High Flow Cats
 

I am ready to buy a set of HFC's. I was wondering if there is any advantages/disadvantages between the following four brands? Is one better than the other(s) in some way or are they really the same product with a different name? Any insight is appreciated. Thanks.

I am undecided between:

Fast Intentions
Berk
Stillen
AAM

i imagine theyre all the same length, use same cores, I hear the Stillen dont like being bolted to exhausts other than there own, fitment issues etc. Gains are similar for all. Pick a brand, thats basically it.

if u want a used pair of berks, mattkim85 has some for sale

Id go with the fast intentions cats, Longer defoulers make a less chance of throwing a CEL.

Actually, I don't think they are using the same cores.

FI uses 300 cell whereas Berk and AAM uses 200 cell cores. I'm not sure about the stillen though.

I'm not so sure the difference between 300 vs 200 cell cores can be felt or would make a big difference.

FI is slightly cheaper to buy, if that is a pulling factor! :tiphat:

interesting...so power gains are essentially equal and fi are cheaper and less likely to throw codes... seems like a no brainer then.

HFC's
 

Are you planning to upgrade the CBE or have you already done so? If so, go with the same brand as the CBE to eliminate fitment issues. If not, it doesn't really matter (as far as performance gains). However, I do like F.I.'s craftsmanship and price.

I take it 200 Core would essentially flow better?

no difference in gains.

Well I don't suspect that there really would be too much of a difference. I was just figuring if its a lower core count then it must theoretically flow better

Kind of what I thought.

It all depends on how much air is being pushed through the cores. If you keep increasing the air flow, the 300 cell count core should become a restriction before the 200 cell count does. How much cfm it takes to become a restriction... who knows. But it definitely looks like it makes no difference on a N/A Z.

If I understand you correctly, you are saying that the stock-ish engine does not put out enough exhaust for the cell count to matter?

For 200/300 cell count, it definitely seems like it.

Anyone know what a stock cat's core count is?

Hello,
We at AAM been using 200 cell HFc on Multiple 350Zs, G35s, G37s and now few 370Zs. We have not had any problems with our HFC throwing CEL codes.
Check out our site, AAM, HKS, Greddy, TEIN, ARC, JWT, Eneos, Volk Racing, Carbonetic, Motul

and also search toohip on this site, he has our exhaust and HFC on his 370Z.
Hope this helped.
Thank you!
-Jae

I think the cell count on stock is 400

Thanks

is there a major difference between test pipe and hfc? i'm just wondering if its worth it to upgrade to full test pipes and save some money...i'll also throw on an o2 extender on my test pipes to avoid throwing a CEL

also, is it hard to see the hfc or test pipes under a 370z? i'm just hoping its being blocked by something so cops can't see it if they look under the car

In CA it's a toss up whether or not you want to get them. HFC are illegal there as well as Test Pipes so you're technically screwed either way if a cop looks and is capable of seeing them. This car is pretty low and it would be fairly difficult to get a good view under there, I would think, but I wouldn't rule it out. Granted this is also assuming that the cop can tell the difference between stock and aftermarket but the lack of heat shields is usually a dead give away.

Now with a HFC you may actually pass a smog sniff check but not the visual, which as I understand it, some places often just skip. With the TP you will NOT pass a sniffer and certainly not pass a visual. There are obviously other methods of getting past smog checks but that may or may not be something you are interested in doing.

As far as gains go, Test Pipes net more power but not a whole lot more. Dynos have shown TPs to gain between 1-4 more HP than what a HFC will gain for you.

If you want TPs look at the Fast Intentions (F.I.) or the GTM ones. They offer extended O2 sensors so CEL shouldn't be a problem with them. They also offer them resonated so that you don't get a raspy sound in your exhaust.

So far, over 5K miles on my Berks with no CEL's :tup:

I really can't see the benifit of test pipes on the 370z, the extra 2-3hp in the upper rpm range is just not worth it. HFC's will get you nice 10-15 HP gains, are not as raspy, and clearly look more stock on any visual inspection. Unless your out tracking the car every weekend, go with HFC's. :tup:

:iagree:If I lived in CA I would do HFC.

gotacha...thanks for the response...i'll just man up the extra $100 and go with HFC

would it be recommended to throw on an o2 extender with my hfc? i'm pretty sure the hfc will flow alot more than stock cats....therefore increasing the chances of cel...just wondering thats all

yeah i heard both are illegal in cali...theres a new law that passed saying anything other than OEM cats are illegal...this was passed back in jan 09

anyway, the car sits low as it is...is this my only chance of defense against a cop looking for cats on my car? is there a suspension member or brace blocking the view of HFC?

I don't think there is anything like that blocking htem but from what i've seen in pictures it would be difficult to see that actual cat portion because it sits closer to the flanges that connect to the headers instead of closer to the flanges that connect to the CBE.

You sure are worried about a visual inspection, do you get pulled over alot?
The Berks already have the extenders built in.

^+1

The F.I. HFCs have O2 extenders as well, fyi.

Here's a quick comparison chart. :tup:

Whatever feature you could possibly want in an HFC, Berk has it.

http://i183.photobucket.com/albums/x...risonChart.jpg

The O2 extensions help with keeping the CEL light off on the HFC applications but have been met with only limited success in the test pipe application on the 370Z. However it does work well on the older 03-06 350Z's. The HR motors have much tighter control over the emissions system with an entirely new monitoring algorithm that's much harder to crack with mechanical fixes. Darn cars are getting smarter and smarter. If OBD III, aka "Big Brother", ever comes to fruition we are all in for a world of hurt....

We've had the extended O2 bungs on our HFC's and test pipes since 2005, long before it became "standard" for everyone else.

No problem with CEL on my Stillen HFC's. I have 2000 miles on them so far. I chose them basically I got a deal I couldnt refuse from Stillen at the time by buying thier power pack for the 370. I didnt like the sound at first but after putting some miles on the car with the new exhaust it sounds totally different now. The rasp that it used to have has now all but dissapeared. It has a very deep tone at low rpm. It definitly sounds modified.

Well there you go. I don't think anyone could have explained all the Pros and Cons any better than that.

Berk HFC's FTW! Love mine.

My only issue is the efing hiss

Running Berk's, no issue's here!

I actually kinda like the hiss, lol.

I'm curious about the hiss everyone's talking about. I don't hear any hiss can you guys point to where the hiss appears to come from? or is it associated with the stillen Gen 3 intakes?

I also have the AAM HFCs with their True Dual Exhaust installed at approximately 1800 miles. No thrown CEL codes to date. Love it! Oh by the way FWIW, before I had the exhaust and HFCs installed I contacted my Nissan Service department service manager to ask him if there was anything warranty wise that I needed to be concerned with with new HFCs and Exhaust. He indicated that as long as the installer used the stock 02 sensors that there was no warranty concerns. I say this only because of what he said. This may be different from others in different locations but I wanted to at least share that with everyone.