Testing the bypass valve
05-20-2004, 09:38 AM
#1
Drifting
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Location: Tucson AZ, Dallas Tx sometimes
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Testing the bypass valve
Ok another one of my "how do you test the _____?" posts.
How do you know if your bypass valve is bad? I plugged the hole in the J tube and put a small piece of paper in the outlet for the bypass valve (air coming out would remove it), went driving and the paper is still there.
Could it be a vacuum hoze problem? The hoze going to the valve is getting boost pressure.
Can you test it any other way and if not does anyone have recomendations for an aftermarket valve or dos anyone have a stock Bosch valve cheap?
I dont like the idea of not having a working bypass valve.
Thank you
Sean
How do you know if your bypass valve is bad? I plugged the hole in the J tube and put a small piece of paper in the outlet for the bypass valve (air coming out would remove it), went driving and the paper is still there.
Could it be a vacuum hoze problem? The hoze going to the valve is getting boost pressure.
Can you test it any other way and if not does anyone have recomendations for an aftermarket valve or dos anyone have a stock Bosch valve cheap?
I dont like the idea of not having a working bypass valve.
Thank you
Sean
05-20-2004, 10:29 AM
#2
Nordschleife Master
To test the stock valve itself is fairly easy. Pull it off and suck and blow on the 2 main ports. You are looking for the diaphragm being torn and if any air passes in your test, it is.
The next problem is whether the vacuum line going to the little port on top of the BOV is pulling vacuum. Just put your finger over the end of it and see if it pulls a vacuum. I guess you could get more sophisticated and attach a gauge and see how many inches of vacuum it is pulling.
If you want to go away from the upgraded Porsche BOV a lot of people like the Forge one - I think there is a group buy going on for that. Though it will be quite a bit more expensive than the stock BOV at $25 or $30.
The next problem is whether the vacuum line going to the little port on top of the BOV is pulling vacuum. Just put your finger over the end of it and see if it pulls a vacuum. I guess you could get more sophisticated and attach a gauge and see how many inches of vacuum it is pulling.
If you want to go away from the upgraded Porsche BOV a lot of people like the Forge one - I think there is a group buy going on for that. Though it will be quite a bit more expensive than the stock BOV at $25 or $30.
05-20-2004, 11:23 AM
#3
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If your bypass valve is totally bad, like mine was when I first got the car you don't even have to remove it to test.
Just pull off the vacuum fitting at the top and put your lips over the small pipe and see if you can blow or suck. On a good valve you will be able to do neither.
Just pull off the vacuum fitting at the top and put your lips over the small pipe and see if you can blow or suck. On a good valve you will be able to do neither.
