How did you know it had gone bad? Did you see a loss in power or did you hear the exhaust note change? Did it smell like rotten eggs?

Exhaust had an odd noise, a little rattle like something was loose (which it was) so we checked it out and it was falling apart on the inside.

My passenger side factory cat is done, its rattling and is all busted up inside, haven't got around to installing my test pipes.

I would hurry and try to get to it if you are still driving the car, if it ends up completely clogging the pipe it might pop the motor.

How many boosted miles?

You could always move the cats down stream. Get the millspec cats welded on to your exhaust. Or order from F.I. it would be far enough down stream to not be destroyed by high egt's

This is what I did. FI put a set of cats in the lead pipes of the exhaust, and they've held up well.

I too have been very curious about this same issue. ...Like TopGunZ all my reads on this topic have been conflicting.... also read in Swiss370Z's thread that his stock cats gave out....the pic was crazy. ....so even at 8PSI the stock cats broke down for you (Dreamer)? So is it definitely better to go stock cats vs HFC'S with a S/C? I have read of people runni g HFC'S that are ok while some with stocks blowing out...Has anyone experienced actually blowing out an HFC with the S/C?

this sounds like the simplest solution. test pipes up front and move the cats further back.

the more elegant solution would be to control the vvel. i am guessing that it´s possible with the new EcuTek rom (not sure though).

for the OP the first option should keep you happy and your neighbors happy with the lower noise level. For me the second is more interesting since I don´t DD my car and love loud noises! So I would love a way to run resonated TPs and keep my PSI up.

I ended up going with the Motordyne ART pipes. They are supposed to suppress the sound the most of any resonated test pipe and even more than hfc's. I haven't really been able to evaluate it though yet. However, ill know more by the end of the week.

I would go the ART pipes, but I want to stay legal where I am. So I will habe to stay with stock cats until they blow, then I will decide what to get from there.

At this stage Im leaning towards getting the HKS 150 cell cats, they were released just after their GT SC kit for the VQ35 came out and were designed with boosted VQ's from the outset.

"Target Hp Rating of 500-600ps"

"Metallic low-resistance carrier is equipped to provide the advantage for supercharger tuning"

"For GT Supercharger specs, the difference from the factory CAT is more noticeable, and advantages of the product can be taken from low rpm range"

"Oval Type can be used for 85mm – 90mm and Round Type can be used for 115mm. Modification is required."

RHDJapan : HKS Metal Catalyzer Nissan Fuga Skyline Fairlady Z
METAL CATALYZER /MUFFLER | EXHAUST | PRODUCT | HKS
lol this price
33005-AN004 Metal Catalyzer - HKS USA

If you do order make sure its AN004 as AN003 is for the VQ35

I'd like to know what the Revyou 370z is running all it says is "high flow cats" does anyone know? Im pretty sure its the HKS cats.
Pretty beastly Z actually, it's running twin HKS blowers on a built CP/Carillo 10.5:1 motor making 739whp 622lb/ft @ 17psi.
Revyou Supercharged Nissan 370Z - DSPORT Magazine

What id really like is a custom job consisting of PPE LTH with HJS 200 cells, anyone done this or know if it will work/fit?

Mil.Spec :: Universal

Those might work?

Thanks, I'll have to check those out :tip: To get it running I just threw my stock cats on, but would like to pick up some resonated test pipes instead. Sold the ART pipes, in conjunction with the e370 exhaust it was just too loud - and would be moreso now with the blower. And I'm not swapping out the e370 it is far to sweet to part with!

I saw the post below from Topz about HFCs in another thread, and was wondering if there might be more long-term data available from various users?

The logical part of my brain wants to catalog the failures into specific reason(s) *why* the problem occurs. I hate it when things happen "sometimes!"

I'm guessing that the difference between sc and turbo applications is that the turbo somewhat mitigates some of the pressure/flow in the exhaust? For the ones who blew their stock cats, is there a common mod or circumstance that seems to precipitate failure?

I recall reading in one of the threads that the stock cats are 400-cell, so does the cell count not have anything to do with the flow capabilities, say, compared with a 200-cell Berk? Sounds like if you do take the plunge in upgrading to Berks, that you should save the OEM cats in a box...just in case.

What do the manufacturers have to say about their HFCs being used in sc cars? Do they stick a clause or two in the warranty to limit their liability?

And, on a purely practical note, does a cat give the driver some advance warning when it is blown, or is it possible that chunks could catastrophically get thrown into the muffler with no time to limp to the curb?

Thanks for your input!