can I have the cake and eat it too?
 

At the risk of sounding like a wussy I am still writing this post... I have Berk HFC and Stillen CBE. Bottom line, I think it is too loud from 3K-5K under load of any amount. It is hard to stay talking to the passenger at this RPM range and flat out I think it is quite annoying. Unfortunately this RPM range is used almost all the time. I would like to not sacrifice the performance gains from the 2 exhaust items. I welcome your suggestions!!!

Nope, not really. Not unless you add more sound deadening. When tossing on mods like that (anything with the exhaust really), you're just asking for the dreaded drone right in that RPM range.

Remove the mods would be my suggestion, to fix it.

wait till you get an intake.

I would suggest not talking and just listen to the sweet music of the engine!

You can always have extra resonators welded inline to the exhaust. It won't eliminate the drone, but it can greatly help.

the stillen cbe doesnt drone at all..

You could use the stock catback....sacrifice some power for quietness. I think thats nuts, but thats just me. I love the noise and I can hear conversations fine. I like Phimosis' suggestion.

I noticed you're planning to add a blower (per your sig). You definitely don't want to plug up the exhaust if you're adding a blower.

Contrary to what has been said, there is a drone between 3.5K and 5K rep. At least there is in my Z. I guess that is what is most annoying. Does anyone have an opinion as to which is most likely to either remove the drone or substantially improve it: Removing the CBE, Removing the HFC, or adding some type of resonator or something like it in the exhaust track? I plan on adding a supercharger in the future but with the noise issue it is making the car less enjoyable to drive. I appreciate what some of you have said reguarding loving the exhaust note and not listening to the radio etc. But I do love the radio. Thanks for the imput!!!

I think you stepped over the line with the HFC's. From Vids I've heard they make a substantial change in the sound level. I have a Stillen Cat back (which seemed pretty tame) and just added a custom intake (which made it just perfect for me). After reading reports here I'd probably have the same issue as you if I went to the HFC's. I think I'll hold where I am...

I think you're going to have to sacrifice one or the other to get the sound levels where you want them.

Well you can't add exhaust parts and not expect loudness/drone. If you're willing to pay the price, try fitting a custom butterfly valve that closes at low rpm's and opens up when you're driving aggressively. Try header wrapping the HFC too.

I think you are right!!! Sucks to think I will have to sacrifice about 10 or more WHP by putting the cats back on. Is it everyones opinion that the drone will be gone with only the Stillen CBE on the car?
Thanks for all your input...

drone.... hmm. to me, that means you get resonant frequencies in the cabin that amplify the volume of the sound..... kind of like the resonant frequency of a ported speaker box will make more Db than a sealed box. Corvettes and Mustangs with Borla exhausts will do this from 1800-2200 or so rpm. right at your cruising speed, even under light load. This phenominon is kind of a growl that is like an engine soundtrack superimposed over your normal engine soundtrack

I have stillen intake, header, cat and exhaust and don't get that phenomenon.

Now.... could you be referring to what others call rasp? That is a phenomenon where you hear the indivual exhaust pulses without them being pressure equalized through an x-pipe to distribute them over both exhaust pipes or to adequately squelch the noise through a highly effective muffler. That phenomenon gives a "blat, blat, blat" sound and gets louder under more throttle and stay around even as the revs climb. Drone tends to go away as the rpm's rise, where rasp is there all the way to the redline.

I don't really hear rasp with my Stillen setup, but when I took the rear muffler section off, it was more raspy than any exhaust I've ever heard. Maybe you're hearing some rasp?

Drone is only on the highway when you are cruising. Its that constant howling from the exhaust. That does not happen with the Stillen..when i throw it in 6th and cruise I hear nothing but the radio and the damn tire noise.

I believe it is drone. At higher RPM's it disappears into a beautiful racy sound. I don't think it is rasp from what you described. It seems like a amplification of the exhaust due to factors I don't understand inside the cabin. It almost has a pressure feeling to it in the ears. IT is similar to the "drone" I had in Mustangs past at cruising speeds. I think I might be a little more sensitive that others on the post, because I enjoy the GT aspect of this car just as much as the racing side. I just hate to consider taking off one of these awesome parts...

a) give them to me for free
b) just deal with it
c) use those squishy ear plugs when driving
d) none of the above

my mods listed in my sig even with them
i think i too quiet its not as loud and deep sounding as my celica with tanabe exhaust and aem intake

John...What you describe is drone for sure. Some people are more sensitive to it, some have it but don't know they do until their wife tells them she's getting a headache..;)

I had a bit of that with my Vette after adding headers and HFC;s. One thing that helped a lot was a complete sound deadening of the rear hatch area. I used Damplifier from Second skin. It was a bit of work, but dampened the resonances and other noises nicely. I plan to do this to the Z as there is a fair amount of thin, undamped sheet metal back there. For $100 it may solve your problem and give you some other benefits too without pulling off parts.

