I'm looking to add a set of hi-flow cats to my Borla TD system but want to keep noise levels (especially raspyness) down to a minimum. Does anyone have an opinion on which I shoud buy? RT/UR/Kinetix etc.

Thanks....

 

I can't comment on the others, but I have the Kinetix, mated with DC headers and Borla TD. Absolutely NO rasp. Throaty down low and aggressive, but not overly loud growl above 5000 rpm when floored.

 

I think you're going to find them all more noisy than the stock cats, which are very restrictive. The R/Ts are probably make the most noise with the most rasp. The Kinetix and the Crawfords are probably the quietest. My experience is with the Crawfords. They do open things up, the growl sounds great, and no rasp. They also have perfect fitment, and the build quality was excellent.

Lou

 

I had the RT Cats installed 5 months ago and they are definitely louder and freer flowing than the stock ones but do have a nasty metallic rasp sound mostly between 2.5K and 3.5K rpm especially when not at Wot. They make the engine sound tinny and low end and it was embarrassing but above 4K rpm, they don't sound bad. I couldn't put up with the sound any longer so I placed an order for the Crawford cats last week and will be installing those when I receive them then will follow up with a report. When I had the NISMO exhaust installed at the same time as the RT Cats, I didn’t notice the rasp but the combo was too loud for my taste at the lower rpms so the NISMO came off minus the Y-pipe. I'm planning on getting the NISMO Headers installed very soon if they do fit and I'm wondering if the sound is going to be too loud especially bellow 3.5K rpm? I would like the sound not to be too loud when I want it to [bellow 3.5K rpm] but sounds not horrible in the rest of the rpm range.

 

save your money and gut your stock cats. i had the rt cats and after about 5k miles i couldnt stand them anymore and gutted my stock cats. they sound almost identical to the stock cat but a bit louder (although more quiet than the rt's), and i'm sure the performance gains between any aftermarket cat and stock gutted cats is very little. also no issues with the stock cats not wanting to fit as with some of the rt and kinetix cats.

 

Are you close to our shop? If so you can go for an E-Ticket ride in my car and see how loud it is with... Cams, Nismo Headers, R/T Cat's, JIC Y-Pipe and Nismo Exhaust. I personally like the sound of my car.... so do the local cops....

 

Definitely Ultimate Cats. I'm very happy with mine coming from RTs. Now those are loud!

 

Ultimate racing cats + borla Td = pretty quiet setup

got mines from z1auto.com

 

Jeff, thanks for the E-Ticket ride invitation. I had the RT Cats, NISMO Exhaust and UR Pulley installed at your shop and I installed the Stillen intake with a JWT Pop charger filter, Z-Tube and C.Plenum. As I've stated earlier, I'm planning on replacing the RT Cats with the C.Cats due to the rasp and possibly adding the NISMO Headers if they do fit.
1) Do the headers fit on the FX35?
2) Will these Headers with my combo add a lot of sound bellow 3.5K rpm? Above that rpm is fine but bellow I would like it somewhat quiet with no rasp. Any ideas?

I'm aware that the headers will give that low rpm rumble and add volume but not sure by how much on this car.

Thanks.

 

How did you do it? What's inside of stock cats?

 

Its a honeycomb setup which suppresses noise and also traps harmful chemicals. Eventually, the honeycomb material becomes saturated, and new cats are needed.

 

Cheers guys, I guess anything other than the RT cats would suit.

Choice between Crawford cats + plenum + strutbar or Kinetix cats + plenum

 

How easy it is to remove that honeycomb? I hate spending 200+ backs if I can achieve the same results for free

 

i love the sound of my rt cats, but its all personal pref., to me a little rasp sounds good, all high end cars had a little rasp when you get on it. if you dont want any rasp, id stay away from the rt cats for sure, even though they give you the most gains of any highflow cat.

 

Received the C.Cats yesterday and I had them installed today. What a huge difference in sound. There is no rasp. It is still too early to tell if there is any power difference and I'll wait until they are broken in before I make a judgment. It turns out that the left RT Cat internal material was imploding while the other one seemed to be getting loose. I had the RT Cats on my NA car since last March and for a total of around 7K miles. I always wait until the car is warmed up before getting on it. With all the reports of failing RT Cats, I'm very dissatisfied with the RT Cats and to high extent Performance Nissan. And no. I didn't make my judgment hastily.