I'm going to be running a Nismo exhaust with both Berk HFC's and an XYZ pipe (I also have a 5/16" spacer and pop charger, if it helps to answer my question). I was originally going to run the setup I mentioned above with the straight pipe on the XYZ, but after browsing around this forum and youtube sound clips, it appears that I might be running the risk of having a lot of rasp. And if this is the case then I will go with a resonator or HFC on the XYZ. What I want most from this setup is to basically get the most unrestrictive flow from the exhaust (I plan on getting tuned from UpRev after the install), while also getting a great sound from the setup. That being said, a little bit of rasp at high rpm's might not be an issue, but if you guys think that there is going to be a lot if I run the straight pipe then I will definitely go with either the resonator or HFC.

Is there somebody that has run a similar setup that can chime in? Or are there people who have run HFC's with the XYZ straight pipe who were having to deal with a lot of rasp?

 

Ran the Nismo cat back + HFCs for years (with spacer and popcharger too), by my ears wasnt raspy at all. Technically they are both "straight" y-pipes.

Just get the HFCs with the straight XYZ...you are nitpicking about something very minor...esp since you are running HFCs and one of the quieter mufflers on the market. And isn't that the whole point of the XYZ...that you can swap easily.


Besides, based on your criteria you should be going a completely different direction with your setup **IMO** you should be going resonated TPs (max flow), resonated XYZ (rasp control), and a higher flow muffler (use OEM style to further minimize rasp - since you are sensitive to rasp dont even consider true dual or single). Otherwise why even buy the XYZ.

 

Want to add though that **IMO**lol*** the HFC+Nismo catback was and still is one of the best and most true-to-form sounds for the 350z.

 

I haven't seen too many resonated test pipes available. Are there any quality ones that you know of? Also, wouldn't an HFC have very similar gains to that of a resonated test pipe? The reason why I wanted to go HFC --> XYZ --> Nismo was to get great airflow and beef up the sound of the Nismo, while trying to keep it's iconic sound as much as possible. And yes, it should be relatively easy to change out the piece on the XYZ. However, I just wanted to get it right the first and call it good.

 

perhaps you should consider the ART pipes

slightly more power than hfc, and retains the torque.

From what I hear, ART pipes remove most of the rasp

 

Nismo isnt a very large improvement over stock in the flow dept.

Either way you go the power difference is going to be negligible, might as well just leave the stock cats then no? ...But you said you want the"most unrestrictive flow from the exhaust" and a tune. It will sound badass no matter what.

Decide what is more important to you and thats all there is to it. Make a decision matrix lol.

HFC+XYZ+Nismo will not rasp - except for a small rev band iirc somewhere between 2.5-3.5k when WOT where you will hear some super light rasp, most noticeable when cold. If this bothers you then you should probably just leave the stock cats on.

There are definitely resonated options available.

 

I have ART pipes, XYZ + resonator, Tomei expreme TI. I don't have rasp because of ART pipes (used to have TDXv2 exhaust). The XYZ is said to flow better than most 'Y' pipes, but I also like the feature of being able to add a HFC if need (for different racing classes?). The XYZ flows very well and gives you options to add in later for your specific feelings, I love the way my Tomei sounds.

I have a guy in my group with test pipes and tomei Y pipe; I personally can't stand driving behind him on the highway...my ears really feel like they bleed. My exhaust is loud but clean sounding (probably because of the ART pipes), the XYZ is a great buy for being "modular".