Sorry for being a newbie but what exactly does it do? I believe its for turning your boost up or down? What is the stock boost and how much can you increase it without damaging your engine? If you can lower your boost then its benefit is for normal driving so that you can save more gas? Can someone shine some light on this, Thanks

 

It controls the boost of the turbo, i.e. up or down.

 

stock, i believe, is 19psi. i'm running at 21psi and all i've got is the MBC (with guage).

if you get an MBC, you SHOULD REALLY get a boost guage. otherwise you have no idea how much you're pushing. i don't know about electronic one's - though i'm assuming you'd still want a guage just so you could easily keep an eye on the boost at all times.

 

actually he brought up an interesting question:

would lowering the boost increase fuel effeciency??

 

1. If you don't know what a boost controller, you SHOULD NOT, repeat, SHOULD NOT be playing with the boost level. That's a recipe for disaster.

2. Boost is a function of throttle position and engine load. The Evo can run up to 19 psi.

3. If you want more boost, you'll need more fuel. If you want a lot more boost, you'll need major engine work. You can't just crank the dial up without compensating. Engine control is a delicate balance, and you can't just mess with it.

4. The entire point of the turbo is for the smaller motor to perform like a big motor without sacrificing fuel economy. If you want fuel economy, don't rev above 3k RPM and use a light throttle. Avoid unnecessary changes in speed. Your right foot is your boost controller.

 

I have been researching stuff for awhile....Can you run a constant 19.5-20psi to redline with no other engine mods (except a greddy type s) without running into an sort of danger? I know the engine runs very rich, but basically I'm asking if it would be safe. I want to get a MBC until I can get the Vishnu Stage 1+

 

my stock evo was hitting 19-20 all the time no problem (during the winter-lately its been more like 17-19 with summer).

now that i did my exhaust im hitting 20-21.

but i got a boost controller and dynoflash coming to make it constant.

 

To correct some of the misinformation given thus far:

1. You can turn the boost up without any supplemental fueling. The MAF (Mass Airflow Sensor) will read more air coming in (i.e. more boost) and compensate with more fuel. Once you either a. exceed the limit of the MAF or b. exceed the limit of the fuel injectors then you will need to upgrade. The only way to know that you are exceeding those is to monitor the Air/Fuel ratio and your exhaust gas temps.

2. A boost controller cannot, I repeat, cannot turn down the boost. Boost is controlled by the actuator and a boost controller intercepts the boost signal going to the actuator then once the target boost is reached the boost controller sends the signal to the actuator and allows it to do it's job. This process is repeated so you can always hit your target boost level. The more acurate the boost controller the steadier your boost levels will be.

3. Please do research before turning up your boost!!!!

 

To explain why you cannot turn down the boost is because if the boost controller is intercepting the signal before it gets to the actuator for a target boost that is lower then stock once it sends that signal to the actuator the actuator still won't open because it is set for the stock boost level. Hence the lower target boost level will not be achieved.

 

Actually, if you install an MBC and bypass the factory boost control system, you CAN lower the max boost below stock. If you turn the MBC all the way down, the wastegate will open at 10 PSI...

 

Is the stock actuator set for 10psi?

 

So what is a good MBC...i intend only using is temporarily until I get the Exede...so i don't want a super expensive one

 

Moving to FAQ's Forum.

 

Correct...the stock wastegate opens at 10 PSI...the MBC merely creates a differential above the stock wastegate level of 10 PSI, allowing you to control the boost. It's simple and works very well. My Hallman Pro MBC holds 20.5 PSI solid as a rock!

 

The Hallman Pro is the best MBC, IMHO...