Fancy Tech: How to Get Rid of Exhaust Drone, works great!

kevin8086

[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?

beemerkid

I just started on this today. Invidia gemini with FI resonated hfc's. Its not bad but its riiiight at 2800 to 2900 rpm...75to 80 mph, perfect cruising speed. So ive welded caps on so far. I wanted to package this so they sat above the mufflers, not adding extra weight to the middle, so the pipes arent an ideal length. One is 21and the other is 26. Maybe itll cut out more frequiencies because of the different lengths, I dont know. Im using 2.5 in. tubing, so the volume of the space created is pretty big. [IMG][/IMG]