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Homemade MBC in the works...

RockVegas

Sport Mode
Joined
Jun 6, 2005
Location
Rock Hill, South Carolina
1.jpg


The "D.I.Y. Manual Boost Controller"
....Home Depot? style
Found at http://www.geocities.com/chmwatson/FAQs/mbc.html[/b]



This controller was conceived from deep within a tight pocket, along side the lint and gum wrappers. There are two reasons I made my own MBC. First, I was not going to spend money on an expensive MBC (though I did want something that would properly and effectively control boost). Second there was the challenge to build it and be able to think "heh.. see.. I didn't need to spend 50 or 100bux to buy a pre-made one!"

Since a fellow Club DSM Canada member shared the basic idea behind this controller with me, thanx Steve ;-) I'm sharing it with you... If you have even the slightest bit of mechanical ability you can make one of these; building this MBC won't cost you more than about $12 in parts from the local hardware store and an hour or two of your time...

NOTE: Before making and installing a MBC you MUST have a Boost Gauge installed to monitor the changes you will be making while adjusting your boost. Failing to do so may result in nasty engine destroying demons attacking your engine. I would also highly recommend doing the fuel pump rewire mod if you plan on increasing boost beyond 15 pounds

the parts:
2.jpg


all of the following parts should be available at the local hardware store, in my case, it was Home Depot in the air tool section.
  • 1/4" NPT Tee (I'll refer to it as the 'Body')
  • 1/4" Male NPT coupling
  • 1/4" Female NPT x 3/16" hose barb
  • 1/4" Male NPT x 3/16" hose barb
  • 5/16"-18 x 1 1/2" SHCS (I'll refer to it as a 'Bolt')
  • 5/16-18 Jam Nut
  • 1/4" dia ball bearing (I actually purchased mine from a bicycle shop)
  • Spring ~ 1.69" lg x 3/16" dia
  • Straight thru 3/16" plastic hose barb coupling (commonly used in windshield wiper systems)
  • length of 3/16" I.D. vacuum hose to connect MBC

the tools:
  • drill
  • 1/32" drill bit (to drill vent hole in plastic straight thru coupling)
  • 5/16"-18 UNC tap
  • hack saw
  • teflon tape

the procedure:
1. Cut the top part off the coupling using a hacksaw as shown.

I will refer to this piece as the "Cap"
step1.jpg


2. This is what the Cap will look like after being cut. Discard the piece you cut off.
step2.jpg


3. Since the hole thru the fitting is already slightly over .257" (required taps size for a 5/16-18UNC thread) drilling to the correct size to tap is not necessary. Tap the Cap all the way thru. Make sure the hole is tapped straight (concentric to the hole)
step3.jpg


4. Take the jam nut and thread it part way up the Bolt. Wrap the Bolt with Teflon tape, to prevent air leaking between the threads, and thread the Bolt and nut into the Cap, place aside for now. I will refer to this as the 'Cap Assembly'.
step4.jpg


5. Use some teflon tape when threading the following together... take the male hose barb and thread it onto one end of the tee. Take the female hose barb fitting and thread it onto the middle part of the tee.
step5.jpg


6. Place the ball bearing into the tee, so that it is now sitting at the bottom against the Base. Gently follow with placing the spring down on top of the bearing. Now take the Cap assembly and using some teflon tape thread it into the tee.
Note: The dimensions I have given for the spring are what worked for me. Your spring will have a different 'rate' and therefore will act differently, a little experimentation for length and compression is required to find what works for you. MAKE SURE the compression on the spring (from the Bolt) is completely released and increase compression on it, which increases boost, gradually.
step6.jpg


6.1 Here is a basic cutaway view of what the internals will look like once the controller is completely assembled. Because the spring is sized closely to the inside of the Body, there is no need to modify the Body or spring to eliminate any lateral deflection that might occur if the clearance between the two components been greater.
As a side note, a second ball bearing can be added between the spring and the Bolt. I've found though, that due to the spring's size, it seats fairly well on the Bolt without binding (which could cause problems with adjustment accuracy) and doesn't require it.
step61.jpg


7. Carefully drill a small (1/32") hole into the body of the MBC as shown by the arrow in the cut away aside. With the bleeder hole in this position the same end result is achieved as with the coupling, but it reduces the number of parts required to fabricate and install the MBC.
The bleeder hole is not large enough to affect the signal to the Waste Gate but it is necessary to gently vent off excess vacuum or pressure in the line which causes a type of signal lock. If the hole wasn't put in, the controller would have difficulty controlling boost above about 15 pounds.
step7.jpg


mbcschematic.jpg


8. Attach this 'bleeder' to the fitting on the side of the MBC with silicone hose. Attach a piece of silicon hose to the other side of the 'bleeder' this line now goes to the waste gate.

