I've seen sporadic information on using two 3 port mac solenoids with one wastegate, to allow for a finer resolution when trying to adjust boost levels. I want to avoid some issues I've seen in the past where a 1% change in Hondata is equivalent to a few psi.

Currently, I have a 4 port installed, but wanted to see if anyone had experience running two 3 ports with a single wastegate and if that was able to provide a finer resolution so it isn't as touchy when making adjustments. From what I've seen it's ideal to have each 3 port wired up separately, but that they can still be wired up together if your ecu can't control two individually (I don't believe s300 can). I do understand you can change the hz setting in Hondata so maybe that's why I've seen setups in the past that were so touchy, I'm not sure.

I'm also not really opposed to running co2 boost control, but that seems like a lot of effort if two 3 ports is an easier way to provide more resolution when making boost adjustments.

Any input is much appreciated

 

Right about the time I was ready to pull my hair out in frustration over the very dilemma you're trying to avoid, I was reading about using a manual boost controller inline with the solenoid for essentially the same purpose. The MBC, I assume, serves the same purpose as the 2ndary MAC without the wiring/control concerns.

 

So I'm running a 4 port mac solenoid on my setup and I believe my duty cycle was like 72% which equaled 22psi and just upping the duty cycle to 73% made the boost jump to 30psi.

I'm about to get rid of it and just switch to a regular electronic boost controller because my solenoid is very inconsistent some pulls it'll make full boost and others it'll make half that.

 

Edited post..

 

%Duty cycle does not convert to a positive boost pressure. It's the solenoid's actuation rate compared to 100% (maximum actuation rate).
Wise idea to switch to an independent EBC

 

The real benefit of the 4 port is running a lot of boost on a weaker wastegate spring. For example I tuned a car a little while back that made 10 psi on spring, and 30 psi at full boost. Made for some of the best boost by gear action Ive experienced in person, where 1st, 2nd, and 3rd were able to be tuned to the max the tires would hold. Kind of a crazy feeling to get the same G force acceleration in the seat of your pants through 3 gears.

If you only need to double the wastegate spring pressure, just stick with a 3 port solenoid.

It would be nice if Hondata could do proper closed loop boost control with a PID controller. But the open loop seems to work well enough if you get it dialed in.

 

Yea I put I think a 9 lb spring in my wastegate and hooked it up a leakage tester (pressure regulator), it started opening at 11 psi and then was fully open at 16 psi. I'm guessing I won't need more than 30-35 psi at full boost.

I ended up finding pictures of someone using two 3 ports on a single wastegate, which seem to be wired together although it's hard to tell since the picture isn't the best





Anyone feedback from someone who's seen this or done this in the past would be awesome

 

That looks like a 3 pin deutsche connector, so they may have wired the positives together on 1 pin and grounded the solenoids separately to different outputs. I dont know what kind of control scheme they would be trying to use for that though.

I would run both wastegates on a single solenoid. If it ended up limiting control in some way, you could run 2 solenoids wired together on one output. Just have to make sure the transistor/mosfet could drive them both.