The previous owner of my 1990 TII FC5S apparently removed the duty solenoid which I discovered this while redoing all of the vacuum, fuel, and coolant lines. (Many vacuum lines weren't even blocked off...dumbass...) and I believe I found out why the engine blew out on him. He wasn't using any aftermarket boost control, but I was wondering if anyone knew where I could find one of these solenoids? Ive been search the parts section and also online but I can't find one anywhere. Does anyone have any input?

 

Place a wanted ad in the classifieds. Alternatively, you could convert an emissions solenoid, but the plugs are not the same shape. There are also 2 different kinds of solenoids on the rack: one is opened with 12v applied, and the other is closed. You'd have to be sure you grabbed the right one.

 

Ok, thanks, Idk why people remove this kind of stuff if they don't understand it enough to know they need some form of boost control.

 

You'll pick up ~2 psi of boost, and better spool up with the duty solenoid back in place.

 

So how exactly does the solenoid affect the wastegate? Im just curious how it all work. I noticed on the "solenoid block" that has 3 different solenoids which have a few vacuum lines that I have room for a 4th solenoid on it and it explains a few of the vac lines that aren't hooked up to anything. Im wondering if maybe my vac line is from a s4 or maybe s5 NA because I truly dunno where stuff is suppose to go:/

 

The solenoid bleeds air off from the line to the wastegate actuator. The other end connects back to the TID, so it ends up pre-turbo. Bleeding pressure makes the wastegate crack open later (better spool up), and it allows the turbo to build higher max pressure. It's an ECU controlled boost controller.

S5 TII vac diagram: https://www.rx7club.com/showpost.php...56&postcount=5

 

Just to follow up I installed two MAC's as illustrated in the first image of post #4 and they work well. It takes some messing around to get it to hit the target boost level without creeping or falling off, but overall all I am happy and would recommend this method...

 

Reviving this thread here! I am a bit lost, Since this is all about twin turbos, Where would you wire the 3 way mac valve into the ECU for a single turbo? Since obviously all the twin turbos will be gone . Do you wire it up to the factory wastegate control? ( 4U - L/W ) and ground output ( 4A - B/W )?

Could someone please clear this up, Using a Power fc.