9. Take another piece of silicone hose and attach one end to the Base of the MBC and the other will tee into the signal line between the BOV and the manifold.
Refer to the above Schematic for a visual layout of what I have just explained

the result:
You can now begin to adjust your boost by turning the Bolt in or out of the Cap (turning the Bolt in, will increase boost; turning it out will decrease it). This places resistance, thru the spring, onto ball bearing which will reduce or increase the signal that the waste gate sees (thus controlling the boost). Once you find the 'sweet spot' of the controller, you will notice that it should only take minor adjustments to the Bolt to increase or decrease boost. Once you have achieved the desired boost setting, snug the Jam Nut against the Cap to lock the position of the Bolt.

Additional installation and adjustment

You will require:
  • length of 1/8" I.D. vacuum hose [or equivalent]
  • (1) 1/8" plastic tee [or equivalent]
  • (2) 1/8" rubber cap [or equivalent, a piece of vacuum hose with a bolt will work too)
  • zip ties

Procedure:
1. Determine where you wish to mount the MBC. Find an area that is easily accessible, so it can be adjusted without difficulty. Mounting to the radiator cooling fan shroud as seen in the aside picture, for example, is convenient.

procedure1.jpg


2. Before connecting the boost controller you must disconnect the BCS (Boost Control Solenoid) plumbing from the waste gate, air can and turbo outlet.
Note: If you have the Knock LED mod installed in your car you likely have the resistor1 installed inline with the LED circuit and must leave the BCS connected electrically. If you do not have the Knock LED mod, or wish to remove the resistor1 from it?s ?inline? position, you can install the resistor1 into the connector for the BCS after removing it.
-For information on the Knock LED mod see the following url http://members.home.net/dsmweb/ledmod/ courtesy of Damian Sigman
-resistor1 is the appropriate resistor value for the LED used in the above mod, either as described in the mod, or calculated for your specific LED

3. Using the below plumbing schematic, cut the vacuum hose to an appropriate length and connect to the MBC. Secure all connections with zip ties and the MBC in it?s mounting position.
mbcschematic.jpg


4. Cap off the nipple on the air can and the turbo outlet with the rubber caps. Secure them with a zip tie as the example in the aside picture depicts for the turbo outlet.

lastadjust.jpg

NOTE: due to minor revisions to the MBC it is no longer necessary to install a straight through coupling with a small hole, described as the ?Bleeder? in my FAQ. The bleed feature has now been incorporated into the body of the MBC (small hole drilled into the body)

Adjusting the MBC:
It is critical that the MBC be adjusted before you drive your car under sustained boosted conditions; Failing to do so could result in boost levels higher than the engine maybe capable of maintaining, leading to possible engine damage. I have preset the MBC at approximately 15psi of boost to provide a basic adjustment starting point. This may be slightly higher or lower on your car.
After you have installed the MBC, gently drive your car in a controlled environment (ie. empty parking lot or unused country road) gradually ease on the accelerator building boost and noting maximum pressure on the boost gauge. Under any circumstance DO NOT operate your car over the maximum known sustainable boost pressure according to other modifications completed. If you are not sure what the maximum sustainable boost pressure for your DSM is, do not exceed 13psi.

To Increase boost:
Loosen the jam nut off gently and turn the bolt in (clockwise). Adjustments are very minute, so do them in small increments, adjust, test, adjust, test?etc. failing to do so could result in generating extremely high boost levels and damaging your engine.

To Decrease boost:
Loosen the jam nut off gently and turn the bolt out (anti-clockwise). Adjustments are very minute, so do them in small increments.
Once you have achieved your desired boost level setting, tighten the jam nut down against the body of the MBC. This will lock the bolt into place.
Failing to tighten the jam nut could result in the bolt backing itself out which would create higher than desired boost levels. The worst case would be loss of the bolt and internal components, resulting in complete loss of control over boost.
 
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I didnt read the submission guide. Dont think I'm doing this correctly. Any ideas where I should throw this? I've never built one, so cannot verify functionality, but dont see any reasons it shouldent work like all the others. Should I just make this a thread in the Performance forum?

Suggestions?
 
