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Discussion Starter · #1 · (Edited)
Alright, I decided to replace the Wastegate and Turbo elbow hoses, so I had to remove the MBC. Now, reinstall, this bitch is not stoping at any boost- just keeps on going to 20psi then I have to let off the gas. I don't even floor it in 3RD and it does this!!! WTF!!!


I have searched all this site and performance probe. The Vacuum from the solinoid to VAF intake is capped off. My source is the Turbo elbow and the other is the Wastegate. <sigh> I am to flustered.... I've tried everything I can think of. Its a ball and spring MBC. All the hoses I am using are 1/4" Fuel Line hoses and are no longer than 6" each.

Ryan



Also to add, I put the Brass piece fromt the old hose back in.
 

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looks backwards to me homey...you have the Joe P ?

the bottom inlet comes frome the boost signal, the outlet on the side goes to the wastegate solenoid

EDIT: Looked at the pic again...it's not backwards... :freak: haha
 

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only other thing is that your MBC isnt getting free flow. meaning your hoses are kinked, or the MBC is shot.


Also could be that your Wastegate actuator is stuck?
 

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I have a $15 ebay one and it works excellent.

Extremely solid, cosistant boost no matter what psi I set to. I have run it as low as 9 psi, which the turbo will make even with the flapper wide open, and have hit 18 psi a few times as well. The KPA stays solid.

Sounds to me like you have it hooked up or adjusted wrong. Looking at your diagram, its BACKWARDS
 
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Discussion Starter · #10 ·
I didn't notice the nice hole in the back until Sick mentioned it.. I am going to the HD tomorrow.


Everyone keeps saying it's backwards?? Is it really- The nipple on the compressor is what pushes the ball back right?? Or am I backwards today:freak:. Could have sworn that's the way it was on the old MBC..
 

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No actually that is right.

The hole is a vent to keep the pressure of the slamming ball from tearing your wastegate diaphragm or other such damage and it is necessary.
 

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91MazdaMx6GT said:
Also to add, I put the Brass piece fromt the old hose back in.
Dude, that's why. Damian, remember that brass restricter you sent me with the throttle body boot? I wanted to experiment with it since i lost mine. Well, with the boost controller, it spiked like hell. I even tried turning the boost down and it still spiked. So, I removed the restricter. Been great without it.

So, 91MAzdaMx6GT....try removing the resticter and see what happens..post back to let us know.
 

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rebel2k4 said:
No actually that is right.

The hole is a vent to keep the pressure of the slamming ball from tearing your wastegate diaphragm or other such damage and it is necessary.
But all holes aren't drilled the same is the point. You don't need anything larger than a pinhole and some people use whatever bit they have. If the hole is too large then you have no control over what is bled out.

MazdaMan069 said:
Dude, that's why. Damian, remember that brass restricter you sent me with the throttle body boot? I wanted to experiment with it since i lost mine. Well, with the boost controller, it spiked like hell. I even tried turning the boost down and it still spiked. So, I removed the restricter. Been great without it.

So, 91MAzdaMx6GT....try removing the resticter and see what happens..post back to let us know.
Yeah, with a ball and spring there isn't a need for the stock restrictor because the ball and spring is the restriction. You only need the brass restrictor if you're using an ordinary bleed valve or the stock boost solenoid. Although something tells me he unknowingly ditched the brass restrictor a long time ago.

91MazdaMx6GT said:
I didn't notice the nice hole in the back until Sick mentioned it.. I am going to the HD tomorrow.

Everyone keeps saying it's backwards?? Is it really- The nipple on the compressor is what pushes the ball back right?? Or am I backwards today:freak:. Could have sworn that's the way it was on the old MBC..
If it is exactly like it is in the picture, it's installed correctly. Your problem is most likely that the spring tension is too high, the spring is too long, and the boost pressure is bleeding out through the hole before it pushes the ball and eventually gets to the wastegate.

Try taking it apart and feeling how hard it is to compress. Sometimes you can cut a coil or two off and it will make a difference so long as the spring is weak (soft) to begin with.

These guys put any old spring in and call it a day. It's up to you to adjust it but most end up with posts exactly like yours. Try any webforum and you'll see the same thing. Sometimes you get lucky, most of the time you don't.
 

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Discussion Starter · #14 ·
Alright then. I'll take to the brass resrtrictor out, I did put it back in there. The hole in this damn thing is a nice small drill bit size. So the spring might be to hard to compress? I'll look into it- thanks guys so far!


Ryan
 

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I had the same problems trying to replace the hoses to the wastegate on mine, and still use the restrictor in the hose. it would give a solid 6psi with no restrictor, and then when i put it in, it was like the wastegate wasn't even hooked up. boost would spike out of control until it hit cut. try hooking everything up without the restrictor, and see what happens.
 

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SixSick6 said:
Although something tells me he unknowingly ditched the brass restrictor a long time ago.
Actualy, I had pulled it out of the hose when I installed the MBC. I had it in a safe place, I thought. I wanted to experiment with it and it was gone. Because with it, the boost is really smooth and it pulls harder, but then on the cons side, it spikes. But, no...at the time, I really didn't think i needed it, so in a sence, I was right to just ditch it. (which i didn't just throw away because there was the chance I still needed it.)
 

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MazdaMan069 said:
Actualy, I had pulled it out of the hose when I installed the MBC. I had it in a safe place, I thought. I wanted to experiment with it and it was gone. Because with it, the boost is really smooth and it pulls harder, but then on the cons side, it spikes. But, no...at the time, I really didn't think i needed it, so in a sence, I was right to just ditch it. (which i didn't just throw away because there was the chance I still needed it.)
Not you, him, but he just said he has it so.....

Most people don't even know about the restrictor and they tend to be IHI specific. According to a couple of the Subaru guys, the new VF's have them as well.

91MazdaMx6GT said:
The hole in this damn thing is a nice small drill bit size.
Probably way too large. You only need a pinhole.
 

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Discussion Starter · #18 ·
So pretty much just the "target tip" of the dill bit is all I need as I saw in the "how-to". I actually found out about the restrictor after searching the site for help.
 
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