Hi guys,

Looking to get correction dialed in better for cold weather.
based WGDC tune was done @ around 50 degrees

Concerned with overboost @ WOT.
I know I can lower the WGDC across the board,
however I thought I could address it through correction.

I'm using load based settings:
here's what I'm currently running:
correction interval is set to 2.

thanks

 

make sure you set your boost desired engine load table properly along with your boost error correction table and change your correction interval to 1. this should make sure that you maintain your target load regardless of the weather.

 

I took load from several 3rd gear pulls
I'll change the interval and see if it's more
Responsive

 

What boost solenoid are you using? I find that on my 3-port using an interval of 1 is too fast; it tends to over-correct. I'm using 2 right now.

I'm guessing that correction table is for load-based boost control? If so I think those values are too aggressive, and may also cause your boost to always fluctuate between "too high" and "too low". Here's my table if you want to compare.

 

This is what I recommend for error correction:

-20.0= +1.5
-17.5= +1.5
-15.0= +1.0
-12.5= +1.0
-10.0= +0.5
-07.5= +0.5
-05.0= 00.0
-02.5= 00.0
0.0= 00.0
+2.5= 00.0
+5.0= 00.0
+7.5= -0.5
+10.0= -0.5
+12.5= -1.0
+15.0= -1.0
+17.5= -1.5
+20.0= -1.5

A boost error of +/- 5 load is totally acceptable IMO.

Set correction intervals to: 1

Set your MAX UPPER WGDC CORRECTION table to all zero's. This will prevent most overboost conditions.

Now all you need to adjust is your MAF IAT WGDC CORRECTION table as the seasons change. In the cold winter, you will overboost so you need to figure out the appropriate amount of WGDC to remove at specific logged IAT's. In the hot summer, you will have less boost and may never reach your desired load curve so you'll need to add WGDC.

As a generic starting point, assume that you will lose 1psi in the hottest climate and gain 1psi in the coldest climate. So after you dial-in your WGDC curve during average air temps, with NO error correction activated, globally lower your WGDC until your boost curve lowers an average of 1 full psi. Do the same to determine how much WGDC is required to raise your boost curve 1 full psi.

Hopefully that helps.

-Jamie

 

Pretty much the values I'm using with interval 1. If you set MAX UPPER WGDC CORRECTION to zero's, it means boost controller cannot set duty any higher than value there is in Base WGDC tables, only lower. Am I correct?

 

Yes. It'll prevent overboosting during spoolup but if boost falls lower than desired in the middle of a pull the ECU can still adjust WGDC upwards to compensate, but not any higher than the original values.

For instance, if error correction is at -1.5 at some point in the pull, the ECU can increase WGDC by 1.5, which will return the correction to 0. It can't increase it any higher though.

 

Got it, I have to try this later. I have found that if I leave some room for controller to make upward corrections, it can hold boost pretty well but it fluctuates around reference a little bit no matter how you tune error correction table. This method would work as I also found that if I let my controller saturate itself, boost is very stable.

 

Raptord,
I'm using GM 3-port and load based.
Max Upper correction has always been zeroed out.


Jamie, thanks as usual for offering advise, it's very much appreciated by all.
I'll give your suggestions a shot.

It's crazy how boost responds to very little changes to BWG changes.
I'm running a Forge piston style waste gate actuator with not much preload.

Thanks for all the help guys...