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488 Question about Exhaust Bypass Valves

Discussion in '458 Italia/488/F8' started by bisel, Feb 28, 2016.

  1. SAFE4NOW

    SAFE4NOW F1 Rookie
    Sponsor Owner

    Aug 25, 2004
    4,019
    Dallas Texas
    Full Name:
    Steve F
    The files will not download. PM me your e-mail and I will send them to you.

    S
     
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  3. SAFE4NOW

    SAFE4NOW F1 Rookie
    Sponsor Owner

    Aug 25, 2004
    4,019
    Dallas Texas
    Full Name:
    Steve F
    I have not noticed a drone while driving. I will pay special attention to it today.
    I expect the Turbo may muffle any droning , but that's just my opinion.

    The good thing about disconnecting the bypass valves is that it's simple to put back the way it was. AND, if you ask , you can have a rubber line T'd into the vac line, routed up into the engine compartment , so you can " plug " or "unplug" it when you want.

    We don't charge any extra to do it. Not as fancy as the Capristo , but just as functional.

    S
     
  4. bisel

    bisel Formula 3

    Sep 12, 2012
    1,225
    Scottsdale, Arizona
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    Steve Bisel
    Yes, several people have installed the Forza bypass valve switches on 488's and Cali-T's


    Regards,

    Steve
     
  5. Melvok

    Melvok F1 World Champ
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    Jul 25, 2008
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    Mel
    #29 Melvok, May 10, 2016
    Last edited by a moderator: Sep 7, 2017
  6. Melvok

    Melvok F1 World Champ
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  8. bgomez

    bgomez Karting

    Nov 3, 2003
    59
    How hard is to access the vacuum lines? Someone indicated it requires rear bumper removal and maybe another body part?
     
  9. bisel

    bisel Formula 3

    Sep 12, 2012
    1,225
    Scottsdale, Arizona
    Full Name:
    Steve Bisel
    Not sure of the correct answer. But, get down under the rear of the car and determine if you can see two vacuum lines going to the exhaust systems (one for each). Can you trace the lines to the diaphragm actuators? If not, can you easily remove the air diffuser? This might give you better access. The diffuser should be pretty easy to remove vs. the rear bumper. Let us know what you find out.

    Steve
     
  10. PhilNotHill

    PhilNotHill Two Time F1 World Champ
    Silver Subscribed Owner

    Jul 3, 2006
    27,566
    Aspen CO 81611
    Full Name:
    FelipeNotMassa
    That yellow 488 looks like it has buck teeth in the video. I would wrap them black or carbon fiber.
     
  11. bgomez

    bgomez Karting

    Nov 3, 2003
    59
    So I took my 488 to the dealership and asked them how hard and what had to be removed to access the vacuum lines so that the bypass valves could remain open. Some had mentioned the bumper had to be removed and the rear diffuser too. I was told just the rear diffuser had to be removed. 1 hrs of service and it was complete. Much happier now. Sounds so much better. No annoying open close open close. Startup and warm up sounds great too. No highway droning either. Driving at low speed low rpm sounds great too.
     
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  13. IMPEX4

    IMPEX4 Karting

    Feb 5, 2006
    138
    Full Name:
    Eric

    at low RPM's that 458 sounds atrocious...like a chevy small block with a bad carburetor and a hole in the muffler
     
  14. lamarmotte

    lamarmotte Karting

    Feb 5, 2014
    194
    France
    I think in the 488, the position of the exhaust valves have not a big impact of the engine noise in the cabin. Because the 488 is fitted with the sound generators, the vaccum plenum is connected to the cabin.

    See the video at 24:18 in the cabin and 24:39 outside, simultaneous filmed, you can hear brieffly the noise with the valves opened and closed

    https://youtu.be/ndkX5Z2MY3E?t=24m15s
     
  15. metaldriver

    metaldriver Formula Junior

    Apr 6, 2015
    611
    Houston, Texas
    Full Name:
    Andy Vecsey
    Or a Forza Componenti, offered by the OP.
     
  16. BLKM3

    BLKM3 Formula Junior

    Jun 26, 2005
    396
    California
    Full Name:
    J
    Awesome post! Thanks for the education!
     
  17. old man

    old man Karting

    Jul 8, 2010
    54
    On my 488, I paid about $550 for the Capristo bypass. Unfortunately, the selonids wire connections are about 10mm too far inboard for easy grabbing so the bumper has to come off - otherwise it would have been as difficult as unplugging a lamp and replugging it in. Didn't want to risk the paint so I had the dealer do it for $350. Everytime you start the car, the vacuum closes to valve so you must use to switch to open them. However, on my wife's 2016 Cal T, I removed the rear tires and back liner, plugged the vacuum lines and within an hour had the valves open - for free. Woudl do the same with the 488 had I realized how easy it was and that the valves should be open all the time. Turbo cars don't need backpressure like normally breathing engines, so there is no power/torque loss.
     
  18. bgmix

    bgmix Formula Junior
    Owner

    Aug 1, 2009
    612
    AZ|NYC|FL
    Full Name:
    Bob Giammarco
    Just installed Steve's (Forza) bypass controller in my 458 and it's excellent. A much needed upgrade.
     

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