Help with vac plumbing bd5/bg5 ej20h 2nd gen twin turbo legacy

[tankbot34]

Hi guys,

I\'ve taken some pics show my plumbing for boost gauge and mbc in cabin turbosmart controller using the apexi avc r diagram. I know I know... I shud get an ebc a true apexi or zerosports seq controller but I like fiddling and it\'s my own stupid fault if down the road I stuff my engine up lmao.

my question is has anyone done a mbc on a twin turbo 2nd gen ej20h and can you guys check ova my plumbing plus give me advice on whether its near the mark or constructive criticism as to why this is stupid etc. totally open to your guys expertise.

k off to right engine bay not pictured near battery hose 10 and 23 capped cutting off boost solenoid in fender.

following apexi avc r diagram for ej20h tt

1) t\'d the wastegates together

2)taken from drivers side above secondary turbo holding 8 removed and capped on bbod (as per apexi\'s instructions) and my hose from the t to secondary wastegate

3)passenger side primary turbo t piece(turbosmart) correct wat arrow pointing to hose for wastegate t and other side connected to primary source port then controller connected to tpiece and vent wif bit of hose not just nozzle

4)my boost gauge tapped into line 11 near bbod

from my bbod I have the 0.8mm restrictor pill in line 1 , 2inches in to reduce lag vod etc.

now.. aside from this there was a thread in another forum which a user called telekamus told someone to block off hose 2 on bbod both ends the bbod and the end of the hose taken off bbod. I tried this last nite with the old setup which was the same except I hadn\'t t\'d wastegates together and had the original line 8 hose plugged back between the bbod and secondary wastegate. I noticed a massive boost response almost immediately like overtaking a car in town it just whipped round it. however here is what telekamus thinks happens by blocking off hose 2 port(bbod end & hose end)

"Hose 10 is the bleed off from the subaru 2 port boost controller to the intake.If hose 23 is disconnected and blocked off their is nothing going through hose 10.

0.5 bar is the approx wastegate actuator spring pressure.The boost controller should allow you to restrict the amount of boost the actuator sees hence raise boost.If the boost controller is totally shut you would be free boosting.

In addition Hose No:2 going to the solenoid box from the boost port under the IC.Disconnect the hose from the solenoid box. Block the hose and cap the solenoid box port.This will stop any boost lost to prespool from the primary turbo." and elsewhere "Block and cap the hose No 2 ports.This will disengage the prespool boost solenoid."

here is the full thread http://sl-i.net/FORUM/viewtopic.php?f=59&t=27609

its interesting as an addition to rossubs thread http://www.clubsub.org.nz/forum/index.php/topic,41358.0.html

k thoughts guys especially on 2nd gen but im sure it wud also apply to 3rd gen legacys.

EDIT: my real q is is there anything you guys can see that is adverse to the system by capping hose 2 off disabling the prespool solenoid from operating? havn\'t tried blocking off on this configuration yet.

cheers

[Rosssub]

Telemekas.

 Marky said:

Early RS does not use both wastegates, the second got deleted for that reason in later revisions

Can you hear it change over? Might be as simple as the secondary BOV being stuck open, intercooler valve staying shut or exhaust valve not opening

Or the turbos dead

[tankbot34]

thanks rossub looks like even if wiring is right for this engine rev. (apexi) I myte have to refurbish the bbod and start from there its just that I cant feel the same boost push wen secondary shud be running which is kinda making me sus. guess I cud start there then work way to those valves after cleaning bbod?

[Rosssub]

 tankbot34 said:

thanks rossub looks like even if wiring is right for this engine rev. (apexi) I myte have to refurbish the bbod and start from there its just that I cant feel the same boost push wen secondary shud be running which is kinda making me sus. guess I cud start there then work way to those valves after cleaning bbod?

1-Fit your MBC to the Primary Waste Gate.

2-Leave Secondary Waste Gate connected as OEM. As Marky said, it does nothing anyway.

3-Open hose 2 to your BBOD. This is the Boost Pressure Feed, to Open your Exhaust Control Valve. Your Secondary is getting No/Minimal Exhaust Flow.

Is your Check Engine Light currently on? Or flashing when you Boost?

[tankbot34]

hi ross nope no check engine light coming on wen boosting or flashing error code when I had it configured that way before? does this indicate it cud be my exhaust control valve starving my secondary of boost?

