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MBC questions

Posted: Wed Feb 18, 2004 10:26 pm
by max boost
Man i have tried every possible thing to get my car with more boost i read all the info but no one here actually tells or shows were. can someone show me a pic and explain

Posted: Wed Feb 18, 2004 10:29 pm
by DLC

Posted: Wed Feb 18, 2004 10:30 pm
by boostjunkie
HUH? What exactly are you trying to do? Hook up an MBC? I can show you a link but only after you tell me you have a boost gauge hooked up first. Don't need you blowin your motor up.

Posted: Wed Feb 18, 2004 10:30 pm
by boostjunkie
I guess DLC doesn't care about people blowin up motors! LOL!

Posted: Wed Feb 18, 2004 10:38 pm
by vrg3
I would actually argue that unless you're knowledgeable enough about this stuff that you don't need instructions, those instructions aren't good.

The right way for a beginner to hook up a manual boost controller is to use the compressor outlet as the pressure source, not the intake manifold. Using the intake manifold allows overspeeding of the turbo at part throttle.

There are also some errors in the writeup... it calls the pressure exchange solenoid the map sensor and the well-taken photo calls the compressor outlet nipple the turbo inlet.

They're very well-written, though, with useful photographs.

Posted: Wed Feb 18, 2004 11:30 pm
by DLC
That's an oooooold page.

Posted: Wed Feb 18, 2004 11:44 pm
by DOA
Thought Id mention that Im working on a boost controller that hopefully will be relatively cheap and easy to install using an already available pneumatic valve and will get rid of a couple of problems that I can see in Vrg3's ghetto one. Ill post more when Im sure the valves available.

Posted: Wed Feb 18, 2004 11:59 pm
by boostjunkie
I had no idea vrg3 was developing a boost controller, let alone a GHETTO one. Something doesn't jive here.

Posted: Thu Feb 19, 2004 12:08 am
by vrg3
Hehehe...

http://bbs.legacycentral.org/viewtopic.php?t=1837

I was bored that day and happened to go into a hardware store. I was surprised nobody commented on it at all.

I'm actually working on another top secret boost control mechanism... Details will follow after a proof of concept. :evil:

Posted: Thu Feb 19, 2004 12:10 am
by boostjunkie
Woah, back in August. Right around the time my car was being REALLY FLAKEY!! That explains why I didn't see any other posts besides the ones on how to fix my car! LOL!

Posted: Thu Feb 19, 2004 2:35 am
by max boost
yeah i have a boost gauge, and i have a air fuel gauge aswell but its no in yet.

Posted: Thu Feb 19, 2004 2:40 am
by max boost
oh i not sure about my mbc my buddy gave it to me, he said that it will work he has used it before on his talon. he is the on that could not figure out how to boost my car. these cars are harder than his car for boosting

Posted: Thu Feb 19, 2004 5:26 am
by boostjunkie
If your buddy had the MBC he'd know how to hook it up. Just hook one section to the wastegate and the other to the compressor outlet (he should know which part of the boost controller goes to which nipple) and you're done.

Posted: Mon Feb 23, 2004 7:28 pm
by max boost
the mbc is in my car now, i think that it does not hold the presser because it holds at 6-7 psi but sometimes it goes past ten then falls down to 6-7? does this mean i need a better mbc?

Posted: Mon Feb 23, 2004 10:28 pm
by vrg3
What kind of MBC is it?

6-7psi is what happens if the wastegate is connected directly to the compressor outlet.

Not knowing anything more, all I can guess is that your boost controller is somehow doing nothing other than just acting as a restrictor between the compressor outlet and the wastegate actuator. That could cause boost spiking but wouldn't elevate the stable boost level.

Posted: Tue Feb 24, 2004 8:05 pm
by max boost
Man i dont know too much about this stuff. all i know is that there is two nipples and a screw on the top. Now i might be doing it wrong am i supposed to bleed or restrict? i think that i am restricting the flow.

Posted: Tue Feb 24, 2004 8:09 pm
by vrg3
You should take the boost controller off until you learn about boost control in general and your controller in particular.

A simple restriction is not a method to control boost. A bleed can be, but it usually needs to be coupled with a restriction.

Posted: Sat Feb 28, 2004 10:37 pm
by DOA
Hmm, the controller wasnt bought of ebay was it. Think I undersstand how it works anyway and it sounds like it will just be a piston with a spring and a screw to adjust the spring preload. Basically to set it up undo the screw till you cant feel the spring pushing against it and screw it back up again in small increments till you get the desired max boost level your after. BE VERY CAREFULL THO! if you set it up wrong the turbo will just keep boosting till it pops the engine (or the fuel cut comes in if your lucky).