That's the fiberglass going through break in. Give it about 1500 miles for break in.

Then again the HKS system is 600 or 700 more with no real power gains to speak of. Nice system don't get me wrong, but 700 is almost a house payment for some people

The more I think about it I'm going to let these pipes do the break in thing before I hack my exhaust. But if it sells thats a different story!

As I had mentioned in my PM, put your foot down and drive the car hard for a little while. Heat those suckers up it'll all go away.

Eh, closer $300-$400 more actually if you shop around and power is pretty much the same. Its costs a little more but I think the quality is a little higher then similar models. Its also JASMA certified (japan cert. for aftermarket exhaust for Db). The extra $$ is also likely due to the fact that HKS uses real titanium tips that are also adjustable. To me the extra money is worth it not to have to deal with a less then desirable sound with HFC/TP's on an ark. The HKS also is the nicest sitting straight thur exhaust that I've seen with no clearence issues like some have experienced with other models. Just saying that power isn't the only thing to consider when purchasing an exhaust. CNT's exhaust would be a more cost effective alturntive since its design is modeled after the HKS. It's so close you can even swap out the titanium HKS tips for the rolled CNT tips. I've heard the art pipes on an HKS and its pure mechanical music. I'll be looking to dump my berk HFC's for a set of art pipes here pretty soon.. :tup:

Power isn't everything no. I realize that an exhaust is something we must deal with everyday, so it's better to make a wise choice. I think the HKS sounds fine... I personally feel the F.I. and the ARK both sound better... but that's to me and not everyone will feel the same way. The whole JDM thing is WAYYYY overrated and i've never understood it. If a car came with JDM parts on it, people would find something else to replace it. JDM means one thing and that is overpriced.

I'm not trying to knock on your exhaust, that's just my opinion. My Fiancee' had an HKS on her old Evo and she loved the sound it had... I had a Megan that I paid 600.00, but I loved the sound of it (on my Evo IX)... to loud for the Z's though.

you said that a month ago, slowpoke :P

Agreed, exhaust are a completely subjective choice but I didn't buy it because it came from japan. IMO the extra $$ was for better design and quality in several different respects in comparision to ark's product, but I do agree that parts from japan are more expensive. I don't think that JDM means as much to people as it used too and perhaps even less to alot people on this forum, myself included. Personally I would have liked to have bought something made here in the US, F.I was a serious consideration for me but it comes with more drone and a 6 month wait. I bought HKS because of its design, sound, fit, and finish. Ark is a cheaper altunitive if it suits your taste and you don't plan on HFC/TP's. HKS is just a better quality peice then the ark IMO. I'll be giving serious consideration to the Motordyne's exhaust when it comes out in which case the HKS will be out.

I'm experiencing basically the same thing on my polished set of ART's. Keep me posted on your issue. I've got about 450 miles into my install and I've been experiencing a rattling/jingling sound which has progressively gotten worse since about 150-200 miles. At first it was only noticeable from the 1750-2750 rpms range, now it's noticeable from 1750-5000 rpms. It's noticeable at a good distance from my car at this point, and a little embarrassing. Sounds like bad bearings on an alternator or something like that coming from inside my pipes.

Tony says it should go away, but in the meantime, it's bugging the hell out of me. Fingers crossed because I really don't want to have to swap these back out.

Actually two things that keep me away from this set , rattling and SMELL .

the rattling will go away. didnt take 1500 miles for me. most like around 700 for myself. but that was quite a few heat cycles

Yea my rattle went away too. Prolly took 300 miles? Something around that.

Take it out on the highway and drive her hard. That's when the rattle really quieted down.

Thanks guys. Awesome to know that I'm not the only one. I trust Tony entirely, and definitely know that everything will be ok, but it's a little annoying when you pull up at a stop light and your car sounds like your exhaust is slowly working it's way off the car.

looks like i'll have to do some spirited driving this weekend. :driving: I'll let you know how it goes.

It sounds like grinding right! Lol it first sounded like metal being dragged now it kinda sounds like grinding. Im at the same mileage as you now (About 500, I got it on friday, yes I know I drive A LOT). So Ill keep you posted when it dies down. Quick tip the rattle does not appear if you downshift when coming to a stop lol.

I just got done driving from FL to NY yesterday, yes I'm in NY at a hotel. Drove the Z straight thru. The ART pipes got slightly deeper as anticipated. Currently have 2200 miles on the ART pipes. Holding up good so far! :tup:

started off sounding like a couple tiny pieces of ceramic bouncing around. the sound was very high pitched and the pieces sounded small. that eventually worked itself into sounding like a couple steel ball bearings bouncing around inside there. little bit deeper sound. pieces bounced longer after i let off the throttle. yesterday it sounded like a single marble. like, a large one. much louder, deeper clanking. today on the way to work was by far the worst. sounded like a flat metal plate bouncing around. sound is present under any driving condition.

i find myself shifting before the car hits 2,000 rpms to keep the volume of the clanking to a minimum. this is not fun. almost drove my vw to work today in order to avoid the clanking. i've really got to get this under control.

