3 hours Dyno calibrations. need some consulting (logs, images, config included)

[fizban]

Hello all,
Been to the dyno 2 days ago.
We have optimized the maps with boost controller off and with boost controller on. I am using an external boost controller.

With the boost controller off. kPa starts at 170 (4000 rpm) and ends at 189kPa (7200rpm) - 265bhp and 31kgm at the wheels

With the boost controller on. kPa starts at 225 (4000 rpm) and ends at 198kPa (7200rpm) - 316bhp and 39kgm at the wheels

I've been wondering what can be the reason for the boost drop-off, and whether they can be estimated from logs:
1.  Can it be that the  spring for the internal wastegate (GT28RS)  cant hold the boost.
2. Maybe the catalytic converter (3 inch, 100 cells) is restricting the flow?
3. Maybe the boost controller is simply not good (AEM Tru-boost)?

I've included the logs and config. Also 2 pics of the logs can been seen below:

Boost Controller Off:



Boost Controller On:



Config:

https://docs.google.com/open?id=0B6l1SB-S-teyRVRpLVZnc1UwaUU

BC off:

https://docs.google.com/open?id=0B6l1SB-S-teyNldoUmxNNl83bHc - bc off

BC on:

https://docs.google.com/open?id=0B6l1SB-S-teyNnlmVktrcEliLU0

Dyno Graph:



Thanks

[GintsK]

What kind of BC you use? Mechanical? Electronic? Closed loop? Open loop? How you tune it?

And for what reason you do not use VEMS BC?! It gives wonderful possibilities to 1) control and compensate various system oddities 2)keep track on what happens inline with other parameters in log files. 3) Let the VEMS to protect engine in case of high temperatures.

Without BC boost probably rises because of flow restriction trough W-gate path. It is common phenomenon.

Gints

[fizban]

It an electronic one. You tune it by adding to the duty cycle of the solenoid.

I dont use the BC of VEMS since it probably require more wiring (unit is PNP) and i am interested in having 2-3 boost options without using config switch.

[GintsK]

So - it is open loop style with fixed duty? Then no way to keep boost steady. As exhaust pressure rises also force what help to open w-gate rises. In this case force is high enough for affecting boost.

[fizban]

Ok, i looked at the boost controller options in the VEMS and it has very nice features. Like boost per rpm and gear based reduction.
Are there any instructions how can i enable boost control in VEMS?

[GintsK]

Once you chose solenoid output channel VEMS BC is enabled. solenoid electrical connection is similar to injector.

You can start with simple open loop with PID values zeroed. Then just BoostDC table will be in effect.

But [IMHO better way] depending on solenoid/w-gate you can try P I D from 80 20 60 and integral limit 100. Write DC table little lower than at target boost and in your case rising with rpms. Construct some reasonable target table and watch what happens during pool. You can control result by overlying boost target and MAP traces in log viewer. And protect engine with overboost protection.

Gints