Hi-Flow Cats too loud!

2fast4thelaw · 08-21-2009, 12:08 PM

Have any of you felt that when you install Hi-Flow cats that it makes the Z a little to loud? I have a Gen3 intake, Stillen HFC's, and a Stillen CB and it makes my car really loud when I tromp on it! I am almost considering putting the stock Cats back in to tone it down a little. I like the power gain and greatly improved throttle response and top-end but I am not sure I like the sound.

m4a1mustang · 08-21-2009, 12:55 PM

Fast Intentions makes resonated HFCs which would probably quiet it down a bit while keeping power gains.

OVERZLUS · 08-21-2009, 01:06 PM

Do you have a video so we can hear what it sounds like? I'm thinking about getting HFC's too, but I'd like to hear others first.

Thanks

6MT · 08-21-2009, 01:12 PM

Quote:

Originally Posted by 2fast4thelaw

Have any of you felt that when you install Hi-Flow cats that it makes the Z a little to loud? I have a Gen3 intake, Stillen HFC's, and a Stillen CB and it makes my car really loud when I tromp on it! I am almost considering putting the stock Cats back in to tone it down a little. I like the power gain and greatly improved throttle response and top-end but I am not sure I like the sound.

No!! That sound is wonderful!! Yes, it is louder than stock. And through some revs, the resonance is a real "drone", but I love it. As I mentioned in an earlier review, the 370 (with the Stillen exhaust mods) is not a car that you should try and have a conversation with someone who is hard of hearing...

2fast4thelaw · 08-21-2009, 01:24 PM

It sounds great at idle and start up but when you stomp on it, it really wails! Its really freeking loud when I floor it. It sounds like a crotch rocket!

The funny thing is its louder inside the car with the windows up. It drones a little with the windows up but not at all when they are down.

The Stillen CB sounds awesome with the stock cats so I am probably going to put them back in.

Hindsight, I wouldnt have bought the HFC's

My Stillen Cats may be up for sale.

6MT · 08-21-2009, 01:25 PM

Quote:

Originally Posted by 2fast4thelaw

It sounds great at idle and start up but when you stomp on it, it really wails! Its really freeking loud when I floor it.

The funny thing is its louder inside the car with the windows up.

Yeah.... isn't it great?

BerkTech · 08-21-2009, 01:26 PM

Before you start with the exhaust mods it's important to hear what the car will sound like with ALL the mods. For the OP it wouldn't be cost effective to swap exhausts with something that sounds better with HFC's so going back to the OEM cats would be your cheapest option to get the car to sound better.

Here's a quick clip of the Berk Technology exhaust on the DoubleDown Motorsports 370Z. Clip shows the car with our BERK HFC's.

Brazilbro · 08-21-2009, 01:29 PM

If you pull them off let me know.. I got test pipes but want some HFC for Time attack

Shift_Xz · 08-21-2009, 01:31 PM

The Berk system sounds awesome! I can't wait to get a hold of my 370z... $$$

FricFrac · 08-21-2009, 02:02 PM

Quote:

Originally Posted by 2fast4thelaw

It sounds great at idle and start up but when you stomp on it, it really wails! Its really freeking loud when I floor it. It sounds like a crotch rocket!

The funny thing is its louder inside the car with the windows up. It drones a little with the windows up but not at all when they are down.

The Stillen CB sounds awesome with the stock cats so I am probably going to put them back in.

Hindsight, I wouldnt have bought the HFC's

My Stillen Cats may be up for sale.

Opposite for me - idle is weak - way to quiet. Sounds fantastic under load. The drone is around 3-4K RPM and its because that's the resonant frequency of your cabin - open the windows and you change that resonant frequency (somewhat). It doesn't matter what exhaust you have you'll get that frequency where it "throbs" like that.

