You need Helmholtz resonators, not inlines. You could A. Buy ART pipes, or B. Add your own as far forward as possible. I used the resonators in the stock mid pipe to make mine. You'll gain horsepower and kill the rasp! You will lose decibels too though.

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so Guys I have a shop and I do my own work and buy, fix and sell Nissan/Infinitis from Copart and IAAI actions , I just did motor swap from my parts car g37 Sedan with 18k miles to Stillen Superchargered G37 with blown motor LOL . He had PPE headers , Y pipe and greddy catback and when I finished the motor swap and test drove it around, that car had no RASP at all and sounded like 2014 GTR I have in the shop .


I have
3 sets of extra OEM cats
2 sets of OEM y pipes
2 sets of Sedan Mid-pipes

i want to get rid of Rasp and need a advice where to start or I am just gonna put everything stock and changed part by part to just diagnose the source of RASP

MY 02 sensors went bad from vibration from using impact gun / Air chisle my worker used to remove stock exhaust without telling me, So 02 sensors unpluged car made 299.7 whp and 270wtq on dynp jet dyno

Stock intakes , stock tune , stock clutch just test pipes and exhaust

first off, never use a rattle gun to remove O2 sensors, just use a wrench or a slotted socket(these are made for removing O2 sensors)

second, put cats back on and your rasp will go away, but you will lose power, another alternative is to weld in resonators to help with rasp

heck i have a stock nismo exhaust with test pipes and its raspy as hell(granted i like the sound) from 2k-3k

noone used a gun on the actual sensors , they Used very strong SNAP-ON impact gun taking stock Y pipe and test pipes off thats all .

Raspy noise is fixed ! Used stock Y pipe with obx test pipes and topspeed Pro1 exhaust , now car has ) rasp and all the exhaust noise comes from back of the car instead of under the car from 2.5" Y pipe