Meeting 90dB Noise with GT350/R

Discussion in 'Drivetrain, Exhaust and Electrical' started by Black Boss, Aug 2, 2017.

  1. Black Boss

    Black Boss TMO Addict

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    Went to Mont Tremblant and the GT350R failed noise by over 3dB. Unlike some other tracks, they move the microphone location, and do not disclose where it is, so short shifting only worked on day 1 when I spotted mic location.

    The fix: Disconnect the exhaust valves (there's a connector on the valve pigtail each side), as they default to closed. This fixed the noise, but you can't select Track mode with them disconnected. You can however select Sport steering and damper settings.

    So net result is you have to run with Sport damper settings and obviously the car is down on power, but it will pass 92dB noise limits.

    Edit:

    More discussion on this topic can be found here

    https://trackmustangsonline.com/threads/controlling-the-gt350-exhaust-valve.14051/#post-206026
     
    Last edited by a moderator: Sep 15, 2018
  2. yotah1

    yotah1 TMO Race

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    We need to work out some plugs for the exhausts while they have the valves open, so we can still use the Track mode!!
    Doesn't anybody (i think I saw some chatter about this) have a software to plug into the car with your laptop? Maybe there's a way to "fake" the valves opened for the computer to still allow Track Mode selection.

    The tracks near me don't give me any trouble, but I know when I'll take it to Europe to do some o the tracks I used to race at, I'll be in trouble :(
     
  3. 8250RPM

    8250RPM TMO Addict

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    When I prototyped the American racing headers for the GT350/R a few years ago, Nick made a complete system for our cars. His mufflers do not use a exhaust valve. And to allow use of the modes, he offers a module that plugs into the oem harness. The problem is, you can not buy this module separately. But it does allow the suspension and steering modes to work like normal.


    Sent from my iPhone using Tapatalk
     
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  4. VoodooBoss

    VoodooBoss Rick Moderator

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    A solution would be very useful for Laguna Seca too. Nick do any lights light up on the dash when you unplug the connector?

    @mattlqx has a plug he used to block the open side of the exhaust that seemed to work.
     
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  5. Black Boss

    Black Boss TMO Addict

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    Rick, No lights.
     
  6. 85Gold

    85Gold TMO Intermediate

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    I got the McMaster Carr plugs but haven't needed them yet. Going to AMP in 2 weeks so that will be a test if the stock exhaust fails sound.

    Peter
     
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  7. j3st3r

    j3st3r Brian S.

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    Isn't AMP db limit 98?
     
  8. 85Gold

    85Gold TMO Intermediate

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    Yes it is. I know some GT350 have passed but it is weather dependent and I don't want to get booted for not passing sound.

    Peter
     
  9. Etchhead

    Etchhead TMO Intermediate

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    So for a stock car is the only work around to leave the exhaust in quiet mode jus leaving it in Normal and not Sport or Track?

    I have a new R so excuse the dumb question- seems like if in Sport mode, but exhaust in normal the valves will still open under load and RPM right?

    Headed to LS in a few weeks and want a chance to run her a little bit before the meatballs!
     
  10. VoodooBoss

    VoodooBoss Rick Moderator

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    @Etchhead the valves fully open at WOT in normal mode hence the problem. I haven't looked under my car yet but I'll snap some photos when I do. If anyone else is under there please post photos of the connector and it's location.

    @Black Boss are you able to disconnect the connectors while the car is on the ground?
     
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  11. Black Boss

    Black Boss TMO Addict

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    @VoodooBoss Yes, but it's easier to jack the rear end a little -- that way you get a line of sight to the connectors and don't have to rely on feel. Also I zip tied the loose ends -- that's probably not necessary, but would be tough without raising the rear end a bit.....
     
  12. Mad Hatter

    Mad Hatter Gotta go Faster

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    Our local track has a static sound booth with a 96Db limit. My buddies Zl1 was at 98Db so he did a emergency hack job at a local muffler shop.......... He slapped on 3 glasspacks a side and got it down 90 Db. Silent race cars.....what is the world coming to!!
     
  13. The_Dead_Cow

    The_Dead_Cow Mike

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    I've used the high temp plugs from McMaster Carr with success on my local track with a sound limit of 96 db. Arizona motorsports park is the track. Here's a link for the plugs.

    https://www.mcmaster.com/#5117t31/=18uwmwt

    BTW, McMaster will give out free samples if you ask nicely
     
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  14. DocWalt

    DocWalt TMO Advanced

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    Supposedly these work on the GT350. I had one on my Focus RS which looks to have the exact same actuator motor. I have the delete plug left over and I can test it to be sure...

    http://www.grimmspeed.com/exhaust-valve-defeat-module/

    Is it actually safe for the engine to plug the "sport" pipes while on track? No concerns about extra heat in the exhaust?
     
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  15. VoodooBoss

    VoodooBoss Rick Moderator

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    @DocWalt welcome to TMO and great first post! So you have a GT350 to try this on? Would you need two plugs for the GT350?

    [​IMG]
    [​IMG]
     
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  16. DocWalt

    DocWalt TMO Advanced

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    @VoodooBoss yep, replaced the RS with a GT350 :)

    Correct, you'd need two plugs. I can test with one because it tests both valves and would immediately throw an alarm and say you can't enter other drive modes (as mentioned above)

    If I remember, I'll test this weekend sometime. I've been meaning to actually verify that it will work.

    The other option is a mechanical simulator like the one Vivid Racing sells, but I'm not sure where or how you'd mount it on the GT350. I have one of those too, but that's more involved than I want to mess with.
     
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  17. VoodooBoss

    VoodooBoss Rick Moderator

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    I just sent Grimm Speed an email and will report back when I hear from them.
     
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  18. DocWalt

    DocWalt TMO Advanced

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    I tested the Grimmspeed plug tonight, it works perfectly. A bit of a hassle to reach up in there with the car sitting on the ground, but it's doable.

    OEM valve actuator plugged in. You have to slide the red safety lock towards the back of the car, this was the hardest part of the swap.
    [​IMG]

    Here's a pic of the Grimmspeed exhaust valve delete plug connected (note, I didn't latch the red safety latch or ziptie the wire/plug up away from the exhaust)
    [​IMG]
     
  19. VoodooBoss

    VoodooBoss Rick Moderator

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    Great news, thanks for posting the photos. So you were able to engage Track Mode? I did not hear back from GrimmSpeed today.
     
  20. DocWalt

    DocWalt TMO Advanced

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    Yep, engaged track mode (and all of the other modes) with no problems.

    Any concerns over running the car with the center tips plugged up for extended track sessions?
     
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