Anyone here run a MBC?

**EVIL-AUDI** · 07-21-2004 10:04 AM

I just wanted to see who has run an MBC and wat did you do with your N75? Burnt, any thoughts?

**Devious27t** · 07-21-2004 10:41 AM

i run a GFB manual boost controller hang on i will find the install diagram for you that i used. works like a charm contrary to popular belief, though i ran it inline with my AMS stg 2 chip...

**EVIL-AUDI** · 07-21-2004 10:45 AM

Thanks for any info.

**Devious27t** · 07-21-2004 10:46 AM

here you go.... from what i have gathered all of the manual boost controller start at 8 psi of boost if you have it closed all the way you will hit normal boost and it is not until you get above your normal boost level will the boost start building so if you have to give it some turns to get the boost up dont get discouraged it works....

**EVIL-AUDI** · 07-21-2004 10:52 AM

Hmm, I've also heard of it done another way. hmmmmm.

**MKGIY** · 07-21-2004 10:55 AM

Why not run an EBC?

Mike

**FITZ TITS** · 07-21-2004 10:57 AM

boostjunkie ran a TXS dual stage on his drive-by-wire and it wansn't anything but trouble for him.

**Devious27t** · 07-21-2004 11:00 AM

Originally posted by EVIL-AUDI
Hmm, I've also heard of it done another way. hmmmmm.

i have heard of running them otherways such as just replacing the N75 with the boost controller, but since i know how boost is derived in this car it didnt really seem like a good idea, i post this because this is the way that i installed mine and i can personally vouch that it works.... this is the common way for the S4 and TT guys on AW to install which is where i found the diagram.

**Devious27t** · 07-21-2004 11:01 AM

Originally posted by MKGIY
Why not run an EBC?

Mike

i have never had an EBC hold as well as an MBC, maybe apexi and greddy are just shitty ones...

**EVIL-AUDI** · 07-21-2004 11:03 AM

For what I want the MBC is better for me. I've seen the N75 being left plugged in but the hoses going to the MBC

**Devious27t** · 07-21-2004 11:07 AM

Originally posted by EVIL-AUDI
For what I want the MBC is better for me. I've seen the N75 being left plugged in but the hoses going to the MBC

i know two people who did that (pes kits on the cars) that blew up their cars. there are adjustments in boost and more importantly with fueling that might still need to be made a la map pressure and intake temp that an mbc wouldnt forsee... maybe that is just me being paranoid but iirc the n75 reading also play a role in adjusting fuel as well, if the reading was consistent couldnt that cause issues with A/F at WOT?

**EVIL-AUDI** · 07-21-2004 11:08 AM

No, I can see your point, but I also have a some sources who say otherwise. We'll see. I'm not sure this is what I wanted to do anyway. just checkin it out.

**Devious27t** · 07-21-2004 11:11 AM

Originally posted by EVIL-AUDI
No, I can see your point, but I also have a some sources who say otherwise. We'll see. I'm not sure this is what I wanted to do anyway. just checkin it out.

i am curious to see what the other sources have to say about it as most people are afraid to run a BC on an audi just so i can learn other options myself. i have my bcs out right now as i am doing test and tune on my new turbo set up and have other bugs to work out before i start really boosing on it, perhaps another better option might be out there?

**Devious27t** · 07-21-2004 11:12 AM

either way i would run one even if you dont turn the boost up as i saw a very noticable increase in turbo response out of the hole and on the fly just having the controller in there.

**EVIL-AUDI** · 07-21-2004 11:18 AM

Thanks for the help.

**JMG** · 07-21-2004 12:35 PM

Originally posted by DVS18t
either way i would run one even if you dont turn the boost up as i saw a very noticable increase in turbo response out of the hole and on the fly just having the controller in there.

[noob ?]

So what does the boost controller actually do? Does it build up boost until a set level then releases it instead of letting it all out? Does that mean boost comes later, but with greater efficiency?

[/noob ?]

**Devious27t** · 07-21-2004 12:55 PM

Originally posted by JMG
[noob ?]

So what does the boost controller actually do? Does it build up boost until a set level then releases it instead of letting it all out? Does that mean boost comes later, but with greater efficiency?

[/noob ?]

lol its okay i am sure most people here are happy you had the balls to ask the question... boost controller controls the amount of vacuum pressure that is sent to the wastegate. as vacuum pressure rises the wastegate opens and boost is retarded.... most manual boost controllers have a very small opening at one end of the pass through called a bleeder this regulates the vacuum pressure. on the top there is some sort of adjustment valve (allen screw, turn valve, etc.) the valve usually looks pointy and as you loosen the boost control valve it increases the size of the chamber inside and allows more vacuum pressure to be stored in the chamber before the bleeder.

**DDQ** · 07-21-2004 01:21 PM

I always thought MBCs were a lost cause on the 1.8T, due to the superior programming offered that does the job better than one could do manually.

I can't go into the specifics, since I have no experience with MBCs, but can you explain the advantages (and disadvantages) of running one? From what I've read by people that run some of the fastest tuned A4s, none seem to mention a MBC.

**Devious27t** · 07-21-2004 01:33 PM

Originally posted by DDQ
I always thought MBCs were a lost cause on the 1.8T, due to the superior programming offered that does the job better than one could do manually.

