Ordered from VAST, couple of questions

**CheesmoS4** · 08-12-2008 02:47 PM

I just ordered the MBC that runs parallel with the stock n75 vavle. I looked on their website and saw the picture diagram, i was wondering whether those have done this mod can throw their two cents and give me any advice. To do- and not to do before i go jumping into this. Also where is the best setting for this MBC. Right now i am running APR 93 oct program, other mods include piggie pipes, neuspeed exhaust (getting rid of very soon),710n. I guess those mods would go hand and hand with MBC mod ( i have other mods). So please if you guys can give me some information to make this mod a success, it would be greatly appreciated.

After this mod i plan on doing AWE sidemount intercoolers, and meth injection along with electrical fan. I will be done till the ko3s blow.

So thanks in advance.

**exorcet** · 08-12-2008 02:55 PM

running and MBC in parallel is simply done as a safety net against overboost, or to lower boost. With N75 control, the MBC will only come into play in two situations:

1) you want to lower boost below what N75 is requesting (i.e. bad tank of gas, extremely hot day, lending your car to friend, etc).

2) set just above max PSI request (i.e. if your ECU is programmed with a 21 psi spike, set the MBC just over that.. if for any reason your N75 fails, etc, the MBC will prevent overboost).

it's straightforward. just hook up per diagram. just know that every 1/4 turn clockwise increases boost by approx. 1lb, and every 1/4 turn counter-clockwise decreases ~1lb boost.

**Rajan147** · 08-12-2008 04:08 PM

+1
parallel setup to clip boost spike
standalone to keep the boost at a constant pressure but once set at pressure, the rest is vented off.

A standalone can be used in parallel, hence the standalone boost controller from Vast is the way to go, or any other brand you feel is comparable, Forge UNOS, JHM etc etc. (I like the in car functionality of JHM but i would play around too much with it)

Personally, my research has led not to run a MBC in standalone with APR 93 software as the tune is not setup for this. I have read that vehicles have been running rough and inconsistent with a MBC and APR.

I personally have APR 93 myself and would not run an MBC in standalone on it. I would rather search out a GIAC chip or tune and then Boost away at my hearts content.

Parallel setup is basically using 2 tee fittings and hooking up the Manual Boost controller much like standalone.

**Blue AWD** · 08-12-2008 04:25 PM

As far as I know, you can not run a MBC in any form with APR software. APR has strong control of the N75 and throws the car into limp mode on anything over part throttle.

**BITRBO** · 08-12-2008 05:33 PM

^I've heard this too. Cheesmo, you might wanna get your money back or look for a GIAC ECU

**AB18** · 08-12-2008 07:15 PM

I have a Giac X A box if you need one...

**CheesmoS4** · 08-13-2008 02:25 PM

i spoke to the guys at vast and they said i shoudl have no proble running that setup. why would they tell me that?

**exorcet** · 08-13-2008 03:25 PM

Originally Posted by CheesmoS4

i spoke to the guys at vast and they said i shoudl have no proble running that setup. why would they tell me that?

you haven't told us what your goal is with the MBC. MBC will work perfectly well with APR if you are using it as a safety backup.

if you want to run an mbc in standalone (i.e. bypass n75 control) then that will not work too well with APR. but considering you didn't get a standalone MBC i'm assuming that's not what you want to do.

**Audi S4 Turbo** · 08-13-2008 06:30 PM

Tip. You need to cover the hole on the mbc. I used JB weld. This is only when running parallel with the N75 not standalone.

**CheesmoS4** · 08-13-2008 06:46 PM

Originally Posted by exorcet

you haven't told us what your goal is with the MBC. MBC will work perfectly well with APR if you are using it as a safety backup.

if you want to run an mbc in standalone (i.e. bypass n75 control) then that will not work too well with APR. but considering you didn't get a standalone MBC i'm assuming that's not what you want to do.

I just want to add some extra power without losing boost (more fluent boost). i am gonna buy awe side intercoolers with the meth injection . So i figure this would be a great addition to what i am gonna be adding

**exorcet** · 08-14-2008 10:17 AM

Originally Posted by CheesmoS4

I just want to add some extra power without losing boost (more fluent boost). i am gonna buy awe side intercoolers with the meth injection . So i figure this would be a great addition to what i am gonna be adding

well.. you're not going to add any power with an 'in parallel' MBC. it will work for capping potential spikes due to other failures or to turn boost lower than requested.

**CheesmoS4** · 08-15-2008 02:22 PM

Originally Posted by exorcet

well.. you're not going to add any power with an 'in parallel' MBC. it will work for capping potential spikes due to other failures or to turn boost lower than requested.

do you think i will hve a problem with running this with my apr chip?

**Rajan147** · 08-15-2008 02:30 PM

will you have a problem?

parallel-no, standalone-probably to yes

**exorcet** · 08-15-2008 03:37 PM

Originally Posted by Rajan147

will you have a problem?

parallel-no, standalone-probably to yes

yeah.. it will work fine in parallel (as VAST told you), but not in standalone and for two reasons:

1) APR doesn't like standalone MBC and might 'freak out' as others have mentioned
2) it's a parallel MBC (i.e. no bleed hole). you don't want to run that in standalone unless you want to kill your turbos. which might not be so bad if you replace them with K04's or better.