Don't shift that low. We all told you to punch it and heat the ART Pipes really well. Drive it hard for a day or two, it goes away.

I hear you. but man, I scorched the thing all the way home and back to work on the highway this morning. I don't understand how or why this is considered "Normal" break in. I'm a little uncomfortable with the fact that I'm screaming up and down the highway so that I can get a product to settle properly. The truth of the matter is that I don't *normally* drive like this off of the track. A pull at a stop light here or there, maybe, but this is excessive. Seems like there has to be some sort of agent or alternate product that can be used in order to get around this terrible sound.

Sound is absolutely unchanged, from cold start up all the way until I pull in my parking spot at work today. That includes a couple redline shifts, some goosing the throttle, and all around abuse that I wouldn't normally subject the engine to. No change at all. If it was a little sound, I'd be able to deal with it better, but this sounds like someone banging a serving spoon on an empty coffee can. Getting pretty frustrated with this.

Let it break in to 1500 miles. If it doesn't dissipate we will replace them for you.

Also, make sure everything is tight. Did you make sure to cut the bolt? And what exhaust do you have? Did you make sure it isn't hitting the cross member?

The rattle for most of us didn't exist past 3500RPM. It mostly happened between 1500-3000RPM somewhere.

Sound should go away bro. I am in the same boat as you and trust me itll be worth it. You and I both have G37's and around same mileage Ill keep you posted if there is change!

Man I know how you feel drift. I was so embarrased to drive the Z with all the rattling. I even made an appointment with a shop to have them inspect the pipes. Drive 30 minutes on the highway and upon arriving to the shop, I couldn't reproduce the rattling. Lol

I couldn't believe a rattling sound is part of the break in process either but I guess Motordyne knows their products.

I know we cut the bolt on the first batch but I can't remember it exactly. Tony do you have a pdf of the instruction manual?

I was on a creeper at 6:30 am this morning under my car, checking for anything loose or banging. Bolts are torqued, clearance is no issue. It's a perfect, text book installation. I started the car up and got under it. Sound is from inside the chamber. Can't tell if it's one or both, because the one closest to my ear drowns the other out.

My family owns a machine shop and we build race engines for a living. You have no idea how much of an earful I'm catching from my brother and our mechanics about this. I've been the laughing stock for 2 days now. "Ask him how much he paid for that rattle!" :bowrofl:

Can I get a price for the tp to 98275?

Better head up to the mountains this weekend and get your :driving: on.

They are in stock and we have free mainland shipping at the first of each month $585 shipped.

At least for this fiberglass, the 1500 mile break in process is such that the fiberglass goes from semi soft, to a solid mass and then back to soft and fluffy again. Its due to the silica binder being used to keep the fibers under control during manufacturing and handling.

Does the silica release a smell as well? I'm starting to smell something like burning plastic within the last few days.

No. The silica is a mineral analogous to glass. Its smell and thermal characteristics are like glass. No smell and a very high melting point.

Check to see if you don't have something else causing the smell.

It appears most HFC/test pipes have a mounting bracket welded as part of the design for the catalytic converter cross brace. From the pics on the Motordyne site it does not look like these are utilized. Is the cross brace simply not used when running ART pipes? Has this caused any issues with expansion joints on common CBE's?

None I'm aware of.

kosstick - any changes in sound?

I passed the 900 mile mark today, still jingling away.

as a note on the sound. I think ive passed around the 1200 mile marker with the ART pipes now and its actually settling in again. Gotten slightly tamer without a noticeable change in deepness/pitch from a few hundred miles ago.

Which im happy with. loud exhausts = not for me (P.S its still loud when you go full throttle, the way it should be. tame for normal, screamer when you gun it)

I was wondering the same thing, but A LOT of people are using these and i've not seen any complaints on them.

When you bolt them up, they are solid though... it certainly doesn't feel like the brace is needed. The stock cats are about 3.3 lbs heavier each from what the OP said as well so that takes a little stress off.

On top of all of that you probably save another 2 or 3 lbs from not using the brace ... so 9 lbs weight savings from these sounds good to me :)

daisuke, what exhaust are you running?

CNT exhaust

Update: Went back and forth to NY from FL and have 4600 miles on these without issues.

Im right around there and yep still jingling away as well

37drift has the chrome and may actually have the ceramic beads in there. I'm sending him the newer ones.

Kosstich, Do you have the chrome or titanium?