ARK r-spec hi-flo cat.. Friends, I need help.
 

Friends, I'm new to this forum, please bare with if I not fluent with the lingos & abbreviations. Please I need ur advice on what to do. I have a 2011 black 370z nismo. Last month I got a new HKS hi-power titanium tip cat back exhaust system. 2 weeks after, I got an ARK R-spec hi flow catalytic converter. 3 week's later my service engine light came on, I went to the dealership, they said it's bcoz of the aftermarket cats (it messes up d O2 sensor). They advice me to put back d factory cats or go to a tuner shop to adjust d settings but it will void my warranty. What should I do now? Is this expected once u put on a HFC? Please advice.. Thanks!

They gave good advice

But, option 3 is to get O2 bung extenders or anti foulers. (Google those)
And that should get rid of your CEL

did they clear the code? if yes then just let it go for now. When i had hfc(cnt) it would throw the code once in the blue moon. I cleared it and never looked back. If I were you, I would wait to see if it comes back again, if it does within few weeks then you should look into O2 bung extenders that Depointfive0 mentioned.

It is normal...car leans out. Need tune or revert back to stock cats. Simple as that. Check my sig for dyno tu e at stillen.

F.I. offers test pipes that have extended bungs that won't throw a code. It is also said that once you hit around three breather mods you'll throw a CEL regardless. Half those guys have Uprev. That can and will void your warranty if anyone figures out you have it.

99.9999% chance the CEL has to do with catalyst efficiency below threshold or something. NOTHING to do with too lean. If it was running lean, it would throw a code for that and the dealer would've said something more than put the stock cats back on

When I did gen 3s and hfc I got that and thats what they told me...leaned out.

...... Kinda of strange, and unless you saw the code yourself, never believe people.

(And yeah, I know breather mods "lean" your car out, but the car has a computer and sorts it out, and if on the rare circumstance it can't adjust fuel to make up for the mods, and it's outside spec for the A/F ratio, then yeah, you'll throw a CEL, but I HIGHLY doubt that happening)

It's very normal with HFCs or TPs. Even with FI HFCs it still has the chance to throw the code if you drive too hard. I see this ALL the time. Just reset the code and if it comes back again try the non-fouler/extender mod like DEpointfive0 mentioned.

Hey Andrew remember?
http://www.the370z.com/engine-drivet...-after-g3.html

I do have a full ark exhaust system down to the converters....mine had the same issue it throws a code saying possible exhaust leak but the car checked no leaks what so ever...except the first time my gaskets got fried and caused a leak.

Being said I had to accept its normal in the sense it will not hurt the Z.the car is running as fast as hell can burn a soul....it's just when you do change your exhaust plus intakes you tend to open up air into your car and with huge diameters of the arks the sensors are reading to much air and possibility of being lean.

A tune might be in the works in the future..:tup:

I do agree with Roy'sz analysis...

Yup had it rest a couple of times and everytime I floor her the light turns on like she just had an orgasm of some sort! So it's normal!:tup:

I tired the bung extensions from z1 and they didn't work. The tuner at stillen told me and showed me that the 02 sensor didn't fit in the bung fully. It also rattled itself out of the bung. I was pretty disappointed because I kept on throwing the same codes.

With the hfc's your cat is smaller, therefore you are not filtering as much gas as your stock cat. you car leans out thinking it can burn less fuel to compensate for the lack of filtration causing a lean error. Larger cat more filtration, smaller cat less filtration and more power.

The only way to fix it with the current equipment that you have is to get it tuned. They will go into the fuel map and adjust the a/f for best performance. I suggest that you do any other breather mods before getting the tune so that you get the most of what you paid for.

Just read all ur inputs,
The dealership tried to reset d code but they said that everytime they rev it hard, d engine light comes back on again.
I forgot to mention on my first inquiry that I also got a stillen gen3 (d same time I got my hks exhaust system).
When I was reading ur replies, someone mentioned about CEL, what is that?
Again, THANK YOU VERY MUCH to all of u my new friends. Please advice..

UpRev ecu tuning will eliminate the inputs for those o2 sensors. They will still work, but the ecu won't see when they operate outside their range.