Im putting a true dual exhaust on my 95 1500. i want to put dual high flow cats on, when doing this what do i do with the o2 sensor inside the cat? i was looking around and found that you can buy a simulator but thats for a 96 and up.

 

I am pretty sure that there isn't an O2 sensor acutally in the cat, just before and after I think lol I don't have a cat so i am lucky

 

don't go with a sim, i had a bad experiance with one of those. I think most of the guys with your year of truck get an x pipe installed prior to the cats and put the o2 in the cross piece.

 

I wish I had a pic of how my exhaust is, without a cat or x pipe. I have videos on youtube though with my exhaust sounds lol

 

On the single cat models, the down pipes from the manifolds join at the cat, and the O2 sensor is indeed mounted there. To do duals, and keep the O2 sensor, you need to put in an H, or X pipe, and mount the upstream sensor there. The downstream can go anywhere after that. (I wouldn't put it closer than 10 to 12 inches though, and a non-fouler may be required to prevent setting a code. and then, there is the possibility that you only have ONE O2 sensor, which makes it even easier.)

I really don't recommend a simulator. You engine NEEDS the data from the REAL sensor to run properly. Don't stick a box that 'fools' the PCM into thinking one of its MOST important sensors is really there, and doings its job.

 

First 94-95 trucks have a different exhaust setup then the 96+ trucks. 94-95's have two down pipes into a collector (where the O2 sensor is mounted) then into the cat with a similar exhaust after that. 94-95's are also OBD 1 and have EGR and no 2nd O2 sensor.

To run true duals with one O2 you should either put the sensor in a x-pipe or in one exhaust bank. I would not suggest putting it in a H-pipe as h-pipes get very little exhaust flow; they are simply there for balancing the pressure pulses in the exhaust.

Also pipe size is important, with the 318 2-2.25 would be good and with the 360 2.25-5.5 would be good. You do NEED a crossover of some type too (h-pipe or x-pipe).

 

You can't sim the front O2, only the rear. Perhaps that's why some have problems with them.

 

Cool thanks for the info guys

 

Here's a pic of what some have suggested, Works great.