my friend has a 07 z and just recently went out and got the cats removed from his hr and i was asking him if he noticed a big difference in gas mileage and he said he couldnt tell. i was looking into getting some berk test pipes for my 08 and going with an isis stlyed exhaust. but my question mainly more for the no cat deal is this. obviously his car threw a CEL. is having this CEL going to negatively affect anything, like horsepower, reliability, and gas mileage. any info would be appreciated. thanks z heads

 

Get art pipes, they won't throw a cel code

 

i have the ART pipes and just installed the TDX2 and i just recently started throwing a code (420 and 430) not sure why all the sudden i would do that. i know i need to get a retune so maybe that is it.

regardless you will love the ART pipes

 

I would also recommend the ART pipes, I've had good gains with them on the HR, +8whp and +11tq I believe.

travelee9372, I threw the P0420 after being on cruise control for >30 minutes (I am tuned and have never usually thrown the code). After clearing it and driving normally, it doesn't come back on. If I cruise for lengthened periods of time, it does.

 

yeah mine does it on the highway, and noticed that it does it when i let off the gas and then engine does the run on.. the couple blubs (for lack of better word). i have changed intakes, went from hfc to art pipes, and from invidia gemini exhaust to tdx2 so it is time for a retune, hopefully that will solve it

 

thanks for the input guys. but you havent heard anything from just removing cats. my buddy just went to an exhaust shop and had them cut out with piping in its place. hes only had his done for a couple days and hasnt had any issues yet. hes just wondering if it is going to affect anything in the long run

 

that is essentially a home made test pipe, i would be willing to bet that it is just a matter of time before his service engine light comes on

 

Sometimes it will take a certain number of cycles for the light to come on. The catalyst readiness is one of the longer ones. I had a test pipe on my old Maxima, when reset, the light would usually take about 2-3 days to come back. Basically as soon as the ECU finished all the readiness checks, the light would come on. If you don't have emissions and don't care about the light, no big deal.

The ART pipes have the O2 sensors set back from the exhaust flow. So the rear O2 sensors read less emissions than the front. This tricks them into thinking there are cats there. Same as putting O2 extenders in. If you have test pipes and don't do something like this, the rear O2 will read the exact same as the front. The ECU then thinks your cats have failed and will throw a code.

 

^ great explination

 

+1^ i appreciate the info. ill let him know. he said it came on for like 5 minutes and then went back off and then hasnt come back on yet lol