Installing home-made MBC - need help

Stubble

Active member
I'm going to install my home-made manual boost controller this weekend, and I know to cap off the line to the Turbo VSV. I'm running a stock CT26 without a BOV. I couldn't find the detail I'm looking for on the board here.

Tell me if I have this right: I leave the hose connecting the CT26 compressor to the wastegate actuator, and connect the MBC to the other port where the Turbo VSV was connected to. Where do I connect the "exit" port from the mbc to? Does this just vent to atmosphere? That doesn't seem right. It looks to me like the Turbo VSV routes its air back to the intake pipe upstream from the compressor.

If I need longer hoses, what can I use? I have some small Toyota hoses, but they are smaller diameter than the wastegate actuator hoses.
 

Gary

Moderator
Nope, the MBC goes between compressor and wastegate actuator.
Then, you cap the line to/from the T-VSV, see pic.



The MBC limits amount of air that pushes on the actuator's diaphram. Hence, the actuator won't see the real boost and allow the turbo to built up the boost more than stock setting.
 

Stubble

Active member
Yeah OK Gary, that makes sense. I had thought that the compressor supplied it's full boost to the wg actuator and the MBC bled it away from the other port. Is standard vacuum hose from an autoparts store sufficient to use here?
 

Gary

Moderator
Stubble":3g7w82p6 said:
Is standard vacuum hose from an autoparts store sufficient to use here?
Yep. just get the strong/reinforced one and make sure you secure it with clamps.
 

bboytou

New member
I don't know if this is different, but when i had my MBC installed. I had to let the turbo-vsv that comes from the wastegate open and off course i did plug the t-vsv to the ecu. The reason why i did this was because the turbo was lagging when the cap was on the t-vsv from the wastegate. Once i took that off...that's when the boost really kicked in. So you might want to try that too. But, be careful not to boost too much! That was how i blow one of my cylinder and piston ring. Yup! and my car ain't running right now.
 
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