Leon ASV: Quantities & DZR (038 906 012 is wrong)

HI.

I was right, the Leon ASV had very high boost pressure overshoots.
/viewtopic.php?t=12864&highlight=assess

After I had rotated the VTG (first 2 degrees, then rotated one degree back, so a net of one degree), the whole thing looked better.

Right now, I have the Leon here again (to fix the door seals) and I've just finished taking its measurements again.

He is quite sluggish, at least relatively slow compared to my "extended" 1Z.

Now I've seen that it actually takes him quite a while to get hard.
If I make your VTG shorter, it will swing more strongly over .

What would you recommend?

m;

Attached is the Russgrenzen log file for 4 short acceleration runs up a hill in the city.

and three excerpts showing boost pressure from a dynamic road test.

Hello Dieselmartin,

So, regarding those 'overswings' that you described, I also experience them with my Leon.
'There, they peak at up to 0.25 bar. However, since they only occur at relatively low engine speeds, I won't do anything about it. The turbocharger won't be damaged by such low mass flow rates. Furthermore, I believe that Seat intentionally implemented this to emphasize the sporty character of the vehicle. At least, it positively affects the responsiveness.'

What I find interesting is the behavior when you let the vehicle coast down from a high RPM (without or with very little braking).
(See the third case in the DZM measurement.)

I don't know what the engine is doing, but it seems to build up boost very late. Perhaps it fully opens the EGR valve when decelerating and only closes it before building up boost.
My Leon exhibits the same behavior. If you want maximum acceleration, it's best achieved from a relatively high RPM. If you try to accelerate directly after coming to a stop, it will be sluggish. In this situation, the amount of air entering the engine is limited, and the smoke reduction system reduces the fuel injection amount due to the lack of turbo boost.

Back to your question:
Personally, I live with the overshoots and would reset the controller to its 'factory settings.'

What I still find interesting:
I have software version 3357 installed in my Leon. In our discussions, we always assumed that this was the same as a VW application. However, I know that a separate application is used for each body variant. Seat does this as well.
Does the engine code 3357 also appear in VW and Audi vehicles, or is it 'unique' to Seat as well?
If the over-the-top features were intentionally implemented, then Martin unfortunately acted counterproductively, even though he had the best intentions.


Best regards, Jochen.

dieselmartin wrote:

Now I've seen that it actually takes him quite a while to get hard. If I make your VTG shorter, it will swing more strongly over . What would you recommend?

Hi Martin,

It depends on your preference which problem is less severe for you (slowness or high overshoot) -> as you've already noticed, the total amount of "badness" remains the same, only the proportions can be adjusted.

The way out of this dilemma is either a "new charger" or "chip tuning" (correcting the pre-tax fuel consumption) - although, lacking comparative information, I cannot estimate where the better chances of success lie .

I consider the overboost (some TDIs produce more power, others less) to be relatively harmless, considering how much air the turbocharger has to pump in at full load and beyond - taking into account the reduction in boost pressure. Does it not eliminate the extreme overboost at the top end, or am I mistaken?

Nebelwerfer_TDI wrote:

I consider the overboost (some TDIs make more power, others less) to be relatively harmless, considering how much air the turbocharger has to pump in at full load and beyond - taking into account the reduction in boost pressure. Does it not eliminate the extreme overboost at the top end, or am I mistaken?!

Perhaps the charger hasn't yet started to degrade prematurely, but what about pressure spikes and the risk of head gasket damage?