Who makes the best HFC's without rasp?

SophiaZ · 02-07-2010, 10:44 PM

I have the Stillen HFC's and they took away back pressure and that left me with a hiss. I've seen on the Fast Intentions site for their HFC's and that said they free up back pressure. Can anyone say that their's don't have that hiss? I'm going to get the F.I. exhaust but want to make sure that both the exhaust and HFC's would be better than my set up now. Any help would be appreciated.

spearfish25 · 02-07-2010, 10:46 PM

I don't have the FI HFCs, but I think the hiss is inherent in anything you buy. I've noticed that every addition I made that relieves outlet resistance leads to louder hiss. Nature of the beast.

Minicobra1 · 02-07-2010, 10:54 PM

Quote:

Originally Posted by spearfish25

I don't have the FI HFCs, but I think the hiss is inherent in anything you buy. I've noticed that every addition I made that relieves outlet resistance leads to louder hiss. Nature of the beast.

Agree. I have the Berk HFC's and they do the same thing, you are hearing the whoose of air through the lower cell count in the cat, more air flow, more whoose.
Not as noticeable when i put the Berk CBE on though.

SophiaZ · 02-07-2010, 10:55 PM

Really?!! I just thought it was from loss of back pressure cuz when I put on my S-Tune exhaust, it sounded fine until I put on the Stillen HFC's. I can even hear it when I'm upshifting , not downshifting

radio5boro · 02-07-2010, 11:10 PM

Yeah but the catback has nothing to do with it. The hiss is from the cats because of the lower cell count inside the cat. (as mentioned before)

m4a1mustang · 02-07-2010, 11:15 PM

Yep. Hiss and rasp are inherent to the HFCs.

Ztoon · 02-07-2010, 11:19 PM

Stock cats have 400 cell count, F.I. 300

Zsteve · 02-07-2010, 11:34 PM

Quote:

Originally Posted by Ztoon

Stock cats have 400 cell count, F.I. 300

and others have 200 like berk and erz. Thats why im going ERZ, less cel count, way less price than FI, and same results. FIs being 300 count might help stop the cel tho.

m4a1mustang · 02-07-2010, 11:36 PM

Insofar as we can tell, there is no real difference between the 200/300 cell count in terms of performance. This is not surprising as the difference in peak power between the FI HFCs and Test Pipes is only about 3-4 whp.

For me, I would just choose ERZ because of the price.

SophiaZ · 02-08-2010, 12:13 AM

Wow..so the Stillen has the most hp increase?!! Sucks I gotta deal with that nasty rasp sound

m4a1mustang · 02-08-2010, 12:26 AM

Quote:

Originally Posted by SophiaZ

Wow..so the Stillen has the most hp increase?!! Sucks I gotta deal with that nasty rasp sound

All of the HFCs are roughly in line with one another in terms of gains. There is no clear cut winner.

But yes -- you're going to have to deal with the rasp if you run any HFC.

B1nks · 02-08-2010, 12:42 AM

I don't think the sound has anything directly to do with the cell count because I've been told and as far as I can tell the hiss is on Test Pipes also and even more noticeable and they are straight through..zero cell count. Maybe I'm wrong though and someone with TP can attest to the facts.

Nikon FM · 02-08-2010, 12:54 AM

Quote:

Originally Posted by B1nks

I don't think the sound has anything directly to do with the cell count because I've been told and as far as I can tell the hiss is on Test Pipes also and even more noticeable and they are straight through..zero cell count. Maybe I'm wrong though and someone with TP can attest to the facts.

I just installed FI resonated test pipes along with the FI exhaust including the 18" CF resonators. There is a hiss with the whole system but it really is not that bad....very subtle compared to the low frequency growl...love that

SophiaZ · 02-08-2010, 01:06 AM

Yea, the F.I. system is what I want; exhaust, and HFC's....but which would be better in terms of loudness/tone...12'' or the 18"?

Nikon FM · 02-08-2010, 01:19 AM

The 18" resonators will provide some lower frequency noise reduction over the 12". The CF is a different build (material and modal response) than the SS and just responds a little differently so there is most likely a subtle sound difference. I've only driven mine two days but am liking what I hear.

02-07-2010, 10:44 PM	#1 (permalink)
SophiaZ A True Z Fanatic Join Date: Dec 2009 Location: South Jersey Posts: 1,463 Drives: 2020 50th anniv 7AT Rep Power: 6732	Who makes the best HFC's without rasp? I have the Stillen HFC's and they took away back pressure and that left me with a hiss. I've seen on the Fast Intentions site for their HFC's and that said they free up back pressure. Can anyone say that their's don't have that hiss? I'm going to get the F.I. exhaust but want to make sure that both the exhaust and HFC's would be better than my set up now. Any help would be appreciated.

