F40 straight exost | FerrariChat

F40 straight exost

Discussion in 'Technical Q&A' started by giamma, Aug 30, 2005.

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  1. giamma

    giamma Rookie

    Nov 4, 2003
    20
    #1 giamma, Aug 30, 2005
    Hi, I have a tubi exost on an F40 and I am planning to change the catalitic converte pipe with a straight pipe, so the car will be straight all the way (no cat, and no silancer). By taking the catalitic out should I vary the blow off valve? When I took the silancer away there was no need to adjust the blow off valve but now with no backpressure at all I wonder if I should adjust the blow off. Please advise if any of you have any comments.Plus has anybody listen to a total straight pipe of an F40? if so how does it sound? too much?

    thanks
    giamma
     
  2. Jerrari

    Jerrari F1 Veteran

    Jul 24, 2001
    5,463
    Michigan
    Full Name:
    Jerry Wiersma
    #2 Jerrari, Aug 30, 2005
    I have no answer to your question but I assume that you're from outside the US??
     
  3. hanknum

    hanknum Formula 3

    Nov 1, 2003
    2,050
    Santa Barbara
    Full Name:
    Henry
    #3 hanknum, Aug 30, 2005
    Isn't the Tubi a silencer (muffler)?
     
  4. arium

    arium Karting

    Jun 16, 2005
    126
    Port Coquitlam, B.C.
    Full Name:
    Steve H
    #4 arium, Aug 30, 2005
    From my experience with turbo cars the turbo(and ex. manifold) give you all the back pressure in the world your valves may wish to see. Post turbo is just along for the ride and removing restrictions does little to help performance. Removing the cat will get you a big reduction in heat however and there may be performance gains in having a cooler engine compartment. Obviously the tree huggers will not love you for the extra pollution. Mind you, grass fires are all but eliminated too.

    The usage for modern BOV's is not so much as to control or regulate boost being delivered but more so to vent it when the throttle plates are closed. With a very wound up turbo from a spirited run you're delivering max boost and letting off the throttle can deliver pressure so high as to actually stall the turbo. Needless to say, broken compressor blades are a bit tough on things so the bov vents unwanted boost to atmosphere(or the airbox). It also allows for faster spoolup when you open up the throttle plates again as it(the turbo) didn't get dragged down by all that undelivered boost.

    Hope it helped.

    Steve
     
  5. zsnnf

    zsnnf Formula 3

    Sep 11, 2003
    1,877
    #5 zsnnf, Aug 31, 2005
    Which Tubi do you have? The sport or the LM? The LM has no muffeling effect.
    When you are reffering to a Blow off valve do you mean the waste gate?
    I have run the Tubi sport with straight pipes and picked up 2 pounds of boost. I did not readjust the waste gate. Tubi and straight pipes were good for 35rwhp over stock.
     

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