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458 Can someone explain the stock 458 Valve operation, installing a Forza controller!

Discussion in '458 Italia/488/F8' started by s4play, Mar 29, 2020.

  1. s4play

    s4play Karting

    Oct 25, 2006
    161
    hey guys,

    So I bought a new Forza exhaust controller for my 458 Spider and was going to install it today. I pulled the rear diffuser and noticed the top of the solenoid tubes were not connected to anything.

    In stock form, the exhaust valves open in the "RACE" mode after a certain RPM, I wanted to keep it open all the time since I think it sounds great.

    This is the Forza controller I planned on installing since I want to keep the valves open:

    [​IMG]


    You can see in the red circle what I'm referring to, what are these supposed to be connected to? In my car both are just hanging there? can anyone tell me where those open hoses are supposed to go? If it's pulled why does my car still work properly with the valves opening at a certain RPM?

    [​IMG]



    This is both exhaust valves that looks properly hooked up to the solenoid:

    [​IMG]
     
  2. 348ts92

    348ts92 Rookie

    Sep 27, 2002
    36
    St Louis, USA
    Full Name:
    Magnus Tannfelt
    I had a Forza controller on my 458 too and it is a great product.
    The third picture shows to me that the valves are connected as they should. I guess the open hose is for drainage or similar and have nothing to do with the exhaust valves.
    Since you have the diffuser of you can always check if the valves function when starting up the engine and rev it up to about 3500 rpm.
    Just connect the controller and you should be good to go...and enjoy the sound.


    Sent from my SM-G955U using Tapatalk
     
    s4play likes this.
  3. Corradosv

    Corradosv Karting

    Oct 17, 2016
    108
    Monaco MC
    Hi,
    the system is based on a couple (one per bank) of open/closed (no modulation) flap valves that deviate the exhaust flow in or out of the main silencer. The flap valves are operated by the pressure difference between atmosphere and engine intake vacuum working on the opposite sides of the actuator; such pressure gap between the actuator surfaces becomes an actuating force that moves the flap valve rod.
    The open hoses you ask about are the atmosphere pressure intakes, and the solenoids route (or don't) the intake vacuum on the other side of the actuator; the solenoids opening is controlled by the ECU, based on the throttle/rpm combination and the throttle/rpm opening threshold depends on the manettino position.
    The system is "fail open", which means that if you want the flaps to always be open, what you need to do is to disconnect the rubber hoses that connect the solenoids to the actuators on the exhaust side and plug them on the solenoids side (so-called "golf-tee hack" as a golf tee is normally used to plug the hoses): this way there will be no vacuum routed on one actuator side and the valve will stay always open. You can do that (I did it) accessing the actuators from under the car by just removing the rear diffuser, a 1hr job the first time, anybody can do it in like half an hour the second time.
    No CEL will light on, as there is no closed-loop check of the actuator position, and the system is ON/OFF and fully pneumatic, whereas in other systems (e.g. the new Mustang) the flaps are operated by electric motors (so they are not just open/closed, but they are modulated) that send a position feedback to the ECU.
    I personally like the valves to be always open so this is what I did on my car, thus saving the cost and the install pain of a control module.
    Whatever anyone says be confident you will have ZERO ISSUES in disconnecting and plugging the vacuum hoses on the actuators' ends.
    I hope it helps.
     
    s4play likes this.
  4. s4play

    s4play Karting

    Oct 25, 2006
    161
    thanks for the replies! Really appreciate it as we finished the install last night and took some fun videos of the BEFORE and AFTER, check it out here!




    Hope you guys enjoy the video!
     
    348ts92 likes this.
  5. Corradosv

    Corradosv Karting

    Oct 17, 2016
    108
    Monaco MC
    apologize: you will of course plug them on the actuators' side, but I realize it's too late and I hope you enjoy the controller!
     
    s4play likes this.

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