Ford Focus ST Forum banner
1 - 20 of 26 Posts

·
Registered
Joined
·
89 Posts
Discussion Starter · #1 ·
So couple months back I went and had the muffler delete done. Had some nice blued tips up in its place, love the exhaust overall! But man I just drove to Vegas and I wanted to blow my brains put because the Drone was getting to me.

Main question now is what to do?
Remove the res and replace with 2 aftermarket ones?
Put a cut out in front of those?
Some ideas will be great thank in advance
 

·
Registered
Joined
·
79 Posts
put a different muffler in? I went straight pipe on my tundra, it droned like crazy. took a 6 hour trip to dallas with my mother in law, and she didn't complain once. did a smaller trip with my mom, and she didn't complain, not once. my conclusion.. I'm a little *****. after a few years, the drone toned down a little.
 

·
Registered
Joined
·
9,129 Posts
put a different muffler in? I went straight pipe on my tundra, it droned like crazy. took a 6 hour trip to dallas with my mother in law, and she didn't complain once. did a smaller trip with my mom, and she didn't complain, not once. my conclusion.. I'm a little *****. after a few years, the drone toned down a little.
You're mom is awesome.
 

·
Registered
Joined
·
1,715 Posts
Milltek ftw


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
744 Posts
I'm planning on doing a rather complicated exhaust setup in the near future and to do it, I'll be getting a 3" straight-pipe exhaust done from a muffler shop and welding a MagnaFlow 12867 Muffler and a Vibrant 1142 "Ultra Quiet" Resonator in myself. There shouldn't be any drone after those two and the exhaust should sound great from separate videos I've heard. I'll be going from a CP-E catless downpipe + CP-E 3" catback and the drone is too much with my current setup.

But then again, it's all just theory at this point since I haven't started. :big smile:
 

·
Registered
Joined
·
304 Posts
Here's my advice as an Exhaust NVH Engineer:

Adding two resonators will not help. Resonators attack higher frequency noise (200Hz or so) and drone is typically lower frequency noise. Add a muffler, and not just a small cylindrical muffler. Those aftermarket mufflers are typically piped through with perforations and glass pack/roving. Although they do work to a degree, they will probably not work as well as you want. I suggest adding something larger like the Ford Performance or Mountune mufflers, or an aftermarket muffler company with a larger volume muffler that will fit into the OEM location. Those have chambers to eliminate alot of the drone.

What is your cruising engine speed at which you hear the most drone? If you are cruising at ~70-80mph, you probably will be spinning the engine at 3000rpm. This converts to ~80-120Hz drone noise. You can also add a helmoltz tuner into your system that is tuned to that frequency. that will help, but it will not kill all of your drone and low frequency content. Most exhaust systems will have larger chambers (to meet back pressure targets and NVH requirements) with turn arounds in the piping, chambers with roving and helmoltz tuners.

Dynamat (or similar brands) will help with sound deadening the vehicle so you get a quieter ride, but this material is primarily used for higher frequency noise. If you go this route, I suggest putting it on all the body surfaces and applying two layers, but it will not completely solve your issue.

Hope this helps. Let me know if you have additional questions.

-Geoff
 

·
Registered
Joined
·
1,706 Posts
to be honest, of all the crazy thing you mom has seen you do over the years, having a loud drony car is probably not too much of a surprise to her.

if you want to reduce the drone, you have two options. either change out more exhaust parts until you can quiet it down enough to your liking, or add in a J pipe to cancel out the drone you have now.



I've got an MBRP and am about to either swap out their muffler/resonator or possibly move it up a little bit and add a second muffler in behind it. I think I'm going to start out by swapping out the muffler, and then after I end up getting a new down pipe, Ill probably have to add in a second one at that point to keep it from getting worse again.
 
1 - 20 of 26 Posts
Top