The Z isn't my first car with exhaust, and it won't be the last. I don't usually mind cabin drone, but holy hell it's really bad in this car. I'm trying to figure out what would be the best setup to eliminate some of it, but I'm not unrealistic and expecting it to all be gone by changing out some parts. I just want to be able to take a trip on the highway for an hour and not feel like my head is gonna explode.

Current setup: Agency Power Single and Stillen Y Pipe

I'm looking into either the Motordyne XYZ with resonator and keeping my stock cats, or ART pipes and Motordyne XYZ with hi flow cat. Emissions is a concern and I'm not 100% sure if I'd pass with the HFC. I was hoping for some suggestions.

 

i did a search for 'agency power drone' and got a full page of results.. there has to be some suggestion in there somewhere. Good luck.

the art pipes would have been a decent option if you didnt need the cats for emissions.

I think the most popular option to get rid of the single exhaust. My motordyne single is ridiculous without the helmholtz axle-back section. Adding an in-line resonator won't help you much.

 

Appreciate it. I geared this more towards product suggestions and experiences with parts I'm already considering.

 

I would look into a different exhaust

 

Yeah, it just sucks because it's only been on the car for 2 months. I love everything about it except for the drone.

 

Would dynamat sound proofing help?

 

Possibly...but it's kinda heavy and doesn't "solve" the issue per se.

 

unless you hack it up and add resonators, theres nothing you can do.

might as well sell before you kill the resale value

 

Definitely look into resonators

I wish Motordyne sold those resonators as stand alone units. I found the formula for making them and made an Excel spreadsheet to calculate the length and volume needed for any frequency but that is an expensive experiment

One thing you can do in the short term is throw on a 3" turbo muffler. Summit Racing has some for like $30. They won't flow like an open can but they won't drone either.

 

You can lower the exhaust noise by adding sound proofing in the trunk/spare tire
area.There are many threads on this.One that does work but really sounds strange is
cramming all areas around the spare with old towels,clothes--pack it in after you line the floor&sides with sound proofing.In addition,a design flaw with the Z is that the rear wheel wells are IN the cabin.A heavy coating of spray undercoating in the rear wheel
wells is also important.
Drone however involves harmonics that like bass in a sound system,tend to travel
within the car.I'd change exhaust systems.I had a Borla system in another car
that had the same drone problem at steady hwy speeds.I solved the problem by welding
resonated tips to the pipes.Most single systems I've heard are pretty loud and have
drone.

 

If anything, I'd try the Motordyne XYZ w/resonator. That's what I run. It's paired to momentum headers, z1 test pipes, and a tomei ti single. It's stupid loud, but surprisingly it doesn't drone on trips. Maybe I'm just used to it, but it doesn't bother me. I've taken it on 7+ hour trips without an issue.

 

Really? I'd go deaf if I took a 7 hour trip straight and that's w/ stock headers/cats. How about when other people get in the car? Any remarks?

I'd really rather not get rid of the single as I like the sound and look...so if the XYZ with resonator would actually help then I'll get one.

 

When I had drone with my Greddy RS, I tried using dynamat all around the trunk area, but it did little to help. Then I went to Lowes and got some insulation foam or whatever and stuffed the trunk area around the spare tire, didn't really do anything to help. I ended up getting a Motordyne TDX2, great decision since there is absolutely no drone.

If you're not willing to get rid of the single exhaust, I'd take a look at getting the XYZ with the resonator, or getting a resonator welded into your single exhaust. Motordyne does sell the attachment as a standalone, $154 per according to their website. However, from my understanding it's hard to really know how a resonator will help your drone since it depends on the RPM that your drone is present, along with the length of the resonator and a whole bunch of stuff I really don't know much about. Assuming that the XYZ + Resonator will help tone it down though.

I would suggest looking into getting another exhaust. If you do end up getting the XYZ + resonator and you still have a good amount of drone, then you'll have no choice but to grab another exhaust. Better be safe than sorry and have to pay more later!

 

Well, my girlfriend slept in the passenger seat on the way up to Z Nationals last hear (about a 5.5 hr trip). I may not be explaining it properly, but I think my cruising volume actually dropped once I installed headers. Now, under WOT it's definitely louder...but I believe the headers "smoothed" out my exhaust flow, so under cruising conditions it isn't that bad. Switching to headers, I believe, changed that frequency of my exhaust that causes drone. I've had multiple different setups:

1. Stock
2. Stock + test pipes
3. Test Pipes + AAM Y-pipe + Momentum Dual: Very Loud
4. Test Pipes + Motordyne XYZ w/Resonator + Momentum Dual: Quieter than 3
5. Momentum Headers + Motordyne ART Pipes + Motordyne XYZ w/Resonator + Momentum Dual: Extremely toned down (Great exhaust note)*
6. Momentum Headers + Test Pipes + Motordyne XYZ w/Resonator + Momentum Dual: Very Loud, but quieter under cruising when compared to 4
7. Momentum Headers + Test Pipes + Motordyne XYZ w/Resonator + Tomei Ti Single: Loudest under WOT. Comparable to 6 when cruising.

*This setup actually robbed ~9rwhp from using ART pipes. I did a same day dyno test compared to standard test pipes and made more power. I have a dyno sheet to prove it.

All in all, if I were to pick a setup based ONLY on sound I would run my number 7 setup, but with ART pipes instead of test pipes. However, I'm more concerned with keeping the whp higher hence why I switched back to test pipes. (Also $$. Number 7 + ART pipes would be about $3200 retail)

For your situation, if you really like your single and want to keep it I would try the XYZ w/resonator...if that still doesn't tone it down enough, then shop for some used ART pipes. Those will definitely give you a great exhaust note. Now, there's tons of info out there proving that ART pipes make power on most setups with OEM exhaust manifolds. I believe I was the first to do a same day dyno when paired to the momentum headers. Yet, each car is different. I guess mine just prefers test pipes.

Hope this helps.