Let's talk Bypass valves
08-05-2012, 02:36 PM
#1
Rainman
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Let's talk Bypass valves
Would like to find some input from the crowd here as the intertubes do not produce much in useful results.
Found this Bosch bypass valve at the boneyard yesterday, got it for $5. Came off a Saab 900 turtlewagon. Came home and compared to 951 bypass valve - they have the same body, the same size inlet and outlet ports. Only difference seems to be part number. Porsche is 0280142102, Saab is 0280142105. Research shows that the Saab part was fitted to turbocharged automatic 2.0L engine, don't know if 8 or 16v. The 16v apparently came with 11psi boost from the factory, the same as the 944T...so why would they make two seemingly identical valves for the same purpose?
There is something interesting though, a number on the diaphragm on the inside of the valve. The Porsche says "1.6" and the Saab says "4.3"...does this have any significance? Maybe valve closing pressure (but then why would Bosch use PSI?)
Porsche on left, Saab on right.
Found this Bosch bypass valve at the boneyard yesterday, got it for $5. Came off a Saab 900 turtlewagon. Came home and compared to 951 bypass valve - they have the same body, the same size inlet and outlet ports. Only difference seems to be part number. Porsche is 0280142102, Saab is 0280142105. Research shows that the Saab part was fitted to turbocharged automatic 2.0L engine, don't know if 8 or 16v. The 16v apparently came with 11psi boost from the factory, the same as the 944T...so why would they make two seemingly identical valves for the same purpose?
There is something interesting though, a number on the diaphragm on the inside of the valve. The Porsche says "1.6" and the Saab says "4.3"...does this have any significance? Maybe valve closing pressure (but then why would Bosch use PSI?)
Porsche on left, Saab on right.
08-06-2012, 05:12 AM
#5
Professional Hoon
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call up a spare parts store and get a price on both, would be quite interesting if there's a difference.
might be the same part just a different part number because the car it's used in or might be a year thing
might be the same part just a different part number because the car it's used in or might be a year thing
08-06-2012, 10:43 PM
#7
Three Wheelin'
The Bosch 110 BPV worked great on my mothers mid-2000 Saab 9-5 Aero and my 951. If you look around on some Audi forums you'll see them all prefer this valve over all other Boschs. I replaced it with a used Forge unit that I got a good deal on, otherwise it'd still be on my car.
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08-07-2012, 02:41 AM
#8
i use the audi TT valve 710N 
Here are som testing of the bosch valve
http://www.s4biturbo.com/art-dvtests.php
and here are some more info
http://www.s4biturbo.com/art-dvtests2.php
Here are som testing of the bosch valve
http://www.s4biturbo.com/art-dvtests.php
and here are some more info
http://www.s4biturbo.com/art-dvtests2.php
08-19-2019, 09:50 PM
#9
Three Wheelin'
I want to bring this thread back because I've been reading up on the turbo system all day and discovered that there is also a bypass valve with part # 0280142108. This one looks to have been used on Porsches. However, the bypass valve on my 86 951 has part # 0280142102 (only difference is the last digit).
Are they different? Is one better than the other? I read one old rennlist post that said the 108 preserved boost better during the shift.
Are they different? Is one better than the other? I read one old rennlist post that said the 108 preserved boost better during the shift.
