Inside the BBOD

[Rosssub]

"VOD gone in 24hrs" 8)

Perfection, "ABSOLUTE PERFECTION". 0.8mm Restrictor Pill into Hose #1 at the BBOD (IACV Vac Control Hose)

- Primary Boost Loss throughout the entire VOD is less than 2psi. 8)

- Primary Boost Loss to Full TT Boost is less than one second. 8)

- Completely smooth and powerful transition into Full TT, just more "then more" power.

- Stable Boost throughout entire RPM range. 8)

- No Boost Spikes. 8)

- No CEL\'s at all, through entire testing. 8)

I "HIGHLY RECOMMEND" everyone that owns a TT Subaru with a BBOD. Fit a 0.8mm Restrictor Pill into Hose #1.

If you have fitted an \'EBC\' or \'MBC\', then your Primary Waste Gate \'OEM\' Hose contains a 0.8mm Restrictor Pill.

- Push the "OEM Pill" out, with a piece of wire.

- Pull hose # 1 from the top/front port of the BBOD.

- insert the Pill into hose 1, use wire to push it up the hose at least 50mm (2 inches).

- Refit hose 1 onto BBOD.

- GO and enjoy your TT Subaru, the way that Subaru should have built it.

If you do not have a 0.8mm Restrictor Pill, the OEM Subaru Part Number is:

0.8mm Pill - 22326AA260

1.0mm Pill - 22326AA010

Subaru Pill Part Number Source:

http://www.perth-wrx.com/vb/mechanicals/48287-restrictor-pill-what-why-you-need.html

Amazing. ;D

[Rosssub]

I\'m not calling it VOD anymore, it\'s TT Transition.

[Rosssub]

BBOD Wiring:

Solenoid: +/- Colour Code

ECV Duty Solenoid + Pink P

- Black B

Map Sensor + Pink P

- Green G

ecu signal White W

ECV Negative Pressure + Brown Br

- Brown Br

ECV Positive Pressure + Blue L

- Blue L

IACV Solenoid + White W

- White W

Supercharged Relief #1 + Pink P

- Pink P

Supercharged Relief #2 + Green G

- Green G

Map Vac Solenoid + Yellow Y

- Yellow Y

;D

[les666]

Dude! Awesome thread! I think I may have to try this later today in my BG5!

[Rosssub]

 les666 said:

Dude! Awesome thread! I think I may have to try this later today in my BG5!

Do it Man, trust me. Please post your findings/changes in detail after you do it.

;D

[les666]

Yeah will definitely let you know what happens! Am keen to see how the factory boost control deals with it.

[Rosssub]

 les666 said:

Yeah will definitely let you know what happens! Am keen to see how the factory boost control deals with it.

Good point, you\'ve got me curious too. I\'m going to reinstall my OEM Primary Boost Control now, then Reset my ECU.

Edit: Maybe later on today, it\'s been a long night. I don\'t see it being a problem at all though. I only started to get "Boost Control/Boost Spike" problems, after I De-Catted my Primary Down Pipe. The big change in Exhaust Flow made my Primary Turbo Spool/Make Boost faster, so my ECU\'s Primary Waste Gate Duty Cycle (boost solenoid) couldn\'t keep up.

[lachlan]

you need to bore out the wastegate hole in the primary turbo . the hole is like 13 mm but the flap is like 23 . i took mine out to 19 ish and it will run 7 psi stable as ( if on wastegate only )

[Rosssub]

 lachlan said:

you need to bore out the wastegate hole in the primary turbo . the hole is like 13 mm but the flap is like 23 . i took mine out to 19 ish and it will run 7 psi stable as ( if on wastegate only )

After doing these tests and seeing how much the ECU uses the ECV during primary turbo mode. I\'m guessing porting the primary Waste Gate alone could have a negative effect on the ECV/ECU.

Since altering the ECV duty cycle I have no boost spikes now, running the same boost.

Edit: De-catting my Primary (altering waste gate duty cycle) I got spikes because I didn\'t change my ECV duty cycle to match. Every time I boost spiked on primary previously, I was tripping the Differential Pressure Sensor, also making my Zerosports Controller have a relay seizure.

Now that I\'ve altered my ECV duty cycle to match my Primary Waste Gates Duty Cycle, I have no boost spikes/CEL\'s running the same boost as before

When the ECU (monitoring Differential Pressure Sensor and MAP) sees that the Primary Waste Gate isn\'t keeping up or it\'s over working, the ECU opens the ECV to control exhaust flow from the Primary.

ECV Stabilizes the Primary Boost Levels.

I haven\'t touched my GFB Bleed at all, but now my Primary Boost is higher, stronger, more stable and spools faster.

[Rosssub]

I\'m now pretty sure this opens a whole new list of capabilities for my TT Legacy ;D

To alter the Primary Waste Gate Duty Cycle (Boost +) (pills/bleeds/mbc/ebc)

Also alter the TT/ECU ECV Duty Cycle (Boost +) (pills/bleeds/mbc/ebc)

This allows the ECU to control the Primary Boost (exhaust flow) evenly with the ECV. During Primary Turbo mode/TT Transition/Full TT Mode.

Stopping the "big pressure difference" at the Differential Pressure Sensor (which is always reading).

This stops the "Differential Pressure Sensor" from tripping fault code 65. Readings either side, too far apart=Sad ECU :\'( =CEL 65.

The Map sensor doesn\'t trip until almost 20psi (limp mode). 8)

So to change both the "Primary Waste Gate Restrictor Pill" and the "ECV Control Hose Restrictor Pill" to match. Gives even boost readings at the Differential Pressure Sensor for the ECU to be happy. No Code 66.

VOD or TT Transition length, can be completely altered by restricting the Vac flow to the IACV. Slowing it\'s opening. The 0.8mm Pill I\'ve fitted in hose #1, makes the IAC Valve take 1 second to open completely. This timing seems perfect for "my cars" current set up.

Allowing the Primary to hold boost easier. Less "Initial Pressure Drop", or "Slower Pressure Change" as the IACV opens.

Also less "Counter Pressure" on the Secondary Turbo, as it tries to spool.

A 2.0mm Restrictor Pill in hose #1 changes the IACV opening time (VOD/TT Transition) down to about 0.4 seconds with slightly less Vac Restriction. If you already have reasonably high Primary boost this may be better suited to your car. Which will be an even faster and more powerful transition into full TT mode.

As long as you have a Boost Gauge fitted Too much boost=dead engine.

[telemekas]

Excellent work ;D

On reading the post I was surprised how soon the IACV opened.

I always believed the IACV opened when the primary boost and secondary boost where equal.

I assumed the pressure difference would be zero and the output voltage (OV) would be 2.0 as per Subaru literature etc.

See pages 12- 13 on switching to twin charging.

http://www.veloce.pwp.blueyonder.co.uk/Twin%20Turbo%20Operation/ttopprt2.htm

However this is not the reality as you have shown

I have checked the ECU maps on several TTs including the lastest S401.

The IACV opening threshold is set between -7.3psi (0.86 OV) and -1.16psi (1.82 OV) pressure difference.

This can be easily modified in the ECU map (tunable ECU) to get OV of 2.0

[Rosssub]

Mint ;D Thanks telemekas.

I didn\'t realise the newer ECU\'s were tuneable to that degree, nice.

[GorGasmSpecB]

Good luck even if you have a tuneable ECU, I spent ages trying to dump out my ECU with no success

Interesting thread though, I might have to pill my #1 hose. I replaced all the hoses from my BBOD yesterday plus added the bigger intercooler hoses and the car seems to run a little better.

I haven\'t been entirely happy since the FMIC install but it\'s slowing getting better. I think I really need to decat the exhaust.

[lachlan]

yes de cat . i replaced primary turbo , de cat and intercoolet hoses all at once and fuck it made a difference . like 100 % improovement

[87_starion]

 GorGasmSpecB said:

Good luck even if you have a tuneable ECU, I spent ages trying to dump out my ECU with no success

I\'ve read the map from mine, removed the speed limiter, just never got round to writing it back in.

Where in the country are you?

Seriously cool write up! What\'s different between the earlier models and my Rev D? I noticed that it has a less apparent VOD than the earlier twin turbo models.

[Rosssub]

 87_starion said:

Seriously cool write up! What\'s different between the earlier models and my Rev D? I noticed that it has a less apparent VOD than the earlier twin turbo models.

AFAIK the only major change has been the Secondary Waste Gate deletion for the later TT\'s.

Then Tuneable ECU\'s post \'Rev D\' I think? Then the Rev E has an adjustable AFM.

Also Turbo changes from:

VF18/VF19 on early TT\'s

VF26/VF27 up to Rev D BE/BH

VF32/VF33 Rev E (E-tune) BE/BH, with a bigger 60mm Secondary Turbo Outlet and an adjustable AFM (fuel mix).

