2 Stage MBC

[DiamondStarM]

Here is a diagram I put together from the Taboo Speed Shop diagram. I noticed a few people using 2 or 3 solenoids to switch between a MBC and the stock BCS which I did get to work with my experiments. Ends up with alot of hoses and wires. Heres a methed I came up with(sorry if somone else already did, but I havent seen it posted anywhere).

Basically with the swith on, you run through the MBC as normal and the solenoid blocks and vacuum to the nipple on the turbo. When the switch is off the solenoid allows some vacuum to "bleed" off the the turbo minimizing the boost level.

Mine is set to 16psi, switch on, and 10 psi, switch off. This allows me to have an economy/power mode so to say or I found it helped to launch at 10psi and switch to 16psi in a higher gear, being a FWD.

Let me know what you guys think, is this at all harmful?

 

[4GSixty3]

That looks like a really good idea. I really dont know jack about electronics but where do you find a 12v solenoid? And what other lines do you have to run? Ex.. like a flip switch inside cockpit run to like a fuse for power and then another run too that? I think ima try that when I get my talon on the road being as it is fwd also. Good idea man.

Rick

 

[4GSixty3]

And what exactly is that drawing right above the wastegate solenoid picture?

Rick

 

[DiamondStarM]

Above the wastegate solenoid (BCS) is the air intake. If you look along your firewall, there are three solenoids. I took one from an old GS in the junkyard with the wiring clip for $2, it only has two connections for vacuum, and two wires, positive and negative. I ran the negative to a ground under the hood and took the positive inside to a rocker switch which is powered by the cigarette lighter so I cant leave it on when the car is off.

 

[4GSixty3]

Got ya . One more question. Is 10 psi the lowest that soleniod runs until you flip the switch? Because if so, that would be cool. Did you have to do any modifying to make it run 10 psi or just simply hook it up and run 10 and then at the flip, it runs 16?

Rick

 

[DSMKevan]

Yeah this has been discussed before. Its fairly simple actually, you just need a MBC and one stock BCS, and wire it to a 12v source with a switch. Im personally going to use a 1g automatic power/economy switch, looks stealthy and stock-like.


I really dont know why you would attach that one end of the solenoid to a vaccum source. The purpose of the solenoid is to "bleed off" some of the vaccum pressure that goes to the wastegate actuator, making higher boost. In your diagram, the solenoid isnt bleeding off the vaccum, its just putting it right back into the compressor housing of the turbo. Thus you arent really "bleeding off the turbo, minimizing the boost" like you said. You are in no way "minimizing boost" by adding the solenoid, youre actually increasing it. Since the less vaccuum pressure (by "bleeding" it off) the wastegate actuator receives, the more boost youll get.

Heres the link to my idea http://www.dsmtuners.com/forums/showthread.php?t=131780

 

[DiamondStarM]

I found that the stock BCS setup tee's off to the turbo from the factory, if you run it straight stock and cap off the turbo and the other side of the tee, you will get spikes up to 22psi. And if you tee a MBC to the turbo, you are basically running the same as stock, no matter what the MBC is set to, if you tee it to the turbo you'll get 10psi. The switch allows you to open or close that vacuum line with the solenoid. So its 10psi and whatever the MBC is set to. I have it setup now and it all works so far. Day one, 30miles, no problems.

 

[DSMKevan]

Thats really weird, I guess I dont understand how mitsubishi solenoids work . I just kind of figured that the solenoid is pretty much an additional MBC. Since bleeder valve MBC's "bleed" off vaccum pressure that is going to the wastegate actuator, I figured thats the same thing solenoids would do if they were placed in the vaccum "circuit" that goes to the wastegate actuator. And in Taboo's diagram, the solenoid only has one vaccum line going to it. I wonder why the solenoid is hooked up to the lower intercooler pipe in the stock configuration, and in your configuration.

I just went by taboo's diagram but modified it for low/hi instead of low/med/hi settings.

In a stock configuration (as shown) the pressure signal is sent from the Air Cleaner to the wastegate actuator. A boost control solenoid is placed in line of this circuit to restrict boost. I really dont understand why they put the T on the wastegate actuator pressure circuit, as it only runs to the lower intercooler pipe, serving no purpose.

 

[DiamondStarM]

I really dont know why you would attach that one end of the solenoid to a vaccum source. The purpose of the solenoid is to "bleed off" some of the vaccum pressure that goes to the wastegate actuator, making higher boost. In your diagram, the solenoid isnt bleeding off the vaccum, its just putting it right back into the compressor housing of the turbo. Thus you arent really "bleeding off the turbo, minimizing the boost" like you said. You are in no way "minimizing boost" by adding the solenoid, youre actually increasing it. Since the less vaccuum pressure (by "bleeding" it off) the wastegate actuator receives, the more boost youll get.

Well your right, except the methed I'm trying works the oposite of yours. With the solenoid closed its exactly like running the MBC at whatever setting it is at. But rather then bleeding off vacuum off with the solenoid open it allows more vacuum in(my mistake in the first post), thus lowering the boost, similiar to a stock level.

I might have to give your method a try also, looks interesting.

 

[DiamondStarM]

Just remember a solenoid is only a on/off switch for vacuum. Blow through a solenoid, then hook it up to 12V and you cant blow through it anymore. It "closes the door"

 

[DSMKevan]

Yeah, I kinda figured it was like that. I have mine all wired up, except I never got it going, due to the fact that my soldering iron broke, and my switch didnt work . God I need a butane iron!

 

[kicker91laser]

Ah, this would work really good for my colt it doesnt get much traction