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Exhaust bypass valve, Capristo - 355

Discussion in '348/355' started by eulk328, Apr 4, 2010.

  1. eulk328

    eulk328 F1 Rookie

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    #1 eulk328, Apr 4, 2010
    Last edited by a moderator: Sep 7, 2017
    I recently installed the Capristo exhaust bypass valve on my 355. I've attached a couple of photos of the solenoid valve supplied with the bypass valve and some minor modifications for mounting. The Euro cars have more space for mounting since they don't have the bypass valve thermocouple and the associated ECU (one with the letters BY on it).

    I removed the left-hand solenoid from the bracket and moved the right-hand solenoid over to the left-hand location. This made room to mount the Capristo supplied solenoid which is shaped differently.

    Note: I found the Amp connector terminals on both original solenoids to have some "growth" on them. Other Amp connectors on my car look fine so this may be a location to keep an eye on.

    Red arrow shows the solenoid port that connects to the bypass valve. White arrow shows the port that stays as is (not connected or sealed in any way).

    You need space on the left-hand side of the new solenoid valve (the way I've mounted it) to be able to attach the Amp connector. That's why I've mounted the new solenoid as close to the vacuum tank as possible (although there's no contact between them).

    I used a loop in the red vacuum hose because the nipples to be connected don't line up height-wise (can't really see it in the photo). Using a short piece of hose "just the right length" would have created sharp bends possibly reducing or collapsing the interior of the vacuum hose (cutting off vacuum).
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  3. johan6504

    johan6504 Formula 3

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    Great write-up, I will be doing my swap for Capristo valve later this week :)
     
  4. darrenliu

    darrenliu Formula Junior

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    An added benefit of the capristo valve is that you can add another peirburg solenoid valve in series with the primary one and control the second valve via a remote 12 volt switch which then give you the choice of keeping the exhaust valve open full time. I know that a lot of people on this forum think this is a bad practice, but the car sounds better and feels faster.
     
  5. f355spider

    f355spider F1 World Champ
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    #4 f355spider, Apr 6, 2010
    Last edited by a moderator: Sep 7, 2017
    Interesting, the solenoid looks a bit different than the one I was supplied (picture supplied by Capristo attached). BTW, water tends to run down these cables to the Bosch connectors. The boots do not fit tightly enough and develop splits in the accordian folds, and allows water to get into the connection. The solution it to buy the tight fitting boots from Dave Helms along with the tool to take the pins out. Heck, just buy the entire kit from him, and immortalize your connectors and boots! ;) That is what I did.
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  6. f355spider

    f355spider F1 World Champ
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    Watch your catalyst ECU's, I see you have the early black style...they have a pretty high failure rate...not that the later 360 (green) ones are perfect, I still had one of them fail too about 1.5 years ago.
     
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  8. johan6504

    johan6504 Formula 3

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    Got the capristo valve with UPS this morning and found two small rubber rings enclosed, one red and one blue. Anyone that knows where these are supposed to go?
     
  9. eulk328

    eulk328 F1 Rookie

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    #7 eulk328, Apr 12, 2010
    Last edited: Apr 12, 2010
    Mine did not come with any o-rings. I SUSPECT they are meant to go on one of the nipples of the two solenoid valves to identify them (are they sized correctly for this??). Put markings of the same color on the AMP connectors and you will avoid mix ups when putting them back on after doing some work. That's my theory anyway.
     
  10. f355spider

    f355spider F1 World Champ
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    Do all the latest product Capristo exhaust bypass valves have the heatshield around the Pierberg diagram?
     
  11. johan6504

    johan6504 Formula 3

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    Not sure if all do, but mine sure did.
     
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  13. eulk328

    eulk328 F1 Rookie

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    Pretty sure they do. One of the F-Chatters had a diaphragm that failed fairly early in it's life and Capristo replaced it with, what I guess is, the new style.
     
  14. f355spider

    f355spider F1 World Champ
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    Interesting...when I bought mine a couple years ago, it came with a spare diaphram....now I know why. ;) It if ever fails, I will ask for the update.
     
