THE GREAT Diverter Valve FACE-OFF
that and all you ever wanted to know about a recirculating valve
+ some
Forge vs Bailey vs Bosch TT vs 1998 Bosch vs Stratmosphere vs TurboXS vs Porsche
by Eric Tam member of Passatworld.com
How does the DV work?
What ways can the DV can fail?
How does a DV cause surging?
Installing the DV in reverse?
Testing the Diverter Valves
Results of the Testing
Interpretating Results
Visual inspection/Pressure Test
How about Blow-Off Valves?
Shimming the DV spring?
My conclusions/recommendations
Cleaning Instructions for DV's
Frequently Asked Questions
Links!!!
Pictures
Installation Instructions
Contact me
What happens when you install the DV backwards in Reverse?
Thanks to user feedback, the PRESSURE TEST was added. This pressure test not only distinguished the better DV's apart from each other, but it also helped provide useful feedback about how the individual DV's should be installed. The testing did not take into account the boost pressure in #3 (the vacuum line) during acceleration (but that's ok). Many people (including myself) tap their boost gauges from this 3.5mm vacuum hose! This explains why some DV's can be installed in reverse. The pressure test performed is still correct in that it determines which way it should be installed. aka... if the spring end can hold more pressure WITHOUT the assistance of boost pressure, then it should be installed in reverse.
Orientation the DV is supposed to go (look carefully)
Note: 18 is where the Mity Vac Plugs into for vacuum suction
Also from Here: http://forums.audiworld.com/performance/msgs/47197.phtml
| The function and sole job of the dv is to maintain an
air-tight seal during acceleration, and remain open at all other
intervals. It's as simple as that. No matter which way you install it, there is pressure that's going to try to open up the spring and release air. During accelerationg (installed in reverse): spring tension (13-14psi) + Manifold pressure (15-16psi) - turbo pressure (15-16psi) --------------------------- Total pressure against port #1 (13-14psi) During acceleration (installed normally): spring tension (13-14psi) + manifold pressure (15-16psi) - turbo pressure (15-16psi) --------------------------- Total pressure against port #2 (13-14psi) Proof of this is given in the experiment that was done with the bike pump. If there were no pressure pushing the spring open, then I would have been able to EASILY pump more than 10psi of air into port#2 before it started leaking. Now that being said, one can argue about the surface area that's pushing on it and so forth. (look at example below) Now that we have determined that at each port, there's the same amount of pressure keeping the DV shut, We go back to my original wording of "if the spring end can hold more pressure WITHOUT the assistance of boost pressure [than the other end], then it should be installed in reverse." It's hard to understand the above unless you visualize it. I had to read it three times to myself, and I wrote it!!! The question is why? and prove it! Firstly, proof is that I simply blew air into each port. The winner (side that held more psi) gets to point down into the IC piping. (In the Forge's case, the port that held more pressure was the one with the spring) Why? Well I'm sure someone can explain it better than me, but I'll take a gander at this... Let's use a balloon as an example. 1. You have a water balloon (small) symbolizing the port end with the spring (less volume) 2. You have a regular balloon (normal) symbolizing the other end (more volume) Which one is easier to blow bigger? (normal balloon) The Boost pressure from the turbo is doing the exact same thing your mouth is to the balloon. In the end though, does it REALLY REALLY matter which way the aftermarket forge is installed? As long as you don't leak and the DV does it's simple job of opening and closing, then you're aok. That's how good the forge, strat, and bailey are. Remember that not all springs are the same, and that springs do become weaker over time. |