If you're doing FI catback does G3 make a difference?

ped

Agreed - I find myself doing the same. Bummer that it negates some of the benefit of having the auto tranny.

This is another time I wish Nissan would wake up and give us a "sports" mode tranny button like the Evo has. Three or four settings for how aggressively you want (or don't want) the tranny to seek out taller gears would go a long way to being ale to stay in D but get the result we're after.

Chuck33079

They work better together, but they both will give you power individually.

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2011 MB Touring-Sport-6sp-Nav/GTM TT/FI TT TDX/JTran/Kosmic/Eibach/Hotchkis/SPC/CSF/RPS/SoThatsWhereAllMyMoneyWent

mag_black

Take a video of your car driving away. You'll find that it sounds different and quite good. Think of all the people you drive by and will let down if you go back to stock exhaust.

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ped

Ok for those who care or later find themselves in the same position, I want to let you know the answer to this problem is that Fast Intentions (and possibly other manufacturers) are building their exhausts minus a very important item - a Helmholtz resonator. This type of resonator attaches to the main pipes at a 90-degree angle, and is capped on the end. He shape doesn't matter (J shaped, etc) as long as it's the proper length - basically what you need is to know the frequency of greatest drone (say 120 Hz for example) and then shoot for a resonator that is 1100 / frequency / 4 which gets you a tube length which will have a natural resonance 1/4 of the wavelength of the worst drone. Since this tube is closed on the end that doesn't attach to the exhaust pipe no exhaust really flows, it rather a standing wave is established (like when you blow over the top of a Coke bottle) which cancels much (or all) of the drone. Similar to noise-canceling headphones.

Why FI and possibly others are leaving this out? I'd guess it's the inability to determine the proper frequencies since the catback may eventually be combined with other items like an HFC, different exhaust header, etc. Thus what would work with stock cats and headers wouldn't necessarily work (at least as well) with aftermarket replacements of these items.

My beef isn't so much that they leave them out, it that so many fans of FI in this forum make FI exhausts out to have NO DRONE which is absolutely nonsense as I can tell from having it installed two days ago. At a minimum people need to have REAL information before blowing 1100-1200 dollars on an exhaust that can induce headaches or at a minimum be highly annoying. I'll probably get flames for this since FI seems to be so well regarded here but I wish someone would have warned me before I wasted money having this installed and now will be paying labor charges again to have the stock system out back on (or to have Helmholtz resonators welded on) plus loss for restocking fee since the exhaust can't be sold as new anymore.

For the curious who want to see the outcome of the calculation above, for a drone that is worst at 120 Hz:

1100 / 120 / 4

= 9.16667 / 4

= 2.29167 feet

(times 12 for inches)

= 27.5 inches for the length of he Helmholtz resonator tubes

Leuz

OP, while we wait for F.I. response to your post, I would like to note a couple of things as you are effectively one of the very few (the only one?) F.I. customers who are not completely happy with the product
- each individual is different so they noise you perceive could be very different from the one I perceive
- there are many alternatives with the type of exhaust you are mentioning, iirc I believe Motordyne has one; forum search should have pointed you to that
- F.I. have never claimed their exhaust has NO drone, even on their website they say NO rasp but they mention they use resonators to cut down the drone (not to remove it)
- if you searched the forum, you would see people mentioning drone with F.I. I am actually one of those who said at least once that the exhaust with 12'' resonators does definitely drone
Again, please don't think I want to be a j**k about it, but F.I. exhausts are probably the most reviewed and the ones with the largest amount of opinions on this forum. I believe that when you are planning on spending +$1k on a product you have to be a well informed buyer and that should mainly come from doing good homework, which translates in searching, reading and searching again.

Also an advice, you have probably barely used your exhaust. I am sure there would be people here willing to buy it off of your hands for the same price you paid to be able to have it shipped right away instead of having to wait 3 months, just sayin'

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2013 PW 370Z Touring+Sport, NAV
Tint 35% side, 18% back | RJM clutch pedal | ZSpeed SS lines | Stillen Gen3 CAI | Fast Intentions HFC and TDX 12'' CF CBE | UpRev

F.I. Inc.

Very well put!

Thank you, Tony

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ahhlun

FI exhaust options HFC or ART test pipes or?

I also mentioned here the 18" SS FI's drone to be just tolerable for me.

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2004: MCS
2010: 370z 40th

pinoyZ

3 AGONIZING months and sleepless nights!

Getting my 12" res cf cbe and nonres hfc nextweek! planning to order the gen 3 intake too. How much does it cost to install this whole set up? sorry to ask here dont know much autoshops here in VA beach and hate getting robbed =)

ped

That's a good point... Hadn't thought of that!

:-)

Riptide67

I had the FI CBE alone and it was great. I just paired it with Stillen G3's, Stillen UD pulley, and Motordyne ART pipes. Ever hear a car that you said...damn I wish mine sounded like that?

I now own that car! I am so pleased it isn't even funny. No one will be disappointed with that set up.

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2009 Nismo 370Z and 1975 Datsun 280Z 2+2 - PNW_INC - Legacy_Ohana
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