[Main Performance Bulletin Board | BBFAQ | Prev by Date | Next by Date | Post Followup ] Member Login / Signup - Members see fewer ads. - Latest Member Gallery Photos Relax Like This Post: - Subscribe to Daily Digest for this Bulletin Board Posted by AdamB [Email] (#3) [Profile/Gallery] (more from AdamB) on Fri, 22 Nov 2002 01:37:21 In Reply to: Dean/Adam: OK, so where's your new test?, Greg Netzner, Thu, 21 Nov 2002 15:36:37 Alert me when someone posts in this thread: Members do not see ads below this line. - Help Keep This Site Online - Signup

It wasn't an attack on you or the guy testing the valves. Just trying to correct a misunderstanding.

Of course, there are decisions to be made: do you want as light a spring as possible to allow the valve to open as quickly as possible to avoid any potential damage to the turbo, or do you want as stiff a spring as possible so that the turbo is on-line as long as possible? The downside to the first choice is less boost-time, while the second choice might allow the pressure wave to kick back to the impeller."

As the tester, you've gotten the idea that the important thing about a diverter/BOV/dumpvalve is that it should hold boost as long as possible ("Less boost time"). This is not the case. What causes lag is if the valve *doesn't* open fast enough, and the pressure wave is allowed to slow down the impeller. Thus a too strong spring will just create more lag. Of course the spring shouldn't be so weak that it leaks during full boost.

Thus the optimal is a spring that is weak enough to allow quick and full opening, preventing compressor stall, and strong enough to hold boost.

That is why I responded both then and now. Because the test has a basic misconception of how the valves work.

posted by 212.242.115...

• Need to replace my BOV..., Aero9k, Tue, 19 Nov 2002 23:05:47
  • So you're replacing a BOV with a DV?, Greg Netzner, Wed, 20 Nov 2002 11:59:27
    • Re: So you're replacing a BOV with a DV?, Aero9k, Wed, 20 Nov 2002 22:11:50
    • Some comments and analysis, Dean, Wed, 20 Nov 2002 12:58:13
      • That's exactly what I thought when I read it..., AdamB , Thu, 21 Nov 2002 05:34:35
        • Dean/Adam: OK, so where's your new test?, Greg Netzner, Thu, 21 Nov 2002 15:36:37
          • Relax, AdamB , Fri, 22 Nov 2002 01:37:21 <-- Viewing This Message
            • I'm relaxed, man, Greg Netzner, Fri, 22 Nov 2002 12:33:33
              • Say what?, AdamB , Fri, 22 Nov 2002 14:02:14
                • And contradictory? (...and I'm still relaxed...), Greg Netzner, Fri, 22 Nov 2002 18:00:00
                  • Not contradictory, AdamB , Fri, 22 Nov 2002 19:51:07
                    • Sounds good to me, Greg Netzner, Sat, 23 Nov 2002 01:19:00
      • I have trouble with the piston facing the pressure., SteveW, Wed, 20 Nov 2002 15:14:05
        • Re: I have trouble with the piston facing the pressure., Dean, Thu, 21 Nov 2002 11:13:38
          • Not sure I understand what your suggestion is..., SteveW, Thu, 21 Nov 2002 15:33:28
            • Steve, take a look at this link..., Greg Netzner, Thu, 21 Nov 2002 15:42:55
      • Thanks, more info is a good thing, Greg Netzner, Wed, 20 Nov 2002 14:14:11
        • same I think, Chris M, Fri, 22 Nov 2002 16:08:33
          • Viggen valve an upgrade?, Greg Netzner, Fri, 22 Nov 2002 16:40:21
            • could be, Chris M, Sat, 23 Nov 2002 09:24:23
              • Let us know what you discover! +, Greg Netzner, Sun, 24 Nov 2002 03:04:00
  • Re: Need to replace my BOV..., zeke, Wed, 20 Nov 2002 05:12:07
    • First post be gentle...do you really need to buy only, Tony O, Thu, 21 Nov 2002 00:07:43
      • try this tony, Chris R., Fri, 22 Nov 2002 03:59:02
        • Re: try this tony, Tony O, Fri, 22 Nov 2002 04:11:14
          • Tony, more info, Greg Netzner, Fri, 22 Nov 2002 12:45:27
          • Re: try this tony, Wade, Fri, 22 Nov 2002 12:20:14
          • Reason for better performance with higher octane, AdamB , Fri, 22 Nov 2002 04:21:31

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