High Flow Catalytic Converters

jumbosrule

jumbosrule

Fully FX Invested
Premium
Location
Redondo Beach, CA
Car
2003 FX35T
Name
Brad
Couple of threads on High Flow Cats on here, some sort of talk about the advantages/disadvantages, but not enough detail for me:

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Looking at some of the gains on various cat brands with dyno tests, it seems that a high flow cat can add up to about 8whp. This was on a 350Z, so for the FX I'm sure it's lower. I have spent a lot more money to get a lot less gain, so i was really wondering why this is not a more common mod, especially when everybody does the exhaust as a standard?

I could guess maybe it's not as common in California because people are worried about emissions? But from what I could read, HFCs do the same job as OEM and should not negatively impact emissions if you get good quality. I'm not worried about an increase in noise. Anybody have any direct experience with any brand/fitment on an FX?

These Berks are the ones I am currently looking at. The distributor is here in Houston, so I was thinking about driving by to pick them up rather than ordering. Instant satisfaction. I called the shop and they offered me a walk-out price of $415. Decent discount for pick-up.

http://www.importpartspro.com/betehiflcatp.html

I want to make sure the O2 sensors bolt-up, there won't be any compatibility issues or ECU codes thrown. Anything to watch for would be appreciated.

Y'all hit me with some knowledge or some links I didn't find - thanks.
 
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2 things I can hit you with, #1 is rasp... probably why there not so poular with the fx crowd... it's one thing to have a little sports car sound like a rice burner, it's quite another to have a luxury suv sound like that...

#2 is something that you may have not realized, but if your considering forced induction then you really should get metallic core cats instead of ceramic core, as the ceramic cores can melt & close up on you with fi from the excessive heat...
 
The Berk Technology HFCs I'm eyeballing are metallic, not ceramic. And I absolutely do plan on going FI, which these cats specifically mention in capability. I can't imagine it would hurt to go NA on these for now, would it? Or even with FI, would you suggest staying with the OEM cats?

I do worry about too much rasp, but it's something I need to hear so I can judge for myself. True - I don't want to make this luxury SUV into something it's not. I have already tried a couple mods that I did not like and went back to OEM for the preservation of the luxury feel. This could be one of those mods, but it's not so expensive that it'll kill me to try and then sell off for a small loss if I don't like it.

I have the Stillen cat-back exhaust and I was thinking the exhaust has to have some impact on the sound of the cats. I've never thought my exhaust was too loud - in fact I wouldn't mind a bit more volume.

If I could choose high flow cats with the least amount of rasp among all my options, would the sound difference be enough to matter? The same site that has the Berk Technology HFCs also has Crawford and Kinetix HFCs. The Berks sit in the middle in terms of price. The Crawfords LOOK like the OEM cats, with a bigger heat shield. Just not sure about how they are resonated, if at all. Speaking of which - is adding resonators an option if I don't like the HFC sound?
 
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I didn't click on your links, didn't know you were looking at metallic core cats already:shy:

as far as the sound, I couldn't say much haven't heard many in this application, but the ones I have heard have made a significant difference in sound & added raspiness, the only ones I heard that weren't such a severe difference was a set done on a bmw 335 tt, but I guess the turbo's limit the exhaust raspyness to begin with too so?...
 
the berks will give you a little bit of rasp.

go for the crawfords. they are 600ish new but worth it....
i bought a set of used ones and sent them back and im going to buy new ones.... hopefully before oyu do yours hehe i wanted to bee the first ;) jk
 
Fair enough. It might just have to be one of those try-n-see things. If anybody else reading this thread has any experience, I'd love to hear about it...
 
well i did alot of research on my350z and some other sites on high flow cats.

