I'm guessing this post will mostly be met with blank stares. I don't know of anybody still using the TAP BPV anymore, but here is one for any of the Old School still left out there...the Mafioso...the Jedi Knights.

Back in the last millennium (really), one of the very first aftermarket bypass valves was one marketed (though probably not manufactured) by TAP. It was an aluminum bodied, plunger type valve that had the additional distinction of having an adjustable spring preload.

It was very successful and many of the early S-Car listers used this BPV. Soon though, the market was flooded with aftermarket bypass valves and I think many, most, or all folks moved-on to different products. I always thought it was a very nice product, though, and found no need to go solving a problem that I didn't have, so I have been using it ever since.

This past weekend, I was at a track event and I came rushing up on a Z4 who threw me a passing signal and checked his speed way more than I would have preferred. I didn't want to take the pass, so I completely lifted out of the throttle at full boost (which was turned down to just 20 psi). I heard a loud "pop" and I lost all of my power. I was certain that I had popped-off an intercooler hose. Eventually, I made my way back to the paddock, we opened the hood, and this what we saw:



The body of the TAP bypass valve had separated! I have never known the body of a bypass valve to fail - not even the plastic ones we are so fond of replacing.

Judging by the above photo, it appears that the separation occurred at a press-in fitting, which was under some off-axis tension. In other words, it looks like the valve didn't square with that orange silicone hose and with the help of some boosting around, the press-in nipple was pulled off.

I still think this is a great little valve, so I will probably just have the nipple TIG welded back on. Since it has to go in for surgery, I thought I would re-anodize it and service it as well. TAP used to sell rebuild kits. If they don't have any more, does anybody know:

a. who was that actual manufacturer of this valve,
b. where rebuild kits (probably just spare polyurethane plungers) can be purchased,
c. and what the best alternative would be, should I choose not to use this valve again? I haven't seen a good BPV fight thread in a long time. ;-)

Jimmy

• Poster Sized Post Mortem Photo of TAP BPV

'00 A6 2.7t (Sold)
'94 UrS4 (Street)
'93 UrS4 (RIP)
'90 eS2 (Track)
'83 UrQuattro (Sold)