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DIY MBC boost controller
Posted: Sun Apr 17, 2005 6:02 am
by kidwired
I found this for those wanting to build your own MBC as I may do.
http://www.geocities.com/chmwatson/FAQs/mbc.html
order everything here.
http://www.mcmaster.com/
they might even have the stuff for coffee cups.
Posted: Mon Apr 18, 2005 9:36 pm
by Warp3
That's the instructions I used to build the MBC that my RX currently has installed (which will be making its way to the Legacy at some point).
The only difference I would suggest is to go to the plumbing department and buy a brass "bushing" which is pretty much the exact same thing they have you making from the male-to-male coupler and tap set in those instructions and the bushing costs about the same as the coupler does anyway (adjusting the size of the bolt to make sure it matches the inside threads of the coupling of course). In fact, in my build, I used the brass bushing that came with one of my Autometer gauges that I didn't end up needing for my gauge install, but happened to be the right size for this.
Posted: Mon Apr 18, 2005 9:53 pm
by vrg3
I usually just solder a nut to the end of the tee.
And I actually also had success just retapping the 1/4" NPT threads to a regular parallel thread... I think it might have been 1/2"-20 or maybe 7/16"-20.
Posted: Mon Apr 18, 2005 9:54 pm
by IronMonkeyL255
And I believe that someone mentioned that you could put another ball bearing at the other end of the spring for added safety. That way, it would keep the car from boosting uncontrollably if the bolt backed all the way out.
I have that page saved. I plan on making one once I get a boost gauge.
Posted: Tue Apr 19, 2005 12:11 am
by gustavohuber
hmm, maybe I can use that to control the rate of freon leakage from my AC system. damned n/a engine really minimizes my chances for making cool gadgets.
Posted: Tue Apr 19, 2005 2:33 am
by Project_Legacy
kool. thanks for the info yo. ill probably be doing this sometime soon as well. i have a question on this though. does the MBC only replace the Boost Control Solenoid and not the other 2 sensors that are on the passenger side strut tower? or does it replace all of it? im wondering because i bought those three sensors all together and the wires were cut.......... any help would be appreciated. thanks
Posted: Tue Apr 19, 2005 2:53 am
by vrg3
It replaces the boost control solenoid only.
Posted: Tue Apr 19, 2005 3:20 am
by Project_Legacy
ok kool. thanks a lot.
Posted: Tue Apr 19, 2005 3:26 am
by kidwired
yea, it replaces but doesnt the 3rd (elevation thingy) not work anymore once you remove the other lines? may as well just cap it off both on the black box and the selenoid.
Posted: Tue Apr 19, 2005 3:33 am
by vrg3
Elevation thingie?
http://www.graphics.cornell.edu/~v/vacuum/
You're talking about hose J, right? You can either leave it or remove it and cap the stuff off. It doesn't really matter.
You should cap off the now-unused fittings on the solenoid though. One 3/16" cap and one 1/4" cap should fit neatly.