Recirculating BOV/BPV. Let's see them.

jake8790

Life's too short for N/A
Dec 18, 2011
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Oregon
I got sick of my car stumbling and going rich whenever I let off the gas, so I refitted the stock BPV. I now have a small amount of compressor surge whenever I let off. If anyone has pics of a recirculating setup that can flow enough air to eliminate surge at higher boost levels than stock I'd be grateful. :1zhelp:
 

Dan_Gyoba

Turbo Swapper
Aug 9, 2007
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I have a recirc fitting on my '89 for my HKS SSQV. It gets rid of the riceboy whistle, and lets the air out through a 1" fitting. I fit an angular hose I found at a parts store back to the turbo intake, like stock. This works great for the 60-1 turbo.

The '90 has a Greddy style BOV, also with a recirc fitting, and it going back to the accordian hose. This is a knockoff though, and I don't think that it's working like I really want, I get some compressor surge sound, however I haven't adjusted it myself yet.

So the aftermarket BOVs have ways to make them recirculate, and not cause you the problems that vent to atmosphere will. It seems to be accepted that the Bosch BPV flows more than stock, but I've never seen numbers to back that up. I'd put my bets on a recirc fitting for the aftermarket valve myself.
 

jake8790

Life's too short for N/A
Dec 18, 2011
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Oregon
jnybbad;1952026 said:
Here is mine.

I think I'll run the bov a few inches down the pipe, facing the other way, so I can use a simple 90 degree hose from the BOV to the fitting.
 

emiliorescigno

Supramania Contributor
Sep 17, 2006
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Woodbury, MN
+1 to TurboSmart. I have a TurboSmart Kompact Plumb Back. Fits great, sounds kinda neat, no surge, doesn't leak boost. Admittedly the furthest I've taken it is on a stock CT-26 @ ~12psi, but it's the best stock replacement out there imho.

(I've had several Saabs in the past, the work great, but they tend to "hoot" when they wear out, and that gets really annoying.)
 

suprarx7nut

YotaMD.com author
Nov 10, 2006
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I run the Bosch bpv and I still get some surge sound on only a few pounds of boost. I think it's the stock accordion connection that's letting me down though.

The Dylan wiggins method yields a significant restriction in the plumbing
 

emiliorescigno

Supramania Contributor
Sep 17, 2006
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suprarx7nut;1953346 said:
I run the Bosch bpv and I still get some surge sound on only a few pounds of boost. I think it's the stock accordion connection that's letting me down though.

Take a look at the part # on the Bosch BPV you're running. I've used a 103, 108, and 110. I don't remember specifics, but some were certainly more capable than others. I had one that could only handle stock boost on a CT-26 (above 9-10 PSI would surge), and others that were good all the way up to fuel cut. That being said, the TurboSmart is more capable than any of them.
 

suprarx7nut

YotaMD.com author
Nov 10, 2006
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emiliorescigno;1953353 said:
Take a look at the part # on the Bosch BPV you're running. I've used a 103, 108, and 110. I don't remember specifics, but some were certainly more capable than others. I had one that could only handle stock boost on a CT-26 (above 9-10 PSI would surge), and others that were good all the way up to fuel cut. That being said, the TurboSmart is more capable than any of them.

I've got a 710n. I think it's also called a 114 and I think is basically a 110. It's used on the Porsche 966 turbos I believe. I love the sound and response, but the surge is annoying. Mostly because every time i hear it i think my turbo is feeling extra strain.

They run a pair of them on the Porsche engines and I'm sure that would help me as well.

First and foremost however, I need to plumb it in a way which doesn't have the factory accordion restriction. :/
 

emiliorescigno

Supramania Contributor
Sep 17, 2006
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Woodbury, MN
suprarx7nut;1953354 said:
I've got a 710n. I think it's also called a 114 and I think is basically a 110. It's used on the Porsche 966 turbos I believe. I love the sound and response, but the surge is annoying. Mostly because every time i hear it i think my turbo is feeling extra strain.

They run a pair of them on the Porsche engines and I'm sure that would help me as well.

First and foremost however, I need to plumb it in a way which doesn't have the factory accordion restriction. :/

What size turbo do you have? I'm not sure the accordion hose is really your problem yet. Those Bosch valves are really unpredictable on how well they work. I went to the local pick-n-pull and grabbed maybe 4-5 of them, and kept trying them until I found a good one.

My 110 (Porsche/awesome/etc.) only seemed to be good to stock boost. I also had a 103 (from a shitty old Volvo) that was rock-solid on a stock CT @ 12 psi. All of these into the stock accordion hose.
 

jnybbad

New Member
Sep 16, 2012
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vacaville, ca
jake8790;1952029 said:
I think I'll run the bov a few inches down the pipe, facing the other way, so I can use a simple 90 degree hose from the BOV to the fitting.

That would be a lot cleaner. Wish the kit pipe would come that way. It was a tight fit doing it my way but works good.
 

suprarx7nut

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Nov 10, 2006
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emiliorescigno;1953355 said:
What size turbo do you have? I'm not sure the accordion hose is really your problem yet. Those Bosch valves are really unpredictable on how well they work. I went to the local pick-n-pull and grabbed maybe 4-5 of them, and kept trying them until I found a good one.

My 110 (Porsche/awesome/etc.) only seemed to be good to stock boost. I also had a 103 (from a shitty old Volvo) that was rock-solid on a stock CT @ 12 psi. All of these into the stock accordion hose.

54 trim CT-26. 6-12 psi, pending my EBC setting. The BPV was bought brand new. Maybe I'll take a look at it tonight. I should have some garage time and I haven't taken it off in over a year.
 

CyFi6

Aliens.
Oct 11, 2007
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My setup with a custom "accordion" pipe
p1953713_1.jpg
 

jake8790

Life's too short for N/A
Dec 18, 2011
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Oregon
CyFi6;1953713 said:
My setup with a custom "accordion" pipe

Very nice, I bet it works great with the larger fitting. Is that 3" pipe? What did you do for a power steering reservoir?
 

CyFi6

Aliens.
Oct 11, 2007
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Yeah its a 3" pipe, the inlet on the CT26 is slightly smaller than 3" but I was able to tighten the clamp enough to make it seal on it fine. This car was originally NA non ABS so I had moved the NA reservoir back where the ABS would be a long time ago, but ya it would probably be a problem in the stock 7mgte location. The recirc works great, no surge or anything. Only problem I have is that it sometimes hesitates when I partially let off the throttle after accelerating, it might be the turbulence right near the airflow sensor, but it could be totally unrelated. My suggestion is put the recirc fitting as far away from the airflow sensor as possible.