Wish I knew about this when I had b&b bullets on my C6. Wife would plug her ears with her fingers for the week I had it. Plus rep!

Im big Depeche mode fan :happydance: .... just trying to prepare myself to get this done as need it badly, lets see if someone with FI exhausts wants to do before me

Man when you posted this thread car was in workshop and I have been calculating this drone on rpm range...the vibration starts at 2100 and is there till 2800 depends on the gear and speed as sometime it dies on 2700. Its more if you stay in single gear and accelerate slowly all the way till 3000, but if you push the pedal hard then its a bit less.

So can you throw some light according to your calculations as I have no means to measure those frequencies.

For the pipes does those be in SS or normal exhaust pipe will do the trick. I am about to pull the trigger:confused: by making hole in FI exhausts

Since the FI setup is the same pretty much as mine and the drone in is the same range, I would use 28-30" pipes, one per side. Any shorter and it will tune out drone above 3000rpms where you dont have the problem. Regular steel is fine but I would use some hi-temp paint to keep it from rusting ever.

Thanks will plan the operation then :)

how do you measure like someone would need 28" or 30" or less?

Speed of sound (typically 1100ft/sec, divided by the frequency at which drone occurs, divided by four because you want it to reflect at 1/4 the drone wavelength to cancel it out).

So for drone around 110hz-112hz (around my setup), you get to 2.5 to 2.4 ft, or 29-30".

So fast intentions CBE drones.... I had no idea. Glad I didn't buy it last week.

But this exhaust doesn't
http://www.the370z.com/intake-exhaus...w-db-test.html

We need to confirm with Tony of f.I and let's see what his advice. I believe Tony tried a Lot of things before he decided to make his cbe. So give him a shot and wait for his respond. That's just only my own idea. :tiphat:

Might want to check the Fast Intentions thread before making a conclusion. I get mine this week and should have a full review soon, then again there are already over a 100 reviews of the exhaust. :p

:iagree: with thedreamer. And take a look how many sets Tony sell out. I'm one of his customer still waiting for his cbe. And didn't hear anything like drone or whatever negative from other forum member. So let's wait from thedreamer. Hey bro keep us updated. Whenever u got yours and installed. Let me know so I can meet up with u. I want to hear from it and see how's good is it. :happydance:

wow, shameless plug much? :ugh2:

So...to get the frequencies of your droning, you put a microphone to your exhaust and ran it through a spectrum analyzer (i.e. Audacity if you're not in a lab...haha) to get the peak frequencies? Out of curiosity, did you run any filters on the output, or was it all raw? How clean was the data?

Nothing serious, just piqued my curiosity. I like reading stuff like this.

:nutswinger:

Running FI exhausts for few months now, I can say the exhaust sounds awesome but what OP was referring to was not the normal drone (I can live with that) but vibration because of it. I do face that if I accelerate the car slowly(normal crusing) not pushing it hard as rpms has to go steady from 2k to 3k and its there for good 500 - 700, mine starts from 2200 and lasts till 2800.

This thread shouldn't be taken anything against FI as they are an awesome company with awesome product, its just people have their own preferences. My daughter(7yrs) hates this drone and avoid sitting in the car LOL. I went through doing a DYNAMAT sound proofing when upgrading the audio it has reduced this vibration (not talking about drone/sound/noise) but its still there and if Tony gives some input on this thread I am willing to do this DIY

Will this only work after the muffler? I have a single exhaust on my 350 and there really is no way of doing this after the muffler.

side note: not to go too far off topic will HFC's cause more drone?