Nissan 370Z Forum - View Single Post - Fancy Tech: How to Get Rid of Exhaust Drone, works great!

kevin8086 · 01-06-2011, 05:27 PM

[QUOTE='10Anamoly;650399]I did this on my car, first with 22" side branches and had no luck. After re-doing my math and using some Audacity frequency analysis, I figured out that they had to be 27-28" to work at the RPM I wanted. Longer pipes tune out frequencies lower in the RPM range. Shorter pipes (increasingly less effective) hit the higher rpms. I had the mechanic fix the pipes to 28" and VOILA, absolutely zero drone from 2200rpms to 2800rpms. At 2000rpms there is a slight rumble in the cabin, but no drone. Same at 3000rpms which changes into an aggressive purr.QUOTE]

i just had mine done and i dont get a drone until 3900-4500 depending on gear and load. how would i figure out how long i would need to make my T branches?

01-06-2011, 05:27 PM	#61 (permalink)
kevin8086 Base Member Join Date: Oct 2010 Location: Austin Posts: 228 Drives: 09 370Z Sport Rep Power: 15	[QUOTE='10Anamoly;650399]I did this on my car, first with 22" side branches and had no luck. After re-doing my math and using some Audacity frequency analysis, I figured out that they had to be 27-28" to work at the RPM I wanted. Longer pipes tune out frequencies lower in the RPM range. Shorter pipes (increasingly less effective) hit the higher rpms. I had the mechanic fix the pipes to 28" and VOILA, absolutely zero drone from 2200rpms to 2800rpms. At 2000rpms there is a slight rumble in the cabin, but no drone. Same at 3000rpms which changes into an aggressive purr.QUOTE] i just had mine done and i dont get a drone until 3900-4500 depending on gear and load. how would i figure out how long i would need to make my T branches?