TAP Bypass Valve...New Failure Mode?

Jimmy Pribble · 11-18-2007, 02:18 PM

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

UrS4boy · 11-18-2007, 02:30 PM

Jimmy Pribble · 11-18-2007, 02:40 PM

UrS4boy · 11-18-2007, 02:43 PM

Only-Emre · 11-18-2007, 02:45 PM

Jimmy Pribble · 11-18-2007, 02:55 PM

...but it kept hitting 30 psi, so I slapped the AutoSpeed MBC on it and turned it down to 20 psi for it's first real weekend at the track.

Jimmy

Only-Emre · 11-18-2007, 03:34 PM

They turn up on eBay all the time used.

tpierce · 11-18-2007, 04:49 PM

they still sell rebuild kits (the two o-rings is all you need) and you can get a variety of springs/washers for it.

|skolnick · 11-18-2007, 08:02 PM

c4S6 · 11-18-2007, 09:00 PM

And, the eS2 project car is done!!! Wow. That is one bad to the bone track slut! I want to build one of those so bad, but I have a few problems like... No money, No time, No place to do it, and No donor car.

Not that those things have ever stopped me before.

Any more pics of it in the finnished state you can post for us?

I see you are still hanging out with that Eric Fluhr guy too. ;^)

I'm on my 3rd ur-S car, and probably not my last.

11-18-2007, 02:18 PM	#1
Jimmy Pribble Junior Member Account #: 4916 Join Date: May 2000 Posts: 1,358	TAP Bypass Valve...New Failure Mode? 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)

11-18-2007, 02:30 PM	#2
UrS4boy AudiWorld Super User Account #: 15624 Join Date: Feb 2001 Posts: 16,974	Jimmy!!! Long time. Nice eS2R. TAP?? Wow. You are old school. __________________ Naturally, IMHHEO(tm), Dave F. aka the Librarian Car and Mods: 93 S4, 1.8t coil pack conversion (First in world using integral POS coil packs (??)), CF (OE), S6 steering wheel, RS2'd, Samcos, MRC, TDS-1, Apikol FMIC, Eibach/Bilstein, BIRA Sys 1, relayed FP Click here to link to the UrS FAQ Thread Start Uncle Dave says "You want my 'high horse, elitist' opinion ?(IMHHEO(tm))Then just post something stupid." Unofficial Chief Cat-herder Vancouver UrS-car club

11-18-2007, 02:40 PM	#3
Jimmy Pribble Junior Member Account #: 4916 Join Date: May 2000 Posts: 1,358	Anybody know where I can get tubes for my TV? __________________ '00 A6 2.7t (Sold) '94 UrS4 (Street) '93 UrS4 (RIP) '90 eS2 (Track) '83 UrQuattro (Sold)

11-18-2007, 02:43 PM	#4
UrS4boy AudiWorld Super User Account #: 15624 Join Date: Feb 2001 Posts: 16,974	You mean the B&W 2 to 13 channel one, right? Radio Shack. Really. __________________ Naturally, IMHHEO(tm), Dave F. aka the Librarian Car and Mods: 93 S4, 1.8t coil pack conversion (First in world using integral POS coil packs (??)), CF (OE), S6 steering wheel, RS2'd, Samcos, MRC, TDS-1, Apikol FMIC, Eibach/Bilstein, BIRA Sys 1, relayed FP Click here to link to the UrS FAQ Thread Start Uncle Dave says "You want my 'high horse, elitist' opinion ?(IMHHEO(tm))Then just post something stupid." Unofficial Chief Cat-herder Vancouver UrS-car club

11-18-2007, 02:45 PM	#5
Only-Emre Member Account #: 102203 Join Date: Dec 2005 Posts: 3,408	What size turbo are you running? __________________ Owners of 1992-1997 Audi S4/S6 sedans or avants, saloons or estates, add yourself to the map! <big>1990 Coupe quattro 20v</big>_________<big>1992 S4 20vT</big> <big>AIM: Emresaurus Rex</big>

11-18-2007, 02:55 PM	#6
Jimmy Pribble Junior Member Account #: 4916 Join Date: May 2000 Posts: 1,358	My car is 100% RS2 + "Lehman" Stage Whatever code from Anderson... ...but it kept hitting 30 psi, so I slapped the AutoSpeed MBC on it and turned it down to 20 psi for it's first real weekend at the track. Jimmy __________________ '00 A6 2.7t (Sold) '94 UrS4 (Street) '93 UrS4 (RIP) '90 eS2 (Track) '83 UrQuattro (Sold)

11-18-2007, 03:34 PM	#7
Only-Emre Member Account #: 102203 Join Date: Dec 2005 Posts: 3,408	Then a simple Hyperboost MX or Froge 007 BPV will do well. They turn up on eBay all the time used. __________________ Owners of 1992-1997 Audi S4/S6 sedans or avants, saloons or estates, add yourself to the map! <big>1990 Coupe quattro 20v</big>_________<big>1992 S4 20vT</big> <big>AIM: Emresaurus Rex</big>

11-18-2007, 04:49 PM	#8
tpierce Elder Member Account #: 32906 Join Date: Feb 2002 Posts: 17,045	2nd, on the Forge 007P they still sell rebuild kits (the two o-rings is all you need) and you can get a variety of springs/washers for it. __________________ ----------------------------------- aim: tmpierce0000

11-18-2007, 08:02 PM	#9
\|skolnick AudiWorld Super User Account #: 67654 Join Date: Jan 2004 Posts: 23,689	710N __________________ 1990 Audi Coupe Quattro - Tornado Red 1990 Audi Coupe Quattro - Black 1992 Audi S4 - Cyclamen Pearl Effect 2008 DR-Z400SM - Black

11-18-2007, 09:00 PM	#10
c4S6 AudiWorld Senior Member Account #: 114659 Join Date: Sep 2006 Location: Atlanta, GA Posts: 3,591	Jimmy, good to see you are still alive.... And, the eS2 project car is done!!! Wow. That is one bad to the bone track slut! I want to build one of those so bad, but I have a few problems like... No money, No time, No place to do it, and No donor car. Not that those things have ever stopped me before. Any more pics of it in the finnished state you can post for us? I see you are still hanging out with that Eric Fluhr guy too. ;^) I'm on my 3rd ur-S car, and probably not my last. __________________ Dan Hussey Atlanta, GA '95.5 Audi S6 Sedan (Silver/Platinum) '87 BMW E30 track slut "Der Warsteiner!" '03 Land Rover Discovery 'S' 4.6 FOR SALE, PLEASE BUY ME "Middle class is defined as a subsection of the population which includes everybody."

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode


Discussion Forums:	Advanced Search