I've seen it both ways.
Is there any difference between the two locations?

 

you all need to learn the difference between the two... Please search for POV vs BOV...I remember explaining this to the famous AArotary a little while back.

cheers..
Johnny

 

http://www.alltrac.net/tuning/bovfaq.html

 

I know the difference between a Pop Off Valve and a Blow Off Valve.

I have seen the BOV mounted on the greddy elbow and have seen it between the turbos and intercooler.

What is the difference in location, if any?

 

Well, in the FAQ posted it says that it should be mounted near the TB for the best responsiveness but it will get louder when moved near the turbos.

 

I got my blitz bov before the fmic. I have it mounted in the stock location as of now. Never noticed a difference sound wise before and after fmic.

 

here is some good read, regarding whether to mount bov before or after ic.

quote
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I'm having new intercooler piping made and I want to know where the best place to install the blow-off valve is?

I've not seen any conclusive results that prove that one position is better than another, but many people have different ideas about this. Some say that it's best to have it close to the throttle, since that's where the back-pressure builds from when the butterfly is closed and it will respond quicker. Others say that it's better to put it as close to turbo as possible so that the valve is venting hot air rather than post-intercooler cold air, so that the inlet pipes after the intercooler are still filled with cool air.

Both positions have their merits, but are really of minute benefit. There is a trap to watch out for when mounting close to the turbo however. There is often a measurable pressure drop between the turbo and throttle body, especially as the RPM and hence the airflow increases. A BOV uses two pressure signals to stay shut, one from the manifold and one from the inlet, which act on opposite sides of the piston and since they oppose each other they should balance out, and the spring then holds it shut.

The problem is when the revs rise and there becomes a pressure difference between the two signals. The pressure leaving the turbo may be say 16psi, while only 13 or 14 psi makes it to the manifold. So this means that there is 2 or 3 psi of pressure acting against the spring, which is enough to move the piston a fraction. In the Hybrid and Bovus Maximus valves, since the outlets are staged and one is placed very close to the seat for rapid response this slight spring compression can be enough to open the valve a small amount. It is not a problem with the other valves in the range, and it depends on the flow efficiency of your intercooler and pipes, but for the Hybrid and Bovus Maximus valves it is best to locate them after the intercooler.

If this problem does show up then it may also be a good idea to test the efficiency of your piping by measuring boost at redline just after the turbo, and after the throttle body. If there's any more than about 3 psi difference then your turbo is working harder than it needs to.
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it came from here
http://www.gofastbits.com/faq.htm

hope that helps

Randy

 

thank you