MBC and our MS3 ECU...

[tru-boost]

is your car still runnig 20psi and normal timing ?
on my car the cars ecu basically un-did any boost increases we did to it.
i also did not us the atp fuel cut device...... updates ??

 

[bast525]

Got the boost gauge and MBC. Boost gauge is installed, but running ECU controlled boost, won't get the MBC installed til maybe next week.

Boost definately spikes a LOT with stock boost control... I've seen it hit 20 psi a couple times. So I don't think the computer is 'recording' anything over 15.6 psi and keeping those records to use against you and void your warranty.

It shoots up quick, taps 19-20 psi, and drops right down to 16 psi.

I'll be installing the MBC and turning the boost up to where it holds 18psi after the spike, and see what happens

 

[BoostedSpd6]

just to get my say in i showed up at the dealership with all my mods and my dealership actually loved it.. the owner wanted to take it for a ride to see how much faster it was...and all the techs were around my car checking it out..no hassle's for me!!.. and i have a front mount, intake, custom exhaust and a few others... too bad every other dealership isnt like mine.. sentry west mazda of shrewsbury MA...

EDIT: till i showed up with the front mount.

 

[mghunt]

One of the benefits of an MBC used in conjunction with the factory controls is for the purpose of limiting boost, not raising it. In ideal conditions, raising the boost might raise power output. However, high temperatures might offset this. Also, you definitely don't want to force the boost to be higher when the boost is tapering off at higher RPMs. This is happening because the flow map of the turbo is starting to get outside of its efficiency range. My 1.8t Passat was notorious for this with it's little K03.

I had a Dawes MBC on the 1.8t to restrict the boost of my chipped ECU to 15psi. It didn't run rich like the MS3 does, so restricting the boost was necessary in the hot summers here in Phx. I limited the car to 12psi when it was >100F and then turned up the boost during the winter. The chipped ECUs for the 1.8t would raise the boost in the turbo's efficiency range, but still rely on the turbos flow to limit boost. So, the additional power was at low and mid rpm, and it tapered off seriously. Using an MBC to raise the boost worked really well, as long as you didn't push the boost at high rpm's too much. Not sure what this level is on the MS3.

Another thing to be careful of is that the boost doesn't build too faster than the fuel can be delivered. I'm assuming this isn't as big an issue with the MS3, but still something to consider.

 

[speedi3]

One of the benefits of an MBC used in conjunction with the factory controls is for the purpose of limiting boost, not raising it. In ideal conditions, raising the boost might raise power output. However, high temperatures might offset this. Also, you definitely don't want to force the boost to be higher when the boost is tapering off at higher RPMs. This is happening because the flow map of the turbo is starting to get outside of its efficiency range. My 1.8t Passat was notorious for this with it's little K03.

I had a Dawes MBC on the 1.8t to restrict the boost of my chipped ECU to 15psi. It didn't run rich like the MS3 does, so restricting the boost was necessary in the hot summers here in Phx. I limited the car to 12psi when it was >100F and then turned up the boost during the winter. The chipped ECUs for the 1.8t would raise the boost in the turbo's efficiency range, but still rely on the turbos flow to limit boost. So, the additional power was at low and mid rpm, and it tapered off seriously. Using an MBC to raise the boost worked really well, as long as you didn't push the boost at high rpm's too much. Not sure what this level is on the MS3.

Another thing to be careful of is that the boost doesn't build too faster than the fuel can be delivered. I'm assuming this isn't as big an issue with the MS3, but still something to consider.

I thought that you had to remove the "factory boost controler" to put on a MBC. the solenoid has to be removed and then hoses rerouted to put on a mbc? How would they work together if they are removed?

 

[laloosh]

simply put, no. A mbc will work on this car just like any other car. Mine is going in monday. IM not installing the fuel cut defender im just turning it up untill the car cuts fuel at 18psi and backing it down a little

 

[mghunt]

I thought that you had to remove the "factory boost controler" to put on a MBC. the solenoid has to be removed and then hoses rerouted to put on a mbc? How would they work together if they are removed?

nah, you don't have to remove the factory control to install an MBC. Talk to some VW guys. There are tons of 1.8t guys that had to keep the factory control on there and bleed off pressure before it was sent to the MAP sensor. One of the big issues on VW turbos was that the boost could build too quickly causing overboost issues and lean conditions because the fuel system couldn't keep up. They would keep the factory controls in place to control the rate of boost buildup, but use the MBC to control the amount of boost and to bleed pressure so the MAP doesn't see the extra pressure.

They were also used in conjunction with the computer control to limit the amount of boost and eliminate boost spikes. In the extreme heat, where I live, boost spikes and surging are the enemy. The MBC was a good "boost insurance policy" to cap what the car could demand from the turbo system. It essentially forced the wastegate open early. The timing of the motor was much happier and my car actually ran better when I eliminated boost spikes.

I don't see why an MBC couldn't be configured in the factory wastegate piping to raise the boost and allow the factory systems to control the rate that boost builds.

-Mark

 

[speedi3]

nah, you don't have to remove the factory control to install an MBC. Talk to some VW guys. There are tons of 1.8t guys that had to keep the factory control on there and bleed off pressure before it was sent to the MAP sensor. One of the big issues on VW turbos was that the boost could build too quickly causing overboost issues and lean conditions because the fuel system couldn't keep up. They would keep the factory controls in place to control the rate of boost buildup, but use the MBC to control the amount of boost and to bleed pressure so the MAP doesn't see the extra pressure.

