RebekahsZ Posted June 13, 2013 Share Posted June 13, 2013 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. Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 13, 2013 Share Posted June 13, 2013 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! Quote Link to comment Share on other sites More sharing options...
LanceVance Posted June 13, 2013 Share Posted June 13, 2013 Just don't forget to drill a small hole on the bottom in case you ever leave it parked in the rain. Filling your entire exhaust up with water can't be good for anything! Know anything about this car Tony? Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 16, 2013 Share Posted June 16, 2013 Midnight Club, Torrance. Hangs with Kyunio and that crowd. Nice car. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted June 16, 2013 Author Share Posted June 16, 2013 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. Quote Link to comment Share on other sites More sharing options...
tube80z Posted August 9, 2013 Share Posted August 9, 2013 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 Quote Link to comment Share on other sites More sharing options...
Tony D Posted August 10, 2013 Share Posted August 10, 2013 Bozouku Pipes.... Quote Link to comment Share on other sites More sharing options...
johnc Posted August 10, 2013 Share Posted August 10, 2013 San Diego has a 91db sound restriction for autocross events at Qualcomm stadium. Pointing the exhaust up on cloudy days adds .5db. On clear days it drops the db by .3. I know from personal experience. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted August 10, 2013 Author Share Posted August 10, 2013 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!!!! Quote Link to comment Share on other sites More sharing options...
Tony D Posted August 11, 2013 Share Posted August 11, 2013 Sign the delivery attempted slip, and leave instructions where to leave it. Solved. Quote Link to comment Share on other sites More sharing options...
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