MBC Install Help Needed
okies lets see..
i dunno if these are all the boost/vacuum but here is what i did..
First of, i have the BR intake (PIA to reach the compressor housing discharge tube with this!)
Now.. i removed the hose going to the Wastegate ofcourse thats the "J" connecting to the compressor housing discharge tube.. (thats the hose which has the boost pill as they call it..) and then removed the ones on the factory boost solonoid.
Now, I put a cap on the discharge tube. On the boost solenoid, i just covered it with one hose that just connects both the nipples together just to cover them up.
I removed the line going to the BOV and put a Tee there and put an extra hose that goes to the MBC inlet and then a hose from the MBC out to the WGA.
ill post a drawing of what i did in a bit..
i dunno if these are all the boost/vacuum but here is what i did..
First of, i have the BR intake (PIA to reach the compressor housing discharge tube with this!)
Now.. i removed the hose going to the Wastegate ofcourse thats the "J" connecting to the compressor housing discharge tube.. (thats the hose which has the boost pill as they call it..) and then removed the ones on the factory boost solonoid.
Now, I put a cap on the discharge tube. On the boost solenoid, i just covered it with one hose that just connects both the nipples together just to cover them up.
I removed the line going to the BOV and put a Tee there and put an extra hose that goes to the MBC inlet and then a hose from the MBC out to the WGA.
ill post a drawing of what i did in a bit..
So, you didn't reuse any of the factory boost/vacuum lines(hoses)? You used new and different 4mm rubber vacuum hose, right? The factory lines can't be reused for an MBC install because they have a couple of internal restictor pills.
You need to make double sure that you capped all vacuum nipples tightly. If you still are using the black, rubber, articulated factory air intake hose which connects from the MAF sensor to the turbocharger's compressor inlet, you'll notice there is a vacuum nipple on it. You need to cap it off.
Also, the nipple on the compressor discharge "J" tube, which you say that you capped off, needs to be done correctly. If you just put one of those wimpy rubber caps on it then it will probably not hold under turbo's radiant heat and boost pressure.
For this compressor discharge tube nipple you need to use a 30mm long piece of 4mm vacuum hose. Find a short, fine threaded machine screw that you have to force fit inside the hose, screw it tightly into one end of the hose with a screwdriver and secure it with a ziptie. Install the other end onto the compressor nipple and secure that end with another ziptie.
From your illustration it looks like you routed the MBC correctly. But just to make sure: There are two ports on the MBC. The port on the bottom of the MBC, that is, the one axially inline with the adjustment knob, should be routed to the "T" in the diverter valve/intake manifold line.
The second, or side port, of your MBC should be routed to the port on the top of the wastegate actuator, which is mounted onto your turbocharger. Secure all hose fittings securely with zipties.
Also, the nipple on the compressor discharge "J" tube, which you say that you capped off, needs to be done correctly. If you just put one of those wimpy rubber caps on it then it will probably not hold under turbo's radiant heat and boost pressure.
For this compressor discharge tube nipple you need to use a 30mm long piece of 4mm vacuum hose. Find a short, fine threaded machine screw that you have to force fit inside the hose, screw it tightly into one end of the hose with a screwdriver and secure it with a ziptie. Install the other end onto the compressor nipple and secure that end with another ziptie.
From your illustration it looks like you routed the MBC correctly. But just to make sure: There are two ports on the MBC. The port on the bottom of the MBC, that is, the one axially inline with the adjustment knob, should be routed to the "T" in the diverter valve/intake manifold line.
The second, or side port, of your MBC should be routed to the port on the top of the wastegate actuator, which is mounted onto your turbocharger. Secure all hose fittings securely with zipties.
Last edited by sparky; Aug 24, 2008 at 09:33 AM.
Just got back home. This was bothering me so much that i just couldnt leave it like that..
First thing i did was completely take the MBC out and started blowing air through the inlet port and noticed that it was very easy to blow thru.. this got me confused..
I opened the up and what i see was the dumbest thing ever.. It was all my bad.. i had opened the MBC all the way just to see whats inside and how it exactly it worked. After this i had left it on my desk and asked my friend to put it back together.. THIS IS WHERE IT ALL WENT WRONG.. He put the ceramic ball on the outlet port side and only the spring on the otherside.. this let free flow thus boosting all the way!
Sorry for the trouble guys! And many thanks to you Sparky! Appreciate it!!
First thing i did was completely take the MBC out and started blowing air through the inlet port and noticed that it was very easy to blow thru.. this got me confused..
I opened the up and what i see was the dumbest thing ever.. It was all my bad.. i had opened the MBC all the way just to see whats inside and how it exactly it worked. After this i had left it on my desk and asked my friend to put it back together.. THIS IS WHERE IT ALL WENT WRONG.. He put the ceramic ball on the outlet port side and only the spring on the otherside.. this let free flow thus boosting all the way!
Sorry for the trouble guys! And many thanks to you Sparky! Appreciate it!!
If you will be replacing the totally stock boost control system, then it's best to remove the stock boost/vacuum hose assembly as a unit. Install the MBC with new 4mm hoses. If your MBC comes with the hoses, then use those provided.
