.

ROM:   CUKWLL,DLUKW,DUKK,FSTAUKM,FUKNSTM,FVANST,KFABAK,KFAVAK,KFBAKL,KFBAW,KFVAKL,KFVAW,KLWF,STEUKKL,TLWNSP,TNSUUK,ZBALM,ZUKK,ZUKNST,ZUKW,ZVALM,

RAM:   B_LL,B_NSP,B_ST,B_UKG,E_DK,FBAKL,FBAW,FSTAUK,FVAKL,FVANS,FVAW,N,SDTLW,SDWFK,SDWFL,TEUKG,TEUKK,TEUKL,TEUKW,TEUKWM,TL,TUKNS,WF,XKSTAA; 

[Boxman 102]

No clue what all those variables do, but emperically I got somewhere today, and it helped quite a bit. I love the Ostrich and the ability to switch between extremes within seconds. 

• Accel enrichment DK = fast initial enrichment 
• Accel enrichment K+L = secondary(?) slower enrichment.

When I slam the throttle, and playing around with the extremes, it was pretty clear that there's a primary enrichment controlled by the DK and a secondary one by the K+L. If I turned off DK entirely, upon slamming the throttle, AFR would blip lean followed by rich before settling. Turn DK up, and this initial lean blip will turn rich. Increasing the values, of course, meant richer. 

Upon turning up the K+L quite a bit, the slower enrichment became obvious as especially when pulling away, it would hold 'rich' (AFR's towards 10) for a longer period.

I ended up dividing the DK table by 5 in the appropriate temperature range, and the K+L by a factor 10. Still it blips rich upon blipping the throttle, but only to 13.8-ish - my VE table might still be off. Pretty good, compared to the 12 AFR blip I consistently hit when I increased throttle.

Decel tables were harder, and I wasn't able to get a great characterization since my CBV setup is sub-optimal atm, causing it to actually run rich when lifting, but I'd assume they operate the same as the accel tables, basically. A higher K+L definitely gave me a much leaner deceleration in situations where it doesn't cut the fuel entirely.

 

Now if only someone could point me to how the STFT values exactly alter the injector time (the factor, how is the 'maths', -0.78 = divide VE by 1.0078, or something similar?), I can tune my VE table properly and methodically first, then work on the accel/decel tables and have a nice tune. :D

Edited October 14, 2017 by Boxman

[Calvin Sonnik 6]

Alright guys, now that Boxman hs filled in a blank for me I am going to share some of the things I have figured out.
I was initially curious about how I can change the way the car feels to drive, looking at factors like accelerator feel and crackling on deceleration, but as I dove in I learned more.

I found some values responsible for changing RPM float down and deceleration noise.

-Deceleration Leaning Factor (both DK and K+L)-
Boxman had a great explanation so see above.

The next value is the scalar called   - tL - threshold ZWB1 -> ZWB2 -
It looks like above the set value in MS the ECU sticks closer to the ignition map and offers fewer corrections
the corrections I speak of look to be driveability corrections, it limits how fast the ignition timing changes leading to a more delayed throttle response but an overall smoother driving experience, I bet it also helps prevent part load misfire or knock due to a sudden but small change in throttle position, ECU might rely on this more than acceleration enrichment at low part load.
When in the ZWB1 mode it looks like the ignition angle changes slower, both on deceleration and acceleration, and uses at least one other map that is not used in ZWB2.
When in ZWB2 mode the ECU sticks much closer to the actual ignition map before knock corrections.
I am going to change the scalar to .5 or so and see what ends up happening with the feel of the car.

The next map is called -Re-engage Ignition Advance-
For a while when driving I have seen the ignition angle dip into the negative values when under mid RPM deceleration. But none of my ignition maps have anything in the negatives.
The negative values in this map correlate perfectly with the timing I see missing as compared to the ignition map while decelerating down towards idle. I am going to change this value more and see if there is a delay on when it triggers, and if it can be triggered on part throttle deceleration. Lowering the values even further and over a wider RPM could lead to a quicker drop in RPM and a burble on deceleration out of the exhaust.



There are a few more values I want to investigate and if anyone has more info about them I would be grateful in figuring these out and adding descriptions to the WIKI and to the XDFs.

-RPM Boundary for ZWD-off -
I think it controls when the idle air motor is no longer sent a signal and it flops over to the default semi-open position
this limits engine vacuum to prevent component damage and decreases engine braking to a reasonable level, I remember a full page or two dedicated to this 'mode' in my factory manual for my SAAB LH2.4.2 systems I was working with for a while.

-Throttle angle boundary for ZWD-off -
This should be the same concept except that it shuts the power to the IAC off when you reach a set throttle angle. 
I don't know if the IAC corrects or smooths throttle changes when you are in part throttle cruise, if my oscilloscope was lighter and not from 1965 I would take it for a drive with me and see what the IAC does, I guess I could use a multimeter to detect average voltage, i might just add a resistor and capacitor so the multimeter has a steady signal. If it does, this value might be to prevent the IAC from moving about while the pressure difference between pre and post throttle plate are high, the turbo is spooled and just ready for the throttle to be opened more. In that case, a small adjustment in the IAC may cause the car to feel unsteady.

-Delta Ignition angle when LL was- (seems like a mistranslation but I can't find a better one)
I have no clue what this is, but it looks like ignition values at part load, but those values look really big to be actual changes to the ignition.
I can change the whole map to a single significant value and see what that does to the engine and datalog.

-load threshold for ignition angle override in transition from idle to part load-
This map could be part of the smoothing I was talking about earlier. How much load has to change within a specified period for it to enact smoothing.

-TLW-map from DK-angle including bypass correction-
XDF and translation show it may be a limp home map, it should be easy to test just unplug maf, rev the engine and listen carefully, change values drastically, repeat.

