550 exhaust valve/back pressure/engine torque question | FerrariChat
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550 exhaust valve/back pressure/engine torque question

Discussion in '456/550/575' started by Mario149, Aug 25, 2014.

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  1. Mario149

    Mario149 Rookie

    Dec 11, 2009
    17
    London, UK
    #1 Mario149, Aug 25, 2014
    Hi all,

    I'm normally active over on the UK PistonHeads forum and Club Scuderia forum under the same username, but do drop in here occasionally :) I thought I'd post this up here as it'll have a wider audience....

    My understanding is that part of the reason the standard 550 mufflers have a valve is that at lower revs some back pressure from the exhaust system is required in order to increase engine torque (to complement opening at higher revs for increased power).

    Does anyone have any idea (from say before and after dynos) how much low down torque one might lose by fixing the valve open or fitting an unvalved system?
     
  2. tazandjan

    tazandjan Three Time F1 World Champ
    Lifetime Rossa Owner

    Jul 19, 2008
    39,071
    Clarksville, Tennessee
    Full Name:
    Terry H Phillips
    #2 tazandjan, Aug 25, 2014
    Mario- I doubt you would lose any torque you could feel with your rear end dynamometer. The primary reason for the valves is noise reduction for European and other nations' noise standards.

    Much of the other writing on the bypass valves is marketing hype.
     
  3. Mario149

    Mario149 Rookie

    Dec 11, 2009
    17
    London, UK
    #3 Mario149, Aug 26, 2014
    Good to know :) I've been trying to find an exhaust "solution" that I like - currently have straight pipes replacing the x pipe with standard mufflers but with valve perm open. Sounds pretty good but haven't had a chance to drive it out of the car park due to being away! Was wondering what to expect!


    Sent from my iPhone using Tapatalk
     
  4. 575

    575 F1 Rookie
    Owner Silver Subscribed

    Nov 20, 2009
    4,643
    #4 575, Aug 27, 2014
    Do a search on youtube there are various examples of different 575 exhaust sounds.
     
  5. tazandjan

    tazandjan Three Time F1 World Champ
    Lifetime Rossa Owner

    Jul 19, 2008
    39,071
    Clarksville, Tennessee
    Full Name:
    Terry H Phillips
    #5 tazandjan, Aug 27, 2014
    I love my HGTC exhaust with factory straight pipes, but they are hard to find used and unaffordable new. But that is too quiet for some. I have Steve Bisel's bypass override kit, but have not installed it yet.
     

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