Just a question - if you don't like the exhaust note why did you get a loud exhaust system? The NISMO exhaust should give you better flow and its much quieter. IIRC someone is getting rid of their NISMO CBE because its too quiet.

john370z · 08-21-2009, 02:12 PM

I have the exact same setup and feel the exact same way! I have added much sound deadening material which has reduced the drone by 50% but it still had that sound that hurts my hears a bit between 3K and 4K rpm. I love the gains in power but do not like the loudness. I too have been thinking of putting the stock cats back on but have not done it yet. Mine are BERK....if someone in interested in buying it might push me over the edge and sell them. Let me know what you do?

john

BerkTech · 08-21-2009, 02:19 PM

Quote:

Originally Posted by FricFrac

Opposite for me - idle is weak - way to quiet. Sounds fantastic under load. The drone is around 3-4K RPM and its because that's the resonant frequency of your cabin - open the windows and you change that resonant frequency (somewhat). It doesn't matter what exhaust you have you'll get that frequency where it "throbs" like that.

Just a question - if you don't like the exhaust note why did you get a loud exhaust system? The NISMO exhaust should give you better flow and its much quieter. IIRC someone is getting rid of their NISMO CBE because its too quiet.

Agree with you on that one. The Nismo exhaust is what I would describe as "the exhaust the Z should have gotten from the factory".

Nismo exhaust w/ Berk HFC's. Minicobra's car.

Sonic370Z · 08-21-2009, 02:20 PM

Quote:

Originally Posted by FricFrac

Just a question - if you don't like the exhaust note why did you get a loud exhaust system? The NISMO exhaust should give you better flow and its much quieter. IIRC someone is getting rid of their NISMO CBE because its too quiet.

That would be me!

370Z Nismo Catback Exhaust

Agreed, if you are happy with the HFC's and want to keep them, but looking for a quieter exhaust note, check out the Nismo. Guaranteed to be quieter than any aftermarket setup. I don't have videos of mine, but the user Minicobra1's YouTube videos are what convinced me to go with the HFC+Nismo combo. He has 2 vids on YouTube if you want to check it out.

In the end, it was still a little too tame for me. In fact, I took the Nismo muffler off and ran it for a few hours with only the resonators installed and it sounded FANTASTIC. But I like loud exhausts, haha. Anyhow, definately worth looking into if you want to retain the HFC's. And if you're interested in the Nismo, I know where you can get a like-new one for a good price.

2fast4thelaw · 08-21-2009, 02:40 PM

I loved the sound of the Stillen exhaust from the clips I heard. The HFC's radically change the exhaust note. I am not changing out my exhaust system, thats like throwing the baby out with the bath water. I am just not happy with the HFC's It makes the car sound ricy. Plus I doubt I will pass emissions when I have to test car in the next 3 years with the HFC's. Plus I dont like the hiss the HFC's make. It makes it sound like I have an exhaust leak. I think my HFC's need to go.

CrownR426 · 08-21-2009, 02:44 PM

I wonder if cops look at these launches and try to find out where it is.
lol, hope none of us get caught!

08-21-2009, 12:08 PM	#1 (permalink)
2fast4thelaw Enthusiast Member Join Date: Feb 2009 Location: Denver Co Age: 50 Posts: 403 Drives: 09 370Z Sport/MT6 Rep Power: 16	Hi-Flow Cats too loud! Have any of you felt that when you install Hi-Flow cats that it makes the Z a little to loud? I have a Gen3 intake, Stillen HFC's, and a Stillen CB and it makes my car really loud when I tromp on it! I am almost considering putting the stock Cats back in to tone it down a little. I like the power gain and greatly improved throttle response and top-end but I am not sure I like the sound.

08-21-2009, 12:55 PM	#2 (permalink)
m4a1mustang A True Z Fanatic Join Date: Feb 2009 Location: Northern VA Posts: 55,385 Drives: on two wheels Rep Power: 6962	Fast Intentions makes resonated HFCs which would probably quiet it down a bit while keeping power gains. __________________ - Steve Zs & Coffee - Saturdays at 10AM in Fairfax, VA and Columbia, MD (Click the banner!) LIKE us on Facebook!

