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Meeting 90dB Noise with GT350/R

Black Boss

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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
 
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yotah1

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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 :(
 

8250RPM

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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 :(
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
 

85Gold

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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
 

85Gold

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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
 

Etchhead

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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!
 

VoodooBoss

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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?
 

Black Boss

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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.....
 

Mad Hatter

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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!!
 

DocWalt

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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.
 

DocWalt

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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.


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)
 

DocWalt

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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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