Please help regarding cats

[OPS]

Hi,

I am running a 330ci with an 8 PSI ASA-based kit and headers. My problem is with the cats:
1. I put in a Magnaflow universal sport-cat (the one, which you can see through), right after the headers. (Still have the 1st resonator, so the cat is basically besides the transmission, it's lower by app. 5 inches than the rest of the car). The problem was that it did almost nothing at cleaning the air.
2. I changed it to the universal one that Technik recommended in this thread:
http://forum.e46fanatics.com/showthread.php?t=295589&highlight=cat+dual
However, it did last only a couple of month; it melted away.

Question is whether I can put the same cat but replacing the resonator (being further back, temperatures cool down a bit, etc...), or is there something else I should do.

I appreciate all the help.

[omes]

Check this out, i moved my cat's back to basically under / equal to under the driver's seat, my underside will look slightly different as I am a cabriolet.

http://forum.e46fanatics.com/showpost.php?p=2051485&postcount=2

[samir@technik]

However, it did last only a couple of month; it melted away.


That shouldn't happen. Check your EGT, it sounds like your exhaust temps are way too high (AFR must be too lean).

[OCswedishM3]

That shouldn't happen. Check your EGT, it sounds like your exhaust temps are way too high (AFR must be too lean).

That is my ****** problem and im not too happy about it. I thought it was fixed but im still running too lean. Im thinking about getting a fuel management system as a piggyback...what are your thoughts?

[OPS]

That shouldn't happen. Check your EGT, it sounds like your exhaust temps are way too high (AFR must be too lean).

We measure lambda values between .82 and .87 during full throttle (well, except over 6000, but that's known for me so I don't use that range yet) and lambda is stable 1 duing lambda controlled operation.
However, it turned out I got "misfire with fuel cut-off" code pretty frequently. Right now I assume that might be a cause of the problem, although I don't know yet what causes this (always at cyl.4, ECU amplifier leg is measured as OK, plugs and coils changed).

How do you measure EGT, do I have to put in a sensor in the pipe, or can I do that from outside; do I measure it at top part of the header or at the cat?

Thanks

[samir@technik]

That is my ****** problem and im not too happy about it. I thought it was fixed but im still running too lean. Im thinking about getting a fuel management system as a piggyback...what are your thoughts?

Have you talked to AA?

Piggybacks don't work, especially on US cars. A standalone is an option, but at the expense of losing some OE functions. Plus, a good one costs $$$...then you gotta have it tuned correctly, which adds even more $$$.

[samir@technik]

We measure lambda values between .82 and .87 during full throttle (well, except over 6000, but that's known for me so I don't use that range yet) and lambda is stable 1 duing lambda controlled operation.
However, it turned out I got "misfire with fuel cut-off" code pretty frequently. Right now I assume that might be a cause of the problem, although I don't know yet what causes this (always at cyl.4, ECU amplifier leg is measured as OK, plugs and coils changed).

Something's wrong. A cat should never "melt". It should last a VERY long time, if not the life of the car. It will only get damaged if your AFR is off or your EGTs are very high.

How do you measure EGT, do I have to put in a sensor in the pipe, or can I do that from outside; do I measure it at top part of the header or at the cat?

Thanks

Yes, installing the sensor as close to the exhaust port is what gives you the most accurate EGT.