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Thread: Catalytic Converter Help!
11-14-2011, 05:55 PM #1
Catalytic Converter Help!
So I ordered two magnaflow performance catalytic converters the other day. i went to 2 local muffler shops today and the first one said that I ordered the wrong ones and the second one said that the 06 Silverado has the best performance cats on the market. Soooo I have two questions: Will putting a "pre OBDII" cat in my truck make it run bad or just run codes? and is it true that GM's cat is the most high flow cat available?
Also, JEGS told me the cat would work on my truck, it didn't say that is was pre OBDII in the catalog. It says that is is OBDII complaint. The box for the cat is pre obdII. It makes me mad that now I have to pay for shipping so I can return them.
Another question, do high flow cats really do that much because i was thinking about ordering another set for Dynatech but if its not gonna make my truck sound any louder or get any quicker there is no point.
Chad.'07 Chevy Silverado Classic
-Air Raid Throttle Body Spacer
-Bully Dog Triple GT Programmer
-3" Spindle Lift
-Blacked Out Rims
-Blacked Out Taillights
-2 Kicker CVT 12s
-Rockford Fosgate 6.5"
-500 Alpine Mono Block
-Pioneer 6.5" Touch Screen
-2 Boss Tweeters
11-14-2011, 07:48 PM #2
...The Late Model Factory G.M./Chevy Catalytic Converters.......Flow Much Better than Most think they do......unless your Factory G.M./Chevy Catalytic Converter's are going Out/Bad......there's no reason to replace them for aftermarket Cats.......and I have not seen any kind of Dyno Number's showing any big gains with Aftermarket Cats being installed......
Last edited by 99'HEARTBEAT; 11-14-2011 at 07:58 PM. Reason: Added Infor.
11-15-2011, 12:39 PM #3
X2 what Mike said.:cool:
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.
11-15-2011, 01:26 PM #4
Replace the plugged cats with High-Flow cats, i convinced my father to do this on his 2000 silverado, and it doesn't downshift nearly as much going on the highway. He said he got a 1-2 mpg increase from going from the plugged to the highflows. Costed him $100 at the muffler shop.
2002 Chevrolet Silverado 1500 z71 1985 Chevrolet Silverado k10 2006 Chevrolet Silverado 2500hd 6.6l LLY Duramax 6.5" BDS Suspension Lift Key'd to 9" Edelbrock Carb & Polished Intake Manifold & Valve Covers NAPC Race Transmission & NAPC Built Transfer Case EFI Live Comp Cam and Valvetrain Snow Performance Methanol Injection 35" Toyo Open Country Mud Terrain on 18" Ion Alloy 179's Headman Long Tube Headers and True Dual Exhaust FASS 150gph Titanium Series Pump AirAid Cold Air Intake with K&N Dry Filter & AirAid PowerAid Throttle Body Spacer 2" Suspension Lift 33x12.50r15 Tires PPE Tuner until i tune it with my EFI Live Pacesetter Long Tube Headers with Cats Gone True Dual Exhaust FlowPro 3.73 Gears Yukon Grizzly Locker with Mag-Hytec Cover & Traction Bars NGK Iridium Tips & MSD Ignition Plug Wires Baja Spare Tire Holder Leveling kit & 34.5" Nitto Grapplers 18" XD Rims Innovate LC-1 Wideband o2 Sensor x2 HID's all around LED taillights and 3rd brake light BDS Dual Steering Stabilizers Pioneer Double-DIN Touchscreen Navigation with Two 10" Subs under rear seat Electric Fan Autometer Pressure, Boost, and Pyro Gauges 4.56 Gears AFE Stage 2 Intake
11-26-2011, 06:26 PM #52006 Magnetic Black 350Z
2004 Silverado Z71
Nitto Terra Grapplers | Viper Remote Start
11-29-2011, 11:38 AM #6
Like the first post indicated, it is my opinion that as you get into newer vehicles, which I will define loosely as after 1995, the OEM catalytic converter is going to be increasingly more efficient at allowing pass through at a lower pressure than the predecessors. And aftermarket units made for your vehicle have to comply with specifications that I don't think allow them to do much about what back pressure is created.
Again like the first post said, and I heartily agree, if your cat is not malfunctioning, don't replace it and don't blame it for any issue you have with "not enough noise". You can remedy that with the right muffler. Personally, I don't want too much noise. Just a nice rumble.1994 Chevy K2500 Silverado, 454 (modified), original owner.
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