Sound tube/Exhaust effect

[T123456]

Can someone explain the Sound Tube’s effect on the Exhaust?
I thought it only affected the cabin noise, but there’s an audible difference at the muffler when I cover the sound tube hole on the intake and uncover it. If I cover the sound tube hole, the exhaust gets quieter, if I uncover it, exhaust gets louder.

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[ZenkaiRacer]

The sound tube hole is after the MAF, if you've got it wide open then a bunch of un metered air is coming and jacking with the fuel trims, so yeah it'll sound different.

 

[ice445]

The sound tube hole is after the MAF, if you've got it wide open then a bunch of un metered air is coming and jacking with the fuel trims, so yeah it'll sound different.

This. In actual operation zero air passes through the sound tube, it's just a resonant device. By having it removed and opening the hole to the atmosphere, it's pirate air city and the car gets confused.

 

[T123456]

The sound tube hole is after the MAF, if you've got it wide open then a bunch of un metered air is coming and jacking with the fuel trims, so yeah it'll sound different.

This is the conclusion I came to after driving a few blocks with it open to see the difference and the car ran like and sounded like shit lol. Plugged the hole with a napkin for now until I can make it permanent. Put a h-pipe on and the sound on the cabin was giving me a headache. Disconnected the sound tube and I can hear myself think again. Thanks for the info, much appreciated.

 

[T123456]

This. In actual operation zero air passes through the sound tube, it's just a resonant device. By having it removed and opening the hole to the atmosphere, it's pirate air city and the car gets confused.

Thanks!

 

[BoostN IT]

I cut my sound tube with a sawzaw and never heard a difference in exhaust note.

 

[ZenkaiRacer]

I yanked mine off over the nut. It cost me my pinky nail as my hand flew right into the corner of the air box clamp. The force broke the clamp in half and took a perfectly rectangle square out of my pinky through the nail. Was totally worth.

 

[Matthewstorm]

Can you pass electrical wires thru the sound tube hole into the cabin?

 

[Mustang_Lou]

Plugged the hole with a napkin for now until I can make it permanent.

If you're covering the hole at the intake (as mentioned in OP) with a napkin, remove that pronto and connect the sound tube back. You don't want that napkin getting sucked into the engine. Plus you're likely getting unmetered air in by that = car runs dangerously lean.

There are kits out there that have a rubber plug specifically made for capping that intake hole.

 

[Matthewstorm]

Can you pass electrical wires thru the sound tube hole into the cabin?

Anyone?

 

[Chef jpd]

Anyone?

I suppose you could, but the hole in the firewall is directly behind the the gas pedal.

 

[Matthewstorm]

I suppose you could, but the hole in the firewall is directly behind the the gas pedal.

So, where do folks run their cables when they install stuff on the bumper and need to control it in the cabin? Thanks.

 

[Bikeman315]

So, where do folks run their cables when they install stuff on the bumper and need to control it in the cabin? Thanks.

Since it has nothing to do with this topic, you might want to post this question over on Infotainment and Electronics (Nav, Audio, Video, Bluetooth)

 

[Matthewstorm]

Thanks!

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