Mazin

hey guys, how are you doing?
I am a new owner of Mustang 5.0 Manual, and my car had an Xforce catback but the sound is not enough for me, so I'm looking now to remove my catalytic converter but my question is gonna turn check engine light? and what is the solution? and why some people say should remove the second o2 sensor when removing the cats?

08'MustangDude

Yes, the CEL will illuminate, so you need the O2 sensor simulators.

Mazin

how to do that bro? (O2 sensor simulators.)

08'MustangDude

The function of the Oxygen Sensor Simulator or O2 Sim is to mimic the signal of an O2 sensor
sensing the proper levels of emissions. The O2 sim has an output signal wire that will replace
the O2 sensor's signal wire to the engine control module. Now, with the cat removed, the check
engine light will be off and no error message will be logged.

It is advised to use one of these devices for off road use only. They are NOT street legal. The oxygen
sensor simulator may allow you to pass today's emission inspection because the test merely reads
the OBDII log to see if there are any emission related error codes. It will fail a tailpipe test...

You simply wire the simulators to the harnesses. You leave the sensors in the pipes, but
wire/splice the sensor simulators to the factory harness.

This is a basic simulator:

The Product Explanation:

1996-2004:

Norm Peterson

If all you care about is making more noise, wouldn't it be easier (and less illegal) to do a muffler delete instead?


Norm

danzcool

Not necessarily, although that is what they would like you to believe.
I have a copy of a tailpipe emissions test of a modern car without catalytic converters that passed within tolerances for tailpipe emissions. It's all about the tune, as a well tuned performance car runs clean. The emissions levels are set up in such a way so that when a car is 10 years old, when your cats are pretty much spent, if you have everything else maintained properly you will still pass.

Norm Peterson

Regardless of whether it'd pass a tailpipe sniffer test, it'll still fail the visual check if a converter is not present. Having the correct number of converters and in the right locations is important as well, at least in some regions.


Norm

imp

Any idea whether a simulator will effectively eliminate a persistent code for downstream sensors on the 4 sensor system? As I understand it, outputs for the downstreams are significantly different than upstream, and are used by Ford often to call attention to faulty cat operation. In my case it began with "HO2S Heater Circuit, Bank 1 Pos 2"...........Thinking that's pretty clear, I checked the heater resistance: right within spec. Replaced the heater feed wires, both, from fuse to sensor back to PCM......SAME CODE. Replaced all 4 O2s; SAME CODE. Whaddaya think? imp

danzcool

You're right of course, and it is a federal crime to tamper with any part of the emissions system.
But it is possible to meet the intent of the law by means other than catalytic converters, but legislators write regulations in a narrow minded way.

Norm Peterson

On the matter of tampering with the emissions technologies chosen by the mfr, yes they did get picky. But the regs don't exactly require any specific technologies, and have intentionally been left "technolocially neutral", where indeed it's only the results that matter. Not on how the mfrs get there. But once the mfrs have chosen, that's what we're stuck with unless it's possible for an individual to run his approach through whatever EPA certification procedure would be required and meet the applicable requirements.

Catalytic converters got a really bad rap back in their early days where they really didn't flow very well at all. That's not the case any more. I've got a few numbers . . . the pellet-type converters that GM used and at least one Ford cat (of unknown construction) in the late 1970's and early 1980's didn't even flow 200 cfm @ 25 inches of H2O . . . and high-flow converters have reached as high as 600 cfm at the same pressure. 25 inches of H2O is about 0.9 psi, which corresponds to about a 2.2% loss of power if you're actually flowing that much.

Trying to push 600 cfm through a 200 cfm @ 25" cat from way-back-when would push the pressure drop across it up by a factor of 9 (and the power loss to ~20%). That's if it didn't hit "choked flow" first, where no matter how much more pressure you put behind it you don't get any more flow.

Basically, there was a time when you could get a significant amount more power by replacing the cats with pieces of pipe, but that's no longer the case.


Norm