488 Question about Exhaust Bypass Valves | FerrariChat

488 Question about Exhaust Bypass Valves

Discussion in '458 Italia/488/F8' started by bisel, Feb 28, 2016.

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  1. bisel

    bisel Formula 3
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    #1 bisel, Feb 28, 2016
    Anyone who has a 488 or access to one ...

    Does the 488 come standard with exhaust bypass valves or is that an option?

    How many vacuum solenoid valves are there for controlling the vacuum to the exhaust bypass valves? The 458 has two.

    Where are the vacuum solenoid valves located? On the 458, they are under the air box cover.

    Thanks for any info.

    Kind regards,

    Steve
     
  2. junc

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    #2 junc, Mar 28, 2016
    Anyone set their 488 exhaust valves to open full time? It made a huge difference in the previous models and wondering if it has the same effect.
     
  3. DK308

    DK308 F1 Rookie

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    #3 DK308, Mar 28, 2016
    Not only are the valves standard, I believe they are mandatory by law several places.

    When people deactivate the valves to make them stay open, they usually just pull the lines off at the exhaust and plug the holes. Make it easy for yourself, get something like a Capristo remote for the valves instead - best of both worlds.
     
  4. cf355

    cf355 F1 Rookie

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    #4 cf355, Mar 28, 2016
    +1....the valves are installed to pass noise emissions.
     
  5. bigblock737

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    #5 bigblock737, Mar 28, 2016
    No need to make the valves stay open. They open much earlier in Race mode...
     
  6. ChuckStyl5

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    #6 ChuckStyl5, Mar 28, 2016
    Valves are also used so at low RPM's more back pressure is made for lower end torque - There is a reason they are there .. BMW uses them on 3 series and I promise you its not because of sound
     
  7. bisel

    bisel Formula 3
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    #7 bisel, Apr 2, 2016
    In theory, a bit of back-pressure is desirable when the exhaust flow capacity is low (i.e., low engine RPM) to improve exhaust velocity, which in turn improves the scavenging effect to rapidly evacuate spent exhaust gases. This improved evacuation helps improve torque at low engine RPM. At higher engine RPM, to much back-pressure will reduce exhaust velocity. So in high engine RPM conditions, it is more desirable to have low back-pressure. This is the theoretical reason why car manufacturers install exhaust bypass valves. Closed to provide back-pressure to improve low RPM torque and open to improve high RPM power.

    In practice, the effective difference in back pressure is small between valve open and valves closed. And the valves are typically far downstream of the engine, behind the cats, silencers, and whatever is in the exhaust pipes. So although there is the claim that the bypass valves optimize back-pressure, in truth, the reason manufacturer's install the valves is provide higher noise levels when the engine RPM is high ... generally conditions when the throttle is wide open (or nearly so) or the engine RPM is high ... conditions that favor driving in open spaces and outside of city urban areas. It is widely accepted that sports car owners prefer loud exhaust and urban planners / regulators prefer quite exhaust. The installation of valves allows manufacturers to pass the noise abatement requirements and provide the owners with the noise they want. The noise abatement requirements are generally written with specific vehicle velocity requirements with respect to passing through a testing zone with microphones placed in strategic location in that zone. In all cases, the vehicle manufacturers program their cars so they pass through the testing zone in higher gears and lower engine RPM and valves closed ... not for peak torque reasons, but for noise abatement only.

    There is an additional interesting fact about turbo charged cars like the Ferrari California T and 488. On cars with turbo chargers, the gas flow spinning the turbo impeller negates any effect a bypass valve may have downstream of the turbo. On these cars, any back pressure is undesirable. The turbo impeller will provide the exhaust gas evacuation at all engine RPM and trying to design in a degree of back-pressure is basically not required. Hence the reason you see many turbo cars with larger diameter exhaust pipes. Any bypass valves which are installed turbo cars are ONLY for noise purposes ... i.e., closed to pass noise abatement laws and open to please the driver's lust of noise. There is no pretense that the valves on turbo cars optimize back-pressure at specific engine RPM.

    Steve
     
  8. Lesia44

    Lesia44 F1 World Champ
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    #8 Lesia44, Apr 2, 2016
    If you're hoping that this will improve the sound of you 488, it won't.

    The 488's failings in the sound department are not a matter of volume, but the fact that it only plays one note louder or quieter. The 458 sounds better because it plays a range of sounds as you go through the rev range which reflect the relative ferocity of the engine at any given point in the range. The more you stress the engine the more it screams which helps you feel as if you're pushing it to its mechanical limit. Push the 488 and all you get is a louder version of the same monotone. It's a turbo, so until they find a way of overcoming that, it is what it is.
     
  9. MKS

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    #9 MKS, Apr 2, 2016
    Opening the valves will help a lot with the sound .. Just start the car and see how nice it sounds before the valves close
     
  10. Vcruiser

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    #10 Vcruiser, Apr 3, 2016
    My dealer offered to open my valves.

    I'll be picking up the car any day now as soon as i find a proper nice day!

    Will keep you posted
     
  11. mik458spider

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    #11 mik458spider, Apr 4, 2016
    This is true, you don't want something sounds bad to be louder.
     
  12. 458trofeo

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    #12 458trofeo, Apr 4, 2016
    +1

    A soprano she is!
     
  13. hamad488

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    #13 hamad488, Apr 4, 2016
    Try the car with the lunch control, the valve will open on idle, sounds loud trust me.
    Just to give u a glimpse how it will sound with the valves open

    Sent from my STV100-4 using Tapatalk
     
  14. PhilNotHill

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    #14 PhilNotHill, Apr 4, 2016
    Johnny One Note has arrived! ;)
     
  15. Lesia44

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    #15 Lesia44, Apr 4, 2016
    I should clarify that I don't think it sounds "bad". I prefer the sound of the 430 to the 458 so, while I acknowledge that the 488 doesn't sound quite as good as the 458, I still like it as it's got something of the 430's baritone about it.
     
  16. tonybrasco

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    #16 tonybrasco, Apr 4, 2016
    how can someone comment when they have never heard the exhaust in person...
     
    Lennox likes this.
  17. Lesia44

    Lesia44 F1 World Champ
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    #17 Lesia44, Apr 4, 2016
    Me?
     
  18. tonybrasco

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    #18 tonybrasco, Apr 4, 2016
    have you heard exhaust from 488 in person?
     
  19. Lesia44

    Lesia44 F1 World Champ
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    #19 Lesia44, Apr 4, 2016
    Yes.
     
  20. cpiguy

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    #20 cpiguy, Apr 5, 2016
    From what I heard when I drove the 488, the exhaust valves stay closed on start up/idle and at low RPM even in race mode. Because I drove the car hard the entire 20 minutes, I'm not sure what happens when driving around passively or on the freeway at 80 mph. With my 458, the drone was unattractive at freeway speeds with the valves open, so I would just push a switch and put it to sleep.

    Now, with my Porsche TTS, there's no freeway drone, and the car only gets loud when you stick your foot in it. Consequently no need for a bypass switch.
     
  21. cpiguy

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    #21 cpiguy, May 9, 2016
    Last edited: May 9, 2016
    I'm surprised this question has not been answered. I had an exhaust switch installed on my 458 the first week I owned it. My 488 should be here next month and I'm wondering if anyone has put a valve bypass switch on their car. With the 458 it was awesome keeping the valves open almost all the time except for long Freeway drives or if I was with the wife.

    Even start up, idle, and low speed driving was way nicer with the valves open.

    Anyone add this???
     
  22. SAFE4NOW

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    #22 SAFE4NOW, May 9, 2016
    Of the 488 we've had come through the shop, exactly ONE owner has chose to NOT have us perform the bypass.

    I have video - sound clips and while they demonstrate the difference in sound, it does not fully capture the improvement.

    I have not installed the Capristro switcher yet, simply because, no one has wanted to switch back to the stock sound after hearing it open.

    S
     
  23. dolphins08430

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    #23 dolphins08430, May 9, 2016
    Can you please post the video /sound clip ?
    Thanks!
     
  24. cpiguy

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    #24 cpiguy, May 9, 2016
    Thanks for the response. Do you happen to know if it drones on the freeway with the valves open like the 458 did?
     
  25. 458trofeo

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    #25 458trofeo, May 9, 2016
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