3 port over boost

[Turbo.Tim]

I have a 2003 Evo 8 with a tial external wastegate and a grimmspeed 3 port boost controller.  I have always run this just using the bottom port of the wastegate only.

Port 1 VTA, Port 3 to turbo, port 2 to the lower wastegate port.  On the wastegate I only used the lower port and the top was VTA.

I am in the process of setting up a break in tune on a new motor.  I have now changed the plumbing on the wastegate to use both the top and bottom ports on the wastegate hoping to help with spool up time.

I now have Port 3 to turbo with a T to the lower wastegate port, port 2 to the top of the wastegate and port 1 VTA.  

I had the boost controller set to off on the map.  When I went out and did a pull the car hit 28 psi.  

When I was only using the lower port with boost off I hit spring pressure of 18psi.  Do I have the plumbing incorrect of would the boost controller being off not bleed the air off correctly.  Would having the boost control on with duty cycle set to 0 have a different result?

[jdniss]

The Turbosmart single-port connection method lines up with the Grimmspeed documentation - looks to be the same style of 'MAC' solenoid - albeit a different colour
 

 

Though Turbosmart's two-port connection method differs from yours - their "pressure source" is routed to Port 1, rather than your Port 3

 

Grimmspeed: https://www.oakos.com/product_docs/GS-057001.pdf

Turbosmart: https://www.turbosmart.com/wp-content/uploads/instructions/External_Wastegate_EWG_38mm_40mm_45mm_50mm_50mm_GenV_Standard_Motorsport_Fitment_Instructions/English.html

[Adamw]

From the help file:

[Turbo.Tim]

I have always run it figure 3 from jdniss screen shot but i wanted to test out running both ports on the external. I assumed the boost source would still be port 3. Thank you I will try swapping ports 1 and 3. 

 

Is it recommended to run the 3 port or just a manual boost controller?  Would I be able to build boost quicker if i went to a manual?

[jdniss]

46 minutes ago, Turbo.Tim said:

Is it recommended to run the 3 port or just a manual boost controller?  Would I be able to build boost quicker if i went to a manual?

You'd typically see quicker spool with an Electronic Boost Controller / "3 Port" Solenoid as it allows more precise wastegate control.
Adam might be able to explain better.
 

Here's an example of a Manual Boost Controller - a typical "ball and spring" style bleed valve - in blue;
vs an Electronic Boost Controller - a Turbosmart E-Boost 2 controlling a "3 port" MAC Solenoid - in orange.

Both were setup for a boost target of 21psi MGP (Manifold Gauge Pressure);
However the 3 port solenoid allowed the gain rate to be dialed up - I think this is referred to "Stage 1" in Link's Closed Loop Boost Control strategy - to bring the turbocharger on faster, subsequently hitting the 21psi target about 2,000rpm earlier than the manual bleed valve.