  15. eulk328

    eulk328 F1 Rookie

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    #12 eulk328, Apr 12, 2010
    Last edited: Apr 12, 2010
    hmmmm....

    well at least that means you can take them apart (I would hope).

    I think it was Darren Liu who had the Cappy valve failure.


    Yes... just found it: "Old 08-25-2009, 07:33 AM
    darrenliu darrenliu is offline
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    yes, totally rattle free, but the diaphragm failed and I'm waiting for a replacement. "
     
  16. darrenliu

    darrenliu Formula Junior

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    I don't think the diaphragm is made by pierburg (there's no markings on it), but the heat shield is a simple aluminium cup that goes around the diaphragm.

    Now buy a simple remote 12volt switch of ebay (for $13) and another pierburg solenoid valve (around $80) and you keep the bypass exhaust valve open full time or back to OEM at the press of a button on the remote fob.
     
  17. FarmerDave

    FarmerDave F1 World Champ
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    This thread is worthless without sound clips.

    I think a 355 with a stage 3 capristo at WOT is the most beautiful sound ever.
     
  18. eulk328

    eulk328 F1 Rookie

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    Wrong thread to look for sound clips ;-) Bypass valves (operating ones anyway) make for quieter cars at least until about 4000 rpm.
     
  19. johan6504

    johan6504 Formula 3

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    Installed my capristo valve last week and took the car for a drive this weekend. When I got back the capristo valve was stuck in closed position and hardly moved. I have mailed capristo and hope to get it sorted as soon as possible as I have a track day coming up. It looks like this valve might not be the holy grail I was hoping fore... Any one else with this problem?
     
  20. f355spider

    f355spider F1 World Champ
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    #17 f355spider, Apr 24, 2010
    Last edited: Apr 24, 2010
    My thought is a better solution than a heatshield, is some sort of insulation on the platform the diaphragm sits on (insulating fabric or paper). The heat is transferring up from the valve itself, not from ambient heat around it. I am not so sure the metal heatshield is the solution. Even with the heatshield or insulation, heat will transfer through the three mounting bolts holding the diaphragm to the valve. Anyway, I have about 5k miles on mine, no problems. Knock wood. ;)
     
  21. f355spider

    f355spider F1 World Champ
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    Must be defective in construction, since its failure mode is supposed to be "open". I would suspect the bearing surface or flapper of the valve was too tight in tolerance, and once it got good and hot and expanded, it seized up on you. There is supposed to be some looseness in the tolerance to allow for expansion.
     
  22. eulk328

    eulk328 F1 Rookie

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    I thought about that also however I'm not certain if the "tin can" around the valve is there as a heat shield OR... perhaps as a heat sink.
     
  23. eulk328

    eulk328 F1 Rookie

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    Did it work correctly for any amount of time?
     
  24. f355spider

    f355spider F1 World Champ
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    That would make a lot more sense, based on the pictures I have see of it. I noticed the oem valve has a thin piece of insulating material between the valve and diaphragm.
     
  25. johan6504

    johan6504 Formula 3

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    Yes it worked fine for a couple of days. Then, yesterday it just got stuck. I believe it is the bearings that are the problem...
     
  26. johan6504

    johan6504 Formula 3

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    #23 johan6504, Apr 25, 2010
    Last edited: Apr 25, 2010
    Think I fond the main problem this morning.

    The valve axle is held by two screws in each end. These screws puts pressure on springs at each side which in turn puts pressure on the ball bearings. This pressure puts an even load, holding the valve in center.

    On my unit one of these screws had busted threads and didnt go all the way in. This could have put the valve off center and making it stuck on the inside.

    Used a temporary screw and it seems to work again. Think I need a new screw and a probably a new bearing since it has marking inside from moving the wrong way.
     
  27. eulk328

    eulk328 F1 Rookie

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    Glad to hear that it seems you found the problem. But still..... it is disappointing that you received such a part from the manufacturer. Please let us know if they replace your valve for free or at least provide new parts.
     
  28. johan6504

    johan6504 Formula 3

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    I am sure they will solve this, will report back as soon as I have had a chance to talk to them.
     

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