I am thinking of upgrading my cats, but I'm not sure which ones are best or if it is a matter of personal preference. I know I want to see some type of gain but at the same time it seems like there are too many to choose from. What do I need to know and which would you recommend and why?

More specifically, I am looking at HFC's.

 

really you only have 3 choices...High Flow Cats (HFC), Test Pipes (TP), or long tube headers (LTH).

IMO HFC is the best way to go. You can still get good gains from them, and don't have to worry about throwing a CEL. With TP, you might see a slightly higher gain, but you have to worry about CEL, smell, emissions, all that. And LTH I don't know much about but I do know several people who had them and removed them because they just weren't worth it.

 

What brand of HFC's would you recommend and are there any differences between the HFC's that are out there?

 

as long as you go with a reputable brand, you should be fine. I personally have Berk HFC and love them. I can't say if they are truly better/worse than any other brand simply because I've never used any other.

But with anything, as long as you get a well known, quality brand it shouldn't matter

 

Kinetix and Invidia seem to be the least restrictive HFCs. That's probably what I'll go with once I get my exhaust done.

 

You may want to search out any videos posted on Youtube to hear some examples. I understand HFC's can get pretty noisy, and they're very close to your seats so that could be an issue. I know it would be for me.

Stillen is another name you can look into.

 

YouTube videos need to be taken with a grain of salt. Understand that there is a lot gained/lost because of camera mic's. It is best when a video shows the OEM video, THEN the HFC video (or whatever the case may be)

IMO HFC's are slightly (and I mean VERY slightly) noisier in cabin, but absolutely nothing overwhelming in any way. And yes, you do basically sit right on top of them, but that really wouldn't make a difference in terms of noise unless there was a HUGE noise difference

 

I think I read that Motordyne's ART pipes for the 350Z also fit G37/370Z as well.

Advanced Resonance Tuning (ART Pipes) MotorDyne Engineering

 

Invidia - 100 cell
Berk, ERZ, Stillen (I think) - 200 cell
Kinetics (i think) - 250 cell
FI, Exoticspeed (very pretty) - 300 cell

 

good info.

 

I'd get it if labor didn't cost so much.
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Fast intentions has these 5 options

1. Long tube headers !

2. Resonated HFC

3. HFC

4. Resonated Test pipes

5. Non resonated test pipes!

 

The basics of what you need to know are that HFC tend to give a louder and raspier sound to any exhaust including stock. Some may cause more prominent exhaust smell. The install tends to be a bit of a PITA due to the bolts holding the stock cats to the exhaust manifold being quite difficult for most, plenty of penetrating lubricant, time to work in, and elbow grease (preferably impact tools) make it easier. There are some slight gains to be had at the top of the torque curve, not so much down low.

 

ERZ (Contact NissanGeneration on the board) has 200 cell high flow cats that are less expensive than most others. I have them on my sedan and am more than happy with them. More than 5,000 miles on them and no CEL.

I would take your car to a shop for the install. Two of the bolts (one bolt on each side) are extremely difficult to remove.

 

Which HFC produces the least rasp sound to them?