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  1. #1
    Jr. Mechanic SoundZman's Avatar
    Join Date
    Apr 2009
    Santa Clarita, CA

    Default Getting cat's replaced...

    is $250 per catalytic converter (out the door) a good price for this?

    Sounds pretty fair to me...
    >>>2003 Suburban K1500 LT<<<

    ~Rear overhead DVD
    ~Orion 600D
    ~ 12" Acoustic Elegance AV12
    ~Hankook ATM DynPro A/T's
    ~Flowmaster exhaust

  2. #2


    Is that installed? I paid $98.00 each for my Magnaflow oversize cats. Installed myself. Even installed, $250.00 each sounds like alot.

    2005 Chevy Silverado Z71 Crew Cab
    6" Skyjacker lift w/Edlebrock dual front remote resoviour shocks, single rear remote. Rancho skid-plate.
    17" x 9" M/T Classic Lock Wheels, 35" BFG A/T or M/T tires
    4.10 PercisionGears w/factory locker, T/A Performance rear-end cover
    Banks CAI intake, ported throttlebody, JBA coated headers, over-sized Magnaflow cats, Magnaflow cat back exhaust, Diablo tuned
    B&M aluminum deep transmission pan
    Warn brush guard w/Warn 9.5 XP winch, PIAA bulbs, Line-X bedliner, AWS Black tool chest, Extang tonneau cover
    Weather Tech floor mats
    Cover-Craft seat covers
    Dash mat cover
    Formula One window tint
    One black Lab in rear seat.

  3. #3


    Is that for OE/OEM replacement ones? You can get aftermarket "hi-flow" cats for cheaper like silveradotrailblazer said.
    2003 Silverado 2500HD 6.0L Vortec V8
    2" Body Lift
    3" Suspension Lift
    Skyjacker Hydro 7000 Shocks
    Skyjacker Steering Stabilizer
    35" Tires with 20" American Racing Rims
    Velocity Cold Air Intake
    Billet Throttle Body Spacer
    BBK Performance Headers
    MBRP Cat-Back Exhaust System
    DiabloSport Predator- Soon to be tuned by Diablew

    "Soon to be leveling-kit"

  4. #4
    Jr. Mechanic SoundZman's Avatar
    Join Date
    Apr 2009
    Santa Clarita, CA


    Unfortunately being in California, the smog laws are very strict and became even stricter a couple years ago. Therefore the cat's have to be C.A.R.B (California air resource board) approved and stamped in order to pass smog every 2 years. When my Catalysis Efficiency codes began last year the only aftermarket manufacture, who was applying and receiving CARB approvals, was Magnaflow's parent company. The approvals where vehicle specific, not cat specific, so they had to test and provide documentation for each vehicle. Today I know of another company (Walker) which has CARB approved cats for by Burb and so does Magnaflow.

    So needless to say hi-flow it completely out of the question. Which leaves my only options of; $250 installed per catalytic converter OR $700 from my local dealership for OEM cat (y-pipe, flange to flange).

  5. #5


    That does sound like a good price if they meet CARB reqs. Misfiring can lead to converter failure... any history of this? A new converter will pass many tests with flying colors, only to fail prematurely with the infamous P0420.

    Often you can pass the 'check engine' part of emission testing by resetting the light and driving until the monitors runs. You can get the catalyst efficiency test to run much more quickly through a sequence of steps. Only problem is if you are on the threshold of pass/fail the test may run extra times before the PCM makes its 'decision.'

    Many people are rumored to have beat the catalyst eff test by installing non-fouling plug adapters in the O2 sensor bung (sensor 2 after the converter). Install the sensor inside the non-fouler. This spaces the sensor from the exhaust flow, causing it to 'read' differently than the front sensor. Note- when the cat ineff codes set it is because the sensors are reading real close to each other (means nothing is happening inside the converter). At a strict place of inspection (most people) would need to remove the non-fouler (after the monitors have passed) and reinstall the original way. Then drive down for inspection. "But how do I avoid the code flagging before inspection?" Drive as little as possible and avoid the sequence of steps that cause the monitor to run... or so the rumor goes.

    I'll look for the complete regimen of running the catalyst efficiency monitor if someone else doesn't have it handy. It's basically a warm engine... then stopping with your foot on the brake for roughly 2 minutes while in drive. This test must be run more than once... possibly many times.

  6. #6
    Jr. Mechanic SoundZman's Avatar
    Join Date
    Apr 2009
    Santa Clarita, CA


    Thanks for the info TERRYNY....but I can pretty much tell you exactly why my bank 2 cat failed. Just before moving out of state I began getting a Knock Sensor code for bank 2, I reset the code but it began coming back more and more frequently. Well I let it go until after I moved and got settled in (probably about 3 months), then I replaced both Knock Sensors. However shortly after doing so, I found the Catalysis Efficiency code rearing it head. In doing research on a knock sensor code I discovered the ECU has a built in fail-safe, it puts that banks a/f ratio into a rich condition, in which it begins dumping excess fuel down that bank. So leaving it like that for an extended period of time caused the cat to run much hotter then normal which tends to breakdown/melt the internal metals.

    So in testing the temperatures my mechanic said he measured a 40 degree difference on bank 2 (inlet vs outlet) and a 60 degree on bank 1. Since he's dropping the exhaust and the other cat isn't performing quite up to par, I figured to just replace both and throw on a Flowmaster muffler. Replacing both cat's will also help to keep the exhaust balanced...maybe that's just how I rationalize it to the wife

  7. #7


    x3 they are way overpriced whom ever is trying to get $250 a piece for them you can find allot of high flow cat's online for allot cheaper.. i've heard that they really dont help out allot from others online but not 100% sure since i dont have them!

    2008 Chevy Silverado Ext. Cab Lt Z71 5.3 V8
    7.5 Inch Rough Country Suspension Lift
    RBP Replica Grille Black w Chrome Rivets
    Recon Smoked Cab Roof Lights
    N-Fab Powdercoated Gloss black Cab Length Nerf Steps
    5% Tint over 20% all the way around / 5% Eyebrow Strip
    AVS Smoked Window Visors
    Z71 Stickers Black & Metallic Silver
    Tow Mirrors / Smoked Turn Signals
    XM Satellite Radio Fin / Color Matched
    Interior Plastic Pieces / Color Matched
    Power Acoustic Tweeters
    Painted Bowties / Color Matched
    Painted Door Handles / Color Matched
    Smittybilt Bull Bar / Color Matched
    Custom Rolled Edge Exhaust Tips / Color Matched
    Custom 2.5 Inch Cat Back True Dual Exhaust
    Flowmaster Super 40 Series Dual in / Dual out
    Magnaflow Tru-X Pipe
    K&N Air Filter
    18x9 Rockstars Machined Black
    Center Caps / Color Matched
    33.13.50 Nitto Terra Grapplers
    New Front Wheel Well Liners
    Eagle Eye Black L.E.D. Tailights
    Eagle Eye Black L.E.D. Third Brake Light / Smoked
    Eagle Eye Black L.E.D. Halo Projector Headlights
    Notto HID Kit 10,000k Low beams
    Recon L.E.D. Light Bar
    Buschwacker OE Style Tailgate Cap
    AMI Gloss Black Antenna
    Debadged Chrome Lettering
    Door Molding Removed

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