fitting a manual boost controller 850 T5

[gotmeaT-5]

I have bought a manual boost controller about to fit it just need to know do I remove the TCV or fit the MBC inline between the TCV and MBC or as the instructions say just plug the MBC inline between the blue line going from the inlet manifold to the compressor

According to the instructions: "Find your wastegate actuator attached to the turbo, unless you are using an external wastegate. The wastegate actuator will have a vacuum line port that runs to a boost source. The boost source is usually either the turbo's compressor housing, the intercooler pipes, or the intake manifold. This vacuum line is where the manual boost controller will be installed. If there is a T fitting in the vacuum line between the boost source and the wastegate actuator, it will have a separate vacuum line that runs to the boost control solenoid. If you have the T fitting, remove the line that runs to the solenoid, but leave the solenoid plugged in."

[p fandango]

i always bypass the BCS (TCV to you). You will need to keep it plugged in to keep the ECU happy. There are 3 pipes going onto the BCS/TCV, one from the intake/pressure side of the turbo, one from the actuator (disappears behind the heat shield) & one going back to the air intake pipe just after the MAF sensor. The pipe from the intake side of the turbo goes to the MBC inlet side, the actuator goes to the outlet side of the MBC & the remaining pipe from the intake pipe needs blocking

[gotmeaT-5]

So lets see if I've got this right:

I "T" off both the intake and wastegate pipes, block the small pipe to the fresh air hose but leave the TCV electronic supply connected or remove the two hoses to the TCV and block the small one to the fresh air hose? to fit the MBC in a sort of piggy back

[p fandango]

pull all 3 hoses off the TCV, use the turbo & actuator ones for the MBC & block the return to fresh air hose. & yes leave the TCV plugged in then but with no pipes going to it

[z32twinturbo]

This makes for good reading on the subject.
http://webspace.webring.com/people/mo/ozbrick/engine-turbo-keithspage.html

Tony

[p fandango]

This makes for good reading on the subject.
http://webspace.webring.com/people/mo/ozbrick/engine-turbo-keithspage.html
a good read but they got bits wrong, running the MBC inline with the BCS still removes control from the ECU

[Dangerous Dave]

running the MBC inline with the BCS still removes control from the ECU
And doesn't control boost spikes as well.

[Flatout Phil]

So what is I to believe - cos I be all confusified!

[p fandango]

So what is I to believe - cos I be all confusified!
me :wink:

[JelT5]

me :wink:


oh oh ;)

[p fandango]

oh oh ;)
cheeky sod lol

[JelT5]

My work is done for the day now lol

[p fandango]

My work is done for the day now lol
i've done the easy bit (8hrs at Vodafone), now for the serious work of taking the p*ss out of you :hug: lol

[The Flying Moose]

So what are the benefits of bypassing the BCS rather than just putting the MBC between the BCS and wastegate actuator?

[JelT5]

i've done the easy bit (8hrs at Vodafone), now for the serious work of taking the p*ss out of you :hug: lol

not that difficult really is it? :D

[MWT5]

pull all 3 hoses off the TCV, use the turbo & actuator ones for the MBC & block the return to fresh air hose. & yes leave the TCV plugged in then but with no pipes going to it

can i use an mbc without having the bcs as the engine i sourced hasnt got one with it,or will i have to get one just to plug in for the ecu?

[p fandango]

can i use an mbc without having the bcs as the engine i sourced hasnt got one with it,or will i have to get one just to plug in for the ecu?
without one the ECU will throw a fault code & warning light, it will still run but not a good idea & who knows what the ECU has done with the engine settings then

[gotmeaT-5]

my 97 850 T-5's TCV/BCS has the smaller earlier round three pipe unit, I've had the bit out, I've ditched the ugly black box filter for a nice round cone filter [just because] I've found that the centre port is blocked on the TCV is this normal ? as it seems pointless having a pipe from the fresh air hose if it's not doing anything going to a blocked port

Will get a photo over the weekend to show what I'm on about.

[BruceT]

The port only opens when the ECU pulses the BCS/TCV to dump the air to the intake tract.

[gotmeaT-5]

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

[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