Alright iv got a 99 4.0 and right now my exhaust is cut off a couple inch behind the cat so i could keep the 02 sensor and my friend just told me he would sell me a BORLA exhaust so I was thinkin about buying it and cutting off the cat and running straight pipe all the way back to the borla...but my question is will this sound good and if not then wat can i do???

 

If it's to loud you can put the cat back in are you doin it your self? or you can put a resignator in after the muffler i have the cat and a jardine muff and its not loud the jardine is a straight threw muff they are compare able to the magnaflows just make sure the muff has a center inlet and a side outlet or it will not line up right good luck

 

If you remove the cat, the PCM will stay in open-loop. There will be a DTC for either "catalyst efficiency" or "downstream O2 sensor signal". Your gas mileage and performance will suffer in open-loop.

Leave the cat and run the exhaust from behind the downstream O2 sensor.

 

If you were to remove the cat can't you buy the computer plug to tell it the cat is still there thats what i did on my mustang and explorer

But i would leave the cat on any way i think it would sound redneck

 

You might be able to fool Ford's EEC... you won't get away with it on the MOPAR NGC controller.

 

Just wondered thanks for the reply
but like i said i would leave the cat on it will be noisey

 

I cut off my exhaust except for about a foot behind the exhasut manifold I then widend it to 3 inches and shorted it to come out the passenger side. I am running a 40 series flowmaster and It sounds great (atleast theats what most peopel have told me. its alittle on the loud side but I think its cause the exhaust manifold gasket is going bad. I have had to drop in fuel mileage or problems with it. I have heard good things about the borla mufflers they were just too pricey for me.

 

ya I want it louder...Iv heard of the false 02 sensors and figured they would work??? ya its a killer deal on the borla..right now it is cut about 3" behind the 02 sensor behind the cat

 

Mines a 93 and I have no cat and a flowmaster and I love it,but I know that does not help you at all sorry!

 

wat did u do about ur 02 sensors?

 

leabve the cat in and put in a glass pack I was running that it was not too loud imo it was just right and no one ever complained about the noise.

 

His is a 93 so there is no o2 sensor after the cat. just one by the exhaust manifold