New member + BOV issues

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New member + BOV issues

Postby JESTER » Wed Apr 08, 2015 5:02 pm

Hi all,

Recently picked up a b4 liberty as I want something a little nicer for my spine (old car was a first gen mx5 with stiff suspension). It's fairly clean and straight, only issue being it needed a wheel bearing as it was getting noisy. Was originally after a decent gc8 wrx but they don't exist anymore... I looked at my fair share and at the time they were all rubbish. Fell in love with the b4 as it's still semi-sporty but a lot nicer to drive day to day when compared to mx5 life.

I impulsively bought one of the GFB bovs for the b4, fitted it up and all was fine. I was happily enjoying flutterville until driving home one day the bov didn't open and the car felt sluggish. Limped it home to find the vacuum hose that goes down to the primary had split open. A trip to autobarn later I had bought some hose and everything was back to normal. Sort of. The BOV opened but it seemed to shut really quickly, instead of the usual PSSHHT it was more like PST. During a long drive it seemed to work for 30 minutes or so and then just refused to open again. I swapped back in the stock bov and it seems to work normally.

I'm happy enough on the stock BOV now as it's all working as intended (i think) but it'd be nice to know what exactly the problem is with the GFB. Does the hose I replaced need a restrictor pill or something? There was nothing in it when I removed it but it had split open and it could have fallen out as a result. Photo below of how the GFB is fitted up, the red lines are around the hose I replaced. I'm new to turbo's and this twin turbo system is not the easiest thing to wrap my head around (so many vac lines!). I've had a look at a few threads like the one a few posts down but unsure if they apply to my scenario.

Photo below:
http://i.imgur.com/gbXeTH0.jpg

Cheers,

-Jester
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Re: New member + BOV issues

Postby GONEWALKABOUT » Mon Apr 20, 2015 11:54 am

does it do it no matter what the rpms you let off the throttle at?
Perhaps you need to adjust the stiffness of the spring in the BOV
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Re: New member + BOV issues

Postby JESTER » Mon Apr 20, 2015 12:05 pm

I've tried playing around with the spring stiffness settings but its hard to adjust when it's fitted to the car, I planned to take it off tonight when I get home from work (early finish!) and make it stiffer as I did not set it that tightly initially. It seems to only work at lower rpms 2-4k RPM. Boost feels the same as the stock BOV but at higher rpms when the secondary turbo has kicked it in the bov doesn't seem to do anything sound wise. Is their a secondary bypass valve for the secondary turbo? Still trying to understand the complicated TT setup!

Thanks!
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Re: New member + BOV issues

Postby sbv » Mon Apr 20, 2015 12:52 pm

When you install an aftermarket BOV on a TT you need to replace these vacuum lines...

Image
...with this

Image

Have you tried this?
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Re: New member + BOV issues

Postby JESTER » Mon Apr 20, 2015 1:02 pm

Even with the GFB respons valve that everybody recommends for the b4 TT? That wasn't in the instructions they sent out, with that said they didn't send me a new gasket either! Haha.

So basically just remove the T piece and run a single vac line to the manifold? I'll give that a go and report back. Thanks for the diagrams, helpful stuff.
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Re: New member + BOV issues

Postby JESTER » Mon Apr 20, 2015 8:54 pm

Those diagrams seemed to fix my issue, I also clamped down the spring on he bov but I still think it could do with being a bit stiffer, either way much happier now. Cheers! :mrgreen:
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Re: New member + BOV issues

Postby sbv » Mon Apr 20, 2015 11:50 pm

No worries - glad it worked.

There's a pretty good thread on subyclub re modifying TTs. Heaps of diagrams too.
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Re: New member + BOV issues

Postby JESTER » Tue Apr 21, 2015 11:14 am

Cool, I'll go take a look for myself. I'm still using the factory lines, I just blocked off the ones I nolonger need. Car seems to stutter a bit on initial acceleration but I didn't exactly close off the vac hoses correctly (put a bolt in each end, ziptie + a sealant) but I'm sure it's leaking though. Will do it properly on the weekend after a trip to supercheap.
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Re: New member + BOV issues

Postby RSK20 » Thu Jul 09, 2015 6:41 pm

How did you go JESTER? Running properly? I had a BOV on my B4 for a bit, it seemed detrimental to the tt setup.
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