davidluko

Are MBCs used just to raise the boost higher than the wastegate spring is made for, or do they also keep the wastegate closed until your desired boost?

tony413

do not go that route its that simple just save $200-$300 and get an electronic one you will be happier

vladd

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tony413 &raquo;</TD></TR><TR><TD CLASS="quote">do not go that route its that simple just save $200-$300 and get an electronic one you will be happier </TD></TR></TABLE>

he's not asking which one is better, he's asking how a mbc works.

tony413

i understand that an sometimes its better not explain but give advice. but to answer his question. it works by bleeding off flow until you reach the amount that you want then it sends a signal(pressure) to open the wastegate and that allows only the PSI you want. its really simple but not smart once you boost over 8psi although i've seen them used on 23psi cars.... those cars are no longer functioning r.i.p. evo

vladd

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tony413 &raquo;</TD></TR><TR><TD CLASS="quote">i understand that an sometimes its better not explain but give advice. but to answer his question. it works by bleeding off flow until you reach the amount that you want then it sends a signal(pressure) to open the wastegate and that allows only the PSI you want. its really simple but not smart once you boost over 8psi although i've seen them used on 23psi cars.... those cars are no longer functioning r.i.p. evo </TD></TR></TABLE>

no, its not better. he'd ask for a recommendation if he wanted it. he just wants his question answered.

doesn't a mbc work by restricting the air flow through the vaccum line? from what i understand it works the same way as just getting a higher psi wg spring; the wg slowly opens more and more until the set boost is reached, not like a ebc, where the wg is kept completely closed until the set psi is reached, when the wg suddenly pops open. is that right or not?

tony413

a MBC basically works by using boost creep as a means of control it can be used on the compressor side or wg.

"MBC's work on the principal of manipulating the actuator pressure signal from the compressor before it reaches the wastegate actuator. either by blocking flow to the actuator or bleeding off flow."

vladd

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tony413 &raquo;</TD></TR><TR><TD CLASS="quote">a MBC basically works by using boost creep as a means of control it can be used on the compressor side or wg.

"MBC's work on the principal of manipulating the actuator pressure signal from the compressor before it reaches the wastegate actuator. either by blocking flow to the actuator or bleeding off flow." </TD></TR></TABLE>

ok, i know that. here's the real question: with a mbc does the wg stay completely closed until a certain psi at which it pops open, or does the wg still slowly open up as the boost builds?

tony413

it slowly opens as boost builds which is "boost creep" this can cause lag

vladd

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tony413 &raquo;</TD></TR><TR><TD CLASS="quote">it slowly opens as boost builds which is "boost creep" this can cause lag </TD></TR></TABLE>

ok, that's exactly what i thought. i don't see how a mbc would completely block the boost pressure from reaching the wg like a ebc would.

tony413

it could but it would need to use about 2 or 3 MBC's set on different PSI's turbo xs sales them they work but i trust the EBC more

vladd

that doesn't make any sense at all. how would adding more mbc's make them work like a ebc??

tony413

it makes sence its like staged N02 set-ups one for low bost and then one for high boost. because they can only hold about 10psi at a time by adding one more or two more you are adding more force to keep the wg closed untill you hit the psi you want then the wg opens

inspyral

There are two basic types of manual boost controllers - bleeder type and restrictor type.

The bleeder type installs inline with the wastegate's boost signal vacuum line and bleeds off pressure in the line to fool the wastegate into thinking it hasn't reached it's opening pressure yet. Boost is adjusted by varying the amount of pressure being bled off by the boost controller.

Restrictor type manual boost controllers also install inline with the boost signal vacuum line and use some sort of device to restrict the the flow in the line to fool the wastegate into thinking it hasn't reached its opening pressure. Typical variants of the restrictor type are the ball and spring type and the ball valve type. the ball and spring type has a small ball bearing with a spring pushing it against the inside of the housing of the boost controller. The ball blocks the passage of incoming air from the intake manifold in order to keep the wastegate closed. Adjusting boost with this type of controller is done by adjusting the tension on the spring. Ball valve type controllers use a partially closed ball valve to restrict the boost signal to the wastegate. Opening or closing the valve lowers/raises boost.

There are probably other types of manual boost controllers out there, but these are the main types that I know of.

vladd

ok, i know that. here's the question:

with a mbc, does the wg still slowly creep open as the boost builds, like it would if there was no mbc and the wg was ran directly off a vaccum source, or does the wg stay completely closed until the set psi, when it pops open?

b_ron007

it doesn't creep up with a normal ball and spring type mbc. when in line, the mbc holds back the pressure the wastegate would see untill the desired boost level is reached that the mbc is set to, then it pops open then the pressure finally reaches the wastegate, then the waste gate can open. soo to answer ur question....no. without the mbc in line the wastegate starts to cracks open, or should i say creep open untill the desired boost.

with a mbc this how you get better spool times, the wastegate staying closed untill the mbc says it can open at the set psi. correct me if i'm wrong.

almostboostedgsr

are you kidding me. Ive seen a 9sec del sol in honda tuning with a mbc. It had a quad turbo xs. They retail at 300 bucks.

riceball777

most of really really fast high power cars i have seen run the turbo xs dual or quad mbc

i myself run the turbo xs highperformance mbc and it works great

i have also have ebc fail on me but i never had problems with mbc.
i happen to like mbc better because they are so simple and work great

tony413

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by almostboostedgsr &raquo;</TD></TR><TR><TD CLASS="quote">are you kidding me. Ive seen a 9sec del sol in honda tuning with a mbc. It had a quad turbo xs. They retail at 300 bucks.

</TD></TR></TABLE>

notice like i posted in the beginning thats not a single MBC set-up when you add more to the mix you can hold more pressure back

davidluko

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b_ron007 &raquo;</TD></TR><TR><TD CLASS="quote">it doesn't creep up with a normal ball and spring type mbc. when in line, the mbc holds back the pressure the wastegate would see untill the desired boost level is reached that the mbc is set to, then it pops open then the pressure finally reaches the wastegate, then the waste gate can open. soo to answer ur question....no. without the mbc in line the wastegate starts to cracks open, or should i say creep open untill the desired boost.

with a mbc this how you get better spool times, the wastegate staying closed untill the mbc says it can open at the set psi. correct me if i'm wrong.</TD></TR></TABLE>

So basically you're just guessing, or do you know for sure? I want to hear from someone who uses one and actually knows facts.

tony413

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Hatch_R &raquo;</TD></TR><TR><TD CLASS="quote">

So basically you're just guessing, or do you know for sure? I want to hear from someone who uses one and actually knows facts.</TD></TR></TABLE>

all single MBC's have boost creep over 15psi and some spike like hell at around 12psi or more

davidluko

So say on 8 lbs of boost, a MBC should keep the wastegate closed until it reaches that 8 lbs, and then it'll pop open?

b_ron007

correct!

that is how it works.