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Discussion Starter #1
Any telltale signs of a dodgy BOV? My 9k has a stock Bosch one. Dunno it's condition. Looking to delve into replacing it with a Forge one once I get a bit of $$ put aside. I don't want an atmospheric one since I have no interest in bling-boy-racer dump valve sounds, so a recirc one is my target.

Craig.
 

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Discussion Starter #3
Loss of low-end boost, fluttering on shifts, odd boost gauge behavior.
Definitely noticed the first two when driving the car. As the clutch is all now done, and I've fitted an uprated FPR (to match the redbox DI/APC I fitted about 6 yrs ago!) I'm going to replace the Bosch BOV now. Is the Forge FMDV008 the most suitable one for a B202 turbo motor? My 9k has the T25 turbo if that makes any difference to picking the most suitable replacement BOV.

Ta all.
 

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Ahhhh. Forge is the typ Rice Boy fit 'improvement'
It works NO better than the Bosch one... period.
But it's Shiny and vents to atmosphere .. ALL to please their users.
Test the Bosch one by sucking on it's vac line.. a 10 sec test with go ,or no go results
 

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How material change makes it better?
These valves are just spring loaded air seals. It matters not what they are made of. It matters what quality the spring is since that determines how rapidly and firmly it closes. The correct spring to react properly to the air pressure rise when the throttle closes is essential. This device is there to prevent air leaks to the atmosphere (which a dump valve does, dumps to the atmosphere) and react quickly enough to prevent pressure waves reflecting off the closed throttle plate and damaging the compressor blades.

If yours isn't working fit a new one matching oem performance specification. Metal case is not better.
 

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How material change makes it better?
Dohhh! Metal ones are Shiny And Sparkly!
Very Important attributes for.. Too many .. unfortunately
In fairness some feature an adjustment on spring pressure to raise and even Lower ;) Blow off pressure point.. for Mo' noises presumably.
Bosch ones, despite provenance have proven to be fairly solid bullet proof items .. they are also available in hi pressure versions (stronger spring ) to handle much higher boost pressures.
In short; IMO the last part one needs consider upgrading until well into a GTR turbine setup.
 

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Dohhh! Metal ones are Shiny And Sparkly!
Very Important attributes for.. Too many .. unfortunately
Who said anything about the appearance?

If yours isn't working fit a new one matching oem performance specification. Metal case is not better.
If something as stupidly simple as this device (with one moving part) fails, I'm not replacing it with the same part. I'm choosing something that can't or won't fail the same way. The same reason I chose an all aluminum radiator; I'm tired of dealing with crumbling end tanks, but to each their own.

Some aftermarket parts are built better than OEM, believe it or not.
 

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The quality of the BOV depends on the quality of the spring. They all use steel springs. Eventually, the spring loses some of its springiness. You will probably need two bov on your SAAB, the one that came with it and one replacement.
 

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Who said anything about the appearance?


If something as stupidly simple as this device (with one moving part) fails, I'm not replacing it with the same part. I'm choosing something that can't or won't fail the same way. The same reason I chose an all aluminum radiator; I'm tired of dealing with crumbling end tanks, but to each their own.

Some aftermarket parts are built better than OEM, believe it or not.
Have Owned a "forge" BOV It was NO better than the Bosch.. Period.
Despite it's Shiny case it soon proved itself not one teeny bit superior.
Damned Few if Any aftermarket parts equal, let alone surpass OEM bits.
Taken Me 40 years to assimilate that wee bit of wisdom.

Bosch... bless their greedy lil hearts... Got their BOV design Right !.. period

YOU think it's releasing too Early?
Assuming you've used a calibrated gauge to 'verify' this of course ?
Reverse it then ... That puts the pressure with the spring rather than against it .
Gee who woulda thought?
 

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The quality of the BOV depends on the quality of the spring. They all use steel springs. Eventually, the spring loses some of its springiness. You will probably need two bov on your SAAB, the one that came with it and one replacement.
Therein lies the value of an adjustable aftermarket unit. A few turns of the screw (or a cheap spring replacement) and you're back in business rather than trashing the whole part.

Have Owned a "forge" BOV It was NO better than the Bosch.. Period.
A part that is equal in performance and superior in longevity, is superior on the whole.
 

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Therein lies the value of an adjustable aftermarket unit. A few turns of the screw (or a cheap spring replacement) and you're back in business rather than trashing the whole part.



A part that is equal in performance and superior in longevity, is superior on the whole.
Regardless of price?
 

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A part that is equal in performance and superior in longevity, is superior on the whole.
And.. Of course you have had a Forge gizmo in daily use for 20 + years ?
How else could you be Sooo certain of that 'longevity'?
Let it Go :) yer pissing up the wrong tree on this one

Note that most.. Every.. Saab's Bosch BOV has done 20+ years... happily.
Wanna a Hi Pressure BOV? Get a Bosch one for a Viggen. Cheapish too.
 

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Regardless of price?
Yes. If we're going to bring price into the discussion, cheap Chinese wheel hubs could be considered "better" than OEM.

I don't feel strongly either way about the Bosch valve. It's the disposable razor of BOVs. I just prefer the serviceability and adjustability of aftermarket units.

It's obvious the Bosch part was built down to a price, and for the most part, it's adequate. Condemning anything non-Bosch as shiny rice-boy gear is going a bit far.
 

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Are you suggesting that the Chinese can't make good quality auto parts? How about Mexicans? Seriously, you think labour costs affect product quality?
 
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