08-21-2009, 01:26 PM	#7 (permalink)
BerkTech The370Z.com Sponsor Join Date: Jan 2009 Location: Irvine CA Posts: 279 Drives: Lots.... Rep Power: 272	Before you start with the exhaust mods it's important to hear what the car will sound like with ALL the mods. For the OP it wouldn't be cost effective to swap exhausts with something that sounds better with HFC's so going back to the OEM cats would be your cheapest option to get the car to sound better. Here's a quick clip of the Berk Technology exhaust on the DoubleDown Motorsports 370Z. Clip shows the car with our BERK HFC's. __________________ While the others type fast... Berk Technology goes fast.... See you at the track! OUR NEW PHONE NUMBER: (714) 546-BERK READ THE BERK BLOG HERE

08-21-2009, 02:12 PM	#11 (permalink)
john370z Base Member Join Date: Jan 2009 Location: new mexico Posts: 141 Drives: 2007 335i coupe Rep Power: 283	I have the exact same setup and feel the exact same way! I have added much sound deadening material which has reduced the drone by 50% but it still had that sound that hurts my hears a bit between 3K and 4K rpm. I love the gains in power but do not like the loudness. I too have been thinking of putting the stock cats back on but have not done it yet. Mine are BERK....if someone in interested in buying it might push me over the edge and sell them. Let me know what you do? john __________________ 2009 370Z, Had Berk HFC and un-installed them cuz too noisy!, Stillen CBE, 10mm rear wheel spacer, K&N drop in filters. Blower to come...

08-21-2009, 02:40 PM	#14 (permalink)
2fast4thelaw Enthusiast Member Join Date: Feb 2009 Location: Denver Co Age: 50 Posts: 403 Drives: 09 370Z Sport/MT6 Rep Power: 16	I loved the sound of the Stillen exhaust from the clips I heard. The HFC's radically change the exhaust note. I am not changing out my exhaust system, thats like throwing the baby out with the bath water. I am just not happy with the HFC's It makes the car sound ricy. Plus I doubt I will pass emissions when I have to test car in the next 3 years with the HFC's. Plus I dont like the hiss the HFC's make. It makes it sound like I have an exhaust leak. I think my HFC's need to go. Last edited by 2fast4thelaw; 08-21-2009 at 02:42 PM.

08-21-2009, 01:06 PM	#3 (permalink)
OVERZLUS Base Member Join Date: Aug 2009 Location: VA Posts: 34 Drives: 09 Nissan 370Z Sport Rep Power: 16	Do you have a video so we can hear what it sounds like? I'm thinking about getting HFC's too, but I'd like to hear others first. Thanks

08-21-2009, 01:24 PM	#5 (permalink)
2fast4thelaw Enthusiast Member Join Date: Feb 2009 Location: Denver Co Age: 50 Posts: 403 Drives: 09 370Z Sport/MT6 Rep Power: 16	It sounds great at idle and start up but when you stomp on it, it really wails! Its really freeking loud when I floor it. It sounds like a crotch rocket! The funny thing is its louder inside the car with the windows up. It drones a little with the windows up but not at all when they are down. The Stillen CB sounds awesome with the stock cats so I am probably going to put them back in. Hindsight, I wouldnt have bought the HFC's My Stillen Cats may be up for sale.

08-21-2009, 01:29 PM	#8 (permalink)
Brazilbro A True Z Fanatic Join Date: Mar 2009 Location: Indianapolis, IN Posts: 1,131 Drives: Juke/240Z Rep Power: 848	If you pull them off let me know.. I got test pipes but want some HFC for Time attack

08-21-2009, 01:31 PM	#9 (permalink)
Shift_Xz Base Member Join Date: Aug 2009 Location: Erie, PA Age: 36 Posts: 8 Drives: 05 Nissan Xterra Rep Power: 16	The Berk system sounds awesome! I can't wait to get a hold of my 370z... $$$

08-21-2009, 02:44 PM	#15 (permalink)
CrownR426 A True Z Fanatic Join Date: Nov 2008 Location: South Korea Posts: 4,676 Drives: Manual Rep Power: 847	I wonder if cops look at these launches and try to find out where it is. lol, hope none of us get caught! __________________ Love + Hardwork + Passion RIP SVTRacer

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