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Turbosmart single stage mbc

1K views 4 replies 2 participants last post by  nkdwpn40 
#1 ·
So my stock boost controller went bad, so I purchased this boost controller from a local business for 160.00 is dollars. It came with the boost controller, some wires, some sort or flip switch, and some extra electric wire. Now I was just expecting a tee shaped device with a screw on top. This is a black box with one knob to turn labaled high. You turn the nob counter clock wise to lower boost, and clock wise to increase boost. It has two wires which it tells you to connect to a 12v source that can handle an extra amp your also supposed to hook it up to the red flip switch that goes inside your cars dash.

The install
- hooked up the waste Gate hose to the end that shows the arrow going out, and the compressor to the opposite end
-I mounted the box on the right side of the intake.
-hooked the positive wire to one end of the r.h low beam fuse so
-----turned key and herd something click in the box when lights are turned on(so I'm assuming it works lol)
-tuned the knob all the way counter clock wise till I couldn't turn any longer so I could set boost properly

Here's the problem.
I have it turned 4 full turns and its stuck at 10psi no mater how many more turns I try to make it, when I turn it counter clockwise it will lower boost so that part works but I can't get it passed 10psi. **Note the only thing I didn't hook up was the switch but I didn't think it would matter since it just seemed like an on and off switch....buy I could be wrong.

I have tried the whole waste gate detached hose trick and it does rise to about 20 psi no problem lol so the waste Gate and turbo are working fine....

Any help would be awesome I've never installed an MBC before but it seemed pretty straight forward... But I guess its not lol


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#2 ·
Return and buy something like this

http://www.amazon.com/Voodoo-Manual...78160&sr=8-9&keywords=manual+boost+controller

There is no need to spend $160 on a MBC. The reason it is expensive is because it isn't using the same theory as a simple MBC with ball and spring. Having an electrical hookup implies that it's using a solenoid to change the pressure signal between the turbo and the wastegate. More expensive and more things to fail down the road.

It sounds like the boost controller is working if it can actually control the boost up to 10 psi. I am not sure why it is not boosting above 10 psi. Could be your car, could be the controller. Here is how to find out if it's your car: Disconnect the wastegate vacuum line and leave it off. Go for a drive and monitor your boost gauge closely to see if you can boost above 10 psi. It may be tempting but don't go above 14 psi at the maximum. If you can boost above 10 psi, then the problem is in the boost controller. If you cannot, this means the boost controller was functioning normally and for some reason you cannot boost above 10 psi. This can be a multitude of things including a wastegate that doesn't fully close.

I have never had an MBC myself but I understand the theory behind them as I have done research in the past.
 
#4 ·
That's good news, means your wastegate is functional. My last 850 could only hit about 17 psi with the line disconnected. Must be the controller.

That is a good excuse to return it and get your money back. $160 for a MANUAL boost controller is stupid insane pricing. Most electronic boost controllers cost that much.

So if you had a ball and spring type (with a good seal at the ball) and you had the screw pressed all the way down on the spring, the ball would never let air past an you turbo would always hit 17 psi. This is equivalent to having the line disconnected because no air is getting to the wastegate. Now if you back off the screw a tad, the ball may open at 16 psi; your turbo is now controlled at 16 psi. So on and so forth.

How was it with 17 psi? Was it fun? My last 850 was headed to the junkyard because of so many problems. So the last day I had it, I tried running it in the ground. I disconnected the wastegate line and did a few pulls on the highway. I also did not hit fuel cut (which is a bad thing because it means you are running super lean). My engine ran so hot because it was lean that when I opened my hood when I got home, the coolant lines were swollen about twice their normal size. There was so much pressure in the coolant system that it began leaking at all the seams because even the hose clamps couldn't hold back the pressure. So don't do it again, it's bad.
 
#5 ·
I think your right haha I live in Hawaii so its super expensive for everything, they actually discounted it because everyone thinks I'm military. I'm going to return it once I get the new one In the mail. 17 psi made it chirp in second gear haha but it freaked me out cause I thought I was going to bend its poor little rods, but thank god it didn't haha.

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