02-07-2010, 10:46 PM	#2 (permalink)
spearfish25 A True Z Fanatic Join Date: Mar 2009 Location: Naples, FL Posts: 4,117 Drives: to work Rep Power: 1856	I don't have the FI HFCs, but I think the hiss is inherent in anything you buy. I've noticed that every addition I made that relieves outlet resistance leads to louder hiss. Nature of the beast. __________________ 2013 Cadillac V-Wagon, RIP Z

02-07-2010, 11:15 PM	#6 (permalink)
m4a1mustang A True Z Fanatic Join Date: Feb 2009 Location: Northern VA Posts: 55,385 Drives: on two wheels Rep Power: 6962	Yep. Hiss and rasp are inherent to the HFCs. __________________ - Steve Zs & Coffee - Saturdays at 10AM in Fairfax, VA and Columbia, MD (Click the banner!) LIKE us on Facebook!

02-07-2010, 11:19 PM	#7 (permalink)
Ztoon Track Member Join Date: Aug 2009 Location: B.C. Posts: 578 Drives: '09 370a7 Rep Power: 25	Stock cats have 400 cell count, F.I. 300 __________________ Stillen G3\|CBE\|ground kit, F.I. H.F.C., C.F. fangs\|mirrors\|pillars, Hotchkis, SSR Type-F, RE-11, UpRev, BC BR coilovers 15% tint, LED black hdlts, color match handles, Dynamat, tail lt. tint, Mines C.F. frt. lip\|rear spoiler, Amuse rear,skirts, vented fenders, c.f. vented hood, gloss blk. roof

02-07-2010, 11:36 PM	#9 (permalink)
m4a1mustang A True Z Fanatic Join Date: Feb 2009 Location: Northern VA Posts: 55,385 Drives: on two wheels Rep Power: 6962	Insofar as we can tell, there is no real difference between the 200/300 cell count in terms of performance. This is not surprising as the difference in peak power between the FI HFCs and Test Pipes is only about 3-4 whp. For me, I would just choose ERZ because of the price. __________________ - Steve Zs & Coffee - Saturdays at 10AM in Fairfax, VA and Columbia, MD (Click the banner!) LIKE us on Facebook!

02-07-2010, 10:55 PM	#4 (permalink)
SophiaZ A True Z Fanatic Join Date: Dec 2009 Location: South Jersey Posts: 1,463 Drives: 2020 50th anniv 7AT Rep Power: 6732	Really?!! I just thought it was from loss of back pressure cuz when I put on my S-Tune exhaust, it sounded fine until I put on the Stillen HFC's. I can even hear it when I'm upshifting , not downshifting

02-07-2010, 11:10 PM	#5 (permalink)
radio5boro Base Member Join Date: Sep 2009 Location: Queens, NY Posts: 158 Drives: 09 MBlue 370z 6MT Rep Power: 16	Yeah but the catback has nothing to do with it. The hiss is from the cats because of the lower cell count inside the cat. (as mentioned before)

02-08-2010, 12:13 AM	#10 (permalink)
SophiaZ A True Z Fanatic Join Date: Dec 2009 Location: South Jersey Posts: 1,463 Drives: 2020 50th anniv 7AT Rep Power: 6732	Wow..so the Stillen has the most hp increase?!! Sucks I gotta deal with that nasty rasp sound

02-08-2010, 12:42 AM	#12 (permalink)
B1nks Track Member Join Date: Apr 2009 Location: Houston,Tx Posts: 721 Drives: 2009 370Z Base 6MT Rep Power: 507	I don't think the sound has anything directly to do with the cell count because I've been told and as far as I can tell the hiss is on Test Pipes also and even more noticeable and they are straight through..zero cell count. Maybe I'm wrong though and someone with TP can attest to the facts.

02-08-2010, 01:06 AM	#14 (permalink)
SophiaZ A True Z Fanatic Join Date: Dec 2009 Location: South Jersey Posts: 1,463 Drives: 2020 50th anniv 7AT Rep Power: 6732	Yea, the F.I. system is what I want; exhaust, and HFC's....but which would be better in terms of loudness/tone...12'' or the 18"?

02-08-2010, 01:19 AM	#15 (permalink)
Nikon FM Track Member Join Date: Jan 2009 Location: Snoqualmie WA Posts: 973 Drives: 03 996TT Porsche Rep Power: 606	The 18" resonators will provide some lower frequency noise reduction over the 12". The CF is a different build (material and modal response) than the SS and just responds a little differently so there is most likely a subtle sound difference. I've only driven mine two days but am liking what I hear. __________________ Buddy Revell: "One man's sooner is another man's later"

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