NefMoto

Hi,

I'm wondering when the actual boost pressure should meet the desired boost pressure?

According to Audi, full torque should be there at about 2200 1/min in this engine. I know that some manufacturers try to make their car data look better than it really is...

So... with my stock file (everything else is also stock) pvdks meets pssol_w at about 3000 1/min... in some logs a bit earlier...

Unfortunately I don't have experience with similar engines. Can someone tell me if this is normal, or does my wastegate need some adjustement?

Attached a screenshot of a 4th gear WOT log.

Probably fine.

Next time post the complete log, including wastegate dc.

Many thanks!

Sorry, the log file is too large... more than 30mb.

Is there an opportunity to make the file smaller with ecuxplot?

Not easily.. you can hand edit it if you are careful though (and good with a text editor).

Interesting idea for a feature though...

In the mean time, can you add wgdc to the graph you posted?

Ok... I was able to do it manually.  ;D

Now you can take a look at all my logged values.  :D

pssol_w is not the setpoint, plsol is.

pssol_w is desired modelled manifold pressure (post throttle)

plsol is target boost pressure (pre-throttle)

They should be identical however when the throttle is wide open (100%).

Looks fine to me.

Thank you both.

Since it seems that stock is ok, the next step for me will be to increase LDRXN to get more boost pressure.

Hi!

I'm struggling with increasing boost above 4000 RPM. Increasing LDRXN in this area has no effect in this area. See screenshot...
Is there something else limiting? In my opinion KFLDHBN isn't limiting.

I added three log files:

1. Stock file.
2. First tune -> Increased LDRXN to max. 160. decreased LAMFA to 0.9.
3. Second tune -> Increased LDRXN to max. 172. LAMFA stayed 0.9 since temperetares were nice.

I don't see a real difference between the two last logs in actual boost pressure.

Thank you in advance for any input.

PS: Could it be that the exhaust system is already limiting? Or maybe some other "hardware"?

Screenshot:

What makes you say this? Graph ChargeLimitTurboProtection vs EngineLoadCorrected :P

That's why I said this. engine load is not reaching that limit... and since exhaust mass flow isn't getting higher than 165...170 g/s in every three logs... i think the catalyst is limiting... This limiting is also nice to see if you take a look at the WGDC - the boost pressure regulator is trying to decrease LDE by higher duty cycle (from stock to 160 to 172 LDRXN), but boost isn't increasing.

I didn't say why I think like this to have no influence on your opinion...

But maybe I'm off track.

Please correct me, if there is another "limiter" i don't see...

Don't confuse actual (rl) with requested (rlsol/rlmax)

rlmax is definitely being capped by ldrlms

rl, in this case, is entirely irrelevant. Requested load is entirely feed forward if there is no torque intervention.


Totally disagree.

Now I'm really confused!  ??? ;D

rl is capped by ldrlms... this you can easily see in the log... at about 3000...3500 rpm...

but rdrlts isn't limiting... what's KFLDHBN in my opinion...

that's a minor problem at the moment...


the main problem is at higher RPM's... here the LDR tries to increase boost with WGDC but boost isn't increasing, although i don't see any map which is limiting. -> so it's the catalyst(?)!

I'm seeing no such thing.

ONE MORE TIME: ldrlms/ldrlts DO NOT CAP RL, they cap rlmax


I had a typo in my post. I mean ldrlts, not ldrms. One more time: look at your log: ldrlts is limiting rlmax


I'm not seeing that in the last .csv you posted.

Hmmm, I was irritated...



yeah, you're right. But rlmax is capping rl at the end?

It's the maximum allowed rl?


In this case it's not. Take a look at the attached screenshot (TP vs LoadRequest).


Please take a look at the second Screenshot (LDV-WGDC). There you see the difference between requested boost and actual boost as a comparison of stock file and the tuned file...
Additionally there is Wastegate dutycycle plotted. Imho PID is trying to decrease the difference by more WGDC.

No, rl is actual engine load. There is no way for rlmax to "cap" it via feedback loop through the boost PID.

It is entirely separate.

Requested load gets converted to requested boost, which is compared with actual boost to drive the wastegate.

At NO TIME is rl compared with spec load in the boost PID, it is done entirely according to boost.


I was assuming you were talking about the boost taper, not the difference between stock and tuned. Obviously, you need more WGDC for more boost.

If the PID result isn't high enough, likely you are hitting IMX

You are hitting I-max:

Many thanks so far nyet!

But why is the actual boost pressure of the tuned file above ca. 4500 rpm nearly the same as the stock file? Especially when the wastegate is trying to increase charger-RPM (-> boost pressure) by closing the WG.

Imho it's still an exhaust system problem or is there anybody who can eliminate this theory?

Likely you are at the limit of the flow capabilities of the turbos. Increase IMAX and see if more WG will give you more boost

Increased IMAX! There is no difference in actual boost with more DC of N75 @ RPMs above ~4500.
Would be a shitty calibrated PID if it couldn't manage to hold boost with stock file. I think the Audi guys are capable to do this right. :)

So there is a mechanical issue.

Either the WG isn't "strong enough" to hold back the exhaust gas pressure (in the manifold) ->(Could be some issue with the spring, diaphragm, N75...

Or... if the WG IS able to hold back the pressure... there must be a too small delta of pressures before and past turbine... -> charger RPMs are too low for desired pressure.
In this case the exhaust gas system is limiting... most likely the cats... Could be that they are blocked in some way...

Attached the files... one reference file... and one with increased I-Limit.