I have a 97 f150 xlt 4.6 and I am about to change my catalytic converters. I have a shop that wants to charge about 380 to redo the whole exhaust from my manifolds back, they would be replacing the 2 stock cats with one. I talked to another shop that refused to replace the 2 with one and wanted to charge 680. The guys reason was that the rear o2 sensors will give a CEL because the truck was made for 2 cats. Is this a false statement?
Thanks

 

It is false. If your exhaust is stock, you should have 4 cats, not 2. It would be better sound wise to run 2 hi-flow cats with the rear 02s mounted after the cats to eliminate CEL issues. You cant run just one cat. You need to have one per bank at minimum. Other than that $400 for a whole exhaust isn't toooo bad, if its aluminized its a little high. Stainless it would be fair.

 

Yea I was talking about each bank. Sorry didn't make that clear. It's aluminized I'm almost positive. That's the cheapest price from every exhaust place within a 50 miles from my house. I didn't think it was bad from the manifold to the turn downs.

 

Actually I am getting the exhaust done this week. I have all 4 stock cats on and got the parts for a true dual x-pipe (borla, decision made after 1000 vids) exhaust, all stainless. I also got two 94106 high flows.

My question:
I have to pass a sniffer test. Should I replace only the rear cats with the 94106s or can I remove all 4 and still pass inspecion? AND how would it sound with only the rear cats replaced with the 94106s and the precats on?

Exhaust inspection must be passed...

Thank you
John

 

That's the same situation I am in. I am replacing the rears... I just want to find that out for sure as well as I am getting the cats in a week or so.

 

Most important question's the difference of how it sounds with only rear cats replaced with the 94106 and all 4 replaced with two high flows...

 

Bump... can someone answer this?

 

Your front cats are called "pre-cats". If you remove the rears completely, you end up the equivalent of sound from a pair of hi flows. So, if you leave the pre-cats in, your going to be sort of running 2 pairs of high flow cats. This will be significantly quieter when compared to just pre-cats, or a pair of high flows.

Now as far as passing the sniff test...
According to magnaflow's web site, they are 49-State (EPA) legal. So as long as your NOT in CA, you should pass the sniff test running only 1 pair of high flows.

To be 100% certain though, I would recommend emailing magnaflow and asking them.

 

Ugh... I want the 40% louder, I'm gonna talk to the shop about just the 2 94106's that I have and install them in place of the 4. The 02 sensors can definitely be moved to fit in behind the hi flows I have for sure? I guess just tell them to put them where the pre cats are so that the distance would essentially be the same.

 

^ Right! The closer to the collector, the more effective they are.