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      06-10-2012, 02:40 PM   #23

Drives: '08 135/ '11 1M
Join Date: Oct 2007
Location: at Death Valley 127

iTrader: (1)


Akra full time open with straight midpipes (N55 mid with resonator removed) has ZERO drone. I can not say I ever had drone before but with this set up now I have less "drone". I almost want to say at cruising speeds the cabin seems quieter now. My 135 with Borla exhaust and straight mids was MUCH louder than this (Akra completely open/straight mid) set up.

I took some readings with a decibel meter for comparison. Keep in mind the Akra has zero miles on it so it still needs to break in. I will update the "open" numbers when I get more miles on the system. I cannot update the closed numbers since the plate has been removed, BUT Maybe its safe to assume the delta on the open numbers would translate over to the closed numbers (im not sure).

N55 midpipe with a Y pipe (RESONATOR DELETE) and OEM muffler

Idle: 85.0 Max: 105.9

Midpipe form above with Akra closed system

Idle: 90.1 Max: 104.3

Midpipe above with Akra plate cut out for full time open system

Idle:92.6 Max: 109.9

Also, I dont notice any issue with alignment. I havent installed tips yet since I didnt buy the Akra tips. Once I find what I want I will comment on alignment.