View Single Post
      12-10-2012, 10:53 AM   #737
Burrito bowl connoisseur
import36's Avatar

Drives: E92 335i MT, E46 M3 SMG
Join Date: Feb 2008
Location: Seven Cities

iTrader: (1)

Garage List
2008 BMW 335i Coupe  [4.50]
2005 BMW M3  [5.00]
Originally Posted by muzzammil15 View Post

The siren noise is most likely due to you removing the cats and going catless DP's. Cats usually quiet down a lot of the turbo spool up noise, and not they are not there. You are hearing more of the turbo spool up. A lot of people have said, as the car warms up the sound goes away.
Originally Posted by zeenon53 View Post
The whistling is the turbos spooling. If your feeling vibrations though your pipes are either touching the frame or the engine block. You are going to have to go back and adjust them. Once installed correctly the car should still drive like OEM.
+1....with dps you'll definitely hear the turbos more...whistling noise should be more prominent.

however...if you're hearing a 'siren' type noise.....that is not normal and possible your turbos are heading south. does your car smoke at all?
Mods: Procede Rev3 9-10|AE Catless Dual Exhaust|AR Design Catless DPs|AMS FMIC|Stett Charge Pipe w/Tial BOV|Stett CAI|BMS OCC|BMS CDV|Volk TE37 SLs|KW V2 Coilovers|Cusco OS Strut Brace|Macht Schnell Stud Conversion|Work RS-R Lugnuts|Gloss Black Roof|Matte Black Kidney Grills|UED Lower Bumper Grills|OEM Aero Lip and Painted Reflectors|M3 Sideskirts| VRS Decklid Aero Spoiler|Gloss Black Roof|M Peformance Alcantara Steering Wheel(blue)|OSS V2.0 LED Angel Eyes|8000k HID Fog Lights|8000k MTEC Xenons