I already have Borla Exhaust installed. So is it a must for High flow catalytic converters?

Thanks

 

Not a must, but I believe cats/test pipes and a y-pipe give better returns than an exhaust.

 

no mod is ever a must have....but high flow cats will definately improve your performance. since your in cali, make sure get high flows that are going to pass a visual....such as the crawfords...unless you know the right people

 

Does anyone know for sure that the crawfords HF cats will pass the visual in CA? How about Kinetix? Will these pass the visual test as well? I assume both will be no issue for the smog test. Is smog testing required once in two years in CA?

Thanks,
Baron

 

i think they change to 6 years for NEW car.

 

High flow cats are not a must by any means, but they sure do help out quite a bit....

 

It's my opinion that they are the most restrictive part of the exhaust system. I am currently working my way back...

1. TS Headers
2. Helix DNA HF Cats
3. ...? OEM for now

https://my350z.com/forum/intake-exhaust/114798-tp-w-resonators-or-carb-legal-hf-cats_.html

 

Yes, i agree, swapping out the cats really bring the modded exhaust together, and yes, they probably are the most restrictive part

 

I'm about to buy cats. Which cats should i buy tho ? I am considering UR and Crawford. What kind are everyone running ?

 

I am using the crawfords and have never had one issue with them. they do not rasp, and they have not had any issues with breaking or cracking. Also, they fit much better than some others out there and they are lighter than stock, so that's always a plus.
PM me if you want to go with crawfords, i'll take care of a good price for you

 

Tony,

didnt you mention gutting out cats in a previous thread a while back?? In your opinion, is this a better option than purchasing crawford hi flow cats or kinetix/helix ones?? I only ask b/c they would roughly be the OEM shell on the outside for visual purposes...but I am curious about performance aspects of gutted stock cats. Again I am not sure in the thread you were talking about, IF you were referring to gutted stock cats or gutted aftermarket ones....

 

it will never pass smog and you would get the CEL....so its ok if you don't have to worry about the sniffer or mind looking at that light all of the time

 

hehe,
i figured it wouldnt pass smog..but i wonder about performance wise if itd be as good as or better than aftermarket. but we have emissions inspections here once every 2 years...sounds like a real PITA to have to swap em out every year and a half just to pass emissions...

 

no, it's not a "better" idea, since you'll be running a straight pipe in that case rather than a high flow cat. It's not necessarilly better, but it's up to what you want to do.

 

The most important thing im looking for in cats is performance (ie gains). After performance I would say noise, dont want something toooooooooo loud, but a nice gain in sound dB is fine. I was also thinking hi flo to pass the sniffer...not for visual inspection...i have never actually seen the inspectors in VA look under the cars for a visual check. i could care less about smell, gases etc etc. I am not sure if hi flow's will pass the sniffer (crawford, kinetix, helix are the main 3 i have looked at). IF the hi flow's fail just like test pipes will, then I would just rather go test pipes and swap for inspection. any suggestions on brands?? again the 3 I have looked into are the helix, kinetix and crawford cats...

 

I went with the Helix 200 Cell Hi-flow Cats.

"Helix DNA Series High-Flow catalytic converters provide an exceptional balance between maximum power and emission cleanliness. Our high-flow catted products features 200 cell Metal Substrate Catalysts for maximum performance and emissions reduction."

- 100% SUS304 Stainless Steel
- Robotic TIG Welding
- Thermal boundary heat-shield for rapid light-off and maximum catalyst efficiency
- Features: 200 Cell Metal Substrate High Flow Cat with Thermal Shield x 2
- Piping Diameter: 60mm X 2

I went with metal substrate internals out of fear of the ceramic ones collapsing on me in 15-20k. I'm not a 100%, but I think this is unique only to Power Enterprise cats and HELIX cats. If you want some extra info on metal substrates, here you go.
http://www.autocats.com/html/motorsport.htm

 

I agree with the most restrictive part comment. I'm running TopSpeed Headers, Kinetix High Flows, and a GReddy Evo2. I felt the most gains/overall improvement with the cats than the others, although they were all pretty close and work very nicely in conjunction with one another.

 

Agreed, all of the exhaust components really work well hand in hand together.
by the way, if anyone is interested in Crawford Cats, PM me for discount pricing....

 

Isn't there a federal law that says you can't replace your factory cats prior to 50K miles? You have to make sure your factory cats are "damamged (cough cough)" in order to replace them.

I doubt it would ever come up, but does anyone know for sure, and what the reasoning behind the law was?

 

I've never heard of such a law, but there may in fact be one.....
I'm sure that something like that would be enacted to help ensure that the cats on newer cars 1)stay on the cars, and 2)to act as a deterrent to changing them out needlessly.