Magnaflow install question - resonance? '08 suburban 2500

Discussion in 'Performance & Fuel' started by dougtexas, Jul 12, 2012.

  1. dougtexas

    dougtexas New Member

    Little help....Strong consideration to install a cat back system to my '08 Sub. 2500. (part # 16725)

    My concern before pulling the trigger is cab resonance...any of you guys been there done that with either a Tahoe or Suburban with this body style?

    Magnaflow is the only one building a kit for my truck... no flowmaster, borla, corsa

    My purpose to do these upgrades is to hopefully improve tow performance. Installing a cold air filter (afe) tomorrow and thinking what goes in has to come out...
  2. Shyloh

    Shyloh New Member


    I have a 99 Sub 1500 with cold air intake and magnaflow catback.
    I like it, but the 1500-2200 resonance can be defening especially under load.
    A local muffler shop said they can fix it, just haven't done it yet.


  3. Skippy

    Skippy Member 2 Years 100 Posts

    You can pretty much eliminate resonance in the cab by having the mufller shop add a 6 foot section of pipe that is capped that offshoots from the exhaust pipe under the rig. Basically, by lengthening the resonation chamber, you lower the point of resonance below what conflicts with your engine's vibration. It's not an expensive option, but you most definitely have to ask for it when you get your muffler installed. Most shops won't know about it. Basically just have them add a 6 foot tube connected to your exhaust pie after your muffler. Have them put it perpendicular to the length of the truck and weld a cap on the end. SAME principle as what you get with the sound dampening on your stock intake tube (they have the long plastic offshoots to change the tone/dampen sound).

    I've seen this done.. just not done it myself. Personally, I run resonators on the tailpipes. That lowered the sound volume tremendously... I then added 20lbs of angle iron to the pipe near the muffler to further change the resonance. It altered it just enough that I only catch the resonating drone for a second or two before shift.

    If adding lengths of pipe is way beyond what you had in mind (it is for most folks... it's a weird mod!), there's plenty of options out there, in addition to the part number you listed. Most any muffler shop can cut/bend custom pipes pretty cheaply...> this means you can pick your muffler and have them build you the pipe set for it. It's not terribly expensive. Usually you're looking at 300-350 for a whole setup with a Magnaflow exhaust.


  4. dougtexas

    dougtexas New Member

    I bought and installed the Magnaflow kit 16725 . It's been a few weeks now and sounds great. Just took a long road trip and it has gotten a little more "throaty". There is some cabin noise at 1300~1600 rpm under slight load in top gear at any speed....but hell why did you buy it if you didn't want to hear it. A little more gas and it down-shifts so the sound can go away if I want. Love to remote start while walking up to the 'burban... Seems to have smoother pull when towing the boat. Accelerates quicker for passing at highway speeds. Looks cool.

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