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1g BOV trouble/comp surge

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Monty7300

Proven Member
41
12
Jun 25, 2016
Jasonville, Indiana
So this is the story. A friend of mine had an extra SQV blow off valve so for fun we decided to see what it would sound like on the eclipse. We removed my 1g BOV and then realized that the flange for the sqv wouldn't fit so we put a new gasket on the original 1g BOV and reinstalled it. Since then I have had issues with the BOV not releasing pressure correctly and causing compressor surge. I checked all the vacuum lines and and even replaced one that seemed to have collapsed but the issue remains, I do think that after replacing the one section of hose that it is realeasing possibly some pressure but not enough to not cause compressor surge. This is a link to a video of the BOV operating the way it does now,
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And here is a video of how it performed before
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I'm pretty well out of ideas on what to do, so any input or thought would be greatly appreciated!

Ps. I've also had recent trouble with the rpm's jumping like the do in the first video, and I was curious if that's possibly related to the current issue I'm having or something else entirely.
 
Last edited:
It's dark but I did grab my shoplight and try and snag a few pictures.

Engine bay
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The BOV and boost controller set up
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Vac line to fuel pressure
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Why is the bov and boost controller t'd together? Bov needs to be on its own line to the intake mani. And boost controller needs to be hooked up from wastegate to boost source, like compressor cover nipple or intake/jpipe nipple.
 
You didn't accidentally glue your BOV shut with that blue sealant did you? I personally hate that stuff, a good gasket is all you should ever need. I don't see any obvious issue aside from the poor vacuum line job. Your boost controller should be fed from a positive pressure source like an intercooler pipe or the turbo itself. Not sure what type of hose line you are using but that longer line going to the IM looks like it could easily collapse under vacuum causing the BOV to not release.

You should get some silicone hose and ditch all the T connections, I'm sure they're a source of boost leaks.

The rpm jump looks like clutch slip.
 
Why is the bov and boost controller t'd together? Bov needs to be on its own line to the intake mani. And boost controller needs to be hooked up from wastegate to boost source, like compressor cover nipple or intake/jpipe nipple.
To be honest, I'm not sure why exactly it was set up that way. It was like that when I purchased the car 3 months ago, but even with the previous set up I didn't see any compressor surge. I'll do some more digging around and check out all of the lines when I have some daylight.
 
You didn't accidentally glue your BOV shut with that blue sealant did you? I personally hate that stuff, a good gasket is all you should ever need. I don't see any obvious issue aside from the poor vacuum line job. Your boost controller should be fed from a positive pressure source like an intercooler pipe or the turbo itself. Not sure what type of hose line you are using but that longer line going to the IM looks like it could easily collapse under vacuum causing the BOV to not release.

You should get some silicone hose and ditch all the T connections, I'm sure they're a source of boost leaks.

The rpm jump looks like clutch slip.
I had a friend seal and put the BOV back on, we were we're working on several projects all at once and I was laying under the car at the time. So I will probably take it back off and just put a gasket on. It is possible that some of the sealant got into the BOV it does look like he got pretty liberal with it.

My car only has 74k miles on it, and I'm betting it hasn't had a new clutch in a while if at all so I'm sure it's due for one. It does sometimes act temperamental when trying to put it into different gears, some times it's smooth as butter others it almost doesn't want to go into gear.
 
^Which is ridiculous let's be honest. In that diagram they plug the port on the turbo and add a T to a pressurized system. Totally unnecessary, DSMs need very few vacuum lines. I've heard the "colder air from the bov" argument but I haven't seen any proof that it will function better. Even on past cars, I've run 30 psi just fine feeding the boost controller from a hot turbo.
 
Thanks everyone for the input it's appreciated. I would guarantee that the previous owner hooked it up like taboo speed shop article, my setup looks just likes that. I'll be looking at the Vacuum lines again along pulling the BOV off cleaning it and putting a new gasket on it as soon as I get back from work today.
 
There is a small hole on the bottom side of the 1g bov. It might have gotten covered.
Thanks you were completely right, the hole was covered and keeping air from the bottom of the valve. A little cleaning and a new gasket and the thing is back to running the way it should be.
 
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