Yeah i have the Perrin so it should work. It is the grainer type. So you are using the MBC as a sort of check valve? So it will prevent over boosting? I am confused on how this will work. I understand the solenoid and how that will work just the MBC thing is throwing me off.

I thought that the point of the solenoid is to make it so you won't be venting to adjust boost and this will give you absolute control of the boost with being affected by temp and conditions.

Ben

 

ok hold on i figured it out. man i need some sleep

You set the MBC to bleed only when you get passed or to the boost level.
So it won't leak unless it needs to bleed of extra pressure to prevent overboosting. So you will be able to control boost acurately and not worry about over boost. right?

Ben

 

Correct.. best of both worlds.. when used with a stock ECU (or a system that cannot control duty cycle) it will boost to the MBC level, or drop to wastegate level.. Making it possible to remove the UTEC if needed without having to convert it back to the old bleed system or worry about overboosting.

I definitely recommend setting the MBC first to the level you want, then hooking everything up and fine-tuning it, it makes more sense to set the MBC to the maximum boost you'd want and never above it, but it depends on what you desire to do..

 

So have you hooked this up yet? Any good news on it. I am really interested in it. After I get my map senor and WB taken care of this may be my next mod.

Ben

 

I have had it hooked up, had some trouble with the CEL and the solenoid, so I took it out to research what resistors I need to match the impedence.. Then got caught up in my blowthrough setup again and haven't worked on it in 2 weeks.

BUT, it works fine.. when its open, you get wastegate pressure, when its energized you get the boost preset by the MBC.. duty cycle will be between those two points..

 

I am gettting ready to install my soleniod and this is how I am going to wire it up. Let me know if I am doing something wrong. Sorry it looks like a 5 year old made it

Ben

 

Hmmm... the way you have this diagrammed you will have two problems (As far as I can tell)

1) the MBC is in-line with the solenoid, therefore if the solenoid stays stuck closed, it may overboost wildly..

2) the solenoid should have the common port going to the actuator, and the normally open port (the one next to the foam filter) should go to the vacuum source otherwise you will be giving yourself a "Vacuum leak" when the solenoid is closed which could affect other devices on your vacuum ciruit that you tapped into..

This WILL work for you, but the MBC will set the base boost level, and the duty cycle could allow you to overboost (which means in stock mode you could have trouble)

The resistor looks correct however..

the way that seems to work best is to put the solenoid and MBC in parallel basically you take your vacuum source, put a Tee-fitting on it.. Run one to the inlet on the MBC, the other to the normally open port on the solendoid... then do the same on the actuator side, the line from the common port on the solenoid, and the line from the output of the MBC, they both go to a T-fitting, which then merges back into one line, that goes to the actuator.

The reason this will work is because if the solenoid gets stuck closed, or the duty cycle is too great where you'd cause overboosting, the MBC (checkvalve) will act as a bypass, therefore whatever you set your MBC to do, will then be the maximum boost the car will see. At this point, with the solenoid open, your boost will be at wastegate pressure, with it completely closed (100% duty) it will be MBC setting.

(Hope that diagram looks ok)

 

Oh, and if you find you have trouble with the MBC bypassing at the right pressure, you can cap the solenoid's normally closed port (the one with the foam on it)

it really doesn't matter which way you hook up the solenoid itself, but if you do get idle (from vacuum leaking) problems you can switch the ports around on the solenoid.. It may take some trial and error...

 

...

 

I am glad I got one thing right. I guess the year of auto electronics class paid off.

I will look it over retry my diagram and install it. I can't wait for closed loop boost control.

Ben

 

How did your solenoid turn out? Pretty trick mod eh?

 

I haven't had time to throw it in. I need to finish my tuner install. And then track down a 36 ohm 1 watt resistor. It would also be nice to find a female plug to plug into the stock wiring so I do have to cut anything. Did you just cut and connect the GM harness in or did you connect it to the stock plug with solder?

Be

 

I had a connector from a similar solenoid someone was throwing away

 

Malibu,

How is this Boost Solenoid working for you. I currently have a Greddy ProfecB Spec II that i was using before my Utec and want to look for a better solution for controlling boost more precisely. I am also adding a GM Map sensor tonight.

 

I had to swap back to the stock solenoid.. Unfortunately if you want to run in passthrough mode (I have been to collect some data for the colder weather) the solenoid is either open or closed.. which means it may overboost wildly, and then drop to wastegate pressure.. when I had the MBC run in parallel, it would boost to 21psi and then drop to wastegate pressure.. neither of which was good for what I was working on for the past few weeks.

HOWEVER it does work if you don't want to ever use MAP0 (some users can't becauseo f injectors anyway) Works best with closed-loop boost.. But on a stock-ish turbo, there's no real gain to it over the stock solenoid with the ABC installed unless you need boost levels lower than the range you set using the ABC and the duty set to 0%