Does FI CBE have any drone or rasp?
 

Just wondering what has been the experience of FI CBE owners to date in terms of rasp and drone. Thinking about buying the one in the for sale section. However, I need to be sure that whatever CBE I buy is completely free of rasp or drone noises. Let me know if you have feedback based on direct experience.

Thanks,

Mike

ps. I read through the enormous volume of FI pages on this sites and can't find anything definitive to answer my questions. Please, please don't respond with the classic "search" one liner.

I have the 12" with CF and there is a good amount of drone. You will probably be happy with the 18" SS

18" resonators produce some drone just above 2K RPMs. Higher or lower than that and youre in the clear. Truth is, just about every exhaust will have at least a little drone in that RPM range.

Thanks guys, appreciate the honest feedback.

Mike

You only get rasp when you switch out the stock cats with high flow ones. I had Berk, and then switched back to stock because of rasp (when given a good amount of throttle) and loudness.

The 12" one drones quite a bit after a long hot drive, and it's between 2k-3k RPM as others described. Past 3k to redline it is very quiet. At idle after warming up it burbles, and it sounds pretty freaking cool :)

The video below was when I had the Berks, so you can hear what the rasp is like:

I fixed a decent bit of the drone with some custom side branch resonators. No impedence to flow and it negates quite a bit of it. Not many people want to weld onto their FI exhaust though but I didnt care since mine was custom made (and mucho cheaper).

I have the 18" resonators with cf mufflers and FI long tubes and theres no rasp.. there will be some drone depending on which setup you go with.. you planning on getting HFC's or catless? if so go 18" resonators. if your planning on keeping the stock cats then get 12" and youll be fine.. Either way you choose i think youll be happy with the result.

I have 18" CF and FI HFC's and I don't have any rasp. There is a bit of drone like was mentioned above... but hell, I could even get the stock exhaust to drone at a certain RPM, the range is just a bit greater now.

We're all still waiting for Vids of your setup! lol :tup:

The drone can be cured without any performance hit.

See thread: http://www.the370z.com/intake-exhaus...rks-great.html

gah!! lol im just gonna get a camcorder and make the vid myself instead of relying on other people i think

i love me some drone

basically any exhaust that is as straight as possible and has a straight thru muffler will have drone. The bends in exhaust and mufflers are what neutralize frequencies that cause drone, so straight exhaust will have drone but give the most gains and will be louder.

This is why I enjoy this site so much. You actually get info necessary to make a decision. Thanks guys.

Whichever CBE I select, I plan to keep the stock cats. Don't want to mess with that particular element right now. At this point, I think my best option is the FI with 18" SS resonators. There is one other exhaust I am interested in, but it will not be out until October. Keep you posted. Thanks again guys.

Mike

Zsteve, you are partially correct that straight through exhausts have the strong tendency to drone because the mufflers dont break up the sound waves. However, as mentioned above you can fix this drone with tuned side branch resonators. This lets you keep the straight through exhaust and get rid of the drone too, best of both worlds with performance, sound and comfort. Side branch resonators reflect the wavelength of drone back at itself at a quarter the wavelength and effectively cancel out that frequency. Since the drone is actually the pipe resonance frequency echoing in the cabin, you eliminate drone by targeting the frequency at which the resonance occurs.

:tiphat: