I have been reading this section of the forum for awhile and have come up with some specific questions regarding boost control in it's stock form.

First off, I'm trying to understand the BDEL+BCLO+TBEC effect on boost in some specific circumstances.

Let's say we put the MWGD to 100 across the board like stock. Now we run BCLO at 80 + BDEL at 159.4 across the board. So we are saying we want a desired engine load of about 240 at all RPMs. Obviously we are going to have differences between our actual and desired engine loads. At this point is the TBEC table the only thing controlling boost(by altering the target value of MWGD) other than the physical limitations of the stock boost system?

To illustrate: If we were to set the TBEC to 0 at all RPMs in the above case, would boost be totally determined by the stock boost systems physical limitations? Does the "desired load" (BDEL+BCLO) even mean anything at this point? For example, if my actual load is 260, while my BDEL+BCLO load is 240, does the car do anything about it (ignoring boost cut/overboost condition)? It will calculate a difference of 20, look at the 0 in the TBEC field for that RPM, and do nothing. The WGDC remains unaffected by this?

In the same vein, let's say we set the MWGD to the highest value it can be set to (127.5). Now lets say our values in the TBEC are such that they would never bring the WGDC below 100. Is this not the exact same situation? Does our poor turbo just push as hard as it can go at all times???

 

That is correct. Zeroing error correction means you are always running the values in your MWGDC table. Boost cut is a misnomer, that is actually fuel cut. It is not controlled by these tables, it is controlled by the Boost Limit table, along with the Delay Timer... The logic is, if you exceed Boost Limit for x amount of time, cut fuel.

Also, don't think of MWGDC as how hard the turbo is working... that's how hard the BCS is working to bleed air away from the WGA. Values over 100 do nothing here, as this is a percentage.

In short:

MWGDC is used to set the boost curve... on the stock restrictor pills, the table is 100% flat because the pills will not allow you to boost past 20 psi.

BDEL+BCLO are used to determine if you are overboosting or underboosting.

TBEC is used to modify MWGDC to heal the overboost/underboost. Zero it to eliminate error correction. The one exception is if you are on smaller restrictor pills than stock, running less than 100% MWGDC, and you are underboosting, the ECU will add up to 10% MWGDC. This is due to additional tables that were discovered by mrfred (Max Upward WGDC Correction).

 

Yes, I actually meant to say fuel cut. It was late hehe.

"Also, don't think of MWGDC as how hard the turbo is working... that's how hard the BCS is working to bleed air away from the WGA. Values over 100 do nothing here, as this is a percentage."

Ok, so with MWGDC set at 100% across the board like stock, the only thing that can happen is that we somehow get an overboost condition at a particular RPM and the TBEC table has a correction for that that brings MWGDC under 100%. Since WGDC is maxed out if we somehow were to end up with an underboost condition too bad, so sad, nothing more can be done as we've maxed out the WGDC?

So since I have a stock boost system (only mods are Works drop in and Buschur TBE w/HFC), and the restrictor pills limit boost to 20psi, let's say I wanted to shoot for 20psi constant boost curve (just an example). Would I then zero out the TBEC table, set MWGDC at 100% (or 127.5 just because that's as high as I can go) and allow the physical limitations of the system to govern my boost for me? Even though MWGDC is set flat stock, they still taper boost at high RPM using the TBEC table if I'm reading the TBEC and BDEL+BCLO right in the stock map. Or did they just make BDEL+BCLO follow the natural taper of the BCS as boost falls off at high RPM?