basically the cheaper you go, the more rasp, tinny-sounding, and cheaply built you get. the performance is questionable for all of them, but i would thinkt he better built give you better gains...probably like 12 tops since the 350z guys report anywhere from 8-18
I read through countless threads, watched a bunch of videos for sound clips, and came to the conclusion that the crawfords are the way to go, though they are much more expensive. also, looks don't mean anything. you can have polished chromed-out cats but they will sound like crap. the crawfords sound the best in my opinion. no rasp (some berks have no rasp while others did....watched a bunch of vids/read reviews) and they will complement the exhaust note very well: it will get LOUDER but still give you performance. but they look ugly: they look exactly like the stock cats with just bigger heat shield I think and the innards are different (the honeycomb stuff)

also, the cats sound different on different exhaust systems. when i was researching I was looking for mainly nismo exhaust+cat combinations to see how it would sound on my fx....so your stillen may be a tad different. but still, I would go for crawfords just because in this case you actually get what you pay for (according to a bunch of my350z threads)

Like i said earlier, I was turned off by the price but still wanted quality so I bought used crawfords---but they turned out to be a little mroe than "used" they were USED to the point where one cat was missing all the stuff inside and was completely empty while the other still had some material inside...plus they were scratched up....
so i am going to buy a pair brand new instead...unless you want to buy them, try them, and if you dont like them ill buy them off of you ;)

if you look at my thread:
jbaker1121 said:
YouTube - 2007 350Z little burnout / exhaust test
or this (same z)
YouTube - 2007 350Z nismo exhaust w/ berk HFC's

of course there are a few variables that will make it sound different, that z is HR, it's a z so naturally sounds different, different legnth piping, etc. so basically take those exhaust vids and make it a little deeper sounding and that's most likely what it will sound like (plus i have the 5/16th spacer so that will help make it a little deeper)....no more bass, just deeper... of course the HFC in the vid are berks but you get the idea...
Click to expand...


I posted a few videos of a 350z with the same "setup" as me: nismo exhaust and berk HFCS...so the sound should be similar (but a little deeper) because i couldnt find anybody with the exact setup I have--the Z guys love the berks
I may actually end up getting the berks instead of the crawford for the 200 dollar difference..because berks are still noice. i remember seieng a few vids of stillen exhaust with hfcs
 
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It's cool - I'll go with new ones. The local shop I plan to buy them from is out of stock and will be getting more in two weeks. Then I gotta figure out a time for install, so you have a little time to be the first. Really, I wouldn't mind hearing about your install and experience before I buy mine so geterdun!
 
yours may sound something like this:
YouTube- 350Z: Stillen Exhaust + Cats + JWT Popcharger

make it a little deeper though and thats how you should be sounding....there is still a tiny bit of "rasp" or a tinny noise.....


did you know stillen actually makes high flow cats?
on the fourms they said they sound tinny but apparently not in this video.....not that many vids to watch anyways

YouTube- My 350Z: The Evolution of Sound

skip to 0:49 stillen exhaust, stillen HFC, popcharger (intake)
 
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Great posts. After listening to those, I'm pretty sure getting the HFCs will be fine. At normal cruising speeds, you might not even hear any difference. Only when you jump on the throttle does the rasp even try to come out.

I'd like to hear one in person. I'll bet I can find a local at a weekly meet here in town.

Still want to know your experience though. Interested in the install and your opinion about the sound and any changes in feel.
 
I had the Berks metalic core ones. They made the exhaust deeper in a good way. I did get a check engine light though). Felt an increased power going uphill and at cruising speeds. Worth getting IMO.
 
How did you clear the check engine light? And did you get the code that was thrown?

Appreciate the feedback - gives me more confidence I'm making the right decision.
 
jumbosrule said:
Great posts. After listening to those, I'm pretty sure getting the HFCs will be fine. At normal cruising speeds, you might not even hear any difference. Only when you jump on the throttle does the rasp even try to come out.

I'd like to hear one in person. I'll bet I can find a local at a weekly meet here in town.

Still want to know your experience though. Interested in the install and your opinion about the sound and any changes in feel.
Click to expand...

my friend has a full STILLEN g35---as in every single stillen part for it, he has because infiniti covers it under warranty.... it sounds good

Tko512iFX said:
The Stillen setup sounds really nice! minimal rasp but still that exotic sound and a lil louder
Click to expand...
yesssrrr

Chinke82 said:
I had the Berks metalic core ones. They made the exhaust deeper in a good way. I did get a check engine light though). Felt an increased power going uphill and at cruising speeds. Worth getting IMO.
Click to expand...
thats why I want them :)

jumbosrule said:
How did you clear the check engine light? And did you get the code that was thrown?

