I would agree to this. The sound is inherent from an X design, and with the increased flow from HFCs or TPs or LTHs' the hiss is more pronounced... Here check this out:

http://i584.photobucket.com/albums/s...3/image002.gif

See how both pipes come together and even if you get an aftermarket Y pipe, you're still maintaining the X profile.

http://i584.photobucket.com/albums/s...3/image001.gif

Here is the Nismo exhaust, notice the H crossing instead of a Y/X. Very different in terms of how it affects/improves the flow. This is why it's less noticable on a Nismo.

**Pics courtesy of my350z.com

I see what you are saying, but I think that even though the overall shape of the stock exhaust looks like an X, I would not call it an X-Pipe design and don't think it acts the same way.

True X-Pipes are basically 2 tubes with a small opening in the center connecting each other, right after this, they split into separate pipes.

http://www.albertpenello.com/vette/xpipe2.jpg

http://i371.photobucket.com/albums/o...s/IMG_5036.jpg

On the stock design, gases come together on a single relatively long pipe and then it splits again. I think this would have an effect in sound and performance.

http://www.dragtimes.com/images-clas...0491418379.jpg

I guess what I wanna get at is that the hiss is caused by something else. Stock setup uses Y pipe and hiss is there... FI setup uses X pipe and hiss is there. Maybe its something with the engine itself, exhaust valves, gremlins. Lol I don't know.

Well, Chris's explanation about air pressure equalization between banks makes as much sense as anything else I've heard. If that's what causes the hiss, the hiss is probably present on any exhaust setup with a decent connection between the two sides, it's just a question whether and how well you can hear it under what conditions.

This is probably why the base stock exhaust is setup the way it is. To mitigate as much of this hiss as possible.

anyone have FI exhaust with CNT Racing HFC ??

I am sure someone out of my 300 exhaust systems installed has to have that combination.

Do you already have our exhaust or is it something you are planning for?

and im looking for someone with the F.I exhaust with ART pipes to hear what that combo sounds like :)

Well, I have my UPS tracking info, the exhaust is on its way!:happydance: Says it should arrive this Thursday. In preparation I got under the car today and sprayed all bolts with PB blaster (I might hit 'em one more time on Wed). Everything looks like it should be straight forward, it's the first time I actually got a good look under the car.

For others who have done the install themselves I've got some questions. I backed up onto Rhino ramps in my driveway. Seems like I can get to all the bolts fairly easily (with the exception of the connections at the CATs where I had to crawl under from the side of the car. Wondering if I should bother jacking up the front a bit as well in order to get to the bolts near the front a little easier). Does anyone have any tips/tricks they can share? Anything I need to watch out for? I plan on doing the install the day it arrives (take off early from work if I have to). I heard it takes roughly 1.5-3hrs from start to finish.

Thanks in advance!

If you're just doing the catback, rear rhino ramps should be fine. The FI catback is really easy to install. Even if you're also doing HFCs it's still pretty easy, but you might need to lift the front as well to break the Cat<->Manifold bolts easily.

I'd say, if you have the Ability to jack up the whole car, might as well for peace of mind. If not, then I would recommend to jack up the front end first, and get the HFC's on since that will be the most difficult part. And then if you run out of time, you can just bolt them to the stock exhaust, come back the next day and do the rest of the exhaust jacking up the rear end.

^^Agreed. Removing stock cats might take awhile.

Thanks for the tips guys. I didn't opt for the HFCs just yet, so I'll just be installing the catback only. I might find some thick planks to put under the front wheels for a little extra room near the front. I just don't trust jack stands for much other than changing tires/wheels (where I'm not directly under the car).

Boo, i scrapped my CF exhaust can backing into a space on stone curbing...:ugh::mad:

:icon18:

Instant No Button! Star Wars funnies FTW!

:bowrofl:

That sucks Pelican, takes some getting used to the new clearance and the cans. I tend to park front first or give extra room when parking in reverse.

:icon18::icon18:

hahah, that pic described exactly how i felt once i saw the scrape mark hahaa. yea, its going to take a little getting used to and im going to have to give it some extra room for parking. i figured it would happen eventually, at least now i know to me more cautious about it...

Check out the pm I sent you. Call me if you need anything.

Tony

Hey Tony,

Thanks for your reply. I have one other question. When I got the exhaust on, the tips seems aligned fine. But now after driving for a couple weeks, it looks like one is sitting lower than the other, but both seem to sit a little low to me. is there a way to get these to sit higher towards the bumper and to be aligned?

Or if anyone has an idea of how i can get the tips to sit closer to the bumper? seems like they are hanging almost an inch lower than it and kinda looks like they are pointing down a little... maybe its my eyes haha.

