Quote:
Originally Posted by DWR
TDI, the boost peak you had before was in a region where the turbos are compounding boost. Both turbos were still operating within relatively safe regions on the compressor maps. Assuming you were already hitting the torque limit for fueling in the DDE, the extra pressure probably was not doing much except keeping the exhaust cleaner. Of course, the high pressure at higher airflow/rpms was the real concern.
As long as fuel delivery is torque limited and EGT is controlled, I think the lowest boost to achieve that will produce the best results. Meaning, the reduction in boost is probably not going to give any relief to your transmission or tires. 
I'm glad to see your "last mod" continues to be your latest mod. Thanks.  |
I strongly agree with the bolded part above.
The way the EWG is configured in the latest video/log is a very simple manifold to lower port config. So drive pressure + boost is pushing the gate open.
Since the EWG is being forced open at lower boost numbers in the rpm range where only the small turbo is in play (as I'm listening/watching the video more it seems I can hear the EWG start to dump at the ~24psi point on the low rpm range), it seems to me the drive pressure is substantially higher in that region. Then at ~2800 rpm where the big turbo path gets switched in the drive pressure seems to be significantly reduced which then requires a little more boost to get to open up again.
Does this interpretation of drive pressure seem accurate based on your experience? I got a little manual boost controller yesterday I could play with if I feel the need to try to increase the boost a little more in 2000-2700 rpm range, but not sure yet if I want to do that.
Regarding sequential turbo setups and how to combine both turbo maps into a combined map ... I had found this presentation from Ford interesting:
https://www.gtisoft.com/upload/FordD...gines.2011.pdf
Especially this sequential twin turbo map example where they show both maps and then the combined "curve" they used for the twin turbo setup.