So, I gutted a set of used OE cats that I got for $50. It took a while to get all of the stuff out of them, but with a long 1/2" drill bit and 3 hours, I finnaly finished. (Make sure that the drill bit is for metal)

I also picked up the 2 sets (total of 4) of spark plug non-foulers from Kragen autoparts for about $15 and drilled 2 of them out w/ the same 1/2" drill bit.


Removal of cats:
The night before, I sprayed the nuts/bolts w/ 'liquid wrench'. The following night I used the 14mm deep socket w/ swivel, and 3, 12" extensions to get the 2 nuts off of the passenger side and was able to get one of the nuts off on the driver's side, all going from the top of the engine bay. For the 2nd nut on the driver's side, I ended up getting to it from the front of the car (I fed the extensions just above the front sway bar and just above the metal power steering lines and onto the nut...I adjusted the lenght of the extensions so that the breaker bar would have room to rotate in the space between the radaitor and front of engine.

After disconnecting the O2 sensors and middle brace that connects to the cats and transmission, I removed the remaing nuts. (each cat has 3 nuts up top and 2 below, with a middle 1 that attaches to a brace from the transmission)

By pushing on the Y pipe flex joints rearward, I got the rear portion of the cat out and then the unit just fell out - nice and easy.

After installing the new and improved cats, I started it up to check for exhuast leaks - it sounded great and there were no problems. NO SES light either! (I resued the gaskets and nuts)

Sorry, I have no pics, but feel free to ask quetions!

In all, I love the difference. I don't hear any rasp, but I can smell a difference. The exhaust is a little louder at idle, but below 3K rpms, it's hard to hear the difference. Cruising on the freeway at 80mph and in 6th gear, I can barely hear the exhaust. Concerning power, it feels much more responisve and faster...but this is all 'feel'. I also love the sound above 3K rpm!


car info: 2005 enthusiast, 7K miles, stock exhaust, UR pullies, MD 3/8" spacer, Injen CAI...


for $65, this mod is hard to beat!

 

Sounds like a good mod. I used to do that on my older cars... Don't you guys in cali get your cars tested for emissions every year?

 

nice write up. I'm assuming he'll just switch out his original cats back in to pass emissions. I think the fitting, durability and rasp factors make this a good idea, however you lose out on the weight savings. I'd bet the stock cats weigh around 40-50lbs/pair vs HFC's or test pipes at around 15-25lbs/pair.

 

sounds good to me. i may have to try the same. i had mentioned this before, and it came back with a lot of negativity. Most common was the difficulty in gutting the cats, and not having good flow.
Did you get all of the cats cleared or is there still some mesh stuff in there?

 

my car is actually registered in Washington - so no emissions check! (Even in Cali, I don't think I'd need an emission check until after 5 yrs)

the cats are completely cleared out. The cats have two portions; the top has a metal honeycomb and the bottom has a type of brittle ceramic. The metal portion is the hardest to remove...I drilled about 7 1/2" holes through it and used long pliers and further drilling to get it out in peices. The ceramic portion is much easier to drill and after getting several holes in it, I used a breaker bar and hammer to knock the peices apart.

After seeing other's posts about test pipes cracking around the joints and fitment issues during installation, I really like the idea of useing OE gutted cats...The only downside are a few pounds.

 

idunno bout a few lbs. my crawford HFC's felt about half the weight of the stock cats. truth be told I only paid $100 for the HFC's so I can't complain.

 

i am worried about buying hfc's just for them to crack, but would like to see a dyno of a before and after modded stock cat!
not saying that all hfc's crack but there are a few, and those that dont crack are a little out of my price range.

 

Damn, where can I get a set for $100?

 

sorry, a local forum member went turbo and just wanted to unload some stuff so he gave me give crawford HFC's and injen CAI for $100. crazy deal huh?

 

i can bizump that. my kinetix weighed like 10pds total. I swear to god that the stock cats weighed about 30 or 40pds total.

 

I did the same to my cats and then added a Nismo Exhaust. Thinking about the way it sounds makes me wana leave my house right now just to drive around and listen to the sweet sound .

 

did u feel any performance after gutting ur cats out!

 

I've got kinetix cats and nismo exhaust, plus all the other n/a breathing mods, including a KJR crank pulley. Each mod added a little more to the quick-rev/more torque feel of my ZR. The kinetix cats do not require the OEM brace and weigh MUCH less just out of the box. As an added benefit, since I'm dropped 1.5, I no longer scrape coming out of my driveway. The exhaust note may not be to everyones' taste-kinda loud and a little raspy @3k rpm and above. It bothered me at first, but I've adjusted and come to like it.
At WOT my car screams!
As to gutting vs hi flos, I guess it's a matter of preference and $ vs time as well as the modest weight loss w/ kinetix cats. Either way, I think it's a worthwhile mod, and something you'll feel-not in more HP, but in opening up HP that's already there.

 

glad my stock Cats are in good use...

 

I kept my stock cats since in my county in AZ we have to pass sniffer and visual tests. Kinetix promised no CEL and after nearly 10k miles, their promise has been good. I reinstall stock a day or two before testing, pass the test, and go back to the hi-flos. JUst don't need the headache, and it's a 30 minute job.