Looks like you put it in the right place. After feedback, according to the submission guide, submit to dana@turbobricks.com.
Nice clean write up, though. Very sharp. I might attempt it if I didn't already have one installed. Maybe for my Father in law for his van for Christmas......."No, really, it works really simple, I'll show you...."

Bob
 
Lol, yeah, it's the best writeup I've seen so far. It's a direct copy off the website I mentioned in the title. The original page said it was ok to repost on another site, so I hosted the images and converted it to forum language.

It would even be better if you couldent buy the things off Ebay for $15. But, it does allow you to really see what's going on inside them.
 
I've used that type of MBC but I think the type found on Gus Mahons website works better. It's a bit harder to make because you have to order the parts off the Mcmastercarr website.
 
i made 1 using those instructions , its currently on my brick. no creep or nothing and i didnt drill the little hole like it says and it still works perfect

15psi and no problems:-D

i think t cost me like 12$ all together

and i have enough left over parts to make another 1
 
how can you make one that's adjustable from inside the cabin?
what would be the theory and complication of making such device?

1. Run the MBC inside the cabin by using really long hoses. That would probably hurt performance.

2. Make a really long flexible metal shaft that runs through the firewall and let you turn the mbc adjustment screw from inside. This would probably be pretty difficult.

3. Mount a slow turning motors shaft to the screw of the mbc and use a switch to control the motor. I have actually tried this. It would work if you can bond the adjustment screw to the motors shaft securely. Glue wont work, you need to weld it. You still risk backing the screw all the way out if you adjust too far.

4. Get EBC or buy a MS1 box+GMC boost control solenoid and try to wire up just the EBC portion of it. EBC is the simplest and most effective way of controlling boost from the cabin that I know of. It's also much nicer to use than a mbc. I have nothing but praise for the ms1 box+GMC boost solenoid setup.
 
1. Run the MBC inside the cabin by using really long hoses. That would probably hurt performance.

will that cause slow response or boost spike?
 
I did mine differently, I fed the controller from the turbo compressor housing and not inline with the BOV. Would that hurt me in anyway ??
 
You know what's nearly free, takes about 2mins to make and also works?!?!?

Ingredients...

1> 1 y-shaped OR t-shaped piece of plastic tubing, correct size for hosing to squeeze over
2> 3 pieces of hose
3> Mini clamp with bolts either side

Instructions...

fit hose to all three parts of y-shaped plastic
run one bit of hose to turbo
run one bit to the actuator
place clamp over 'open' end of hose
Adjust clamp to fuel cut or spark blow out

Thrash car around till you can afford proper MBC

Result - pikey Boost Control:lol::lol:;-)
 
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Sorry to bump this lol.But ehh im gonna be making one of these soon.I was wondering do we just plug it into the line coming from the turbo housing to the actuator?Thats what i think we do as we have a different set up compared to the dsm guys.
 
QUIT SUGGESTING THIS!! You are going to get some idiot to try it and they are going to blow their engine apart. A MBC is quite cheap. If you don't do it right in the first place, don't do it. Yeah, I know its like the Turbo+ system. Its still STUPID!

You know what's nearly free, takes about 2mins to make and also works?!?!?

Ingredients...

1> 1 y-shaped OR t-shaped piece of plastic tubing, correct size for hosing to squeeze over
2> 3 pieces of hose
3> Mini clamp with bolts either side

Instructions...

fit hose to all three parts of y-shaped plastic
run one bit of hose to turbo
run one bit to the actuator
place clamp over 'open' end of hose
Adjust clamp to fuel cut or spark blow out

Thrash car around till you can afford proper MBC

Result - pikey Boost Control:lol::lol:;-)
 
how can you make one that's adjustable from inside the cabin?
what would be the theory and complication of making such device?

One could have two or more MBCs in place, set at different boost levels, plumbed in parallel with each other.

Plumb a 12-volt solenoid valve in-line on each one.

Have switches in the cabin that turn on the different solenoid valves/MBCs.

Kinda clunky -- you're still only hitting set levels, not fully adjustable -- but plenty cheap enough to do (the Turbobricks way :oogle:)
 
Yes. But personally i don't see the point in making one yourself when you can actually buy a very similar on for a very reasonable price.
http://www.3barracing.com/products.htm

You must be a rich bastard. $40 vs. the $5 it takes to make one.

Just make one and be done. If you need a shiny chrome one, buy it, if you need a MBC, just make it.

Of course if you watch your boost gauge, you won't blow it up unless you're an idiot.
 
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