URGE Scavenger System Launch;
01-20-2017, 09:01 AM
#122
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Sound had greatly varying noise levels at the pressure gets dissipated by a factor between square and cubed depending on the surroundings.
Patrick
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01-20-2017, 11:34 AM
#123
The California test is petty much the standard measurement and is repeatable. A-scale. Slow.
-- Chuck
Microphone Location. The microphone for the sound level meter shall be at the same height as the center of the exhaust outlet. The microphone shall be no closer to the pavement than 8 in. (203mm) when the exhaust outlet is lower than this height. The microphone shall be positioned with its longitudinal axis parallel to the ground, 20 inches plus or minus 1 inch (508mm plus or minus 24mm) from the nearest edge of the exhaust outlet, and 45 degrees plus or minus 10 degrees from the axis of the outlet. For exhaust outlets located under the vehicle body, the microphone shall be located at the specified angle and at least 8 in., (203mm) from the nearest part of the vehicle. For exhaust outlets that make an angle of 45 degree or less with the longitudinal axis of the vehicle, the microphone shall be outboard of the exhaust axis. For exhaust outlet angles of more than 45 degrees, the microphone shall be on the side of the exhaust axis to the rear of the vehicle.This denotes where the sound measuring device is relatively close to the exhaust outlet.
01-20-2017, 12:18 PM
#124
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I just looked at about 20 exhaust on various websites and only one had such reading.
We of course have the exhaust on our car, but we have a 2.5L Stroker with ITBs so it would not be an accurate test. I can tell you the ITBs are much loader than the exhaust.
We would have to reach out to a customer to perform a test.
If you have a concern with noise then the Dual is the way to go. Twin 2.5" mufflers keeps sound noticeably lower than the Single which is a 3" longer muffler.
The Single was design for weight savings for racing. It reads about 100 db at WOT at 30 feet.
Off VTEC is much quieter.
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mcsinc (05-13-2017)
01-20-2017, 03:44 PM
#125
100 db at WOT at 30 feet is Loud. Capital "L". 
The standard test is pretty simple. Done is a quite setting, or course.
I've been burned badly with"not that loud" exhausts and appreciate test data.
-- Chuck
The standard test is pretty simple. Done is a quite setting, or course.
I've been burned badly with"not that loud" exhausts and appreciate test data.
-- Chuck
01-21-2017, 05:24 AM
#127
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Also, we put slightly downward tips that push sound to the ground, which also helps a little.
For all the reasons above, they are noticeably quieter. We dont have before and after readings as we never tested the old set up.
The new systems is also a Y vs a square set up so despite the slightly smaller diameter, there is less piping and no 90 degree bends so no loss in power.
The biggest thing we did was pull 40% weight out due to 2.5 lbs mufflers and less piping!
I hope that answers your questions..
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01-23-2017, 08:57 PM
#128
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FYI, we had a customer email us a DB rating on a local track. They ban cars over 100 db and we were close to that with the previous exhaust.
AutoX at 50 feet.
AutoX at 50 feet.
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01-27-2017, 02:45 AM
#129
Thanks. Have to hear it myself (which is unlikely here in the provinces along Lake Erie). May be too loud for me. My current Tanabe Medalion Touring is 94dBA at 20" (inches) from the exhaust.
In Ohio " When operated at a speed of more than thirty-five miles per hour, a maximum noise limit of seventy-nine decibel." (at no more than 50 feet) but I've not measured mine.
Nor do I know of anyone who has or any local agency monitoring this. Ohio has the same noise limit for cars and motorcycles and the bikes seem to routinely ignore it with no consequences. Some states give motorcycles more noise.-- Chuck
01-27-2017, 09:54 AM
#130
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Thanks. Have to hear it myself (which is unlikely here in the provinces along Lake Erie). May be too loud for me. My current Tanabe Medalion Touring is 94dBA at 20" (inches) from the exhaust.
In Ohio " When operated at a speed of more than thirty-five miles per hour, a maximum noise limit of seventy-nine decibel." (at no more than 50 feet) but I've not measured mine.
Nor do I know of anyone who has or any local agency monitoring this. Ohio has the same noise limit for cars and motorcycles and the bikes seem to routinely ignore it with no consequences. Some states give motorcycles more noise.-- Chuck
Is that Tanabe Single or Dual? I glanced at Evasive sight and I only see a dual?
Is that 94 db is that at redline? 8 or 9K AP1 or AP2? 1000K provides a sound difference.
When you say 20", that tells me the car is stationary and you blipping the throttle in Neutral Gear.
Blipping means you are at partial or no throttle by the time you hit redline due to reciprocal parts momentum, you are probably not at WOT at Redline?
WOT at redline is MUCH louder than partial throttle. More Air, thus more fuel and bigger explosion, etc.
Really just trying to narrow this down.
The reading above was taking at 50 feet, not inches and is at WOT near redline while the car is still pulling.
It is also only a single 3" ID, 14" long Muffler. The Dual is 2.5" x 9" with much more suppression material and muffler volume. It is noticeably quieter.
Also, we use 100% fiber glass which is much quieter than a steel wool blend and the fiber glass can be repacked as necessary for $25.
I hope this helps, if you are worried about sound limits, the dual is way to go and our overall dual weight is comparable to steel singles due to the HFC and ultralight mufflers.
Not to mention, we make 5-15 more mid range HP vs a test pipe, with a HFC!
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