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Insertable tailpipe baffles-to quiet exhaust a bit more


RebekahsZ

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I'm running a LS2 with a single Borla XR-1 3-inch straight thru muffler in the stock 240z location.  The car isn't quite as loud as a straight pipe, but it is still pretty loud.  I have started going to tracks with sound restrictions and my autocross club has added a 96db sound requirement.  I got warned for sound, so I have started shifting to 3rd when I am in vicinity of the meter.  But, I was at a road course last month and they had baffles that can be inserted into the tailpipe to provided that extra sound control when you need it.  I have attached a photo and the site and part number for any who are interested.

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You will note a lot of the Japanese exhausts have a sharply angled up tip.

Sound is VERY directional, and those goofy looking tips direct sound up....

Most sound mics are directional, and at a tangent to the roadway to catch someone going away. Angling that tip up may help.

 

I know on the CA State Exhaust Compliance testing it does!

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They have the sound meter on a 5' tripod anywhere between 10 and 30' from the course. They haven't worked out a standard placement but they are going to have to. They DQd a bunch of cars this month. The course was so open this time that I did most of it in 3rd so the rpms and sound were lower. Between that and the baffle I got no warnings.

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  • 1 month later...

I'm running a LS2 with a single Borla XR-1 3-inch straight thru muffler in the stock 240z location.  The car isn't quite as loud as a straight pipe, but it is still pretty loud.  I have started going to tracks with sound restrictions and my autocross club has added a 96db sound requirement.  I got warned for sound, so I have started shifting to 3rd when I am in vicinity of the meter.  But, I was at a road course last month and they had baffles that can be inserted into the tailpipe to provided that extra sound control when you need it.  I have attached a photo and the site and part number for any who are interested.

 

The other idea that might be useful would be to hang another muffler to the side between the bumper brackets.  A 90 into this muffler would help if you ever run into severe restrictions like 90 dB.  I've seen this done on a couple of 911s that were rather loud.

 

Cary

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Yeah, thought about the additional muffler between bumper brackets. They DQ-ed so many cars last month that they are gonna have to reform their methods. Can't race tomorrow-no driveshaft because The Driveshaft Shop marked the UPS form for signature required and I was off taking Rebekah back to Auburn. Was hoping to find it waiting for me when i arrived so i could wrench thru the night. Maybe I will have it Monday if my wife hangs around all day and they don't try to deliver when she jumps in the shower or something. I HATE it when a shipper makes it so hard for me to receive what I have paid for!!!!

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