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How to make a Manual Boost Controller....that works.

I have noticed that there isn't a Tech Article on How to Make a MBC in the tech article section on So here it is.


(1) 1/2" Brass TEE
(2) 1/2" Brass Fittings with 1/4" Hose Barbs.
(1) 1/2" Brass Plug fitting
(1) 1" medium duty Spring (test a few by squeezing them with your index finger and thumb, you want it to be resistant, but not too stiff)
(1) 3/8 Metal Ball
(1) 3/8-16 Allen Head bolt 1 1/2"
(1) 3/8-16 Nut
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Tools necessary:

3/32 drill bit
3/8 drill
5/16 Drill bit
Small Hammer
Center Punch
Sharpie Black Permanent Marker
3/8-16 Tap
Tap Handle


Take the Brass Tee and put the plug in the top or bottom. (doesn't matter
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Take the Sharpie and mark the center of the plug.
Take the center punch and small hammer and indent the center of the plug.
Use the center punch and hammer to indent the middle of the flat side of the tee.
Use the 3/32 drill bit to drill a tiny hole on the flat side of the tee.
Now, take a grinder and grind the Plug flush with the body of the Tee.
Take the 5/16 drill bit and drill a hole straight through the plug using the vise to hold the TEE still.
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Now, Tap the hole you just drilled with the 3/8-16 Tap and handle.
Take one of the 1/2" fittings with 1/4" hose barbs and put it in the side of the tee.
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Now take the 3/8-16 nut and thread it on the bolt all the way up it to the top where the head is.
Screw the bolt TIP into the hole you just drilled and tapped.
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Flip the Tee over and drop the spring into the Brass Tee from the bottom (or directly opposite the bolt you just screwed in)
Place the Check Ball on the end of the Spring, and put the other 1/2" fitting with 1/4" hose barb on top of the check ball.

Now slowly screw the 3/8 bolt down until you feel a small resistance from the spring and check ball.

Run the 3/8 nut down to the surface of the 1/2" Brass plug and secure with the appropriate wrench.

Now, the barb opposite of the bolt, is fed by either the compressor housing OR the intake manifold. The barb that sticks out from the middle, now feeds the wastegate actuator.

To adjust boost pressure all you have to do IS:

Loosen lock nut, and turn bolt IN for more boost, turn OUT for less, tighten lock nut.

I will have to post my pics later, they are currently not loaded on my computer.

Enjoy safe boosting.

*Not responsible for damage anyone has from overboosting due to lack of following the directions.*

If problems persist such as :

Boost pressure uncontrollable- Make sure hoses are sourced and plugged in properly.
Boost setting to high- get a weaker spring
Boost setting to low- get a stronger spring
Boost spiking to much- drill a slightly bigger vent hole

All parts are usually available at a Ace Hardware. Grab a sales rep and bring the required materials list with you. I know some hardware stores do not stock this stuff and will play 20 questions wanting to know WHY your needing this stuff so bad, just inform them that you are saving yourself $45 - $9.00 (worth of parts) = $36 dollars and some time by doing this yourself. You may have to check around, but parts stores DO stock this stuff, you just have to know EXACTLY what your looking for.

Good luck and hope I saved alot of you some $$$.

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