The back of the vette wa like a big plastic bass drum!

http://images33.fotki.com/v1120/phot...MG_2159-vi.jpg

Excellent advice!!! Thank you!

John, I forgot to tell you earlier -- adding the Stillen headers will smooth out the sound considerably. That's one thing I immediately noticed after I installed the headers; the coarseness of the sound was gone. Now, for me personally, I was kinda disappointed because I loved the coarse/aggressive sound. But for you, it may be just the thing. The reason the Stillen headers do this is because they are equal length pipes. The stock manifold is not -- close, but not quite. The unequal length pipes is what gives off that coarse, aggressive sound. I have an interior sound video clip of my full setup (G3, headers, HFC, CBE). Have you seen it yet?

I believe you did tell me that. That is great advice. I am looking to kill that drone under med-hard acceleration found between the 3K-5K RPM range. Do you think removing the Berk HFC will accomplish this? And leave the Stillen CBE? Or the other way around?

Huh? My advice in my previous post was to consider keeping both and adding the Stillen headers, as the headers smooth out all the rough edges (plus give you a modest gain as an added bonus!).

John,

This is what my car sounds like, after adding the headers. It's not quieter per se, but the tone is smoother, if that makes any sense. You know what your car sounds like. Now compare with how my car sounds.

YouTube - 370Z w/ Full Intake & Exhaust Mods

Hmm, given that, that set up might be too loud for me :(

Hmm...

One man's drone is another man's music.....

That's funny. I wish my car was louder. Both my previous cars were louder so that's what I'm used to! :p

I need to disclose again...I am sorry I am being a wussy about this. And thank you all for all your advice and help! I am a little leary about adding headers. I hear ya on smoothing out the sound but it is not the rasp that is bothersom. I also am on the fence if my car is droning too much or is it tollerable. We all here like to fix "problems" we find in our cars and many times I find the drone to be a problem and other times I love the "power" sound and added performance (usually pulling away from a sti) LOL. I apologize for my ambiguity...and appreciate all your advice...
john

I think I am suffering from acute male vaginatis. I do love the sound and sometimes forget why I got this car and what it is good for. I appreciate all your help and advice. I think I will add sound deadining to the trunk area. I think that might take the edge off. Any advice as the best sound deadening stuff at the best price?

...You let people talk in your car?


J/K

Adding sound deadening will negate the reason for putting the exhaust on in the first place... You'll add enough weight to make up for the HP you gained. However, I still see that as the best solution because nothing will change in the end except that your car will still sound better from outside.

I used Damplifier from: Sound Deadening Materials for Noise Reduction from Second Skin
It consistently gets good reviews for effectiveness and cost..

How long have you had it. I've had a couple aftermarket exhausts, and honestly, you get accustomed to it after a while

I've had it with the exhaust for about 2 months now. I have decided that I am going to install some sound deadening matting in the trunk to take the edge off. Thanks again all!

i wish the set up was louder:driving:

^Ditto. One of my favorite past-times is seeing how many car alarms I can set off as I drive by in a covered parking garage. It's harder now than in my previous cars.

I hated when people used to do that to my Trans Am. The stock alarm on it was so sensitive that if I farted in my house, the car's alarm would chirp a couple times. One time, an old lady with a walker walked by my car and it went off.

Well, maybe it wasn't that bad, but every honda with a fart can that drove by set off my alarm. Damn ricers!

Lol. It's not that loud. It's his microphone. The exahust is no lounder than the turn signals. clunk, clunk, clunk, clunk, clunk, clunk.

...

No need to be so self-deprecating. If you want a car that doesn't drone as much, that's perfectly fine. Try to get what you want, and maybe you'll get it (and maybe not!). I really hate it when someone has a problem and the response they get is "you should have bought a [Volvo/Prius]", or "learn to live with it".

Sounds like you chose the right course. As mentioned, "drone" is where the exhaust frequency matches the resonant frequency of a panel in the cabin. The fix is to reduce exhaust sound, change the frequency of the exhaust, or change the frequency of the panel which is resonating.

I would start with the hatch floor, and work your way forward until it's resolved. Focus on the middle areas which are directly above the exhaust. Sound deadening isn't that heavy (~.5 lbs per sq ft.), so as long as you aren't a weight freak I don't consider that a huge concern. GL.

Excellent advice 2bit. That is what I'm planning on doing. I have purchased high quality sound deadening material and will post s results. Thanks again...