fitting a manual boost controller 850 T5

[p fandango]

Going back to the MBC: What prevents the ECU from sending the fuel out signal from leaving the electronic connector on but diverting the compressor and wastegate pipes to my MBC? Or is my understanding floored on on the TCV/BCS works ?

[My understanding is as follows correct as necessary please: Compressor builds the boost to the desired level, ECU registers this set boost closes the compressor port opening the wastegate port allowing the pressure to act on the wastegate and not as a vacuum keeping the wastegate closed but diverting to the central port going to the fresh air hose]

What is a good baseline figure to start with ? @70mph I'm registering 12-15psi

tbh i'm not quite sure what you mean. But i can clear one part up for you, the ECU doesn't measure boost in any way on 850's. The ECU has a set pattern to open & close the BCS at different rates depending on rpm, load, throttle position etc to raise the boost levels

[gotmeaT-5]

As my T-5 has been remapped the patterns will have been changed from stock. What I mean when I first drove the car home on the motorway once I gave the pedal a boot the boost needle shot full swing, the car kicked till the boost dropped supposedly this was the fuel cut out operating as the BCS pipes were shot so once I fit the MBC what prevents the car from operating the fuel cut out once the boost rises without the pipes being connected on the BCS? Hope this clears the question up.

[BruceT]

Because the MAF is monitoring the amount of air being sucked in, more boost = more air being sucked in.

[p fandango]

As my T-5 has been remapped the patterns will have been changed from stock. What I mean when I first drove the car home on the motorway once I gave the pedal a boot the boost needle shot full swing, the car kicked till the boost dropped supposedly this was the fuel cut out operating as the BCS pipes were shot so once I fit the MBC what prevents the car from operating the fuel cut out once the boost rises without the pipes being connected on the BCS? Hope this clears the question up.

if you've had the car remapped then the MAF limit/fuel cut will be altered/removed anyway now. But as it says it cuts the fuel not the boost.

Please be careful running a remap along with a MBC because as said the MAF limit/fuel cut will be raised/removed so go to mad with the boost level & you could be replacing rods

[gotmeaT-5]

Any suggestions on a max boost level ? I need my remap checked, I don't think it was completed correctly if at all.

[p fandango]

Any suggestions on a max boost level ? I need my remap checked, I don't think it was completed correctly if at all.

max level for a MBC with a remap really does depend on how much the fuelling has been increased & if the injectors can cope etc. I know on a stock map 13psi is considered to be the safe limit