[zeotz]

I thought I'd share my experience of installing a downpipe with cat delete (custom fabricated at a local exhaust workshop). after install, the CEL light came on, so I had to use the OBD2 reader to reset after every few kms of driving. later I installed the angled oxygen sensor space, and it worked fine ... no more CEL lights. pics attached for reference.

in terms of sound ... its always subjective if its a better sound .. definitely louder when valve open compared to original setup.

I also installed an x-pipe without resonator box, but it was too loud and I didnt like the tone... so I replaced back the original resonator xpipe, kept the downpipe w/o cats ... good loudness and tone is ok .. a little "rougher" perhaps as compared to the original with cats.

performance wise, I do "feel" some improvement. so far am happy with the setup.

 

[Jason@ Enzo`s Atlanta]

Pretty sweet, but I`m sure you know that is pretty illegal...I`m shocked that you could get a place do that on a street car or did they make them and you put them on yourself? Did they make the flange or did they cut off OE cats? J

 

[zeotz]

Where i am, you can find workshops that can even make a new car from 4 scrapped cars...anything is possible. Anyway, in my case they fabricated the flanges too and put it on a fresh steel tube so its just like the original piece without the cat... they can also install a hi-flow cat but i didnt want it. I still hav the original downpipes intact, in case the mod does not pass the annual inspection i will swap it just for the test.

Also an update, after driving the car hard yesterday through some mountain roads the CEL came on back.. i guess even the angled spacer isnt the solution. Anyone any idea? It needs tuning or programming work I guess.

 

[AaronE]

how can that *not* throw codes?? isn't there an O2 sensor right after the cat to make sure the cat is working? how could that ever work without a cat altogether?

 

[zeotz]

Yes, there is an o2 sensor before and after the orignal cat. In the catless pipe, the oxygen sensor went back to more or less the same position as before, except without a cat inbetween. With the spacer on the second sensor, the logic is that the flow of gas passing across the second sensor is less than the first sensor because its out of the main stream of gas flow. the two sensors measure the difference. In my case it worked for some days while i was driving modestly... but if you push it i think the pressure goes the same everywhere. Its just my layman interpretation.. not an expert. Although the oxygen sensor trick worked for a lot of other cars which i learnt on forums.... which is why i tried it.

For now i'll just reset the CEL light.

 

[Jason@ Enzo`s Atlanta]

Lol...Yeah, that is why I like the sport cat option better as you do one thing and then end up with the CEL and a PITA ..I well aware of the spacer trick, but honestly it doesn`t work on a lot of makes..I have done it on 355s etc. with no luck...The sensor isn`t measuring the pressure it`s measuring the oxygen content of the exhaust and can still pickup the stream even out of the direct path..I have not used them because I keep the cats on cars ...., but another option is a O2 sensor simulator...you can google it.....Jason