What to do about the diffusers on the 355? | FerrariChat
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What to do about the diffusers on the 355?

Discussion in '348/355' started by treedee3d, Jan 11, 2015.

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  1. treedee3d

    treedee3d F1 Rookie

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    #1 treedee3d, Jan 11, 2015
    My diffusers are pretty banged up, few small chunks missing, etc...

    Can/should they be replaced?

    has anyone fixed theirs? are they fiberglass?
     
  2. yelcab

    yelcab F1 World Champ
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    #2 yelcab, Jan 11, 2015
    It's fiberglass, pretty easy to fix.
     
  3. 308 GTB

    308 GTB F1 World Champ
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    #3 308 GTB, Jan 11, 2015
    They're fiberglass and can be easily repaired.

    Barry
     
  4. 308 GTB

    308 GTB F1 World Champ
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    #4 308 GTB, Jan 11, 2015
  5. 2NA

    2NA F1 World Champ
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    #5 2NA, Jan 11, 2015
    I've fixed quite a few. Easy job.
     
  6. treedee3d

    treedee3d F1 Rookie

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    #6 treedee3d, Jan 11, 2015
    someone's gonna be watching some fiberglass how-to diy videos on youtube...��
     
  7. junglistluder

    junglistluder F1 Rookie
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    #7 junglistluder, Jan 12, 2015
    Last edited by a moderator: Sep 7, 2017
  8. treedee3d

    treedee3d F1 Rookie

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    #8 treedee3d, Jan 12, 2015
    I saw these in another thread and it made me think of my car and the poor condition of the diffusers.

    Rear Dif fuser

    However, too expensive for a part you barely see....just don't wanna spend that kind of money so I'll take them off and repair them myself.
     
  9. junglistluder

    junglistluder F1 Rookie
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    #9 junglistluder, Jan 12, 2015
    I think the rear diffusers are much more visible than the door sills that everyone replaces with carbon, altough the diffusers are double the price.
     
  10. treedee3d

    treedee3d F1 Rookie

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    #10 treedee3d, Jan 12, 2015
    Good point, except the OEM sills are less durable and more prone to degrading than the diffusers hence it's a more popular aftermarket upgrade.
     
  11. GerryD

    GerryD Formula 3

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    #11 GerryD, Jan 12, 2015
    The pieces around the exhaust opening that are riveted on are unsightly and a waste of money.
     
  12. junglistluder

    junglistluder F1 Rookie
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    #12 junglistluder, Jan 12, 2015
    I think everyone agrees on that point. They aren't included with the carbon sills :)
     
  13. ShineKen

    ShineKen F1 World Champ
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    #13 ShineKen, Jan 12, 2015
    Treedee3d. Can you post pics of the chunks missing on your rear diffuser?
     
  14. KMR968Turbo

    KMR968Turbo Formula 3

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    #14 KMR968Turbo, Jan 12, 2015
    I have the diffuser's and belly pans off my Challenge car as I was checking for leaks. I have one belly pan that could use some repairs but luckily my diffusers are still in good shape. Good to know they can be repaired as buying new is not a cost effective option - especially with the ducting for brakes built in.
     
  15. junglistluder

    junglistluder F1 Rookie
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    #15 junglistluder, Jan 12, 2015
    The Challenge rear diffusers have brake ducts?! Can you post a pic?
     
  16. treedee3d

    treedee3d F1 Rookie

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    #16 treedee3d, Jan 12, 2015
    They're not huge chunks but some small bits have come off (probably with a bump in the road contact at some point)

    There are also some cracks near the holes where they attach to the car.

    Unfortunately, car is in winter hibernation tucked in until April so I can't get a pic right now.
     
  17. cf355

    cf355 F1 Rookie

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    #17 cf355, Jan 12, 2015
    I have fibreglass'd mine (small cracks, some pieces missing)....replaced the gel coat as well and repainted semi matt black.
    They look as good as new until the next time I bottom out :)
    Easily repairable in a weekend.
     
  18. treedee3d

    treedee3d F1 Rookie

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    #18 treedee3d, Jan 12, 2015
    What's the gel coat? Is that the finish that goes on top of the Fiberglass to smooth out the surface?

    Pardon my ignorance....
     
  19. 308 GTB

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    #19 308 GTB, Jan 12, 2015
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  20. fatbillybob

    fatbillybob Two Time F1 World Champ
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    #20 fatbillybob, Jan 12, 2015
    Weird. Ducts in the diffuser tray would loose some of the aero benefit no?
     
  21. 308 GTB

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    #21 308 GTB, Jan 12, 2015
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  22. ShineKen

    ShineKen F1 World Champ
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    #22 ShineKen, Jan 13, 2015
    Off topic. How does the air from the scoops going towards the clutch pumpkin vent out?
     
  23. ShineKen

    ShineKen F1 World Champ
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    #23 ShineKen, Jan 13, 2015
    Funny thing is the actual 355 undertray/rear diffuser doesn't seem to have as much curvature towards the rear as the picture depicts. To get more angle the very oend of the diffuser would need to sit right underthe exhaust tips and sealing off the transition between diffuser and bumper completely. If the middle section can be covered up and have naca ducts leading towards the clutch cooler scoops, that should help smoothen out the flow underneath the car.
     
  24. cf355

    cf355 F1 Rookie

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    #24 cf355, Jan 13, 2015
    That's correct. I do not use any body filler or bondo. Only fiberglass with the finish gel coat.....prime and paint
     
  25. drbob101

    drbob101 F1 Rookie
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    #25 drbob101, Jan 13, 2015
    I think what treedee was asking and what was earlier referenced was whether the OEM finish and any subsequent repairs are done using fibreglass/gel coat (pigmented) as in traditional finished fibreglass like boat hulls or is it just painted fibreglass?

    I would think in the OEM application it is gel coat rather than paint but for a refinish/repair, paint will be easier and look acceptable.

    Gel-coat Products
     
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