4 port boost control solenoids

[Chris Wilson]

I am wanting to improve boost control on an RB26 Nissan twin turbo engine, it runs the factory style turbo set up, albeit with greater flowing internally wastegated turbos and ported manifolds. In order to get the boost as high as I would like (1.5 bar) I have to run wastegates with 1.2 bar springs in them. i now see that some people are using wastegate actuators on internally gated turbos that have a pressure seal on the rod side of the diaphragm, and two pressure nipples, like an external gate. By using a 4 port solenoid they seem able to run soft gate springs, yet achieve high boost when desired. this gives the ability to map for wet traction without having to run soft springs and hope that at full duty cycle you get enough boost for the dry. Apparently they work off a normal PID output from the ecu. Has anyone here got real world experience of these 4 port actuators and twin port actuators for internally gates turbos? Are the wastegate actuators reliable, or do they have seal issues, and are there any control "gotchas"? Thanks.

[Ryan.g]

Not used any 4 Port solenoids myself but i tend to if presented with your problem add another Solenoid and drive one nipple with the Phase and other with antiphase of the WGFinalDuty, Works very well.

Unfortunatly you cant do this on the Motec after having a quick glance at the Aux Output list. So you are just going to have to get an S8

Ryan

[Jasper K]

Hi Chris,

I have never seen a 4-port solenoid. Care to post a link so I can have a look.

What I do know is that there are 2-port Actuators for Internally wastegated turbos. That way you can use a 3-port boost solenoid and setup the wastegate plumbing like a External Wastegate. However you will have to remember to swap the TOP & BOTTOM hoses compared to an EWG as the Bottom port on an EWG will OPEN the wastegate but on a Actuator that is normally the TOP port and vice versa.

This should already give you much more precise boost control but indeed you will still have to run a stiff spring to prevent the flapper from opening when spooling.

Another method as mentioned by Ryan is to use 2 pcs. of 3-port boost solenoids. This requires the use of the Phaseduty and Antiphase duty to be setup correctly and you'll have to use 2 outputs to drive the 2 solenoids. However since you can apply the boost pressure on the BOTTOM port of a 2-port actuator you do not need to rely on a heavy spring to keep the flapper properly closed. With the 2 solenoid setup you could basically run an 8 or 10 psi spring and have control of upto 30psi easily provided you turbos can handle it

Cheers,

Jasper Kopinga
CS Racing
Taiwan.