Have you re-checked that the bolts at all of the flanges are still torqued down good, as well as the ones for the hangars right by the outlets?

no i havent but thats on my list but i dont think thats it really. i pulled on the can i little and its pretty solid... the driver's side sits well, and im happy with that. The passenger side sits lower that the drivers. Id much rather raise the passenger side than lower the drivers to have them match up...

lol, im starting to think im just paranoid about it and its not as far away from the bumper as im making it sound lol. maybe ill just shim the one thats higher and see how it looks. ive heard other ideas to raise the cans by putting hose clamps around the hangers and tightening.. apparently it will pull the exhaust can upward...

Assuming nothing came loose, (and forgive me if this seems obvious, but I never know what people already know around here), did you line everything up before torquing everything on the install? With things like this, I always bolt everything together loosely first and get it lined up perfectly, and then snug all the bolts in the system at the same time. If you instead torque everything down as you go while installing the bits, things tend to not sit right.

This is what they do at F.I. as well when installing it. Checking to make sure everything is level before the final snugging.

Funny enough, I feel like mine is too close to the bumper, I can't even read the "fast Intentions" at the top of the tips lol...the fit is great though, so I shouldn't complain.

Hey, it was done by a shop that works on a lot of subaru's and mitsubishi's, they know their stuff. Its weird, i didnt notice it before. but i definitely notice it now. I just measured the two and the passenger side sits a 1/4 inch lower from tip to bumper. Here is a pic... i just feel like if i shim the driver side it looks like it sits too far from the bumper... maybe im just being picky...

Be careful it's not too close. Mine sit about 0.3 - 0.4cm from the bumper (as measured with a caliper, one is a little lower than the other), and over time they've very slightly melted/scorched the underside surface of the bumper in a tiny spot. You can't see it from the rear so I could care less, just FYI. The only reason mine are so close is because I had some tip clearance problems due to (we believe) the output location of the Stillen short-tube headers that are currently on the car. I used washers to space off the rear hanger bolts to give even that much clearance.

Honestly from the pic the clearance and side-to-side difference looks pretty normal to me. Maybe if it were up closer or if I could move side to side and stare at the angles in realtime, I'd notice, but I donno.

Yea its hard to tell by the pic. at this point i think ive just been starring at it for too long and my eyes are playing tricks on me haha.

Sorry to blow the thread up, but i have another question for people who have the hfc's and exhaust. I notice a little "sputter" when coming off the gas pedal. wanted to make sure this was normal. Was wondering if thats the small bit of "rasp" i hear about. Thanks for everyones help with everything..

in regards to the position of the mufflers.. maybe something bent/moved slightly when you scratched it.

Well, the UPS guy delivered my exhaust this evening at 6:00pm. I unwrapped everything, got my car up on ramps and had everything installed by 8:00pm (2 hours exactly :tup:).

I got the TDX SS w/18" resonators. No HFCs for now, since I was a little afraid of it being too loud (I use this as my daily driver and long trips). Sounds great. Not too loud yet not too quiet.

The install went smoothly. A few tips for those installing this themselves.

1. Even though I soaked every bolt with PB blaster 3 different days before the install, the stock bolts were still near impossible to break loose without my impact wrench (I was curious how hard it would be to remove without air tools). With the impact wrench, the bolts just fell right off.

2. I think I got my system to sit as high as possible (without hitting anything of course) using the advice given in the instructions. Once I got the H pipe attached to the pipes that attach to the cats, I wedged a shim between them and the crossbar thingy before I tightened all the bolts. Once everything was tight I removed the shim and everything sits nice and high.

3. The top bolt on each of the 3-bolt flanges were a bit of a pain in the arse to get at. No big deal really, just had to contort my body and find the right combination of wrenches/sockets to tighten them.

Per item #2 above, my tips are sitting ~.25" from the bumper (I can barely read the "Fast Intentions" imprint). Seems to be about the correct distance and doesn't look sloppy.

Overall, I am very happy with the system. Tony was great to deal with.:tiphat:

Great stuff Zole, you didn't waste any time with the install ;) You'll love the combo with the HFCs if you go that route. It will be loud but nothing ridiculous. The exhaust note while driving in tunnels is sweet.

Anyone have any feedback on this? The noise is like a Sputter or almost like a backfire noise... Does it also when the Syncrorev match is on and it revs high quickly and i let off the gas...

This sound is perfectly fine. It's just a flutter from backpressure I believe. Ever heard an SRT4 when they let off the gas coming up to a stoplight and it literally sounds like the car is gurggling? It's kinda the same as that, only more muffled.

Ok I figured it was normal and fine, just wanted to check. I think im too paranoid about my car haha. Thanks for your help...

No prob. :tiphat: You know what will fix that sound... LTH's :stirthepot:

:) I would have gone with those vs the HFCs. I don't think I would have been able to handle how loud they get under load.

They're actually not that loud. They aren't any drastically louder than HFCs. Especially at idle, HFC's are Louder than LTH's. Both Berk's and F.I.'s.

And in terms of sound, it doesn't so much chage the volume, but more the tone. It's a slightly higher tone due to the increased flow/rasp, but you eliminate the rasp with the Exhaust. :tup:

huh! didn't know that Chris. You are giving me a lot to think about :tup: