430 - Advice on annoying exhaust "drone" at cruise speed | FerrariChat

430 Advice on annoying exhaust "drone" at cruise speed

Discussion in '360/430' started by MKTViper, Dec 9, 2019.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

  1. MKTViper

    MKTViper Karting
    Silver Subscribed

    Oct 9, 2018
    205
    Swan Point MD
    Full Name:
    Mike
    #1 MKTViper, Dec 9, 2019
    I greatly appreciate all the amazing advice on this forum. It's one of the best I've seen. So THANKS in advance...

    Anyway, here's my setup:
    Fabspeed Headers and Ferrari Sport Exhaust. When I bought the car the valves were fixed open; the sound was absolutely amazing, but the volume was just too loud starting the car and cruising near (within 3 miles of) the neighborhood.

    I had the vacuum valves reconnected, which definitely helped with volume. HOWEVER, I found that I traded volume for tone at cruise speed (e.g., 3-4K RPM in 4th gear). While the volume is much better compared to valves open, the tone is horrible at low RPMs. It's a low frequency hum, or drone, not at all "throaty", and just as annoying as the valves open cold start. It tends to give me a headache after a while and my wife's already talking ear plugs.

    Side note: when closed the valves chatter quite a bit at idle when cold. Less so when warmed up.

    Possible solutions:
    1. My best scenario is to maintain the same tone as valves open, but reduce the volume. Not sure that's possible, but open to any ideas. I've considered going to back to stock exhaust, but with the Fabspeed headers I've heard that might not make much of a difference.

    2. Another option is to install remote valves. That way I can keep the valves closed when I need to, but while cruising in the 3K RPM range I can keep the valves open for the correct tone and the volume is certainly tolerable. I know Capristo has a set for $650. Are there other sets out there?

    3. A final thought is that I'm getting some sort of resonance in the air intakes and it's not the exhaust at all. If so, not sure what can be done without some major rework of the resonance chamber in the intake plenum.

    Any other thoughts or recommendations? Advice on the Capristo valves or alternatives?

    Thanks again! Mike
     
  2. arizonaitalian

    arizonaitalian F1 World Champ
    Owner Silver Subscribed

    Oct 29, 2010
    19,952
    Wyoming
    #2 arizonaitalian, Dec 9, 2019
    There is a forum member who designs and sells a valve control system for a very fair price. Try the search function here and you will find first hand reports. I think the company name has “forza” in it...
     
  3. Skidkid

    Skidkid F1 Veteran
    Owner Rossa Subscribed

    Aug 25, 2005
    8,755
    Campbell, CA
    Full Name:
    John Zornes
    #3 Skidkid, Dec 9, 2019
    Those are all options. Do you have stock cats or high flow cats? When were your cams last timed? I can tell you that cam timing has a HUGE impact on drone.
     
  4. arizonaitalian

    arizonaitalian F1 World Champ
    Owner Silver Subscribed

    Oct 29, 2010
    19,952
    Wyoming
    #4 arizonaitalian, Dec 9, 2019
  5. Bob in Texas

    Bob in Texas F1 Rookie

    Apr 23, 2012
    2,667
    Just East of Weird
    Full Name:
    Bob
    #5 Bob in Texas, Dec 9, 2019
    The Forza unit is a no brainer, MUCH better built than capristo and about 1/2 the price.
    Go to you tube or the Forza componenti website, several videos on the install on 360/430.


    Sent from my iPad using Tapatalk Pro
     
  6. MKTViper

    MKTViper Karting
    Silver Subscribed

    Oct 9, 2018
    205
    Swan Point MD
    Full Name:
    Mike
    #6 MKTViper, Dec 9, 2019
    Not sure about the cams, just got the car with 24k mile . No drone however with valves open.

    Stock cats
     
  7. MKTViper

    MKTViper Karting
    Silver Subscribed

    Oct 9, 2018
    205
    Swan Point MD
    Full Name:
    Mike
    #7 MKTViper, Dec 9, 2019
  8. arizonaitalian

    arizonaitalian F1 World Champ
    Owner Silver Subscribed

    Oct 29, 2010
    19,952
    Wyoming
    #8 arizonaitalian, Dec 10, 2019
    lots and lots of people, use the search for fabspeed.
     
  9. RedTaxi

    RedTaxi F1 Rookie
    Silver Subscribed

    Mar 1, 2012
    3,253
    New Zealand
    Full Name:
    Glen
    #9 RedTaxi, Dec 10, 2019
    Not Fabspeed but Challenge headers which also have no precats, so louder than stock. With stock cats and muffler absolutely no drone. Valves are closed at cruise speed. Part of the issue I can see with the factory sports exhaust is the 2 engine banks never mix so there is no balance there. The stock exhaust blends the 2 banks together when the valves are closed and smooths it out. A valve controller wont help at all with your problem.
     
  10. mike32

    mike32 F1 Veteran

    May 13, 2016
    5,835
    Isle of man- uk
    #10 mike32, Dec 10, 2019
    In regard to the valves chattering, just fit a tension spring externally -they are probably a little worn and this will hold them shut so all the exhaust goes through the box and keep the noise down.
    I drive mine around without any of your problems so i think the bypass is passing while shut.
     
  11. mwstewart

    mwstewart F1 Rookie

    Feb 5, 2014
    2,641
    England
    Full Name:
    Mark
    #11 mwstewart, Dec 10, 2019
    Can you please post a photo of the exhaust and its mounting system? Let's see if we can change the resonant frequency with a few adjustments (if possible).

    I've done similar on my Capristo system and it worked perfectly.
     
  12. Zed82

    Zed82 Formula Junior

    Sep 28, 2017
    490
    Sweden
    #12 Zed82, Dec 10, 2019
    Image Unavailable, Please Login
     
  13. mwstewart

    mwstewart F1 Rookie

    Feb 5, 2014
    2,641
    England
    Full Name:
    Mark
    #13 mwstewart, Dec 10, 2019
    First thing to do is check the tightness of the rear clamps over the cats - are they very tight?
    Also, check the tightness of the fastenings that secure that central cross brace mount, in fact, check everything associated with that mount.
     
  14. LightGuy

    LightGuy Three Time F1 World Champ
    Silver Subscribed

    Oct 4, 2004
    39,852
    Texas
    Full Name:
    David
    #14 LightGuy, Dec 10, 2019
  15. MKTViper

    MKTViper Karting
    Silver Subscribed

    Oct 9, 2018
    205
    Swan Point MD
    Full Name:
    Mike
    #15 MKTViper, Dec 10, 2019
    FWIW, the posted picture is of a different car, but very similar to my setup. I'm on business through the middle of next week, if I get a chance I'll send a pic.
     
  16. MKTViper

    MKTViper Karting
    Silver Subscribed

    Oct 9, 2018
    205
    Swan Point MD
    Full Name:
    Mike
    #16 MKTViper, Dec 10, 2019
    Thanks, I'll check that out. I'll also check the connections as mwstewart suggests to see if that helps the drone.

    Regardless, I'll probably get the Forza controller. I like the idea of having control. Last resort will be to revert to the OEM setup (with Forza controller) and Fabspeed headers. Valves closed should be tolerable for the wife (& neighbors) and valves open for my "solo" drives.
     
  17. mike32

    mike32 F1 Veteran

    May 13, 2016
    5,835
    Isle of man- uk
    #17 mike32, Dec 11, 2019
    Put some kitchen paper in the 2 tail pipes that should have no flow at low revs and see if it blows out, ie valves are passing or feel the pipe by the valves to see if they heat up from a cold start. I seem to recall an owner was able to feel the wear in the valve pivot shafts- ie the lift in the shaft
     
  18. mwstewart

    mwstewart F1 Rookie

    Feb 5, 2014
    2,641
    England
    Full Name:
    Mark
    #18 mwstewart, Dec 11, 2019
    I forgot to add: as well as tightening the clamps on my Capristo I also moved the position of the clamps between the cats and rear silencer: I had 1.5" to play with so moved them further backwards. This is much like moving your fingers along the strings of an instrument: it shifts the resonant frequency of the assembly. I was very pleased to find that it cured my issue if drone at 3k RPM.

    Obviously, your experience may vary.
     
  19. MKTViper

    MKTViper Karting
    Silver Subscribed

    Oct 9, 2018
    205
    Swan Point MD
    Full Name:
    Mike
    #19 MKTViper, Dec 12, 2019
    Good thought! My guess is moving the clamps "in" to shorten the overall length will increase frequency, while moving "out" (or to the rear) will decrease frequency. Maybe not enough to consciously notice, but may mitigate the drone which is certainly caused by some resonant frequency. I also assume both sides need to be of equal length so they "harmonize" correctly...not unlike syncing the props on a two engine plane.
     

Share This Page