16 replies to this topic

[BigWillieStyles]

Hello all,

lastnight I was reading on another forum about where the restrictor pills are in the 3rd gen twin turbo system (there are four). Well I basically worked out that I had accidently removed one when I replaced a piece of pipe near the vaccume line coming off the BOV (see red arrow in pic).



I cut up the old pipes I had lying around and sure enough that restrictor pill was in one. So I re-installed it and now its boosting heaps more and more in line with what other Legacy's are pulling. Now getting about 0.8bar (12psi) on primary and 1.1bar (16psi) on secondary.

The issue now is, that my vented to atmosphere aftermarket bov now doesnt work. In theory the BOV should be more vocal. I have tried making it softer but didnt work. Just did an ECU reset and still doesnt work. I am however getting a fully hectik flutter now. Does anyone know whats going on? Is there another vaccume line I can T into for my bov?

I think I will just re-install my factory bov and use that for a couple of days and if it works, then revert back.

William

[Alex]

I hate to break this to you....



but:


Flutter > BOV.







In all honesty, find a different vacuum line that doesn't take a reference of manifold pressure via a vacuum line.

Or back off the tension to the BOV.

Or consider using a bleed valve (ie not allowing the ECU control the boost).



Welcome to the wonderful world of modifying a TT.

Wrought with fun and games!!

[BigWillieStyles]

I hate to break this to you....



but:


Flutter > BOV.







In all honesty, find a different vacuum line that doesn't take a reference of manifold pressure via a vacuum line.

Or back off the tension to the BOV.

Or consider using a bleed valve (ie not allowing the ECU control the boost).



Welcome to the wonderful world of modifying a TT.

Wrought with fun and games!!

The flutter sounds way louder than I expected. Since I removed the restrictor pill by accident, I have also added a catback exhaust, now with the added boost, the car pulls so much harder. I do quite like the flutter sound but am going to try and figure this out. Going to install the factory BOV to see if that works now.

[Alex]

I re-read what I just wrote.

What I meant was, try to find a different vacuum line that doesn't use a pill or anything.

[BigWillieStyles]

I re-read what I just wrote.

What I meant was, try to find a different vacuum line that doesn't use a pill or anything.

Thanks mate, really appreciate the help. I just re-installed the factory bov and it all works (no flutter) but I still think I want the aftermarket item on. Any idea why the aftermarket bov isnt working with the restrictor in an attaching line? Im sure that others would use the factory vaccume line for an aftermarket item, so why doesnt it work with mine?

Before I removed the aftermarket item, I adjusted it to the softest setting, and it still wouldnt work.

[Alex]

My theory is this:


BOV requires a vacuum reference to activate it.

The pill is restricting it. Hence, the BOV isn't working like it should be.

The more unrestrictive the vacuum line, the more easier the BOV will work.

I guess a fiddle with the spring tension should help matters?




When I was still running a TT, I just used a GFB plumb back, as the standard one leaked boost.

I had not intention of using the BOV to attract teh wominz.



What boost levels were you seeing with the aftermarket BOV and pill-less vacuum line?

[BigWillieStyles]

My theory is this:


BOV requires a vacuum reference to activate it.

The pill is restricting it. Hence, the BOV isn't working like it should be.

The more unrestrictive the vacuum line, the more easier the BOV will work.

I guess a fiddle with the spring tension should help matters?




When I was still running a TT, I just used a GFB plumb back, as the standard one leaked boost.

I had not intention of using the BOV to attract teh wominz.



What boost levels were you seeing with the aftermarket BOV and pill-less vacuum line?

Boost is the same with both the bov's. With the pill removed, I was getting 0.6 bar (8.5psi) on primary and 0.9bar (13psi) on secondary.

[Alex]

Put the pill back in.





Put BOV back on, but shim it up with lots of 10c pieces.








win.

[BigWillieStyles]

Put the pill back in.





Put BOV back on, but shim it up with lots of 10c pieces.








win.

You lost me!

I think I might do some experimenting with the piping and the aftermarket BOV.

[Jimbo]

Ahhh... the old Uncle-Jims-coins-in-the-BOV-trick. Works a treat.

As Alex said, god knows why you have a restrictor pill in the BOV line anyway. Use a different vac line, and see if you can soften the BOV tension up a bit. You can usually get a good balance between vent and fluttttterrttts.

[acres]

Why is there a pill in that vac line? Does the vac line also tee off to something else? If so just move the pill to after the tee. The BOV should see full manifold vaccum/pressure then and should work correctly without impacting whatever it is that needs the restrictor.

[BigWillieStyles]

Why is there a pill in that vac line? Does the vac line also tee off to something else? If so just move the pill to after the tee. The BOV should see full manifold vaccum/pressure then and should work correctly without impacting whatever it is that needs the restrictor.

Thanks acres, yeah there is a restrictor pill in the vaccume line coming off the manifold. And yes, you can see the blue T connector that connects to one of the solenoids. The pill is actually before the 'T' connection and not in the vaccume line for the bov. When I installed the aftermarket bov, the length of the vacuume line needed extending. I have had another play around and adjusted the lengths to be more stock like, and will try the aftermarket bov again to see if it works now.

There is a 'restrictor pill' thread on uklegacy and there is another member who has the exact issue I have. They have removed the pill, replaced it back in, and now aftermarket bov wont work. Meh, at least I had some decent boost now.

[acres]

So in the picture above - the pill is in the red circle, BOV is connected to the right side of the blue tee and solenoid is connected to the upper connector of the blue tee? If you cut the pill out of that vac line and press it into the line from the upper connector of the blue tee in the pic above, then I think this will solve your problem as it should no longer restrict the signal to the bov.

[BigWillieStyles]

So in the picture above - the pill is in the red circle, BOV is connected to the right side of the blue tee and solenoid is connected to the upper connector of the blue tee? If you cut the pill out of that vac line and press it into the line from the upper connector of the blue tee in the pic above, then I think this will solve your problem as it should no longer restrict the signal to the bov.

Unfortunately, there is another restrictor pill in that line as well. I have seen a few other Legacy's that have tapped into another vacuume line and reporting that it works better. The one I tapped into for my boost gauge seems to be a favourite.

Just for any others who are interested, here are the restrictor pill locations for the type A-C gen 3 turbo models. I expect that they are different for the locally delivered B4.

(Not my car, shamelessly stolen from uklegacy.com) -

there are 4 restrictors, 3 small, 1 big!

Line 2??? In the solenoid box A
Line 8 on the manifold B
And one in the 5mm pipe from BV to manifold, on the manifold end (I think its line 23) C
Line 10 at the primary T D

[acres]

Ha, how spastic. Gen2 only has one pill.

I'd try moving it there anyway, just have both pills in the same line.

[Murf B4]

[BigWillieStyles]

Thanks Ryan B4 for the input, unfortunately, I have a JDM and as such the restrictors are different.