Hallman MBC users please chime in

[91-gsx]

It says on the Hallman website that these boost controllers do not leak air. Frequently Asked Questions Does anybody have any information on this subject? I thought I had seen a hole on the wastegate side of the controller online somewhere..
Thanks for the help

 

[williillii]

My hallman pro does leak from the bleeder hole when BLT'ing.

 

[91-gsx]

My hallman pro does leak from the bleeder hole when BLT'ing.

All I needed to know. Thanks for the help.

 

[williillii]

No prob...Im guessing it depends on what pressure you boost leak test at and what the MBC is set to...makes sense right?

 

[Lavery]

Mine also leaks from a small Pin hole when testing.

 

[eleclipse99]

Mine also leaks from a small Pin hole on the hallman pro MBC, when i Boost Leak Test, is this normal?

 

[snowborder714]

Yes, that's why you're supposed to disconnect the vacuum line to the MBC and cap it off when doing a BLT.

 

[eleclipse99]

Oh! ok thank you man

 

[2g4me]

There bleeder type BC's, they bleed off to allow the wastegate to open later, so yes they will leak air, its normal. You will also hear them sucking air in under vacuume during idle, which is also normal. I'm not a fan of them but i do use one.

 

[Bohrn]

its not a bleeder type. Its a ball and spring type.

the bleed hole is just there to help keep boost spikes in control. Without it the boost will spike until the pressure inside the controller can bleed off and allow the ball to re seat once the boost you want is reached.

A bleeder type of controller actually bleeds off enough boost pressure to trick the wastegate actuator into staying closed longer. Completely a different theory and design.

Early bleeder types, often used by the turbo Buick guys was to cut a wee little slit on the line from a boost source to the wastegate actuator. If the slit was too small not enough boost happened. If too big, too much boost. I know a guy who carried a few different pre calibrated pieces of vacuum hose in the glove box of his GN.

 

[xxNocturnalxx]

Going to wake this one up a little bit.

So with the Hallman MBC when you screw it Minus for less boost it allows more air to bleed out of the pin hole, why does it leak out when it should be adding airflow to help keep the wastegate open?

Also, can the MBC be used in reverse, such as you have the MBC hooked up to the top port of the wastegate instead (port that closes) so basically your minus would be plus?

 

[97-TSi-Hx35]

Going to wake this one up a little bit.

So with the Hallman MBC when you screw it Minus for less boost it allows more air to bleed out of the pin hole, why does it leak out when it should be adding airflow to help keep the wastegate open?

Also, can the MBC be used in reverse, such as you have the MBC hooked up to the top port of the wastegate instead (port that closes) so basically your minus would be plus?

WTF?

These boost controllers work off of pressure differential, overcoming spring tension, when this occurs the ball valve opens up and allows the air pressure to actuate the wastegate diaphragm. the hole in the side allows the air from the waste gate diaphragm to be vented so that the waste gate can close after boost decreases the ball then descend back onto its seat.

right turns the boost up (by increasing spring tension)

left reduces boost (by decreasing spring tension)


If you reverse the lines you will have infinite boost, try it.

 

[xxNocturnalxx]

Sorry for the derpy question.

I was under the assumption that it would be leaking under boost causing turbo lag because when I BLT air comes out unless I screw it all the way in, so it just seemed like a boost leak.

On my set-up the best way to control boost is to have the MBC on the top port and just a boost line to the bottom port. So effectively I am using the MBC in reverse, plus is minus and minus plus. This should work fine as long as I'm not loosing a ton of air through the pin hole..Correct?

The wastegate I am using is the synapse (60lb. spring installed), 2 ports on top, 2 ports on bottom and a pain in my arse to dial in boost.

 

[97-TSi-Hx35]

you should have the side port on the hallman hooked to the bottom port of the wg and the bottom port of the hollman to a boost source.