Hey guys,

Just wondering what anti foulers or 02 sims to use after gutting the precats. Also, while this is happening, would you recommend gutting the main cat as well? Would this be another simple 02 sim or anti fouler as well? Thanks guys! Also, is there any write ups about how to gut the rear precat? I've read almost all the articles about it, and I have a good idea on how to do it, but any advice would be great! Thanks

 

I bought my 02 simulator from here

http://www.o2sim.com/

Specifically this model (dual output)
http://www.o2sim.com/universal-o2-si...put-p-184.html

 

I would go with anti-fouled, aka O2 spacers, because they are significantly easier to install and don't have to do any wiring.

You can buy O2 spacers on Amazon for $10 a piece and they fit perfect.

Don't fit your main cat, just pre-cats. Unless you know main cat to be plugged.

 

So after research on the forums I figured out I can just go to the local parts store and pick up a couple spark plug anti foulers and drill them out to make them work as 02 spacers. My only question now is you install these (2) 02 spacers on the bottom two primary 02 sensors, not the precat 02 sensors, correct?

 

You only drill out the bottom on the second non fouler, not the first.
They are only installed in the downstream sensor location, or after the precats.
If the cats aren't clogged, no need to gut them.
No need to touch the main cat if not a problem.
Purchase the correct thread size for the non fouler.

 

Werd.

 

what does the spacer do? expose less of the O2 sensor head by spacing out the sensor further form the inside of the pipe?

in theory wouldn't it be possible to have the ECU modified or reprogrammed ?

 

I tried 02 spacers and one of them wouldn't even screw in to one of the bungs. So I just returned them. I'll probably have a friend wire up an 02 sim for me.

 

does a sim, just simulate the o2 sensor or does it base the simulations of the current o2 readings so the ECU isn't completely blind?

 

Yes, a spacer pulls the sensor further from the exhaust stream and will give a lower emission reading (tricking the ECU into thinking its a properly working cat).

An o2 sim wires in place of the second o2 sensor and sends a reading of what a normal o2 secondary sensor would read.

In terms of price, spacers are the cheapest, followed by o2 sims, followed by having someone reprogram an ECU.

 

The bottom sensors are the precat sensors :P Yes, they go on the secondaries underneath the cat.

And that is the correct way to buy and make them work (only drill the top defouler).

 

You bought the wrong size. Go to Amazon and do a search. You can get them for less than $10 from Amazon. You don't have to do any wiring, they are plug and play, and you never have to worry about it again.

An O2 sim might give you other engine codes and you have to wire it up, and mask the wiring job if you have a state that checks visually.