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Inside the BBOD


Rosssub
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This is my BBOD (big box of doom). I have a MAP Sensor and a Map Sensor Control Solenoid (atmospheric pressure changeover solenoid). Earlier and Later models have neither in the BBOD:

BBOD_Tests_002.jpg

View From the Bottom:

BBOD_Tests_006.jpg

Loom Plugs:

BBOD_Tests_009.jpg

Exhaust Gas Control Valve Duty Solenoid removed, Map Sensor removed, Map Sensor Control Solenoid removed:

BBOD_Tests_011.jpg

I\'ve wired 2 LED lights, one to the ECV Duty Solenoid to see exactly when it is bleeding (duty cycle). The other LED is wired into the Map Sensor Control Solenoid so I can monitor when the Map Sensor is Cut Off:

BBOD_Tests_015.jpg

Then installed the new light box on the Dash for monitoring:

BBOD_Tests_018.jpg

Now when VOD hits and During Full TT Mode I can see what's happening. After monitoring these 2, I'll connect the lights to two other Solenoids. Eventually working out exactly when everything switches During VOD.

Edited by Rosssub
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I\'ve also installed my spare Apexi Mechanical Boost/Vac Gauge into BBOD Hose #1, this controls the IACV (Intake Air Control Valve). Now I can also see if the IACV gets pulses to open slowly, or completely releases its Vac and opens fast. Also at which stage of VOD it opens:

IACV_Vac_Test_001.jpg

IACV_Vac_Test_003.jpg

This is the IACV or Intake Air Control Valve, it\'s between the Secondary Turbo and the TMIC:

IACV_Valve_001.jpg

This Valve gets constant Vac during single turbo mode to hold it shut. It\'s spring loaded to open when Vac releases. After the Secondary Turbo is spooled.

I\'m holding the IAC Valve (butterfly) half open:

IACV_Valve_002.jpg

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Well, very interesting so far.

The IACV gets vac at engine start up. Then opens completely (releases vac) at initial VOD, it opens as I start to lose Primary Boost. It stays completely open for Pre-spool, Full TT mode then only closes when back into Single Turbo Mode.

The ECV Duty Solenoid, runs a constant duty cycle (pulses) when in Primary/Single Boost (positive manifold pressure). It also pulses (bleeds) during Initial Primary Mode Deceleration. But when VOD hits, during VOD and in Full TT Mode it does nothing.

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often wondered how the system actually lost boost pre vod

so for that to happen then the boost is blowing backwards out the icv and out the 2ndary relief valve ?

not the way i had im my mind

wouldnt you want the icv to stay shut untill the 2ndary is is making boost/spun up to a rpm it "could" make boost then shut the relief valve then open the icv ?

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I\'ve now connected my VAC Gauge into hose #8 this hose controls the Secondary Relief Valve.

Relief_Valve_Vac_Test_001.jpg

The secondary Relief Valve gets Vac to open and then gets Boost pressure to hold shut, it\'s between the Secondary Turbo Outlet and the Main Intake Pipe:

Relief_Valve_Vac_Test_002.jpg

This is what\'s inside the Secondary Relief Valve ;D

Relief_Valve_Vac_Test_003.jpg

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 lachlan']

often wondered how the system actually lost boost pre vod

so for that to happen then the boost is blowing backwards out the icv and out the 2ndary relief valve ?

not the way i had im my mind

wouldnt you want the icv to stay shut untill the 2ndary is is making boost/spun up to a rpm it "could" make boost then shut the relief valve then open the icv ?

Exactly what I thought?

[quote name='tydon said:

wow crazy lol haha ur nuts man the twin turbo setups drive me up the wall would rather do away with it alltogether haha

I figure better to do some proper research/testing. Rather than just throwing Pills around crossing my fingers ;D

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 Rosssub said:

Well, very interesting so far.

The IACV gets vac at engine start up. Then opens completely (releases vac) at initial VOD, it opens as I start to lose Primary Boost. It stays completely open for Pre-spool, Full TT mode then only closes when back into Single Turbo Mode.

The ECV Duty Solenoid, runs a constant duty cycle (pulses) when in Primary/Single Boost (positive manifold pressure). It also pulses (bleeds) during Initial Primary Mode Deceleration. But when VOD hits, during VOD and in Full TT Mode it does nothing.

