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Militant-Grunt
08-04-2007, 12:23 PM
Anyone got a DIY write up? I have the Forge MBC, I don't know which vac lines go where. The search function on the site yields a database error for me for some reason hence Im making a new thread.

SurferForever
08-04-2007, 12:32 PM
http://www.audiforums.com/m_583205/tm.htm

aytheory
08-04-2007, 12:44 PM
seems like you need two T - fittings - where to pick those up at?

Militant-Grunt
08-04-2007, 12:53 PM
My MBC has three openings for vac lines the ones shown in that thread have two.
I have this MBC http://www.forgemotorsport.com/content.asp?inc=product&cat=0016&product=FMICB051

I want to eliminate the N75 completely. One PITA thing I found out is that 2 prong is better than 3.. Grr anyone have this MBC in their car?

aytheory
08-04-2007, 01:01 PM
think you should stick with mbc with n75 the boost are much smoother unless you run a ebc.

GR-RALLYE
08-04-2007, 01:03 PM
replace that where the n75 goes then. the 2 prong is for running it with the n75

Burntaudi
08-04-2007, 02:30 PM
Is this with a stock turbo? Your not gonna like the way it drive's with a MBC. Full boost will come on with only part throttle and it buck violently if you lift throttle while in full boost. Been done that driveability sucks with a K03/K04.

Rosati
08-04-2007, 02:32 PM
Run it with the N75 grunt

The car will shudder and knock while on and off the gas w/ just the mbc

http://ctny.audiworld.com/mark/s4/misc_data/mbc_parallel.jpg

maxspeed
08-04-2007, 02:37 PM
i got rid of my n75 completely and just use a mbc, ocne you learn how to drive it it's not jerky at all

Rosati
08-04-2007, 03:04 PM
yeah by riding the clutch [:p] I learned too bc i ran w/o one for a while and it takes too much effort to "induce" a smooth ride w/o the n75 , In other words, its annoying.

At first i didnt care, then I drove around it , and then I put the valve back in

mike-2ptzero
08-04-2007, 03:08 PM
Hope you like "boost spikes" if you plan on running the MBC alone.


Boost spikes = bad power band since the turbo actual stalls right after the spike.


If you are already trying to reduce boost spike just use the MBC with the N75 valve.

Militant-Grunt
08-05-2007, 09:53 AM
I guess ill do that, what is a good cheap 2 prong MBC to order?

Burntaudi
08-05-2007, 09:58 AM
www.joepmbc.com/mbc.html Get XZ MBC if you want inexpensive.

$teady$upreme
08-05-2007, 09:41 PM
Just bought this from eBay, http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ih=018&sspagename=STRK%3AMEWN%3AIT&viewitem=&item=280136612267&rd=1

Works great, but partial throttle sucks. Got this MBC because im still waiting for my Greddy solenoid harness to come.

But from personal experience, EBC is way better than MBC imo~

mike-2ptzero
08-05-2007, 09:43 PM
But from personal experience, EBC is way better than MBC imo~

1000% times better.

Militant-Grunt
08-06-2007, 01:56 PM
1000% times better.

Also 1000% more expensive, ill get the 12 dollar Voodoo, I just want to hold more boost up top.

On the diagram the "Ambient Pressure" is the tube that is inserted in the inlet hose right?

AudiRacerS4
08-06-2007, 01:58 PM
Also 1000% more expensive, ill get the 12 dollar Voodoo, I just want to hold more boost up top.

On the diagram the "Ambient Pressure" is the tube that is inserted in the inlet hose right?

yes

$teady$upreme
08-06-2007, 07:45 PM
With this set up instead of routing the N75 to itself, will partial throttle still be very violent and big jerk will you let go of the throttle??


Run it with the N75 grunt

The car will shudder and knock while on and off the gas w/ just the mbc

http://ctny.audiworld.com/mark/s4/misc_data/mbc_parallel.jpg

mike-2ptzero
08-06-2007, 08:00 PM
With this set up instead of routing the N75 to itself, will partial throttle still be very violent and big jerk will you let go of the throttle??

It is the way to reduce boost spikes, it will not allow you to run more boost.



Also 1000% more expensive, ill get the 12 dollar Voodoo, I just want to hold more boost up top.

On the diagram the "Ambient Pressure" is the tube that is inserted in the inlet hose right?

Why do you need a mbc for then? Why not just crank down the nut on the wg which will just close it more and give you more boost. Another way would be to get a better chip that runs more boost.

Just a warning, the ndbw has very small injectors so you better keep an eye on your AFR. Adding more boost to the K03 will also increase IAT's which means the ecu will run less adv timing, so expect some tq/hp loss for that tq/hp your trying to gain.