I am also going to see if I can make the exhaust note at startup different using the SAS routine,
I don't even know if the routine still runs with diagnostics disabled but if it does I can tell it to increase idle and retard the ignition to change the exhaust note for a specified number of ignitions.

I will report back after I gather more data and see if I can change the descriptions in the XDF and I might start making new pages in the wiki about each parameter that we have nailed down
 

Regards,
Calvin Sonniksen

[Boxman 102]

I like where this is going, lots of investigations going on in that one, thanks for sharing! There are still a lot of parameters to be properly characterized, and I think tuning is more than just 'finding max power'. Sure, I hit loads of 14 now, but driveability-wise, I noticed I'm doing quite a lot of stuff 'manually' that the ECU should be able to handle for us - for instance the way I lift off throttle or operate the clutch after a pull to not have it jerk around. Knowing what all these factors do as precisely as possible will help us get the cleanest tunes for our cars. I'd like to stimulate everyone who 'fiddled around' with maps to share their raw observations, so we can discuss and figure out what exactly is going on.

Also, @ the Venderbroecks ( @venderbroeck / @Piet ), is there a way / hack to disable or reset the wideband-mod to 0 STFT upon Decel somehow? There should be some switch in the ECU as this too notices when the engine is decelerating.  I noticed that when trying to decelerate, the mod will try and correct for the deceleration leaning by enriching through the STFT, resulting in too rich a mixture upon re-engaging throttle due to the out-of-whack STFT that corrected for the leaning-tables (which, i think, should be tuned on their own. Upon re-engaging throttle, it takes some time to resolve since the wideband mod went pretty far off the mark so to speak. I don't think we should try to correct to AFR's of 14.7 upon deceleration, do we?

Additionally, I'd opt-in for a switch to turn off any lambda-regulation at all with the Ostrich (with the engine running, toggle-able) for investigational purposes. That way I can exactly characterize how each map affects the engine. The wideband-mod 'cleans up' a lot, so to speak (as intended by design, of course).

Edited October 15, 2017 by Boxman

[Calvin Sonnik 6]

@Boxman, the value "probe diagnostic in front of catalytic converter"  if set to 0, disables all fuel trims, STFT and both LTFTs

 

[Calvin Sonnik 6]

I have a question for those smarter than me.
Because the load is measured in MS, does the calculated load change with bigger injectors?
By setting the injector constant lower does it, in fact, change the load?
Or is the load based off of an injector constant of 1 (315cc injectors)?

Thanks,
Calvin Sonniksen

[venderbroeck 296]

The load is based off of the current injector constant.
So it changes with different injectors.

[Calvin Sonnik 6]

@venderbroeck
So if I am understanding this correctly, If i swap Blue/white injectors for green, I must scale every map that uses Load?
So my ignition timing will be off as will my fueling and LDR setpoint?
If so, that would suck.

Thanks for the bad news ;)
Calvin

[venderbroeck 296]

In theory yes. In practice the difference isn't very large. Especially not when talking about ldr setpoint.
It shouldn't give you any problems.

[Calvin Sonnik 6]

So if i was to swap to 750CC injectors, I would essentially be doubling the amount of fuel and boost requested if i just changed the injector constant?
Something strikes me as wrong about this. I have seen screenshots of fuel maps when people are using much larger injectors, and they still are in the 1.x range, not the 0.5x range one would expect if this is true, unless they changed the equation in the XDF itself.
I guess i can see for myself.
Log MAF voltage and load with one injector and swap injectors and repeat and see if the difference is linear or not.

Thanks,
Calvin

Edit: it also occurred to me that there would never be a need for exceeding 10MS or so, if the blue injectors max out about there, then so would the 750cc injectors if the load value scales with injector constant.

Edited October 15, 2017 by Calvin Sonnik
I am slightly intoxicated and therefore slow.

[venderbroeck 296]

The fuel map stays in the 1.x range because you calibrate the injector constant to make it so.
So with properly calibrated injectors you would expect the ve map to be close to 1.
If you wouldn't change the injector constant, then yes you would see quite different numbers in the ve map.

Load is also dependent on RPM, so you would have to take that into account if you want to check the difference between injectors.
 

Edited October 15, 2017 by venderbroeck

[Boxman 102]

7 hours ago, Calvin Sonnik said:

@Boxman, the value "probe diagnostic in front of catalytic converter"  if set to 0, disables all fuel trims, STFT and both LTFTs

 

Thanks, will try this out. Now I just need to know if this can/should be the case when decelerating. Is it supposed to correct to 14.7 in that case, or not at all? What does the original unedited narrowband control do?

Also (just gonna repeat it, surely somebody knows :P), still need to know how STFT values correct the VE map / injector time exactly. Or is this just an unknown?

[Piet 222]

The STFT could be shut off during deceleration.

In fact, I think I already once experimented with this in the past. Not sure.

I'am spending some time in Iceland right now, when I'am back home again I will look into it.

The STFT doesn't correct the VE map btw, as the VE map is a correction by itself.

The ECU calculates the injectiontime out of RPM, airmass and injectionparameters (injector constant and deadtimes) assuming a volumetric efficiency of 1 throughout the whole RPM range, which of course isn't the case. That's where the original VE table comes in, being a correction of the Volumetric efficiency in the injectiontime calculations.

The STFT just adds (or subtracts) extra time to the calculated injection time.

 

Edited October 15, 2017 by Piet

[Boxman 102]

 

Quote

The STFT just adds (or subtracts) extra time to the calculated injection time.

 

Right, but what I actually want to know is what are these units in the calculations, are they straight up percentages added as a seperate correction?

 

Edited October 15, 2017 by Boxman