MOTORDYNE ART Pipes - Review

harp00n

How do you think, if I remove these tab connections on the pic:



will it decrease the drone I get on load at 2000-3000 rpm? I believe these tabs can transfer the drone to the cabin as I had Berk's HFC before and it didn't make such hollow drone, though it had the same sound level outside (and Berk's weren't connected with these tabs).

in case if it won't help, maybe I need to change my additional Moroso Spiral Flow resonators (installed between ART pipes and Borla) to something more efficient?

and what else can be done to reduce drone inside of the cabin? maybe some exhaust wrap, or sound deadening?

Motordyne

It doubt it has anything to do with the tabs. Its likely the interaction of all the exhaust parts. It may also be related to the changes made to the pipes but its hard to say. I haven't tested it like that.

MaDMaXX

As the ART pipes remove drone, i'd hazard a guess it's the rest of the system?

Easy way to check if it's the mounts, remove the brace itself, no need to remove the brackets, then go for a drive, quick and easy.

harp00n

Well, yesterday my muffler mechanic inspected the exhaust and everything seems to be fine with the tabs (they are connected to the engine through the rubber, so I doubt they are the issue) and other components. The only thing he has found is a little leak between the driver's ART pipe and collector, I'll fix that leak soon, but it seems to add only a little rasp at the highest RPM's and not connected with the loud drone issue I have.

I understand that Borla is a very loud exhaust by itself and might did some drone with the stock catalyc converters but it was ok. And when I changed them with the Berk's HFC the drone and rasp became VERY annoying and I had to add Moroso Spiral Flow resonators. They helped that issue, decreasing the drone inside of the cabin and almost cutting the rasp I had.

Now, with the new ART pipes i still don't have any rasp , but the drone is really annoying under the load at 2000-3000rpm. I suppose, my additional Moroso Spiral Flow resonators can't fight such amount of drone, so maybe I should change them to something more efficient? Though I'm limited in the choice as they should be no longer than 15 inches and no fatter than 4 inches...

I started to think, as I already have dynamat materials in the rear of the cabin (rear sits, rear floor and subwoofer deck) maybe I should add some dynamat sound deadening materials to my trunk, as drone comes mostly from the rear, should I? And maybe I even should add dynamat to the front of the cabin (to the floor), as I feel drone a little under my legs too. Though I don't want to make my car too heavy after all those materials

Any other ideas how to reduce my drone?

Motordyne

Yes, change to an exhaust system that has less tendency for drone. If it had drone with stock cats, it will drone with anything.

harp00n

Right now, I cannot afford a new exhaust. I can change my additional resonators though. Current resonators between ART pipes and Borla cat-back are Moroso Spiral Flow resonators, maybe someone knows something more efficient?

And I will try to put some dynamat anti-vibration materials in the trunk, it might help to reduce this drone...

P.S. The last hope is the Uprev tuning, I heard it changes the exhaust note a little and maybe my car won't be at the "drone RPMs" all the time after the tuning, like it tends to do now.

Motordyne

A tune has little effect unless it involves actual cam tuning.
As for the drone and the morroso spiral flow resonators, it may be difficult to know what to do without a lot of experimentation.
If the exhaust has a tendancy to drone, it may be tricky to fix.

AlphaSnacks

I bought a pair of exhaust tip plugs that are fit inside the tips. I'm getting a bit of drone anytime I touch the throttle at 2K-2500RPM as well, and it's began to annoy me. If the plug fix works, I'll let everyone know - because it's definitely not the ART Pipes, the drone is booming straight out of the muffler section.

Motordyne

Drone in an exhaust system has the same operational mechanism as a pipe organ tube.

The tubes of the exhaust system can resonate just like a pipe organ. The problem is there is only one note (or set of notes) that the exhaust can play. And this is why drone BOOMs at some RPM's (frequencies).

When the engine exhaust pulse frequency matches the exhausts natural pipe organ frequency the engine and exhaust sing together making one loud & penetrating note. DRONE.

The exhaust system must be designed to notch out that drone frequency. And that is why we use the side branch resonators on the axleback section of the Shockwave))).

The side branch resonator is tuned to 1.2X the natural frequency of the pipe organ. 1.2 insures the side branch will always be out of phase with the natural frequency and thus they cancel each other out.

AlphaSnacks

Tony, what is the quietest option of your exhaust? I'm curious what to order in case my little fix doesn't work out for me.

MaDMaXX

I'd hazard a guess that the twin cats might edge out the twin mufflers, maybe It depends on how "strong" the mufflers are.

Motordyne

There are the midpipe resonators and there are resonated midpipe HFC's.

Either will be quieter than the straight midpipes.

harp00n

OK, the good news!

My muffler shop modified the ART pipes to fit OEM metal ring gaskets between the pipes and OEM collectors - the rasp has gone (of course) and they say it won't leak anymore (because of the OEM rings)!

I also removed those brackets I had shown on the pic and it seems like it helped to reduce the drone inside of the cabin. The volume of the exhaust is the same but a little bit smoother and it seems like I have less vibrations now! Though I'm not sure if it's connected with these brackets, maybe it's just because I fixed the leak between the ART pipes and collectors (though it had to affect only rasp, but who knows)... Anyway I don't see why I should connect those brackets back, as the ART pipes are lighter than stock HFCs and my Borla is also lighter than the stock exhaust, so I hope it won't crack anywhere

Anyway, now I'm almost happy with my exhaust, maybe will add some dynamat materials to the trunk and that's all!

AlphaSnacks

If you don't have flex sections right past the ART Pipes on your Borla, you'll be fine. I ran my ART Pipes with my Borla on the 350Z for years and didn't have a single problem. And I had my fun with that car too.

harp00n

Has anybody tried ART pipes on the stock exhaust?

I plan to change my car to G37x '09 sedan and it has stock exhaust, so I wonder how would it sound with the ART pipes (I believe stock exhaust is almost the same on G37 and 370z)?