Militant-Grunt
08-06-2007, 10:17 PM
Im just trying to hold more boost in the higher RPMs, Its like hitting a brick wall when you're out of that magical 3-4500rpm. I have a k04 in the mail regardlesS (replacing the one that blew) after I get enough money for software and fmic + injectors ill just get pc-16, and have that go along with the mbc, I just cant have a loss of power down range of the RPM.

Tiluleshpingen
08-06-2007, 10:43 PM
i got rid of my n75 completely and just use a mbc, ocne you learn how to drive it it's not jerky at all

x2[:D][up]

Tiluleshpingen
08-06-2007, 10:44 PM
Im just trying to hold more boost in the higher RPMs, Its like hitting a brick wall when you're out of that magical 3-4500rpm. I have a k04 in the mail regardlesS (replacing the one that blew) after I get enough money for software and fmic + injectors ill just get pc-16, and have that go along with the mbc, I just cant have a loss of power down range of the RPM.

your hitting the wall on k04?? u could'nt possible that bad.... anyway maybe beacuse that Fmic that u dont have is holding you back .... exhaust gonna help you alot

Tiluleshpingen
08-06-2007, 10:45 PM
Anyone got a DIY write up? I have the Forge MBC, I don't know which vac lines go where. The search function on the site yields a database error for me for some reason hence Im making a new thread.

wuts urs dbw or drive by cable(ndbw)?

Tiluleshpingen
08-06-2007, 10:49 PM
But from personal experience, EBC is way better than MBC imo~

i went thru 3 of them already they break easely on me [headbang] so far current mbc is holding good

mike-2ptzero
08-07-2007, 06:51 AM
Im just trying to hold more boost in the higher RPMs, Its like hitting a brick wall when you're out of that magical 3-4500rpm. I have a k04 in the mail regardlesS (replacing the one that blew) after I get enough money for software and fmic + injectors ill just get pc-16, and have that go along with the mbc, I just cant have a loss of power down range of the RPM.

It isn't going to help you hold more boost up top since the turbo is just hitting full spool and the boost just drops like a rock at that point. If more boost you try to push the sooner the boost will drop.

Militant-Grunt
08-07-2007, 08:58 AM
wuts urs dbw or drive by cable(ndbw)?

NDBW. 98.5

ActiveMonkey
08-07-2007, 09:53 AM
What if you cranked the nut on the Wastegate, and added an Adjustable FPR, with those two, could you increase the fuel pressure to allow for the extra boost? or are the injectors that shitty, i mean small. [:D]

mike-2ptzero
08-07-2007, 09:58 AM
What if you cranked the nut on the Wastegate, and added an Adjustable FPR, with those two, could you increase the fuel pressure to allow for the extra boost? or are the injectors that shitty, i mean small. [:D]

Dont need to adjust the fpr since the ecu will do that with the higher maf readings.


Easy way to get more boost is to tighten the wg nut or go with a different N75 valve. Going with a MBC isn't going to increase boost in the higher rpms since the ecu is already programmed to run max boost, the problem is that the small ndbw K03 just cant spin any faster in the mid-high rpm's.

ActiveMonkey
08-07-2007, 10:18 AM
Now if i were to tighten the wg nut and then put in a MBC just for saftey, do you think that would be a good idea? I just don't want to spike above 20psi.

Also, How many turns of the wg nut would you recommend?

mike-2ptzero
08-07-2007, 10:31 AM
Now if i were to tighten the wg nut and then put in a MBC just for saftey, do you think that would be a good idea? I just don't want to spike above 20psi.

Also, How many turns of the wg nut would you recommend?

Just 1 turn at a time and then test it to see how much boost you get. I would do this with the N75 valve.

ActiveMonkey
08-07-2007, 10:58 AM
Yea, i planned on running the MBC in conjunction with the N75.

Militant-Grunt
08-07-2007, 11:40 AM
Right now I get 20PSI at most, just I had a guy with a Passat 1.8t show up at our shop with a MBC, he had the N75 taken out, he said the car held 15psi near redline and hit 21 at spike, which is optimal.

AB18
08-07-2007, 12:28 PM
Just curious, with some of the projects your shop does, why can't you figure out a mbc install? Its pretty straight forward, something your shop should be able to handle.

mike-2ptzero
08-07-2007, 01:03 PM
Right now I get 20PSI at most, just I had a guy with a Passat 1.8t show up at our shop with a MBC, he had the N75 taken out, he said the car held 15psi near redline and hit 21 at spike, which is optimal.

Spikes dont mean anything which is why a MBC is not good to use. Tuners try their hardest to remove all boost spikes when they do their programming. Look at a dyno pull of any car that has a boost spike and you will understand what I mean.


a car that hits 21psi boost spike during high load low rpm pull is not ever going to only hit about 18psi going thru the gears. Wouldn't that actually be a step down from what you run now?

Was that passat dbw? Because the dbw cars have a slightly more aggressive K03.