The Secondary Relief Valve does nothing at start up or during Primary/Single Mode. But, just prior to VOD/Changeover it gets full boost pressure (about 500rpm before VOD). Then at initial VOD it gets a split second shot (0.1sec) of Vacuum. Then constant boost through all VOD and TT mode.

My Map Solenoid LED is working fine. It flashes at start up, then does a single flash with initial throttle movement. When I touch the gas in Single Mode it flashes once. It does nothing During VOD or full TT Mode. I\'m now assuming it only cuts pressure to the Map Sensor when the ECU goes into Limp Mode?

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 lachlan said:

the first picture showed up

tydon how many pictures can you see in this thread ?

yeah the 2ndary relief valve is identicle to the main bov

have replaced both on mine . they holed the diagphram . bother it is a headache to find that fault

13 photos all together lol

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I\'ve now wired my 2 LED\'s to the ECV positive and negative Solenoids. The ECV Negative Solenoid opens the ECV half way for initial Pre-spool of the Secondary Turbo. Then once Pre-spooled the ECV Positive Pressure Solenoid opens the ECV completely.

LED\'s wired into BBOD Loom:

ECV_001.jpg

This is the ECV Actuator:

ECV_004.jpg

This is the ECV (Exhaust Gas Control Valve):

turbo_008.jpg

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where are you based? i built an ecu piggyback datalogger to see exactly what the BG5B TT system is doing.

as with most things i became distracted by something else (course) girlfriend and it needs a little tweaking. not her. the thing. not that thing. shuttup nick.

anyway you might find the preliminary data interesting, this is a snippet of a longer run. sorry the speed detection is always a pain to sort so wasnt recorded but the AFM should give an idea of load. graph scale is % value of total sensor range. digital values are defined as 98% , 96% etc so they are visible on the graph

duty may be messed up, i can\'t remember

tach will be x100 rpm

tt%20plot.png

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yeah i can appreciate the work you\'re putting in here. looking at each system at a time is probably a good way to attempt this. it took me weeks just to get the serial coms working in excel. theres a pic in my build thread.

anyway something you mentioned that i wasn\'t sure of:

 Rosssub said:

The other LED is wired into the Map Sensor Control Solenoid so I can monitor when the Map Sensor is Cut Off:

isn\'t this just the same as the pressure exchange solenoid in a single turbo setup? so the ecu can switch one map sensor between manifold / ambient pressure?

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 kamineko']

yeah i can appreciate the work you\'re putting in here. looking at each system at a time is probably a good way to attempt this. it took me weeks just to get the serial coms working in excel. theres a pic in my build thread.

anyway something you mentioned that i wasn\'t sure of:

[quote name='Rosssub said:

The other LED is wired into the Map Sensor Control Solenoid so I can monitor when the Map Sensor is Cut Off:

/quote]

isn\'t this just the same as the pressure exchange solenoid in a single turbo setup? so the ecu can switch one map sensor between manifold / ambient pressure?

That makes more sense than my explanation, (Map Solenoid), but I didn\'t see a permanent switch over at any stage? Also the Map Solenoid in the BBOD, switches to its Filter/Vent with voltage.

Cool, I\'ll check it out now. I\'m using a lot of gas but enjoying every second of it. ;)

I\'m determined to get minimal VOD with no CELs, without any mechanical changes.

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 Rosssub']

[quote name='Rosssub said:

Well, very interesting so far.

The IACV gets vac at engine start up. Then opens completely (releases vac) at initial VOD, it opens as I start to lose Primary Boost. It stays completely open for Pre-spool, Full TT mode then only closes when back into Single Turbo Mode.

The ECV Duty Solenoid, runs a constant duty cycle (pulses) when in Primary/Single Boost (positive manifold pressure). It also pulses (bleeds) during Initial Primary Mode Deceleration. But when VOD hits, during VOD and in Full TT Mode it does nothing.

/quote]

The Secondary Relief Valve does nothing at start up or during Primary/Single Mode. But, just prior to VOD/Changeover it gets full boost pressure (about 500rpm before VOD). Then at initial VOD it gets a split second shot (0.1sec) of Vacuum. Then constant boost through all VOD and TT mode.

My Map Solenoid LED is working fine. It flashes at start up, then does a single flash with initial throttle movement. When I touch the gas in Single Mode it flashes once. It does nothing During VOD or full TT Mode. I\'m now assuming it only cuts pressure to the Map Sensor when the ECU goes into Limp Mode?