They were also used in conjunction with the computer control to limit the amount of boost and eliminate boost spikes. In the extreme heat, where I live, boost spikes and surging are the enemy. The MBC was a good "boost insurance policy" to cap what the car could demand from the turbo system. It essentially forced the wastegate open early. The timing of the motor was much happier and my car actually ran better when I eliminated boost spikes.

I don't see why an MBC couldn't be configured in the factory wastegate piping to raise the boost and allow the factory systems to control the rate that boost builds.

-Mark

AWESOME! That's how i want to set it up.

 

[bast525]

simply put, no. A mbc will work on this car just like any other car. Mine is going in monday. IM not installing the fuel cut defender im just turning it up untill the car cuts fuel at 18psi and backing it down a little

That's what I was going to do. Should be fine at that boost.

 

[tru-boost]

simply put, no. A mbc will work on this car just like any other car. Mine is going in monday. IM not installing the fuel cut defender im just turning it up untill the car cuts fuel at 18psi and backing it down a little

WRONG !! thats what AMS did to my car. it lasted about a week. then the car felt super slow. the car returned itself to stock boost levels, and even pulled EXTR timing. if you up the boost at all, you need the fuel cut defender...that is the key. without it you are waisting your time .

 

[laloosh]

if I leave it at 17 18 psi and don't hit boost cut what's the point of the defender. how can the ecu sense this if I'm not hitting boost cut. I have a hard time believing the ecu can physically turn down boost if its raised a mere 2 psi. I'm still doing it and watching the boost gauge if it stay at 17 it works

 

[shucky]

Laloosh, nice times (13.6) my man. If you leave the factory boost control solenoid in line with a MBC the ECU can still adjust and compensate to return everything back to stock levels. The VW ECU's did the same thing. Even when chipped on a VW, guys would run a MBC in line with the factory N75 (boost control solenoid) which I did as well, to get just a little more boost and to hold onto boost just a little bit longer and the ECU would still reduce this extra amount over time. Not totally back to the values specified by the chip, but it would keep trying to bring boost down each time you turned up the boost using the mbc. Tru is correct in that you need the ATP piece to fool your ECU into thinking no changes were made when in fact you upped the boost with the MBC.

 

[knowledge007]

I had this very thing happen this week. Infact the car is still at the dealer. the code is p0234. It happens but no light came on a while back. The dealer fortunately for me has been very cool fixed what he could but couldn't clear that code. I get my car back on Wednesday but your tech is accurate. They did try the old "if you mod you void your warranty" but completed the work that they could w/o touching anythign aftermarket. I think its all based on the dealer that you work with.

What is the description of that code?

 

[tru-boost]

if I leave it at 17 18 psi and don't hit boost cut what's the point of the defender. how can the ecu sense this if I'm not hitting boost cut. I have a hard time believing the ecu can physically turn down boost if its raised a mere 2 psi. I'm still doing it and watching the boost gauge if it stay at 17 it works

thats what the MAP (mainfold air pressure ) sensor does...reads boost.
it will see the car consistantly hold more boost, and it will play tricks with the throttle plate to actually reduce the boost. and if it continues to see that is being over rided it will then just pull out a ton of timing. even though at 17-18psi you wont hit fuelt cut, you still need the defender. it will hide the fact that you have more boost, and the ECU will not adjust.
just sharing my own experience.... if you want to learn the hard way... go ahead. the worst part is if you dont re-dyno the car you wont know that you are 25 HP short of where you started.

 

[laloosh]

hmmm, i guess i gotta order this stupid atp thing....oh well so much for being stuck at 17 psi, more like 18 19 now lol, yes yes i know the range of turbo is at its max, this turbo is a pos, the quicker it dies the quicker i have a reason to upgrade(glare)

 

[speedi3]

p0234 engine over boost.

 

[speedi3]

thats what the MAP (mainfold air pressure ) sensor does...reads boost.
it will see the car consistantly hold more boost, and it will play tricks with the throttle plate to actually reduce the boost. and if it continues to see that is being over rided it will then just pull out a ton of timing. even though at 17-18psi you wont hit fuelt cut, you still need the defender. it will hide the fact that you have more boost, and the ECU will not adjust.
just sharing my own experience.... if you want to learn the hard way... go ahead. the worst part is if you dont re-dyno the car you wont know that you are 25 HP short of where you started.

ok so how do you get it back? if you have already hit that point how do you get the hp back that was removed (uhm)?

 

[tru-boost]

ok so how do you get it back? if you have already hit that point how do you get the hp back that was removed (uhm)?

you have to reset the ecu, and drive it without any added boost. the ecu will re-learn the stock maps.
the stock turbo is pretty much dead above 18psi. it is ok to run more in short bursts. you would not want to run 20psi on a autox car. street driving and 1/4 mile use 19-20psi will work. the life of the turbo will be reduced...but who cares !

 

[knowledge007]

you have to reset the ecu, and drive it without any added boost. the ecu will re-learn the stock maps.
the stock turbo is pretty much dead above 18psi. it is ok to run more in short bursts. you would not want to run 20psi on a autox car. street driving and 1/4 mile use 19-20psi will work. the life of the turbo will be reduced...but who cares !

This is a great one. (hitit2)

 

[mghunt]

Tru is correct in that you need the ATP piece to fool your ECU into thinking no changes were made when in fact you upped the boost with the MBC.

For those that are interested... ATP said that this piece is basically just a pressure regulator. It allows lower pressures to pass and peaks at the regulator set point. So, the MAP sensor ends up seeing the capped value and anything below. I just hope the fuel system can keep up with the extra boost. Given how rich the car runs, I don't think that's a huge issue. But keeping an eye on a/f ratios is a good idea if you turn up the boost a little.