View Full Version : CAT Failure Question

07-12-05, 01:09 AM
I posted this in the B&B Header Failure thread, but there were already 20 replies this got burried.
Anyway..... this question is for the people who have headers and had a CAT failure, I'm trying to figure out what happens....

Here come the dumb :cookoo: questions....

When the CATS or a CAT fails, does it trip a code, is there a check engine or other light that comes on?

If you gut the CATS (did this a long time ago on a freinds old Buick GN back in the late 80's by using a screw driver, patience and knocking that crap out of there). If you do this, will the O2's still work? will a check engine light come on?

Just seems to good to be true to be able to get these headers (after a gasket fix PCN is in place by Billy), gut the CATS to get that extra.... as CVP put it... "intoxicating" high RMP power..... just seems too good that this is a worry free MOD.


Hopefully just the people with headers installed answer these questions, w/o actual B&B headers on your V, you would be just guessing like me.

VinMan out........

07-12-05, 01:31 AM
Yes, when the catalytic converters fail, the front O2 sensors will still "work" and provide feedback on controlling the air:fuel ratio. However, the rear O2 sensors will now report a catalyst efficiency error, set a few diagnostic codes and illuminate the MIL (check engine light).

With a custom tune, one can turn off the rear O2 sensors for "off-road purposes only" thus preventing the codes and MIL activation.

Catalytic converter life is all about thermal management. B&B has used this same cat on their Porsche systems for years. Seems reasonable that four cylinders of a LS6 at 6500+ rpm would put out more thermal energy than three cylinders of a Porsche engine.

07-12-05, 08:02 AM
downsides to running without cats?
(given that no sniffer test exists in a person's locale)

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07-12-05, 11:44 AM
downsides to running without cats?

Some say the honeycomb monolith helps to smooth the exhaust pulses and can actually add power at certain RPM.