MBC verses VEMS EBC

[multiplex]

i recently configured the wheel speed sensor, and have gear indicator working well 

i decided to go back and play with vems EBC, using the gear table and DC settings.  I figured i would later apply PID to further dial it in.

At this point i'm still working out the proper DC settings to achieve similar results to my MBC.

personally I love the simplicity of an MBC, and later decided to switch back.. its like driving a whole different car.  Which got me thinking, can the EBC really do what i want?

take this hypothetical situation.

3rd gear, i have boost valve shut until 3500 rpm.  From there up, i have a DC value.

in theory this allows me to quickly build boost, by spooling the turbo with the valve closed much like the MBC would

now say i decide to cruise upwards of 4000rpm, and then apply full throttle.  DC value will be applied, and boost will not build as quickly.  However with the MBC, it would still remain shut until the check valve opens at my desired setting - RPM independent.

What i'm wondering is.. does vems need another set point per gear for 'boost valve off until xxx Kpa'?

or maybe i'm misunderstanding the situation

[MWfire]

you can use boost relative table for that.

[multiplex]

awesome. i never ventured into the secondary settings.

i see where you can set the 'off below' point, but what does secondary mean?  looks like its asking for output details, so can this be set to the same a primary output?

[MWfire]

no, different output.
If you have wastegate with two chambers, then you can with 2 solenoids control each chamber separability.

[mattias]

MWfire; you mean that instead of getting the solenoid at the bottom to stay closed (100% duty) until a certain pressure has been met and then start using DC, you use the 2nd table to control a different solenoid that lets boost pressure in at the top?

Using the whole function sounds overkill, that 2nd solenoid could just as easily be controlled by a misc output function, to let atmospheric pressure into the top section when you are not building boost. I would have it activated between 110 kPa and up to a 20-30 kPa below the boost level run using the DC controlled valve at the bottom.

[Jamo]

I use a 4 port solenoid instead of two independent ones to both chambers, so far seems to work

[multiplex]

guess i'm a little confused on how to use two valves..

can someone explain their setup and configuration a little bit?

I guess my request would still stand to have the 'off below' setpoint for each gear.

[mattias]

I use a 4 port solenoid instead of two independent ones to both chambers, so far seems to work

Without further information on this I have no idea but to guess how it works.

[Jamo]

I use a 4 port solenoid instead of two independent ones to both chambers, so far seems to work

Without further information on this I have no idea but to guess how it works.

O.K i've linked two pics to show how it works, I believe AVP is using the same setup as well, it's something we use on s2forum

[gunni]

My advice is get the DCref dialled in and then tune the PID settings and it will do exactly what you want.
Have a 0-5v input to the ecu from the cabin and you´ll have in-cabin boost control via a knob.

[multiplex]

i agree, and will continue to dial in the DC map.

however i am curious about dialing it in further..

seems it will never be as good as MBC, and MBC is so simple under all circumstance, i keep going back 

[GintsK]

MBC is oldskool 
I can't imagine where it is better. My customers are very happy with TPS dependent boost. It is possible to drive on ice and even drag-race with same settings...
Even with open-loop you can keep constant torque for significant rpm range. With MBC usually it is not possible...

4-port valve is usable when wide boost level range is necessity. i.e 0.6bar for first gear, and 2.8bar for higher gears.
But two independent valves could be even easier to tune in such case.

Gints