Question about this MBC

[AlphaAssault]

I was reading up on manual boost controllers, and i fully understand how the ball-and-spring type controllers work. however, i was looking at my MBC a few days ago, and it is not a ball-and-spring type. Its a homemade MBC it looks like. I attached a quick MS paint doc. showing how it works. The red arrow is the boost pressure. The brass screw on top supposedly controls when the wastegate opens by narrowing the passage the pressurized air has to move through. at full boost, the screw on top would be completely closed. Is this an effective way to control boost, because the theory behind this controller seems different than ball-and-spring type controllers.

 

[knochgoon24]

It looks like it would just cause a boost spike before settling down to stock wastegate pressure.

 

[RSTeclipse97]

I agree

 

[b-morr]

Some homemade boost controllers works quite well, but to be safe go with halman or something like that.

 

[BigSorn]

does it work for you?

no boostspike or anything like that?

 

[TheBagelGuy]

im not so sure i would trust this, but if you have an aftermarket boost gauge just watch it while you do a few pulls and if there are no spikes or any negative effects at all then obviously it works

 

[GRNDSM]

This type of boost controller works only if you use such valve to conroll your "bleed off". But it will NOT work as an "in-line" restriction...

 

[AlphaAssault]

This type of boost controller works only if you use such valve to conroll your "bleed off". But it will NOT work as an "in-line" restriction...

can you elaborate?

 

[knochgoon24]

By adjusting the screw, you control how fast the air leaks out. By leaking air, you decrease the pressure the wastegate sees. Actually, having the screw all the way in would be min boost.

 

[AlphaAssault]

ah, now i see. right now ive got it as an 'in-line' MBC, which apparently isnt right. ill pick up the materials next time im in town to hook it up the way its supposed to be.

EDIT: i was thinking, would fully opening the the valve mean the wastegate would never open? if you have this type of MBC attached to a vacuum line with an 1/8 inch internal diameter, would enough pressurized air escape to prevent the wastegate from opening? also, wouldnt having this type of valve cause you to run a little more lean when not boosting, because air would be getting sucked in through that open valve,right? It sounds to me like this is a less effective method of controlling boost than the ball-and-spring type controller.