Thread: K27-7200 issue
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spuggy spuggy is online now
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Join Date: Jul 2003
Location: Glorious Pac NW
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Quote:
Originally Posted by Alan L View Post
The diverter valve is the small plastic valve body on the rubber elbow?
How would I check it?
Alan
The plastic Bosch recirc valve used is not especially well-regarded in the high-boost watercooled world. They may react faster than the piston type (less mass), but really not by much and flip side is that they're prone to diaphragm tears. And sealed, so can't be serviced.

Cost was very obviously a major factor in the design. (And there's more than one SEAT/VAG part that seems to be identical to the Porsche part, but is much cheaper to buy....)

I held a plastic 965 valve in my hand for about 30 seconds looking at it - then headed inside and bought a Forge billet replacement for $60 on Ebay instead... They're double the price now, but same principle...


http://www.vaglinks.com/Docs/Misc/VAGLinks.com_DIY_Testing_a_Bosch_Diverter_Valve.pd f
https://www.audizine.com/forum/showthread.php/357594-Everything-you-want-to-know-about-Bosch-Diverter-Valves
https://rennlist.com/forums/944-turbo-and-turbo-s-forum/505532-inside-of-a-dead-bosch-recirculation-valve.html

Many aftermarket choices, including brand names like Forge, Tial and TurboSmart, all making recirc/dump valves. Routing is the only difference; you can't dump metered air on CIS, so you recirc back into the intake between the metering plate and the compressor, a dump valve just dumps back to atmo.

The Forge lasted well for me - I'd take the top off every year or so, say "hmm, still lubed/clean/moves", screw the top back on and forget it again.

The Tial dump valve I have seems very high quality too. Oddly, it's much cheaper than the Forge...
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'77 S with '78 930 power and a few other things.
Old 04-10-2018, 01:21 PM
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