Exhaust setups under 90db (Circuit sound restriction)
08-18-17, 11:51 AM
#1
Lead Lap
Thread Starter
Exhaust setups under 90db (Circuit sound restriction)
I am getting ready to hit the track but the one that I want to go to (Laguna Seca) has a 90db limit. I've read on the interwebs that stock porsche turbos have been black flagged before.
Does anyone have experience with sound restrictions, and can recommend a set up? Currently, I have stock headers (with cats) and gutted midpipe/res. I just bought PPE Headers, and I plan on putting on some HFC (magnaflow?) and couple it with the Xforce non-varex. But I am worried about it being too loud.
Any help is appreciated.
Does anyone have experience with sound restrictions, and can recommend a set up? Currently, I have stock headers (with cats) and gutted midpipe/res. I just bought PPE Headers, and I plan on putting on some HFC (magnaflow?) and couple it with the Xforce non-varex. But I am worried about it being too loud.
Any help is appreciated.
Last edited by F_Throttle; 08-18-17 at 11:51 AM. Reason: title
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ModInJapan (08-18-17)
08-18-17, 01:31 PM
#5
Lead Lap
Thread Starter
The first question is: how is it tested?
In many cases, you're required to make a fast lap passing a decibel meter (with a minimum speed based on your class to make sure it's pulling hard), with a maximum reading of 90.
If so, which side of the track is it on? If on the right side, a curved tail pipe extension pointing to the left will make their reading significantly quieter, but make sure that the rules say that once you pass they can't test you again - like with the meter moved. Feel like this is cheating? Only reason why someone else isn't doing it: not smart enough.
If the mere's probe points straight at your exit it won't work, of course.
If it's not known what will be done, a method that reduces DB with minimal effect on max power is a cap over the exit dropping the ID by 1/4" or more. In some cases, even tighter (like 1" smaller) with 1/4" holes around the outer edge softens the released pulse.
Any increase in volume in the system reduces pulsations and dampens DB, you can pick a small section of pipe and patch a branch resonator on to it.
That clip is a no-load test, the actual reading pulling the car will always be different.
In many cases, you're required to make a fast lap passing a decibel meter (with a minimum speed based on your class to make sure it's pulling hard), with a maximum reading of 90.
If so, which side of the track is it on? If on the right side, a curved tail pipe extension pointing to the left will make their reading significantly quieter, but make sure that the rules say that once you pass they can't test you again - like with the meter moved. Feel like this is cheating? Only reason why someone else isn't doing it: not smart enough.
If the mere's probe points straight at your exit it won't work, of course.
If it's not known what will be done, a method that reduces DB with minimal effect on max power is a cap over the exit dropping the ID by 1/4" or more. In some cases, even tighter (like 1" smaller) with 1/4" holes around the outer edge softens the released pulse.
Any increase in volume in the system reduces pulsations and dampens DB, you can pick a small section of pipe and patch a branch resonator on to it.
That clip is a no-load test, the actual reading pulling the car will always be different.
Looks like they made some changes to the track back in 14' that addressed the sound limit issue.
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