Quote:
Originally Posted by 1996 328ti  Your friend is wrong. They will know that the CEL was recently reset. There is some sort of readiness test that their equipment will read.
I've heard success with cats from Magnaflow <I think>. |
+1 on the readiness monitors.
if the cat is 'stinky' as in smells like rotten eggs, then it isn't dead (yet), but soon will be. there is an underlying issue at hand that is working the cat too hard.
*that* is the factor that i have seen kill so many "aftermarket cats" versus the factory is built 'better' argument.
it has been my own experience in emissions repair that shops that 'throw a cat' at a car to clean it up for emissions readings *without* verification of how the rest of the vehicle is running will undoubtedly shorten the life of *any* cat installed, regardless of where it is from.
magnaflow are awesome. as are a great many of them. why?? they all do the same thing the same way with the same materials. obviously the larger the motor the larger the cat will need to be, but think about it....how does a cat work??
it's all chemical reaction via interaction of combined chemicals when exposed to heat. the old days when cars were carburated and had cats, there were dozens of stories where they'd be 'glowing' because they were bad, or catch leaves on fire, and stuff like that.
nah, they were glowing because they were workin their selves to death trying to reduce all of the hc and co due to a poor running condition.
one of my instructors was a complete nut. great instructor. just absolutely *nuts*!!
we were being introduced to a new brand of cat (not important who, never got the name, anyway...). hooked it up to the car, proper application, fit was decent, and away we went. got up to temp, the cat was lit, and the instructor stated ok. now, class, we are going to see what it takes to kill a new cat!!. and we proceeded to kill the coil to one of the cylinders (cop design, simple to unplug...) while @ idle. then @ 1100rpm. the hc *didn't even budge*. i think we killed 3 cylinders and held the rpm close to 2k before the hc was going into the 'outer limits' zone. co was rising by this point as well.
of course the mil was on and we had *all* sorts of misfire and coil malfunction codes, but we ran this test for almost an hour with the gas analyzer sniffing the whole time. that right there taught me an awful lot on what fuel trim, freeze frame data, gas readings, and temperature have to do with regards to emissions and finding the cause of the issue.
apparently this cat mfr claimed that their designs could handle about a 25% misfire rate and still pass. according to the testing we did, i would believe this.
it still doesn't mean that throwing a cat at a vehicle failing emissions standards to get a barely passing reading is a 'correct' fix. you just rented some additional time to sort out the root cause of the real issue.
as far as fit and fitment, oe tends to be better for most applications depending upon the maker of the part and whoever loaded to truck that day...i've seen brand new oe replacement parts bent due to impropper shipping (after it was installed and test driven).
had a lot of fun in that shop...
df
Need some catalytic converter advice 
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