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Found a link to this on FB which in turn liked back here so this will likely be a repost


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Livin' the Legacy

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Posted 11 March 2014 - 08:10 PM



Here is a comprehensive guide to TT operation for easy access. Troubleshooting and modification tips follow.








1. Remove intercooler and check the pipes and connections are in good order and that the ICV works
Check your BOV is not leaking/ block it up temporarily. While TMIC is off, inspect the intake pipe for cracks/ leaks and ensure all breather pipework is in the right spot, in good order and the PCV is operating correctly.

2. Remove each and every vacuum line between the BBoD and other components one by one and clean/ check/ replace them as necessary, making sure you replace any restrictor pills.

3.Remove the BBoD and clean all the solenoids, their vents and lines one by one. ( Subaru Upper Engine Cleaner is ideal, link provided for how-to below )

4.Reassemble BBoD

5.Remove the boost control lines at the Primary Turbo and plug them up (temporary)

6.Fit a piece of vacuum hose between the compressor outlet nipple and wastegate actuator to give you wastegate pressure boost control (7/9 psi)

7.Reset ECU and test the system.

If you still have issues then move down the list here

8.Block up the Secondary BPV. Really it's 99% useless anyway, test.

9.Check operation and adjustment of ECV. It may not be tight enough causing exhaust gas to divert into the secondary at all times. 
you'll eventually get some boost at around 5000rpm if this is stuck open.


LINK FOR INTERCOOLER REMOVAL http://www.subyclub....l-installation/

LINK FOR GEN3 AFTERMARKET BOV INSTALL http://www.subyclub....oosting-issues/

LINK FOR SOLENOID BOX (BBoD) RESTORATION http://www.uklegacy....urself-cheaply/




If you look at the rod going from the ECV actuator to the ECV itself (in the Secondary up-pipe) it has two 10mm lock nuts above a LONG flat-sided section.

1.Loosen off the lock nuts

2.Warm up the car and have it idling.
3.Turn the adjuster part (flat sided bit) to lengthen the rod (which opens the ECV) until you hear it rattling,
4.Tighten it again about 2 full turns.
5.Do up the lock nuts and test

This will put enough pre-load on the actuator so that it's held closed, but once the system gets sufficient exhaust flow it will start to creep open slightly and allow the "pre-spool" to begin on the secondary (the whole bypass above is bypassing the pre-spool system which does bugger all)

If it's too loose, it will blow open too early and you'll get erratic boost, too late and it won't open soon enough, making the VoD worse.





There are a few other mods you can to do simplify the system.

The ECV has two ports, a top port and a bottom port. You can effectively remove the two solenoids and vacuum lines going to the top-port.

1. Place a T piece into line #22 (Line to DPS) about 5-10cm from the SPV.

2. Cut hose #5 (Positive ECV port) about 10cm from the ECV port and place into the T piece we just put in hose #22.
3. Block up the remainder of hose #5 (From the BBoD)
4. Perform ECV Rod adjustment as described above.

The ECV Duty Solenoid, the line feeding it and the restrictor pill has a tendency to clog up and it blows the ECV open early, resulting in dodgy boosting
It is still pulled and held open by vacuum from the tank, when the ECU tells it to changeover.




Essentially, everything marked in red can be disconnected from the vacuum system. (solenoids need to be connected to ECU or bypassed with resistors)



So now with all that junk bypassed and the top port plumbed into the line that feeds the DPS (this line ONLY sees boost once the ECV is open and the Secondary BPV closes) here's your new simplified system.





(Used without permission courtesy of ClubSubNZ, cheers cubts)

*Figures given may not be accurate or performance gains guaranteed as this is 3rd party untested information.


Insert a 0.8mm restrictor pill into line #1 (Intercooler Air Control Valve)


- Primary boost loss throughout the entire VOD is less than 2psi*
- Primary boost loss to full TT boost is less than one second*
- Completely smooth and powerful transition into sequential operation*
- Stable boost throughout entire RPM range*


- 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.

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

0.8mm Pill - 22326AA260
1.0mm Pill - 22326AA010

Alternatively, a second-hand unused stock boost control line contains an 0.8mm restrictor from the compressor outlet to tee-piece.




VF13P and VF14SWG - 1994 to 1996 Gen2 Legacy GT/RS (AT and MT)
VF18P and VF19S - 1996 to 1998 Gen2 Legacy GTB/RSB (MT)
VF20P and VF21S - 1996 to 1998 Gen2 Legacy GTB/RSB (AT)
VF25P and VF27S - 1998 to 2003 Gen3 Legacy GTB/RSK (AT)
VF26P and VF27S - 1998 to 2003 Gen3 Legacy GTB/RSK (MT)
VF32P and VF33S - 2001 to 2003 Gen3 Legacy B4 S401 & Liberty B4 (MT/AT)

NB: Unsure of VF31 placement, possible AT on JDM Models. Some model years may be incorrect.



Although it is not recommended to modify a TT system without proper knowledge, here is a rough guide of what is tried and tested.

Intake :

Intake mods are the same as most Subaru's. Due to high temperatures it's best to avoid running an exposed filter in the engine bay. A hand made in guard CAI will net the best results. The stock airbox is more than capable with a higher flowing filter installed. Silicone under manifold intakes are available on Ebay but will only suit the AUDM B4 with the larger VF33 compressor cover.

Exhaust :

For the exhaust, 2.5" dump pipes leading into 3" piping at the dump pipe merge is optimal.  3" dumps are too large and should be avoided. Combine with a high-flow cat. Mufflers are anybody's choice. For the more experienced, manifold and ECV porting is beneficial to the TT process. Replacing the up-pipes with custom pipes is recommended as the stock units break over time and cause sluggish performance, the same can also be done for the crossover pipe. The stock bi-modal muffler has an electronically operated valve which has been known to seize over time.

Vacuum Lines :

Part of the good running and maintenance of the TT system requires at some point for the vac lines to be replaced. For the non-faint-hearted the BBoD can be dismantled and the vac lines within be replaced. Refer to a BBoD line diagram for restrictor pill placement as these are essential. These lines can simply be cleaned with SUEC. All other lines can be replaced by same ID hose readily available at auto stores. About 10 or 15 meters will do the entire engine bay. Be sure to check a diagram for correct fitment. It is also a handy idea to use small labels to re-number your hoses so they don't end up in the wrong place.

Turbo Swaps :

All Subaru TT turbos are interchangeable within their respective positions (Primary or Secondary) , bearing in mind the VF33P has a larger compressor cover and the matching intake tract must be used. All rear exhaust flanges are the same ( Primary and Secondary). Most primary turbos are bush bearing designs and secondary's ball bearing. Hybrid turbos can be made but are for the more advanced modifier. The most common turbos used for maximum performance are the VF26P and VF27S. The AUDM B4 VF33P and VF32S also are great turbos but has above require the intake tract to suit. Do note the earlier VF14S is not interchangeable due to having it's own wastegate and cannot be changed out of early Legacy GT's due to this.

Intercoolers :

FMIC setups are available, notably the kit made by Scarles in NZ. No further information can be given regarding this kit. Larger TMIC's can fit however clearance of the Primary Turbo should be noted. The cast boost pipes to the bottom of the TMIC sit in the same configuration as the single turbo Subaru's.


1993-1995 Legacy GT/RS (Non-GTB) BBOD Diagram (Secondary Turbo Wastegate Application)







'04 Liberty GT Premium "The Sprog Chariot"


Cheers Jimbo : not sure why the shade tho?



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why would my 1999 legacy BE5 fail to start when no faulty code showing,someone tells me its immobilizer problem.i have no idea hw to solve it coz my remote key stopped working long time and i dismantled it long time.I use it as a normal key to open the door

Edited by david.alig
give more description of problem
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can rule out imobiliser if using blank key


reckon its the starter motor ay : brushes wear out, about $80 for new parts or recon / second hand starter


you can get another month or two out of it by tapping it vigoursly with something long & solid


socket extension handle etc (as the starter is obscured by the TT equipment & also makes it harder to replace / service the starter too

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My 1999 subaru Be5 has failed to start.It cranks but no start.fuel ok,battery ok,

Actually i found out that when i crank the engine it drops crankshaft position sensor code which reset but comes back on cranking the engine again .i clear it and it accepts .Have replaced the senor to a new one but still pops up on cranking the engine.

checked the harness is OK from sensor to ECU.

Could there be a problem with crankshaft Timing.

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