RMB5190

iTrader: (2)

^Here. Anytime you modify a system beyond OEM standards you're going to increase NVH. You'll never eliminate drone or rasp 100% but I think you understand that given your statement:

"My goal is to eliminate as much drone as possible, while maintaining a deep low
tone and to minimize the introduction of adverse sounds such as rasp."

If I understand correctly, you're trying to inject muscle car characteristics into your set-up with a sprinkle of the Amuse system. I think the Magnaflow 3 chambered mufflers will do precisely that.

afrayedknot

iTrader: (3)

@RMB5190 - I really appreciate your input and advice. I will follow-up once I decide what to do. (going to consider an x-pipe in place of resonators as well)

@kroy - I have not heard of any setups in person, only through videos. My assessment is in comparing my stock vs muffler delete vs muffler delete w/pipe ID increase. I find that just the muffler delete was very tolerable in terms of drone, but once I increased the pipe ID, the drone increased exponentially. This is my first vehicle where I've made modifications to the exhaust, so I don't have any experience as in what to expect, but I would think that most members here would classify the drone I have as intolerable.

afrayedknot

iTrader: (3)

I've decided to go with the MagnaFlow 3 chamber mufflers. I noticed the in/outs can be centered or offset, does this affect the sound or is it more for fitment? If the latter, would a center/center in/out be the simplest to install for my application? Right now I just have a straight pipe at the position of the stock muffler. It seems like I would need to introduce another angle bend in the pipe if I get a center/offset fitment.

Also, I have SS exhaust tips I bought on eBay that have been welded onto my new pipes. Is it feasible to remove the tips and attach them onto the MagnaFlows or am I better off just buying a new pair for ~$45?

I have off all next week and hoping to get everything done during that time.

RMB5190

iTrader: (2)

The in/out won't effect sound but you want center in & out; that's what all other aftermarket systems look like. That said, speak to the shop that will be doing the work and see what makes the job easiest for them. You can do an X pipe but that means you'll need to eliminate the stock Y. This is going to raise the cost of the system. The reason I recommended the Stock Y is because it will keep your overall costs down and keep the tone inside the vehicle to a minimum. This is convenient if you ever have to drive passengers who may not appreciate the constant tone of an aftermarket system. If that isn't a concern, nor is the cost, X-pipe with the Magnaflow resonated X pipe will really make the G sound like an animal.

What size is the current SS tips?

afrayedknot

iTrader: (3)

Oh okay, I was under the impression that people were replacing the factory resonators with an x-pipe, so nevermind that route. I plan to install the mufflers first and hopefully I will be content with the sound. If not, I will modify the resonators, but I don't foresee myself swapping out the y-pipe...

As for the size of the SS tips... I originally bought a pair of 2.5"in/4"out, but after seeing them in person, the outlet looked way too big, so I traded them for a similar pair with a 3/3.5"? outlet at the exhaust shop. I am not 100% sure that the inlet on the smaller tip is 2.5", but I will measure the circumference today and calculate the diameter.

RMB5190

iTrader: (2)

Mine are 4'' outlet and I like em. It's personal preference. I was just asking in case they were smaller due to stock piping but forgot that you mentioned an upgrade to 2.5'' piping near the mufflers so disregard.

afrayedknot

iTrader: (3)

RMB5190

iTrader: (2)

I know what you mean. I thought the same thing when I got mine. They look tremendously better once on and they pop if you ever paint the rear valance or go with a AutoKits rear diffuser.

You're right, I never noticed that. I'd go with the offset that favors the inside of the car, pending if it's the left or right side - if that makes sense. You can go round but take the comment about the round mufflers from the Ark system above...drone. That even has hemholtz designed resonators...

I can't see it dictating the price to increase too much since they have to make a cut to install the muffler anyways; the offset just dictates where the cut is made.

obsidiansamurai

Sounds like you're going the route I took, which is the more "experimental" (and expensive) one. I think no matter what you do to your resonators and mufflers, you'll get some drone with that size pipe, unless you add Helmholtz resonators.

My most recent setup has 2.25 inch piping from midpipe back, Magnaflow resonated x pipe, vibrant resonators, and 3 chamber xl Magnaflow mufflers. It still droned a good amount from 2k-3k, which was not tolerable. Luckily the drone has decreased a good amount now that it's broken in a bit. I would consider the small amount of drone it currently has as tolerable, but there's still a bit there. Maybe it'll reduce further the more I break it in, I dunno.

If the drone kept at the level it was when I picked it up from the exhaust shop, I would've have done the poor man's Helmholtz resonators fix that I found on the 370 forums i believe. Helmholtz resonators are those, as a member here so eloquently put it, whale dongs that are attached to and run alongside the axle back piping usually. I think these are the most effective way to eliminate drone.

I can assure you those 3 chamber xl mufflers will sound great though. I'm real pleased with the way they sound - such a nice burble when letting off the throttle. I was told to get the mufflers with offset piping on one end and center piping on the other. These mufflers can be flipped over and used to accommodate either the outside or inside.

RMB5190

iTrader: (2)

woofersus

iTrader: (3)

I had the topspeed y-back swapped out for the Q300 catback and I'm much happier. It does drone a tiny bit at 2k, but even that's mellowed out nicely over the 3 weeks or so since it was installed. I actually wish it was a little louder (outside the car) now, but I'm not messing with it anymore and I'm generally happy with the sound. I'd say it's higher quality than stock but barely louder, even with my FI RHFC's.

I still feel like the car's down on power with the larger exhaust all the way back and am hoping the tune will cure all ills.

RMB5190

iTrader: (2)

Why weren't you happy with the Top Speed? The stock Y pipe has the necessary diameter to still pair with RHFC or test pipes while reducing cabin NVH. Seems like the best all around system if you're <$1000 shopping.

The Invidia is just entirely too quiet for my tastes. The lack of power is probably placebo?...less sound = less power

kroy

@Obsidian dude you're like an exhaust pro now. Never thought to add a HH. Curious how that affects the sound now.

@woofersus the q300 only advertises like 4hp gain so there's that.

obsidiansamurai

I'm gunna give credit where credit is due; I believe RMB5190, the whale dong authority, gave me the idea originally. From what I've read, HH are not supposed to change the sound a whole lot, but I would think it'd quiet it down some. I need to find some before and after vids so I can be certain.

Here's the DIY Helmholtz thread from the 370z forum, if anyone is interested. It's a pretty good read.

woofersus

iTrader: (3)

I didn't really like the sound of the Top Speed. It was also a lot louder inside the car than I really wanted - I think the whole system ended up a little louder than what Top Speed claims because I also had the RHFC's. The Invidia IS a bit quieter than I wanted, but I'd rather have that than what I had before. At least I like the way it sounds. As a bonus, an unpleasant vibration I had at idle ever since I put on the RHFC's is now gone with the stock y-pipe replaced. I assume it's just something with the way everything is attached.

I actually thought it felt a little down on power when I put the topspeed on, and I don't feel like it's really any different now. It certainly could still be placebo, though, as I'm only going by butt dyno. I did reset the ECU each time, which always makes it feel peppier briefly. Maybe for some reason my attempts to reset idle air volume have not worked.