Appreciate the feedback - gives me more confidence I'm making the right decision.
Click to expand...

well the good HFCS are usually guaranteed not to throw a CEL, i think berk is in this category. but i know crawford has like a guarantee that it wont throw a CEL but even if it does there are a few adjustments that can be made--or make them send you a enw one until it works correctly haha.
about the sound...
the HFCS all sound pretty good under normal driving but when you step on it and hit the high rpms especially 5-6's hard it gets raspy, even the less-raspy berks. so figure you get a tune to take the rev limiter off..your 5-7 is going to be all raspy at WOT (based on some videos and posts). but there are other variables that affect it. I think youll be fine with the berks because of other "supporting" modifications that already have changed the sound of your exhaust/engine note.

the thing i like about the berks over the crawfords, however, is that they actually LOOK nice. the berks are all smooth and polished up and just "look" like a true aftermarket part, while the crawfords look like slightly modified stock cats... plus the $100 price difference (the better looking ones are cheaper, but does that mean they dont perform as well?)
I usually find the berk HFCs new around $500-550
http://www.berktechnology.com/shop/...oductIDs=434&strFrom=prodtype&numReturnID=106
while the crawford HFCs are new around $550-600
http://www.crawfordzcar.com/html/high_flow_cats.html

so the prices arent really different depending where you buy them from, you just have to decide based on how you feel about the looks, sound, and "performance", though the only performance that is officially reported is better throttle response, louder exhaust note, and increased tourque (no hp gains stated for the most part)
but what i do know is that its's one of those mods that "help"
 
cel will be thrown ifd the cat is not efficent enough, that'll be the code I think, cat inefficency... goes for all cars really...

there are ways around this, basically the o2 sensor before the cat will be switching or cycling pretty fast, the ecu is looking for the o2 sensor behind the cat to be ocillating at a slower pace, showing that the cat is doing it's job... this can be done with an o2 sensor spacer sometimes or worse case an o2 sensor simulator... of course best case is the cat is efficient enough for the ecu to not see a problem in the first place..
 
turbocad6 said:
cel will be thrown ifd the cat is not efficent enough, that'll be the code I think, cat inefficency... goes for all cars really...

there are ways around this, basically the o2 sensor before the cat will be switching or cycling pretty fast, the ecu is looking for the o2 sensor behind the cat to be ocillating at a slower pace, showing that the cat is doing it's job... this can be done with an o2 sensor spacer sometimes or worse case an o2 sensor simulator... of course best case is the cat is efficient enough for the ecu to not see a problem in the first place..
Click to expand...

aka the berks and crawfords should not throw CEL they have a guarantee
 
Chinke82 said:
I had the Berks metalic core ones. They made the exhaust deeper in a good way. I did get a check engine light though). Felt an increased power going uphill and at cruising speeds. Worth getting IMO.
Click to expand...

jbaker1121 said:
aka the berks and crawfords should not throw CEL they have a guarantee
Click to expand...

Chinke82 said he got a CEL with the Berks, that's why I was wondering what the code was. Since they, "garauntee" I guess they would either replace them or provide an O2 sensor adapater? What a pain to install, remove, install if they decide to replace.

Here's the adapter. Looks just like a spacer and the site says you might have to use two of these together...

http://www.z1auto.com/prodmore.asp?model=350z&cat=exhaust&prodid=3638
 
one on each side but I think you can stack 2 if it's still not enough, it moves the o2 sensor out of the exhaust kinda, almost into it's own side chamber sorta, but of course it's still open to the exhaust flow, but because it's off to the side in a cubby hole the air changes in this chamber is less than if the sensor was in the exhaust stream, thereby fooling the ecu into thinking the cat is doing it's job... pretty simple really...

I think the metallic core cats have a harder time of being efficent than the ceramic cores, are you sure the metal cats also have this same garentee?
 
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