I can't go into the specifics, since I have no experience with MBCs, but can you explain the advantages (and disadvantages) of running one? From what I've read by people that run some of the fastest tuned A4s, none seem to mention a MBC.

the nice thing about chips for A4's is that they are all tuned to run rich from the box which leaves room for a little adjusting, you will hit boost cut before you lean out too much which takes care of a major disadvantage, I am of course assuming the person using one has at least a chip... i would never recommend someone substituting a mbc for a chip without some other form of tuning capabilities for fuel and timing.... all of the people that i know of on audiworld with modded turbo setups run boost controllers whether it be manual or electronic, its seems to be more of a secret around the audi community dont be fooled there are many people who run them search AW....

**DDQ** · 07-21-2004 01:37 PM

Thanks for the info.

So what's the advantage then? What more can you get out of a K03 by using a BC with a chip? I never thought the programming was a limiting factor.

**Devious27t** · 07-21-2004 01:42 PM

Originally posted by DDQ
Thanks for the info.

So what's the advantage then? What more can you get out of a K03 by using a BC with a chip? I never thought the programming was a limiting factor.

well i felt more response from the turbo with the install of the MBC, you wouldnt believe how fast that thing would spool up with it and when i would run race gas i would turn up the boost a little bit to lean out the mixture a bit as AMS doesnt make a race gas program. i wish that i could have found a way to advance timing with my old setup.

**EVIL-AUDI** · 07-21-2004 01:45 PM

hmmm, interesting

**DDQ** · 07-21-2004 02:44 PM

I'm still confused. Isn't turbo spool up directly correlated to exhaust (since that's what powers the turbo)? I don't see how an MBC would allow a turbo to spool up faster. I thought it would only allow one to overrided the system to allow boost to build up higher than it normally would by preventing it from releasing out the wastegate, or by overriding the N75 valve.

I would think any turbo car suffers turbo lag given the nature of a turbocharger. The job of an MBC would not seem to change that factor. If anything, I would have thought an MBC would just let you run higher boost levels, but I don't see how it can help a turbo spool quicker.

**DDQ** · 07-21-2004 03:42 PM

The forum was acting up on me. Not sure if my last post went through?

**Devious27t** · 07-21-2004 03:44 PM

Originally posted by DDQ
I'm still confused. Isn't turbo spool up directly correlated to exhaust (since that's what powers the turbo)? I don't see how an MBC would allow a turbo to spool up faster. I thought it would only allow one to overrided the system to allow boost to build up higher than it normally would by preventing it from releasing out the wastegate, or by overriding the N75 valve.

I would think any turbo car suffers turbo lag given the nature of a turbocharger. The job of an MBC would not seem to change that factor. If anything, I would have thought an MBC would just let you run higher boost levels, but I don't see how it can help a turbo spool quicker.

technically yes but that would be assuming there were no wastegate and the turbo were able to free spool. the bleed valve in a manual boost controller helps to hold the wastegate closed longer which allows the turbo to build boost faster. i am not sure if this is an audi specific thing since the turbo is so small and boost builds so fast that causes the wastegate to open earlier. with the bleeder, vacuum pressure is not allowed to release so quickly.

**EDness** · 07-21-2004 05:12 PM

I run a greddy profec B spec 1 EBC. It'e been working really well for me, easy to use, hold boost perfectly. I took the N75 out completely. No CEL, just a DTC.

**EVIL-AUDI** · 07-21-2004 06:27 PM

Yeah but you're a stage 3 fellow!

**JMG** · 07-22-2004 01:30 AM

Originally posted by DVS18t
the bleed valve in a manual boost controller helps to hold the wastegate closed longer which allows the turbo to build boost faster. i am not sure if this is an audi specific thing since the turbo is so small and boost builds so fast that causes the wastegate to open earlier. with the bleeder, vacuum pressure is not allowed to release so quickly.

ahhh... that was what I was assuming. By allowing the wastegate to open later, boost is already built up to a higher level than normal at that time. The onset of boost during the spool up pushed back a bit, but then the boost at that point will be higher than normal. Hence a faster spool time in general. Is this correct? Interesting.

**EVIL-AUDI** · 07-22-2004 05:05 AM

Pretty much

**Devious27t** · 07-22-2004 08:26 AM

Originally posted by EVIL-AUDI
Yeah but you're a stage 3 fellow!

A turbo is a turbo and not one does anything different then another some just do it in larger volumes.... if you can run an mbc on a S3 than you can run one on a chipped k03.

**EVIL-AUDI** · 07-22-2004 08:29 AM

We'll see what may or may not happen.

**MKGIY** · 07-22-2004 08:33 AM

I will be running a Greddy Profec B on my new set up. No more N75 for me either.

Mike

**EVIL-AUDI** · 07-22-2004 08:50 AM

That's if you ever have an Audi again.

**MKGIY** · 07-22-2004 08:55 AM

Originally posted by EVIL-AUDI
That's if you ever have an Audi again.

Not you too.

Mike

**Burntaudi** · 07-22-2004 09:09 AM

Evil here's the way I have mine setup.
The N75 stays put in the intake. And also stays pluged in to trick the ECU so you wont get a CEL.
You disconect the 2 hoses from the N75 that go to the waste and turbo those hoses get connected to the MBC.

You turn the adjuster till your at the boost you want and will spike right there and never go higher unless of course you turn it higher...I used to run mine at 22PSI when I had a K03 & GIAC software and a EVO frontmount.

Here's the MBC that I use www.joepmbc.com/xz.htm

Piggie form Audiworld recommended it...only bad thing is it comes with the wrong size fittings but is easy and cheap to fix with a trip to the hardware store for the correct size fittings.

Otherwise Piggie started making his own MBC with the correct size fittings (same valve as the MBC joe) I'll put you in touch with him if you like.

I will try and snap some pics later.