00 Gmc Catalytic Converter Bypass
Posted in Catalytic Converters | Asked on Nov 22, 2010
Below is the question about 00 Gmc Catalytic Converter Bypass, Well first want to say michigan dont have smog testing.
my cats are going bad in my truck and not sure whether or not to replace them or bypass them. i heard both sides of this story but need greater advice. i know they have o2 simulaters i still cant figure out how or if those work, if they trully work. also i dont know what o2 simulator to buy. some guy said to me since its fuel injection it will adjust to it.
but im also thinking why waste the time with that and spend a couple hundred more and get magnaflow cats.
i honestly want to take them off. i would like too only if i can hear success from someone else on these trucks. and would like to hear how they ran them.
00 5.3l, ext cab sierra 1500, z71
yeah i know its illegal but i live in the middle of nowhere. uh i also know magnaflows cats are like 350.
There are 4 Answers for "00 Gmc Catalytic Converter Bypass"
Instead of messing around with O2 simulators and bypasses, I have a novel idea. Instead of a cobble job, why not just fix it right.
You don’t have to put the factory catalytic converters on. There are aftermarket ones that you can use that are inexpensive. To see what I mean, search the Summit Racing website. You will find many that will work for less money than one from the factory.
This way, you won’t have to worry about messing up your fuel / air mixture by doing a hatchet job on your exhaust system.
You may also want to look into why your catalytic converters failed in the first place. They should last the life of the vehicle. When they fail, it is usually because of some other problem. Usually from a rich fuel / air mixture.
I would bring it in to your local auto parts store and see if they will get you the trouble codes from the computer. There is a good chance you have more problems than a bad catalytic converter.
If you fix it right, it will start and run right. If you don’t, it will use more fuel than it should, it won’t have the power it should, it won’t start like it should, and it may be junk sooner than it should.
Even if there is no smog test in your state, it is still illegal to bypass the catalytic converter.
Bypassing exhaust components will not net you any significant gains, instead the powerband will be moved around (such that your peak HP/Torque are at a different RPM). While you certainly may gain a HP or two you’ll also need to consider the amount of time it’ll take to get up to that RPM, and how much power you’ve lost to get to that point.
The reason for this is due to the timing&duration of the engine’s valving having been matched to the resistance (or back-pressure if you will) of your exhaust system in order for proper creation of vacuum within the cylinder/head (Bernoulli effect). Part of where the mfgr decides to have peak power generated is based on what they feel was safe for towing X pounds, up a hill of Y grade, in Z degree weather.
Your system will only be as good as the weakest link, but there are ways to work around that. If you are looking for a performance gain, I wouldn’t start with the cat(as it isn’t a major player). I prefer to look at replacement exhaust systems in the following order:
1) Muffler(s)
2) Mandrel bent piping
3) Exhaust Headers
4) Cat
Going with a high flow cat will not help the turbulence created by the piping, muffler, and an inefficient exhaust manifold is just not a good starting point. Items 2-4 are functional, but crumple/non-mandrel bent piping is fairly inefficient in performing it’s primary duty of moving exhaust gasses(as compared to the level of efficiency of the manifold, muffler, or cat in it’s primary duty).
I’ve found that cat’s tend to last just a little longer than entire exhaust systems (tend to last about 10 years/120k, whichever comes first), while exhausts usually start rotting out just a little before that point (at least up here in the salty North East). If you are looking to replace your cat, take a look at the rest of your exhaust and see if it would need replacement in the near future (it will be cheaper to buy an entire replacement exhaust rather than repairing piecemeal).
If you want to spend less than $350, then go with a generic cat sized for a truck with at least your engine size, and have it welded in by a exhaust shop.
It’s very common to eliminate the cats and run a dual system out the back with stainless 3″ tips. Personally I’d go with Flowmaster as opposed to Magnaflow. It sounds better on GM’s. If you don’t want to spend the cash on a full system you can have the cats cut out and just have them weld a piece of tail pipe in their place. Although, alot of garages wont do it due to legal issues,,,you may be able to talk them into it if you pay cash and don’t ask for a receipt. Good Luck