***MAKE A MBC FOR <$12***
08-13-2005, 11:55 PM
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***MAKE A MBC FOR <$12*** Just thought I'd post a little how to for all the cost-conscious folks out there looking to save where and when they can. I say, why pay $50+ for cheap little plastic manual boost controller when you can visit the good ole Home Depot and Ace Hardware and do it for less than 12 bucks...
This is what you'll need:
(1) 3/8" brass tee
(2) 3/8" x 1/4" brass hose barb
(1) 3/8" x 16 Allen head cap screw, 1 1/2" long
(1) 3/8" x 16 nut
(1) 3/8" brass plug
(1) 3/8" ball bearing
(1) 3/8" metal spring, 1" long
Here is how I did it:
1. Take the tee and lay it on it's side. Drill a 3/32" vent hole in the side and clean tee of all shavings.
2. Apply teflon tape to brass plug and insert in one of the end holes of the tee and tighten.
3. Mark the center of the plug and drill a 5/16" hole straight through the top of the plug.
4. Tap the hole in the plug with a 3/8" x 16 tap.
5. Thread the 3/8" nut all the way to the top of the cap screw.
6. Thread cap screw all the way into the brass plug you just tapped only moments ago.
7. Take the 3/8" x 1" metal spring and force it to thread onto the end of the cap screw which should be inside the tee at this point. No need to thread it too far, just enough to prevent it from moving or falling off the screw.
8. Take one hose barb fitting and thread tightle into the side port of the tee, don't forget the ever important teflon tape!
9. Insert the ball bearing into the inside of the second hose barb fitting, and thread the fitting into the remaining port on the tee. If you did everything else right, then the spring should naturally line up with the ball bearing perfectly.
Now to test. Attach the bottom port of your new MBC to the boost reference source, preferably somewhere on the intake manifold, but you can source it from the turbo compressor housing or IC piping as well. Attach the side barb to the wastegate actuator port on the wastegate. Completely back the cap screw out and take the car for a drive. Attempt to bring the car to full boost (which should be what the wastegate's internal spring is set to). Watch the boost CLOSELY. If it spikes any higher than it should, then something was done wrong. Check to make sure that when the cap screw is backed out all the way, you can hear the ball bearing bouncing around inside a little bit. If it checks out, try screwing the cap screw down until a SMALL AMOUNT OF RESISTANCE is felt from the spring, and repeat the test. From here, continue tightening the cap screw until the desired boost level is reached. If you are getting boost spikes, you need to replace the spring with a slightly softer one. If the car won't build andy boost, replace the spring with a stonger one. I used a spring rated to hold 9 pounds and I am able to hit over 10 psi if I wanted to, and run the minimum of the wastegate spring as well. Also note that you should tighten the nut on the cap screw to prevent the cap screw from backing out or tightening from engine vibration and/or thermal expansion and contraction.
I'm going to attach some pics because my picture server is down, but I'll try to update with some larger detailed pics when it's up and running again. I hope this helped some people out.
Again, if done correctly, this MBC will work as well as some other controllers selling for almost 10 times as much. It may not be the prettiest, but damn it, it works well enough for me!
This is what you'll need:
(1) 3/8" brass tee
(2) 3/8" x 1/4" brass hose barb
(1) 3/8" x 16 Allen head cap screw, 1 1/2" long
(1) 3/8" x 16 nut
(1) 3/8" brass plug
(1) 3/8" ball bearing
(1) 3/8" metal spring, 1" long
Here is how I did it:
1. Take the tee and lay it on it's side. Drill a 3/32" vent hole in the side and clean tee of all shavings.
2. Apply teflon tape to brass plug and insert in one of the end holes of the tee and tighten.
3. Mark the center of the plug and drill a 5/16" hole straight through the top of the plug.
4. Tap the hole in the plug with a 3/8" x 16 tap.
5. Thread the 3/8" nut all the way to the top of the cap screw.
6. Thread cap screw all the way into the brass plug you just tapped only moments ago.
7. Take the 3/8" x 1" metal spring and force it to thread onto the end of the cap screw which should be inside the tee at this point. No need to thread it too far, just enough to prevent it from moving or falling off the screw.
8. Take one hose barb fitting and thread tightle into the side port of the tee, don't forget the ever important teflon tape!
9. Insert the ball bearing into the inside of the second hose barb fitting, and thread the fitting into the remaining port on the tee. If you did everything else right, then the spring should naturally line up with the ball bearing perfectly.
Now to test. Attach the bottom port of your new MBC to the boost reference source, preferably somewhere on the intake manifold, but you can source it from the turbo compressor housing or IC piping as well. Attach the side barb to the wastegate actuator port on the wastegate. Completely back the cap screw out and take the car for a drive. Attempt to bring the car to full boost (which should be what the wastegate's internal spring is set to). Watch the boost CLOSELY. If it spikes any higher than it should, then something was done wrong. Check to make sure that when the cap screw is backed out all the way, you can hear the ball bearing bouncing around inside a little bit. If it checks out, try screwing the cap screw down until a SMALL AMOUNT OF RESISTANCE is felt from the spring, and repeat the test. From here, continue tightening the cap screw until the desired boost level is reached. If you are getting boost spikes, you need to replace the spring with a slightly softer one. If the car won't build andy boost, replace the spring with a stonger one. I used a spring rated to hold 9 pounds and I am able to hit over 10 psi if I wanted to, and run the minimum of the wastegate spring as well. Also note that you should tighten the nut on the cap screw to prevent the cap screw from backing out or tightening from engine vibration and/or thermal expansion and contraction.
I'm going to attach some pics because my picture server is down, but I'll try to update with some larger detailed pics when it's up and running again. I hope this helped some people out.
Again, if done correctly, this MBC will work as well as some other controllers selling for almost 10 times as much. It may not be the prettiest, but damn it, it works well enough for me!
08-15-2005, 02:46 AM
#4
Doing it that way, check valve/grainger valve style, you need the bleed hole to let the pressure vent from the gate/actuator can. It can hang the gate open when you drop boost otherwise, and make the next spool up very slow.
You can fine similar stuff premade for about $35, if you're lazy
You can fine similar stuff premade for about $35, if you're lazy
08-15-2005, 03:47 AM
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Ahh, I understand. I made a few of these, but guess I didn't run the bleed hole. Might have to make a few adjustments on the ones I have out there. Guess I just got my info off of one of the DSM boards I used to play on. Kinda miss that little car sometimes.
08-15-2005, 11:17 AM
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Originally Posted by y2khawk
You can fine similar stuff premade for about $35, if you're lazy