The ECV Positive Solenoid (hose 5 to top of ECV Actuator), runs a constant duty cycle (pulses) when in Primary/Single Boost (positive manifold pressure). The same as the ECV Duty Solenoid. Then when initial VOD hits, it stop pulsing. Does nothing during Secondary Pre-spool or mid VOD. Then starts pulsing again well after VOD closer to redline.

I\'ve seen nothing from the ECV Negative Solenoid (hose #6), yet but I need to check wiring when it\'s light again.

Edit: I\'m also going to do Vac Gauge test on these ECV hoses as well. With the LED\'s still running.

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After running these test, and seeing how much the ECU is using the ECV, during Primary/Single Mode. Both the ECV Duty Solenoid and the ECV Positive Pressure Solenoid are working together with the Primary Turbo\'s Boost Solenoid/Waste Gate.

So the ECU constantly monitors the Map and Differential Pressure Sensor, then adjusts the ECV to suit. During Both Single and Twin Turbo operation. The only main changes to the ECV\'s use is during VOD.

So any changes to the Primary Waste gate Duty Cycle (bleeds/EBC\'s) will have a drastic effect on the ECV\'s duty cycle during VOD and while in Full TT mode.

In the Primary Turbo Waste Gate hose is a 0.8mm Restrictor Pill. In the BBOD ECV manifold feed hose (hose #2) is also a 0.8mm Restrictor Pill. Both running ECU duty cycles constantly, while the engine is under boost. Then just the ECV Duty Solenoid under Primary Deceleration.

The IACV opening wide at the start of VOD is the main cause for Primary Boost Loss. All primary Boost is disappearing through the IACV into the Secondary at initial VOD. Just as the Secondary needs to Pre-Spool, this can be improved. Probably quite simply with a Restrictor Pill in the IACV Vac Hose #1. This will slow the IACV opening, giving the Secondary more time to Spool and the Primary will have a better chance of holding boost.

I\'m currently Running a GFB Atomic bleed valve in my Primary Turbo/Waste Gate line, set to 12-13psi depending on the ambient temps (weather). Since De-Catting I get Boost Spikes if I set it at 14psi. I haven\'t ported my Primary Waste Gate yet.

I\'m now going to slightly increase the Restrictor Pill Size in the ECV pressure feed line, from 0.8mm up to 1.0mm. This will change the ECV\'s duty cycle, during Primary boost, VOD and in full TT mode. This will also increase my overall engine boost during Primary, VOD and TT operation.

Edit: My Primary Boost Solenoid is only connected to Loom/ECU (no hoses) but my ECU doesn\'t know that.

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That worked, perfectly. Hose 2 manifold feed inside the BBOD \'Restrictor Pill\' changed. Feeds TMIC Boost Pressure into BBOD, this is the ECV Boost Hose. Identical to the Primary Waste Gate Boost Hose. I\'ve now altered my ECU ECV\'s duty cycle.

OEM ECV Restrictor Pill 0.8mm. 12psi Primary Boost

New ECV Restrictor Pill 1.0mm. 14psi Primary Boost

- My Primary boost comes on faster, the car has more power.

- VOD boost is coming back faster, Primary Boost Loss is less dramatic.

- My HKS Sequential BOV is venting much louder.

- Induction Noise is louder.

- No Boost Spikes.

- No CEL.

:)

I have a spare B4 TMIC and IACV here, I\'ve been bench testing the opening speed. With a Vac hose connected to the IACV Actuator, applying Vac to close it. Then releasing Vac and timing how fast it opens. Then adding Restrictor Pills to the Vac Hose, to slow it down/restrict it.

IACV opening times:

OEM open 4mm hose - 0.15 seconds

2.0mm Restrictor Pill - 0.35 seconds

0.8mm Restrictor Pill - 0.85 seconds

I\'m now going to fit the 0.8mm Restrictor Pill into Hose 1 to the IACV. So instead of opening in less then 0.2 seconds it will now take almost a full second to open completely. This will give the Secondary Turbo more time to Pre-Spool. This will also give my Primary Turbo and Primary Waste Gate more time to adjust, easier to hold boost. The IACV will also close slower when changing back to Single Turbo Mode, but the engine will be in deceleration.

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