EDIT: so by blocking hose 2 both ends will that give my secondary maximum exhaust flow?? actually on my exhaust control valve at the top where the two hoses go in there\'s a vac hose plastic filter that the vac hose goes into. someones mentioned line 1 2 and 3 can often clog up wif grit or oil wonder if the filters clogged not letting the ecv do its job correctly?

[Rosssub]

Your Blocked Hose #2 is Starving the Secondary. Open it so the ECV can open.

Put everything back to Factory using the Vac Diagram. Then we can work through test procedures to find your Fault.

[tankbot34]

rossub. sorry I\'ve been really busy with working away onsite for weeks now but I seem to have boost now in secondary. I followed thru you bbod thread and then cleaned out my bbod solenoids still connected and activated while cleaning in green test mode. quite a bit of gunk was in there overall hoses etc especially 1,2 and 3. anyways after putting back and then reconnecting hose 2 I get the vod then the secondary kicking in now.

thanks so much for your help and expertise in the matter also to len as well.

thanks guys think I\'ve rectified my issue now.

cheers

ryan

[Rosssub]

 tankbot34 said:

rossub. sorry I\'ve been really busy with working away onsite for weeks now but I seem to have boost now in secondary. I followed thru you bbod thread and then cleaned out my bbod solenoids still connected and activated while cleaning in green test mode. quite a bit of gunk was in there overall hoses etc especially 1,2 and 3. anyways after putting back and then reconnecting hose 2 I get the vod then the secondary kicking in now.

thanks so much for your help and expertise in the matter also to len as well.

thanks guys think I\'ve rectified my issue now.

cheers

ryan

Awesome news, thanks for the update. Amazing the trouble some \'Crud\' can create.

[tankbot34]

thanks ross ;D i do have another question for you though. after following the refurb solenoid box article you were involved in from the picture of the open solenoid box i have a map feed solenoid. now i connected the green and black to cycle them all and spray carb cleaner through but on the map feed one it wasnt makeing the popping sound like switching. i was getting good boost but sometimes if too heavy on the accelerator itd boost up then dramatically drop to like 0.3 from 1bar then if i took foot off accelerator pedal and immediately applied again itd hit 1bar then hold? is that normal behaviour? like when i floor gas and it reaches target boost shud it hold rock solid even when changing over gears because my car doesn\'t. just wondering. cheers

[Rosssub]

 tankbot34 said:

thanks ross ;D i do have another question for you though. after following the refurb solenoid box article you were involved in from the picture of the open solenoid box i have a map feed solenoid. now i connected the green and black to cycle them all and spray carb cleaner through but on the map feed one it wasnt makeing the popping sound like switching. i was getting good boost but sometimes if too heavy on the accelerator itd boost up then dramatically drop to like 0.3 from 1bar then if i took foot off accelerator pedal and immediately applied again itd hit 1bar then hold? is that normal behaviour? like when i floor gas and it reaches target boost shud it hold rock solid even when changing over gears because my car doesn\'t. just wondering. cheers

The MAP Sensor is just a pressure sensor, so wont switch like a Vac Solenoid.

You might need to clean out your Primary Boost Solenoid, inside the front Passenger guard. This controls your Overall Boost Levels:

Remove F/L Wheel and plastic under guard. Then clean the Primary Boost Solenoid in Diagnostic/Check mode again.

[tankbot34]

awesome mate that\'l be the next step thanks rossub ;D

[Rosssub]

 tankbot34 said:

awesome mate that\'l be the next step thanks rossub ;D

No worries, good luck. ;D

[tankbot34]

hi ross thats running way better holding boost now musta been dirty. one last question for this thread. the ecv valve with the positive and negative ports on it can i spray carb cleaner into those ports if anything inside like carbon or grit etc would that loosen it and make it run better? or wud i be messing with its internal diaphram? also wud it help to spray carb clean into both wastegate actuators actually inside the nozzles?

cheers

[Rosssub]

 tankbot34 said:

hi ross thats running way better holding boost now musta been dirty. one last question for this thread. the ecv valve with the positive and negative ports on it can i spray carb cleaner into those ports if anything inside like carbon or grit etc would that loosen it and make it run better? or wud i be messing with its internal diaphram? also wud it help to spray carb clean into both wastegate actuators actually inside the nozzles?

cheers

Nice.

No don\'t spray Carb cleaner into any of the Actuators, (ECV or Waste Gate). It\'s just a rubber diaphragm reacting with Vac/Boost. Unless you can take them off to drain them out completely.

They would probably do better with a squirt of Silicone spray but I\'ve never had issues the Actuators. Only ever a problem if they wont hold pressure/vac, due to a hole in the diaphragm.