ATFPat

My buddy has a 03 GT with some mods done but keeps having problems with his mid xpipe w/high flow cats (BBK). From what I understand, he basically blew out the cat on the right side. Took back that h pipe to get another which was working fine. He bought a SLP catback and after a few weeks, sure enough, the right side cat goes bad. Before he installed the SLP catback, he was running a stock like exhaust except the long tube BBK headers/highflow cats, dyno tune w. tuner, plentum w/throttle body, BBK cold air intake.

Question is, why would the BBK cat keep failing? could it be from a bad tune or the vehicle running rich etc. He has said he could detect a smell of fuel but the guy that tuned it said it couldnt be from the tune. Also, what other mid pipes could he use? I saw that SLP makes a mid pipe but from what I read it only works with SLP long tube headers and he was told by our local speed shop that being that he has BBK long tube headers he can only put a BBK midpipe on there that comes with the high flow cats.

Any opinions?

I dont understand why he couldnt run another pipe just as long as it "Bolts" up and i m sure that if his car running rich that could kill the cat out.

ChalknCover

A car that runs rich will kill a cat. I have had problems with 5.4's where they have a bad injector and the end up hydrolocking the engine. Well after the engine replacement, there cats go bad because it had been running rich and darn near pouring fuel down the exhaust. So, yes, a rich tune could be doing it. Why does he not get an O/R X and some mil elims? His cat-back is going to be ungodly loud anyway.

Edit: I did just find out that a lean tune will do it a hell of a lot quicker than a rich one will. But if he smells fuel then, I would say it is more of a rich problem than a lean one.

ATFPat

^^ that what I said, as for the cat he want to remain somewhat legal with laws in DE.

Agentl074

Thats what I did... cant go wrong with a O/R X.

ChalknCover

Well, one could argue that they are legal since a mil elim still sends a Ready code to the emissions station, so they have no idea, plus they don't care. Our guys are a joke here, they don't even visually inspect the cars exhaust or check the gas cap. They plug in the OBDII and get a Ready code and you are good to go.

ATFPat

^ yea i hear ya its a joke, but they do check to make sure that the cats are theire. Even if someone just "Hollowed" out the cat they wouldnt notice to fail it.