Militant-Grunt
08-07-2007, 01:08 PM
Spikes dont mean anything which is why a MBC is not good to use. Tuners try their hardest to remove all boost spikes when they do their programming. Look at a dyno pull of any car that has a boost spike and you will understand what I mean.


a car that hits 21psi boost spike during high load low rpm pull is not ever going to only hit about 18psi going thru the gears. Wouldn't that actually be a step down from what you run now?

Was that passat dbw? Because the dbw cars have a slightly more aggressive K03.

I dont think it was, it was a 98.

mike-2ptzero
08-07-2007, 01:11 PM
I dont think it was, it was a 98.

Did you drive it? Because once you drive a car that has boost spikes you will never want to do that again.

Militant-Grunt
08-07-2007, 01:14 PM
Just curious, with some of the projects your shop does, why can't you figure out a mbc install? Its pretty straight forward, something your shop should be able to handle.

Because I'm only an apprentice tech there, I learn from what they do. I simply have not asked them, the other factor is they 95% of the cars they tune are 2.7t's and not 1.8ts, hence I much rather ask guys from the forum, such as Mike, who's done just about everything to his car. [cool]

Militant-Grunt
08-07-2007, 01:15 PM
Did you drive it? Because once you drive a car that has boost spikes you will never want to do that again.

I have not, I have his number actually, I'm going to give him a call later on and ask.

ActiveMonkey
08-07-2007, 06:09 PM
Where's that wastegate nut located? Anyone have a pic?

Is it easier to pull the turbo?

Bic-Ball
08-07-2007, 06:13 PM
the wastegate is actuator is towards the front of the car, it has a rod coming from it to the exhaust side of the turbo. that rod is connected to the flap. the nut is at the end of the rod to where it connects to the flap. it's probably going to be a bitch to get your arm in there but im sure spending an hour to turn the thing is easier than pulling the turbo to twist one bolt.

there are actually two bolts, one on either side of the connection, you obviously have to turn both. they have a little metal bracket going over both of them to hold them in pace.

Bic-Ball
08-07-2007, 06:29 PM
here i took a pic for you. if the turbo were in the car the camera would be in the engine taking a picture of the passenger wheel. the nuts are going to be directly under the exhaust manifold, probably right above the a/c compressor. have fun getting a wrench in there.
http://www.zeroproof.com/bicball/wastegatenuts.jpg

HIERLEVELZ
08-19-2007, 04:54 PM
whats the size on those bolts? what is the easiest way to access those nuts?

projectdarka4
08-19-2007, 05:03 PM
haha wow... i forgot what a turbo will look like over time... Glad when i bought my a4, they put in a complete oem stock turbo kit with lines and all!!!

Bic-Ball
08-19-2007, 09:49 PM
whats the size on those bolts? what is the easiest way to access those nuts?

they're probably 8 or 10 mm, id definitely go from under the car, the a/c compressor is going to be in the way though.

Pat@Forge
08-23-2007, 11:12 AM
The side ports are for boost, doesn't matter which goes to manifold and which goes to the wastegate just so long as you use the side ports. The bottom is the bleed port. You can stick the bottom port into the port on the TIP where the N75 was...

HIERLEVELZ
08-24-2007, 02:08 PM
here i took a pic for you. if the turbo were in the car the camera would be in the engine taking a picture of the passenger wheel. the nuts are going to be directly under the exhaust manifold, probably right above the a/c compressor. have fun getting a wrench in there.
http://www.zeroproof.com/bicball/wastegatenuts.jpg

Btw which direction would you turn the nuts to crank the wastegate? Im assuming towards the rear of the car. Correct me if im wrong.

mike-2ptzero
08-24-2007, 02:52 PM
Btw which direction would you turn the nuts to crank the wastegate? Im assuming towards the rear of the car. Correct me if im wrong.

Well if the arm and wg move in the same direction that means you want to tighten the nuts so that the arm moves more toward the actuator. Basicly you want to loosen the nut closest to the actuator first, then tighten the nut that is on the other side(further down the rod). Once you have the arm were you want you just tighten the first nut(closer to the actuator).

HIERLEVELZ
08-24-2007, 03:17 PM
Ok i got you so looking at the pic we would loosen the nuts so that the arm moves clockwise. Otherwise if you looking at the turbo from the wheel well it would be counter clockwise.

AboveNBeyond
05-22-2014, 01:11 AM
http://ctny.audiworld.com/mark/s4/misc_data/mbc_parallel.jpg

How does this make sense? as depicted in the pic using the "T's" where they are doesn't that render the MBC useless because the N75 is still connected as it would be stock. I would assume connected as shown would allow you to run less boost then the N75 would but never more because then the N75 would just control as intended.

Am I missing something?

I see it's an OOOLD post but it still is something I am trying to do.

ray4624
05-22-2014, 09:19 AM
Running it that way is to lower boost or reduce boost spikes. You don't want it like that if you want more boost


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