weird boost controller install?

[ricktb]

Hi I'm new to these forums, I just bought a '95 talon tsi awd turbo

The previous owner had installed a boost controller, which I see is carelessly wedged between the fuse box and air box. I had to change the left low beam bulb and in the process I noticed that one tube from this controller was not connected to anything. I thought maybe I had accidentally pulled it off, but I spend an hour looking for a nipple or anything it may have been plugged into but nothing..

I did some reseach here and found this great tutorial for a hallman boost controller.. (mine is not the hallman brand)
http://www.belitski.com/cars/talonmods/turbo/vfaqhallman.html

This tutorial says to connect one tube directly to the wastegate actuator, and the other tube to tee into the BOV, with a nipple plug on the turbo and a nipple plug on the inlet tube.

My boost controller is as follows...


[INLET TUBE]----------------[tee]--------------------[tee]----------------[turbo]
(fat rubber tube**********|****************|
attached to airbox)******* |****************|
*******************[BC valve]********[wastegate actuator]
***********************|
***********************|
***********************|
*******************(nothing)


also the boost controller solenoid (BCS) is nowhere to be found as shown in the tutorial.

IS this right or totally wrong, should I stop driving my car until fix it???

ps the car seems to run and drive fine as is, with up to 8-10 pounds of boost showing on the aftermarket gauge,

Thanks for any help!

 

[Mr Peepers]

First off, don't tee into your BOV line for the MBC. It should run directly between the pressure source(as close to turbo outlet/compressor housing as possible) and wastegate actuator. I have no idea after looking at your diagram how you are just seeing 10 psi max. With that setup the wastegate shouldn't ever see enough pressure to open causing open boost, yet what you are describing happening is more like running a line directly from the pressure source to the wastegate actuator.

Block off the hole just behind your MAS that I'm assuming the tube is going to, and hook up the MBC between the turbo and wastegate actuator, and save those tee fittings for something they are actually going to do some good for. Make sure not to have the MBC installed backwards, they only work one way.

 

[twinturbo3k]

You are running wastegate pressure. I personally would be happy since the previous owner never saw more than 10 lbs .

An MBC has only 2 lines, one going to a pressurized intercooler pipe, and one going to the wastegate.

 

[Talesin]

Are you sure that it's a boost controller, and not the BCS itself? The stock BCS is essentially a 'bleeder' type EBC, and that dangling line would normally feed back to the intake pipe. The ECU could then open the BCS, shunting some of the boost reference pressure in the vac line back into the intake system, essentially dropping the pressure that the wastegate would see, without losing any metered air in the process.
The stock BCS (at least on a 1G, not sure if they moved it on the 2G) is normally located on the airbox, with a harness wiring plug going into it.

And yeah, that Hallman tutorial is old... never tee off the BOV/CBV line for your wastegate boost reference source. Should just be a line coming from the compressor housing nipple (or compressor outlet elbow nipple) to any MBC you have, then to the wastegate. If you have no MBC, a direct line from the compressor outlet nipple to the wastegate actuator is a good way to handle matters.

 

[ricktb]

Thanks a lot MRPEEPERS, TT3k, and TALESIN.. this info is much apprieciated.

I'm pretty sure its a MBC since it says "high perforance boost controller" on the side.. I think the only reason the wastegate even functions is because the MBC is mostly screwed down blocking the path, allowing most of the pressure to reach the wastegate actuator... I read up about the duty of the stock boost controller solenoid, and I guess its told by the ECU to let some of the pressure escape to the intake so the wastegate opens slower, to reach a higher boost... or something like that.

I will hook this thing up the way you've mentioned here, and I can't wait to see the real boost increase.. I'll try to keep it below 15psi since the car is pretty much stock. Except for the ### LED street glow lights he put on there . My car looks like a freakin christmas tree hah!

one more question... I unscrewed the MBC all the way and a little steel ball fell out. I was expecting a spring in there also but there was none.. do I need to buy a new spring/MBC to work properly? Thanks for the help.

 

[Talesin]

You'll need the steel ball at the very least. Aside from that, we'd need to see what kind of MBC it was. Generally speaking, yes. You'll need a spring with a diameter to fit inside the MBC, and press the ball down, so you can adjust the pressure.

It'd honestly be easier to just buy a new MBC and install it right, since you have no idea what kind of condition the one that came with the car is actually in.

 

[1992GSX]

For the cost of a new MBC, I'd definitely just go get a new one. Its not worth the risk of boost spike.

 

[ricktb]

great thanks again.. I'm going to buy a digital camera so I can show exactly what I'm jabbering about (next time)

 

[ricktb]

heres some shots of my car, and the MBC I just bought and installed myself. (I paid $130can) I hope its the right kind.

 

[MrBoxx]

hook up the MBC between the turbo and wastegate actuator, and save those tee fittings for something they are actually going to do some good for. Make sure not to have the MBC installed backwards, they only work one way.

MrPeepers: MSPaint diagram, STAT!!!

 

[Mr Peepers]

 

[ricktb]

Ok I'm not sure but I think I may have bought a bleeder type MBC instead of the ball and spring one.. any thoughts on this?

When I blow through it and turn the valve, the air flow becomes more or less like a faucet.. bleeder right? ball and spring would hold out until enough pressure is hit correct? I think I want my money back.

 

[Mr Peepers]

Sounds(and looks) like a bleeder valve, especially if it acts the same no matter which end you blow into. I don't know how much $130can is but I would definitely want my money back. If you wanted a cheap bleeder valve I could tell you how to make one for under $5 US in parts and how to set it up, but I'd go with a ball and spring type personally. It will have better spool up characteristics since the wastegate doesn't see pressure until just before it needs to open.

 

[oldman]

Nice Peepers.

ball and spring would hold out until enough pressure is hit correct?

Not if the spring is missing and a bleeder would not have a ball. Furthermore, I have never seen a Hallman bleeder MBC.

 

[ricktb]

Yea I guess I got a bit excited and bought the first thing I saw .. those "power center" type store love to take your money.. like I say to mrpeepers, I'm going to keep the bleeder type for now while my car is being serviced, then later on I can swap it for the ball and spring type, and get a good feel for the pros and cons of each type. better do some more research next time my bad

 

[Mr Peepers]

I can't post pics in a PM so here you go.

You can even keep it if you still get your money back for your gold plated bleeder valve I have no idea what brand/who made it but it held boost fine for the time it was on my car, and when taken apart everything was intact. I bought the car with it already on it and decided to go with the one I already soldered a tube on the pressure relief to be routed back into the intake tract. Let me know how it works out for you and maybe post the pro's/con's from a bleeder to a ball and spring.

-Matt