Cant Control My Boost!!!

[ALLBoostAWD]

I finally got to take my car out for a spin. I have always had problems with this MBC. I have it connected like this, I know my drawing sucks,

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This boost controller will only let me boost 8-9 lbs, and there is no nipple on the turbo outlet pipe due to it being an upgraded larger pipe, so i cant change the location of the vacum source. No matter how much I screw the contoller in or out I cant get it to do anything unless it's fully closed when it will boot way too much. Should I trash this thing and go with an electronic controller? I dont want to go external yet and I have replaced the spring in the boost controller too and that didnt absolustly nothing. Please someone advise.

 

[DSM-Talon]

First of all you got the lines hooked up backwards, second of all the input should be from the compressor housing, not the bov line becasue it will casue leaks easier. So it should go like this The line you have hooked up to the wastegate actuator should be going to the compressor housing or I guess put it to the bov line. The one you got hooked to the bov line should be hooked to the wastegate actuator.

 

[DSM-Talon]

That will fix your problem or sure and if not which it will you probably have a leak somewhere

 

[Auto RS T]

I'm not sure if this relates to your problem but it can help you with the vacuum source. You can tap the turbo outlet elbow and screw in an 1/8 npt fitting with a nipple on the other end, if you do it, install the fitting close to the flange so you can grind off the excess inside the pipe. I'd like to mention Oldman here for that tip.

 

[ALLBoostAWD]

I thought that the vacum, BOV line, was supposed to pull the ball and spring UP not push to bypass to the wastegate? I have tried it the other way and boosted way to much with the tension all the way out., which was why I thought it was installed correctly.

 

[DSM-Talon]

Im positive the way I explained it is the way it goes.

 

[DSM-Talon]

as for the boosting way to much, gonna have to ask someone else

 

[brute]

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[Auto RS T]

Just for everyones information the turbo xs style controller is supposed to be hooked up like the original poster had pictured. I know that ALLboostAWD has the turbonetics style, I just wanted to share information.
EDIT:
Use the compressor housing as pressure source, not bov line.

http://turboxs.com/faq/turboxshigh.htm

 

[ALLBoostAWD]

Alright cool, I'll give it another shot tommorow, thanks for the input.

 

[DSMcamaro]

What kind of boost controller do you have? sometimes you need to strech or shorten the spring.

 

[ALLBoostAWD]

Just for everyones information the turbo xs style controller is supposed to be hooked up like the original poster had pictured. I know that ALLboostAWD has the turbonetics style, I just wanted to share information.
EDIT:
Use the compressor housing as pressure source, not bov line.

http://turboxs.com/faq/turboxshigh.htm

Oh not anymore, I traded that (Turbonetics MBC) away for a ball spring style one and some cash, I never had the car running when I had that controller, looks like I gotta update my vehicle mods.

It's just a normal Ball spring style, Screw at the top, spring, then ball with the ball sitting over top of the bottom nipple.

 

[oldman]

It's just a normal Ball spring style, Screw at the top, spring, then ball with the ball sitting over top of the bottom nipple.

Like DSM-Talon said, you got the lines backwards.

there is no nipple on the turbo outlet pipe due to it being an upgraded larger pipe, so i cant change the location of the vacum source.

This isn't really a matter of choice, the biggest issue of tapping the BOV line isn't the negative effects on the functions of the MBC, rather it's the negative effects on the functions of the BOV.

I'm not sure if this relates to your problem but it can help you with the vacuum source. You can tap the turbo outlet elbow and screw in an 1/8th inch npt fiting with a nipple on the other end, if you do it, install the fitting close to the flange so you can grind off the excess inside the pipe.

Did it help with your BOV problem?

 

[ALLBoostAWD]

Did you help with your BOV problem?

Yeah, if there is a away to tap into the compressor housing for a better pressure source. What kind of effects will using the BOV line create? not allowing it to fuction as it should with less pressure?

 

[Spoolio]

im sorry but when i seen this thread saying "I CANT CONTROL MY BOOST", it made me laugh. not saying anything mean, but the wording of it kinda makes you giggle, go ahead, say it out loud a few times.

 

[oldman]

Yeah, if there is a away to tap into the compressor housing for a better pressure source. What kind of effects will using the BOV line create? not allowing it to fuction as it should with less pressure?

Instead of me trying to convince you, perform a boost leak test without removing or turning up the mbc, put your hand over the BOV return tube and see what happens. What you will find out is that the wastegate pressure relief hole, required for any ball and spring type MBC, will bleed pressure off this line when under boost resulting in BOV openning. Without mentioning other less significant effects, this alone should be convincing enough for anyone.

 

[Auto RS T]

quote oldman


This isn't really a matter of choice, the biggest issue of tapping the BOV line isn't the negative effects on the functions of the MBC, rather it's the negative effects on the functions of the BOV.


Did it help with your BOV problem?[/QUOTE]

I believe it did, here is what i noticed from switching the tap to the outlet elbow from the bov line.

The bov seemed more responsive and it it was much shorter and quicker of a pop off. It is hard to tell being recirculated but this definately made it work more responsively from what I could tell.

Also after the pop off my car used to buck slightly with the old tap, now it goes into deceleration more smoothly. My car still neeeds to be tuned though, who knows if this is legit

The other effect that I noticed was that boost built slower but much smoother than usual, the car really had a smooth feeling to it. I believe the boost builds slowly because of where I have the boost controller mounted compared to the pressure source. I think shortening the hoses will give me more boost response.

All in all I like it. Makes me fell more secure knowing the tap is finally correct. Thanks for your help. Horse equals bov line tap

 

[98gst14b]

every time I have ever used a mbc I have always had to cut links off the spring, otherwise with the knob all the way out I would still hit like 22 psi. Also, I wouldnt bother tee-ing the inlet line to the BOV, Iv had bad experience doing it this way, for some reason it makes it very difficult to adjust the boost pressure, Im sure theres some other negative Im not mentioning. Try cutting some links off the spring

 

[oldman]

All in all I like it. Makes me fell more secure knowing the tap is finally correct. Thanks for your help. Horse equals bov line tap

You're welcome, glad it made a difference for you. Another advantage of tapping the source at the begining of the intake tract is that any developed leaks will most likely reflect on the boost gauge immediately which should lead you right to a boost leak test, instead of the turbo over boosting itself to death trying to fill the leaks while still showing full boost on the gauge.