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Disconnect exhaust baffles on 360

Discussion in 'Technical Q&A' started by PCH, Apr 28, 2004.

  1. PCH

    PCH F1 Rookie

    Apr 7, 2004
    2,977
    A few parts dealers have stated that I could disconnect the bipass valves on both sides of the exhaust to get a better and or louder exhaust note. Others have stated that although this maybe true it may also hinder performance. Comments....
     
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  3. ferrarifixer

    ferrarifixer F1 Veteran
    BANNED

    Jul 22, 2003
    8,520
    Melbourne
    Full Name:
    Phil Hughes
    Disconnecting will stop them opening. You will need to lock them open with wire or a small weld.

    It will make your idle louder, but it will cost you a little torque in the lower rpm and it will reduce the running temperature of your cats, and therefor their efficiency and life expectancy.

    I think it's a waste of time and a very "tacky" thing to do, but I get paid to do it often enough to not lose sleep over owners preferances!
     
  4. lmpdesigner

    lmpdesigner Formula 3
    Silver Subscribed

    Nov 5, 2003
    1,955
    Atlanta Georgia
    Full Name:
    Brian Willis
    I am confused- I disconnected my relays and the valves are now permanently open, ie, the car sounds louder a idle and every where else. I did not have to wire or weld anything at all. Ferrarifixer-what and why are you wiring/welding anything up? Please explain.

    Also I ran the car at the local drag strip to check before and after times. Results-no difference in 0-60 or 1/4 mile times. So no loss in torque at low RPM as you suggest. (At least for me.)

    Also I thermocoupled the cats for a before/after test. Again absolutely no difference in temperatures could be discerned.

    Results: For me I could not find any negatives and I like the sound. As far as being tacky--why would you say that? I have an exhaust sound that I like more than stock, I can switch back to stock in 30 seconds, if I want and I don't have to spend 4-5k US $ on a Tubi right now.

    Seems like this is the smart choice, to me!
     
  5. ferrarifixer

    ferrarifixer F1 Veteran
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    Jul 22, 2003
    8,520
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    Phil Hughes
    A happy customer is a happy customer. Enjoy your modification.
     
  6. rviant

    rviant Karting

    Jan 22, 2004
    229
    Bedfordshire
    Full Name:
    Richard

    How did you do this? Is it easy to do?
     
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  8. sparetireless

    sparetireless Formula 3
    Silver Subscribed

    Nov 2, 2003
    1,393
    I put the hoses back on the valves, it starts and runs very quiet but seems like the half the power or more is gone, no check engine light, I put it back to disconnect and the all the power is back. I would like to return it to stock, its too loud to drive at night in my neighborhood.

    Seems like the idle is also too low and maybe the timing is not advancing, it really did not like being put back to the stock configuration, what did I miss?
     
  9. GCalo

    GCalo F1 Veteran

    Sep 15, 2004
    6,988
    Northern California
    Full Name:
    Greg Calo
    I have looked at the bypass valve situation for some time, and what I am getting out of this is that when the valve is closed, it is preventing one set of exhaust pipes from functioning.

    The result is that more back pressure is presented to the flow of the exhaust gases because the gasses are now exiting two pipes instead of four which also has the effect to "muffle" or silence the exhaust a bit.

    I can see no other functional purpose for this valve.

    So, it's natural that when the valve is opened there is more available HP because there is less restriction to the gas flow.

    Tubi's are loud at idle on the 360, because there are no valves (at least on mine).

    Any other ideas on this?
     
  10. Mike.H

    Mike.H Rookie

    Jan 21, 2015
    1
    Could you let me know where the relays are located, I wouldn't mind trying it out. Cheers
     
  11. bisel

    bisel Formula 3

    Sep 12, 2012
    1,220
    Scottsdale, Arizona
    Full Name:
    Steve Bisel
    There is no danger of any damage, malfunction or degradation that will be caused from disconnecting the exhaust bypass valves ... either by disconnecting the two vacuum solenoid valves or by pulling the vacuum hoses off the bypass valves themselves.

    There are many threads in the 360 forum about doing this.

    Theoretically, exhaust bypass valves will close at low engine RPM which will increase back-pressure and improve low-end torque ... and they will open at higher engine RPM which will increase power at these elevated RPM values. In practice, there is virtually no difference between the valves open or closed ... with one exception, the exhaust is louder when they are open. The only practical reason cars have exhaust bypass valves is for noise abatement. There might be a slight bit of power improvement when they are open, but not much. Not that you would notice.

    A more practical method of controlling the exhaust bypass valves is the use of a controller. Go to Forza Componenti website ( Forza Componenti - Home ) for a good explanation of bypass valve operation and options that you have available for manually controlling their operation.

    Regards,

    Steve
     
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  13. MerlinTech

    MerlinTech Formula Junior
    Sponsor

    Mar 5, 2010
    548
    Georgia
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    Wade Williams
    The only bypass valve that is closed at rest is 355. Locking a 355 open will cause a CEL because it is before the CATS.

    All others are open at rest and at the exhaust exit after the CATS.

    I have not seen any issues with the valves open all the time. Several customers have had there cars here with the vacuum line removed from the valve and the vacuum line plugged.
    I have also seen the aftermarket control systems installed as well. Again, no issues and it lets you sneak home quietly without waking the neighbors.
     
  14. bisel

    bisel Formula 3

    Sep 12, 2012
    1,220
    Scottsdale, Arizona
    Full Name:
    Steve Bisel
    #11 bisel, Jan 24, 2015
    Last edited by a moderator: Sep 7, 2017
    And, with the 355, Capristo makes a replacement bypass valve that defaults to open when the engine is off or the vacuum is lost.

    Also, with 355, there are two sets of cats. The primary and secondary. If you remove the secondary cats immediately in front of the exhaust bypass valve, then with the valve open all the time, there will be no catalyst to overheat. And no worries about the O2 sensors because they are not in the flow path of the secondary cats ... the O2 sensors are only in flow path of the primary cats.

    This arrangement is only valid with the 355. All other Ferraris with exhaust bypass valves have the valve located downstream of any catalytic converters and the valves open or closed will not affect the temperature of those converters. Also, I believe only the 355, 550 and 575M have exhaust bypass valves that default to closed. All others default open.

    Regards,

    Steve
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