View Full Version : installed mbc

09-08-2005, 07:28 PM
i just installed a hallmans boost controller in place of the n75h valve. i have a k04 with upsolute tuning that would spike at 24psi but would put me in limp mode so i wanted to tune it down. after installin it the boost felt so much more crisp and it would hold so much strong to redline. if u have tuning doen to ur car id recommend using a quality mbc instead but make the boost just a tad bit under what it usually spikes at. i ended up setting it to hit 18-19 and it feels so much harder than when it be at 21-24 psi.

09-08-2005, 07:32 PM
Ugh, you will be sick of it in a week. Part throttle sucks so bad with a MBC alone.

Instead, you should have ran the MBC in parallel with the N75H, to just cut down the spikes. That way, you won't hit 24psi, you can tune it down to like 20psi and not hit limp, AND keep your car driving like stock.

09-08-2005, 07:36 PM
I spent quite a bit of time figuring out exactly how our turbos are controlled. It makes sense why an MBC would work just fine over the N75 valve control. Although I have yet to do any VAG logs of the N75 to see exactly what it's doing and when. Do you get any surging if you do a low rpm (~2.5k) in say 3rd gear?

Does anyone else agree with this? I thought MBC's were no good for our cars.

09-08-2005, 07:38 PM
BranCKY3: You beat my post. But that's what I thought.

09-08-2005, 10:43 PM
do u have a diagram to run in parallel. seriosly the car feels so much better. might i add i have an 01 and there is a diff in the lower years bc this is the only year of this type engine. unless uve experienced this with an 01 im guessin that the sircumstances r diff

09-08-2005, 10:49 PM
I have an 01. It was pretty rough when I had mine installed. Not as bad as with K03, but still, not the best. It was really nice at WOT, but part throttle I just was not a fan of.


09-09-2005, 08:41 AM
so why would havin the n75 valve in there make it better at part throttle if the mbc isnt lettin the pressure past until it hits the desired boost settin its at

09-09-2005, 09:03 AM
i'm assuming the above issues are applicable only to 01 models?

09-09-2005, 09:14 AM
Try this. Drive your car, give it part throttle and try to make the boost stay at say.... 7psi. Not gonna happen with a MBC. It's impossible to make it stay at one level at part throttle. It's either at 0 or on its way to 18psi.

With the N75 in there, it will drive just like stock. The pressure will reach the N75 like it normally would, it will drive like it normally would. However, once the pressure that you have the MBC set at is reached, all the pressure will go thru the MBC and not reach the N75. This will only be at WOT, so you have the drivability of an N75.

No this isn't only applicable to 2001's. It should be the same for all 1.8t's with K03/K04s.

09-09-2005, 09:22 AM
Originally posted by alen
i'm assuming the above issues are applicable only to 01 models?

The issues are for the dbw cars since they are the only ones that into limp because of running over 21psi unless the chip tuner has turned off the throttle cut safety within the chip code.

Running them together allows the mbc to cut the big boost spike while the N75 controls the boost curve as the rpms get higher.

09-09-2005, 01:40 PM
um deff dont agree bc in my car i can hold that boost at part throttle i know this bc i had to drive my grandpa around today and if he knew i had that done to my car hed kill me. it holds the boost so much better than the n75 did in my car. it also doesnt fall off as fast but it does settle down after hitting max boost. im using a hallman pro series

09-09-2005, 01:51 PM
Do you have a boost gauge to even tell if you are holding the boost? Because what BranCKY3 and Mike-2ptzero are saying seems to be the best solution to the cut out problem we were all having.

09-09-2005, 05:01 PM
ya ive got a boost guage. i just did it how they showed me and as soon as the mbc hits the desired setting i have set then the boost completely falls off then re spikes again. i know everyones cars are diff and react to the same things diff in some cases. like the biggest example is the n75 valves. ur car may like it or it may not. im just showin what i am experiencing

09-09-2005, 10:53 PM
So you're saying it drives just like stock... with only the MBC in there?

Post a link to the MBC you bought, I want to see what it looks like.

09-10-2005, 08:55 AM
Originally posted by BranCKY3
So you're saying it drives just like stock... with only the MBC in there?

Post a link to the MBC you bought, I want to see what it looks like.

I ran a ebc with my K04 to break in my motor, had no surge issues at all during part throttle. I ran it with the T28 and run it now with my GT235R and still have never had any surge issues at part throttle.

09-10-2005, 09:07 AM
part throttle on my $15 mbc is excellent

09-10-2005, 03:27 PM
i don't get any surges and i can hold @ 7 psi if i
want and i even have old atp sw i have the hallman $35 mbc.