Opinions on High-Flow Cat
 

Guys,

Im trying to gauge what the general opinion about HFC... Like Berk`s or Stillen and trying to see what would have better gains and which one would be quieter.

I plan to run the Stillen G3 Intakes, along with stillen cat back exhaut. Along with whatever HFC i can decide on. Definitely going with the stillen setrab set up because it gets fairly hot in Atlanta.

I know this must be repost and i just want to make sure i dont miss anything out.

Thanks,
Wilson

With the upgrades you are doing I think it will be a great addition to your other modifications. It will up the sound level, but not sure on what is "loud" for you so that is hard to judge. HFC are probably one of the better bang-for-the-buck mods for this car, plus it will keep you legal in most states for emissions.

:iagree: By FAR the best bang for the buck, I gained 12whp for $300 (bought them used), you'll pay at least 1k for the same power you gain with a CBE.

hey red370 was the sound change noticeable in the cabin? if so what was it like?

At cruising speeds, no, but at WOT, she screams like a banshee, its a definite noticeable change from the stock sound for sure, sounds like the exhaust should have from the factory. Best sound is between 3.5-5.5k IMHO, thats when it really shines.

sweet im trying to get mine put on before i leave on wednesday on my road trip now im just waiting on UPS

How about someone sells me their HFCs (berk or stillen) for $300? These guys beat me to all the great deals in the 'for sale' section.

Congrats red... you beat all of us to buying that Berk HFC... I guess if it only sounds loud at wot i will gamble on it... Thanks guys...

just found out that the internal components of the Berks and Stillen are identical on these HFC. Exhaust wise i was leaning towards Stillen`s sound. But i`ve also heard that there is a fitment issue with Stillens Cat back which have not been fixed. So it some cases it rattles? any truth to this?

There is also a new Berk Exhaust anyone have it yet?

Berk Technologies has their exhaust on the Bonanni Motorsports 370z. Berk Technologies is a small company that spends a lot of time on research and development of their products. They are very well known in the Time Attack World. I personally like the setup they did on Mike's car. I'm sure you can find lots of data on this forum as there is a thread following the build.

Scott

:tiphat:good post

I love the gains/sound of the Berk CBE, but from what I can tell, theres going to be a long waiting list for it, they havent exhausted the buyers from the first group buy yet from what I can tell, and I dont even think its in production yet, the ones that do have one seem to have "one offs", which is why I was leaning towards the Stillen setup, and I called Stillen a few weeks back and the fitment issues have been resolved completely.

does adding a hfc add any rasp to the stock exhaust sound, you know, like that tingy, coins-in-a-can rattle? i havent found any good sound clips of a stock system with hfc's.

i guess for now it will be stillen cbe and berk`s hfc... thanks guys

I believe Semtex is running that setup, hes posted a few sound clips of it, probably going to be the route I go as well.

None whatsoever, the stock exhaust really keeps the tone in check, makes the exhaust sound amazing, you'll have to hear it in person to get a good idea of the sound, but I get comments all the time about how good it sounds, people think I have a full aftermarket exhaust on it.

My only issue with the Berks are the hissing sound on the down rev. I am not sure if Stillen does this or not, but the reason I went with berks was for the gains. If I could choose again , I probably would have done F.I. resonated cats.

HFC's are definitely a good addition to the car. You'll see great gains without any obnoxiously loud/raspy exhaust noise. If you go with a full intake and exhaust system as well, you'll see outstanding gains. Shoot me a PM and I'll hook you up with a good price for AAM HFC's.

thanks, i wish i could hear it in person!

I just got back from having the Invidia Gemini and Berk HFC's installed. I would say it's not loud at all. I'm old and was worried about it being too obnoxious, but it really isn't. it seems loudest on the downshift blips. my previous car was a Lotus Elise with Forcedfed header, sport cat, Arqray muffler, and Fujita CAI. that was FAR louder than this car.

Boy them lotus's are very loud ! After that you could prolly tolerate anything.

How does the exhaust sound at idle and gentle acceleration? Sounds like at half to full throttle it's much better.

Quieter? Don't get HFC's.

i dont notice the sound change during regular driving but at start up and past 4000 rpm the sound change is obvious. when the car is cold the rasp is a little loud but once it warms up it sounds amazing. but the car feels way better under acceleration

If im at WOT i dont mind the loudness, its the everyday driving below 4K RPM that concerns me. I dont want to have rattles and drones... thats all
I just ordered a Berks HFC and Stillen G3 and CBE. I guess i`ll find out next week.
I guess the Fast. Int. CBE with 18" resonators and their Long Headers would have been perfect but louder...

anyone have a sound clip of a stock 370Z with hfc's?

i have the stillen G3 and berk HFC and there is no droan the engine has a very deep done with a lot of purpose if that makes sense. once it hits 4500 rpm it opens up

I have Berks waiting for me at the shop. It will be paired up with Nismo CBE. I have not heard any Berks with the stock exhaust. From what I remember the sound for Berks HFC is:

HFC w/stock exhaust = 4
HFC w/Nismo = 6
HFC w/Berk CBE = 8

Minicobra1' first post explains it all. Good write up. HFC's are the best bang for the buck!

Sound clip here:
http://www.the370z.com/intake-exhaus...on-x-pipe.html

I have had the Berk HFCs for six months and really like the mid-range growl under acceleration. You can feel the power increase and from what I have read the gains range from 15-20 hp (without a CBE). When you are cruising there really isn't much difference compared to stock. I do not hear any hiss at all from them. I added the Invidia Gemini's and really didn't like the increased volume and the low frequency sound (to me it sounded artificial). And it does drone at around 2000 rpms especially in 6th. Removed them and sold them to Bluestyle55 who really likes them but doesn't have the HFcs on yet.

Unfortunately I think this down-rev hiss is a characteristic of our engine. I noticed it subtly when my car was stock. It became more noticeable when I put the Stillen CBE on with stock cats. Now I've added HFCs and it's even more pronounced. The gains and overall sound enhancement are well worth the mods, but the hiss is unfortunate. I'll live with it.