[Marky]

Adjustable afm?

No such thing

Rev d is the one which has all the changes in ecu, turbo type and afm type

Rev e is the aussie market car which is effectively rev d anyway

[Roo]

 Marky said:

Adjustable afm?

No such thing

Some early afm\'s have a screw for idle correction but that\'s as adjustable as they get

[lachlan]

my orange one is adjustable ....

but its aftermarket

[Rosssub]

There\'s something about an Adjustable AFM/Idle Mix Screw, in this 03 Workshop Manual. I thought it might of applied to later Rev?

http://www.clubsub.org.nz/forum/index.php/topic,40353.0.html

[Optical]

Very clever

[GorGasmSpecB]

 87_starion']

[quote name='GorGasmSpecB said:

Good luck even if you have a tuneable ECU, I spent ages trying to dump out my ECU with no success

/quote]

I\'ve read the map from mine, removed the speed limiter, just never got round to writing it back in.

Where in the country are you?

Seriously cool write up! What\'s different between the earlier models and my Rev D? I noticed that it has a less apparent VOD than the earlier twin turbo models.

Im in Auckland. If you have any tips to read the ECU I would be very appreciative. I have managed to datalog off the ECU but I can\'t download the rom at all...

[B4_685]

 Rosssub']

[quote name='lachlan said:

you need to bore out the wastegate hole in the primary turbo . the hole is like 13 mm but the flap is like 23 . i took mine out to 19 ish and it will run 7 psi stable as ( if on wastegate only )

/quote]

After doing these tests and seeing how much the ECU uses the ECV during primary turbo mode. I\'m guessing porting the primary Waste Gate alone could have a negative effect on the ECV/ECU.

Since altering the ECV duty cycle I have no boost spikes now, running the same boost.

Edit: De-catting my Primary (altering waste gate duty cycle) I got spikes because I didn\'t change my ECV duty cycle to match. Every time I boost spiked on primary previously, I was tripping the Differential Pressure Sensor, also making my Zerosports Controller have a relay seizure.

Now that I\'ve altered my ECV duty cycle to match my Primary Waste Gates Duty Cycle, I have no boost spikes/CEL\'s running the same boost as before

When the ECU (monitoring Differential Pressure Sensor and MAP) sees that the Primary Waste Gate isn\'t keeping up or it\'s over working, the ECU opens the ECV to control exhaust flow from the Primary.

ECV Stabilizes the Primary Boost Levels.

I haven\'t touched my GFB Bleed at all, but now my Primary Boost is higher, stronger, more stable and spools faster.

When you say you \'altered your ECV duty cycle\', im guessing you are talking about an ECU tweak? (Thinking about trying the .8mm hose 1 mod in my RevD)

Interesting re: ECV stabilises primary boost comment. I\'ve noticed that running slightly higher boost levels (.8 bar target) with my EBC controlling wastegate, there is massive lag between gears if im pushing hard. If i run lower boost level, secondary doesnt reach full potential but spool up is quicker between gears (strangely enough) - any thoughts? Could be something totally unrelated...but am thinking about going back to stock boost control and troubleshooting properly 😎

B4_685 via Tapatalk HD

[Rosssub]

 B4_685']

When you say you \'altered your ECV duty cycle\', im guessing you are talking about an ECU tweak? (Thinking about trying the .8mm hose 1 mod in my RevD)

No ECU tweaks for me, Rev B.

The ECV\'s control/feed (hose 2 in BOD) has a 0.8mm restrictor the same as the Waste Gate control. I changed the "hose 2 pill" from 0.8mm up to 1.0mm. Altering my ECV Duty Cycle.

[quote name='B4_685 said:

Interesting re: ECV stabilises primary boost comment. I\'ve noticed that running slightly higher boost levels (.8 bar target) with my EBC controlling wastegate, there is massive lag between gears if im pushing hard. If i run lower boost level, secondary doesnt reach full potential but spool up is quicker between gears (strangely enough) - any thoughts? Could be something totally unrelated...but am thinking about going back to stock boost control and troubleshooting properly

That could be more your EBC\'s settings (rev d/hks ebc?) Try adjusting/raising your gain

percentage etc.

Edit: Also your Rev D? Tuneable ECU?

[B4_685]

Thanks man - yeah Rev D with this ECU

Denso

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