I've used a few different types of manual boost controllers (ball/spring type). They all work the same... they hold back pressure to the wastegate (thus keeping the wastegate closed) so the turbo is getting full exhaust flow to the turbine (none bypassed through the wastegate) which allows it to spoolup as fast as it can. Once the MBC reaches it's set pressure point... the ball overcomes spring pressure (inside MBC) and lifts off it's seat and allows pressure to pass and head towards the wastegate. As the pressure builds at the wastegate, it overcomes it's own internal diaphram/spring pressure(between 4-7 psi usually required to overcome this internal spring pressure) and opens the wastegate built into the turbine housing to allow exhaust to bypass the turbine and go directly out the exhaust. This stops the turbo from spooling/boosting higher. Were you asking how the MBC worked?? :lol: :lol:
Anyway... the main problem people complain about with an MBC is part-throttle full(or high) boost. It is easy to acheive really high boost without being at Wide-Open Throttle (WOT). *Most* turbo ECUs are not programed to run high boost at part throttle... since they're often designed to read the O2 sensor (closed-loop) during non-WOT to give best fuel economy, etc. So it is possible to boost higher at part-throttle than the ECU is programmed to supply fuel for and that leads to a lean condition which if severe enough can lead to detonation and engine damage. At WOT... nearly all turbo ECUs are designed to ignore the O2 sensor (open loop) and dump a preset amount of fuel (preset from various cross-linked tables in the ECU code - boost/rpm/throttle position/intake temps/etc) which tends to be more than needed (on the rich side) for safety.
Since an MBC doesn't know weither your at WOT or not... it can't prevent it. Many EBCs are sophisicated enough to work around this issue... some read TPS inputs as well as boost inputs.
So what was your original question again?? :lol: :lol: (I sidetrack easily)
Oh yeah, will using one (EBC/MBC) wear out your engine faster?... If your setting your boost levels above the normal factory levels... then yes... your spinning your turbo faster for higher boost and your pumping more power through your engine... than it would otherwise stock. The question is... how much faster? That can't be answered... there are way too many other variables that play into engine wear. Proper servicing... proper fuel grades... how often you change your oil... conventional oil or synthetic... mostly highway or stop-and-go driving... extremely harsh/dusty/sandy driving conditions... and many more.
I would say... if your only boosting a few psi above stock or increasing your hp/tq mildly... that you're not going to noticably wear-out your engine faster. Proper monitoring(guages)/servicing/"taking care of it" will keep it just fine. Now if you take a 200 hp engine and generate 400 hp through it... yeah... it's gonna go much sooner than a stock one. And all stock engines (especially turbo engines) have performance buffers built in... ie. they're not operating on the ragged edge of self-destruction... so nudging performance level a tad higher into this buffer won't hurt a thing.
Man, am I long winded! :lol: :lol: Just my $.02