Cap off securely all the ports to where the factory boost/vacuum lines were connected except your boost reference source and the WGA. Leave the electrical connector plugged into the factory BCS.
Decide whether you'll use the compressor housing discharge nipple or "T" into the DV/intake manifold line for your boost reference source. Run one hose from the boost reference source to the port on the bottom on the MBC. Then run a hose from the side port on the MBC to the WGA.
You should have no issues. Good Luck!
Cap off securely all the ports to where the factory boost/vacuum lines were connected except your boost reference source and the WGA. Leave the electrical connector plugged into the factory BCS.
Decide whether you'll use the compressor housing discharge nipple or "T" into the DV/intake manifold line for your boost reference source. Run one hose from the boost reference source to the port on the bottom on the MBC. Then run a hose from the side port on the MBC to the WGA.
You should have no issues. Good Luck!
If you will be replacing the totally stock boost control system, then it's best to remove the stock boost/vacuum hose assembly as a unit. Install the MBC with new 4mm hoses. If your MBC comes with the hoses, then use those provided.
Cap off securely all the ports to where the factory boost/vacuum lines were connected except your boost reference source and the WGA. Leave the electrical connector plugged into the factory BCS.
Decide whether you'll use the compressor housing discharge nipple or "T" into the DV/intake manifold line for your boost reference source. Run one hose from the boost reference source to the port on the bottom on the MBC. Then run a hose from the side port on the MBC to the WGA.
You should have no issues. Good Luck!
Cap off securely all the ports to where the factory boost/vacuum lines were connected except your boost reference source and the WGA. Leave the electrical connector plugged into the factory BCS.
Decide whether you'll use the compressor housing discharge nipple or "T" into the DV/intake manifold line for your boost reference source. Run one hose from the boost reference source to the port on the bottom on the MBC. Then run a hose from the side port on the MBC to the WGA.
You should have no issues. Good Luck!
Also what boost reference source is recommended now? Compressor housing discharge nipple or T into DV/intake manifold....thanks!
Go Back to the old picture I made and hook it up exactly as shown. If you hook up hoses to any other places, you'll not get the results you need.....
Thanks to all you guys who have written praises of that old drawing
. I still remember that I added that MBC to my car "after" 
Al had done his famous "road tuning" Dynoflush. I sure could have used more guidance and help but I reckon that the only "EVO guru" was too busy ripping up and down I-75 "road tuning" cars. I found out how to do it the wrong way first thanks to the instructions that came with the kit. I finally got it right and made the drawing to help other peeps from suffering and wasting time.
If you are installing a conventional MBC to an EVO 8, do it "exactly" like the sketch and you'll be fine. Don't get creative and don't pay attention to anybody who tells you differently. They probably have no f*cking clue and are just writing stuff to sound knowledgeable.
Peace
BTW, this instructions are for a conventional MBC. I'm not familiar with any other type of system. If you have some strange hybrid BC or any thing other than a ball & spring with a screw in a fitting, you are on your own.
Oh yeah, I no longer have any boost related issues.. 436 hp at 0 psi
Thanks to all you guys who have written praises of that old drawing
. I still remember that I added that MBC to my car "after" Al had done his famous "road tuning" Dynoflush. I sure could have used more guidance and help but I reckon that the only "EVO guru" was too busy ripping up and down I-75 "road tuning" cars. I found out how to do it the wrong way first thanks to the instructions that came with the kit. I finally got it right and made the drawing to help other peeps from suffering and wasting time.If you are installing a conventional MBC to an EVO 8, do it "exactly" like the sketch and you'll be fine. Don't get creative and don't pay attention to anybody who tells you differently. They probably have no f*cking clue and are just writing stuff to sound knowledgeable.
Peace
BTW, this instructions are for a conventional MBC. I'm not familiar with any other type of system. If you have some strange hybrid BC or any thing other than a ball & spring with a screw in a fitting, you are on your own.
Oh yeah, I no longer have any boost related issues.. 436 hp at 0 psi
Sorry, I can't remember, but I don't think I had a choice of springs. If I had I would have probably used the suggested or default spring. I'm out of the EVO business at least for now... If you have a question about Z51 C6s I might be of more help
^^ Dont forget a Nice CAMSHAFT ... ...
Btw I have a
VETTE Stingray Shark 2 1968 with 327 engine Convertible w/ Soft-top
VETTE Stingray 1974 454 Big Block Convertible w/ Soft-top '' P.S VERY VERY VEY LOW Milage''
VETTE FEVER .... '' CHEERS FOR MUSCLE CAR'' ...
... Btw I have a
VETTE Stingray Shark 2 1968 with 327 engine Convertible w/ Soft-top
VETTE Stingray 1974 454 Big Block Convertible w/ Soft-top '' P.S VERY VERY VEY LOW Milage''
VETTE FEVER .... '' CHEERS FOR MUSCLE CAR'' ...
Just today coming home I went to pass an SUV up a slight hill and I broke the rear end loose right away in second then in 3rd and hit the rev limiter 
... Hell, I think what I really need is a set of drag slicks and some practice in the 1/4 mile
