Ford Mustang Forum banner

2014 Mustang GT Drone Issues. Please help!

10K views 31 replies 15 participants last post by  5.0 Candy REDCS 
#1 ·
I had the Borla s-type Catback with X-pipe installed and I have been getting this annoying drone/resonance/vibration at 2100-2200 RPM. It is only ever at this RPM.

It must have been the honeymoon effect because I only started noticing it about 500 miles after install.

The intensity of the drone/resonance depends on how much load the engine is under (partial or full throttle etc). It just seems so odd that it is only at this particular RPM, and that it is always present.

Another odd note:::
On cold starts when I drive away shortly after starting the engine and not allowing it to warm up completely, there is no drone/resonance at all?? Not sure I understand that.

But as soon as it warms up the drone is present.

Is there any way to fix this? Could it be something other than the exhaust?

I had the muffler shop that installed it check the underside of the car for loose parts or anything that could cause a vibration/drone and they found nothing.

Insight would be greatly appreciated.
 
See less See more
#2 ·
Exhaust drone & exhaust noise while both are different by definition, both are created as a result of impactors/promoters. Exhaust drone is that which is caused by harmonics- a sound wave generated which in essence takes the exhaust sound and sends it back up the exhaust system (towards the engine) and is released or transferred into the passenger compartment. This transfer typically happens where large contact areas exist that have little to no sound dampening qualities and/or materials- as a result of the muffler construction or vehicle manufacturer.

Exhaust Noise (in passenger compartment) is what most people actually complain about. While harmonics do play a contributive role, it is not the primary cause.

Impactors/Promoters

I would love to tell everyone that “x” is the cause 99% of the time for exhaust noise complaints, but it is typically a series or combination of numerous factors which leads or develops the level of noise which is uncomfortable to the ear. The first “rule” of an exhaust system is that the noise should be generated at the point of discharge (i.e. tailpipe tip). Obviously, if the tip terminates at your door or immediately under the passenger compartment, the sound level will be much greater at the exhaust discharge point than if the tip exits the rear of the vehicle, but this is common sense.

Assuming that there are no exhaust system leaks and isolators are correctly installed at all mounting points, what is not acceptable by industry standards, is when an exhaust system has been installed correctly, exiting well past the passenger compartment to have substantial exhaust sound transfer into the passenger compartment at a level which does not allow a person to talk without raising their voice to well above ambient noise levels. Whether you love to hear your engine roar (which I do), stereo blast or have a conversation, this interferes with your ability to enjoy what you like.

Now for the Causes

The first problem is most muffler shop staff today have little to no knowledge of exhaust systems, the “tricks” to installing a system that will “please” the customer, and simply verbally repeat the marketing materials provided to them by the system manufacturer. As previously noted by several others, there are 3 basic muffler designs, Absorption, Diffusion, and Chamber (Resonator), no matter which one suits your ear best, the criteria for promoting unnecessary in-cabin noise is the same.

Impactors:

Exhaust system material thickness should be no less than 16 gauge- double-walled pipe was commonly available through the 1970’s until manufacturers began seeking ways to reduce costs. Many of the “Muffler Chains” who marketed lifetime warranties always used double-walled pipe before “stainless steel” became the “in-crowd”. If a shop had it available, I would choose double-walled aluminized coated steel or 14 gauge stainless steel (depending on environmental conditions or personal tastes) - it is very quiet, solid and in terms of costs, pipe is pretty cheap, depending on length, 16 gauge aluminum coated runs about $11 to $20 wholesale (depending on diameter), stainless about double for the same gauge.

The muffler should be located as close to the axle (far away from the passenger compartment) as possible, allowing at least 3” of straight run pipe before a bend occurring (if installed to the forward position of the axle), with the overall length as long as possible.

Duel Tailpipes should be limited to no greater than 2.25” inside diameter- tips which are larger can certainly be installed but should be limited to 12” in length and have a discharge point past any material that may “catch” a sound wave or exhaust. When you exceed these diameters, it now becomes a contributor.

Tailpipe length in general should be as short as possible, minimal bends, etc, terminating past the axle, 1.5" past the body or bumper. Lengths greater than 4 feet promote “drone” (i.e. harmonics).

Pipe diameter reduction should occur before the muffler. While many muffler installers like to use mufflers which reduce pipe diameter or split the exhaust at the point of discharge at the muffler, or install reducers to connect the tailpipes after the muffler induces “noise”.

Ultimately, it is the quality of the material and the installer which 90% of the time leads to a successful installation. I would like to also emphasize that it is not necessary to spend a fortune on a muffler ($100+) or system to have an excellent sounding, performing and long lasting result.
 
#3 ·
Did you delete your resonators?
 
#4 ·
I think all of what you said seems like good info Beechkid, but might not completely apply in my case. Could be wrong as I don't know a whole lot about this sort of thing.

It's not a custom system, and I don't plan on cutting/welding anything new into it if I don't have to. It's just the S-type cat-back with X-pipe from Borla....a system that isn't suppose to drone. So i'm hoping there's some way to lessen/fix it. Or if it could be something related to a defect in the car itself somehow that I should look at.

The muffler shop that did the work specializes in old/new muscle car custom exhaust and fabrication. They swore there were no areas rattling, and they even let me up underneath the car to see. He suggested it could be an issue with the motor or motor mounts??? Seems far fetched to me. What do you guys think?

And no TommyV, I just had the Cat-back with x-pipe installed. So I assume I would still have my resonators? I didn't instruct the technician to delete them.
 
#12 ·
I am assuming this is what you had installed. Borla Stinger Catback Mustang Exhaust 140370 (11-12 GT) - Free Shipping

If so, this system replaces the overaxle pipes of the OEM system which had resonators. I know this for a fact because I just installed Borla overaxle pipes to eliminate the resonators. As a result I have found that the sound has increased in volume and it seems to me that the bass of the sound seemed to have gone down resulting in increased Treble. If that makes any sense.

I guess I really don't know what Drone sounds like. I don't think my car has drone now or before but I do hear increased sound. And I am not sure I like the new sound yet. But since we live in the same town maybe we could meet sometime and compare exhaust sounds and figure this out.

I have a decibel meter and plan on using it to take a video and determine the difference/increase of the loudness of my system now compared to before my modification.

What exhaust shop did you go to?
 

Attachments

#5 ·
Well, I would look specifically at the wall thickness of the pipes, insulation & location of the mufflers and one of the most important....the hangers...are there enough (switching from the oem to aftermarket may require additional hangers), are they of the correct type/style and does one have more stress on it than the others especially when torque is applied.
 
#11 ·
According to the manual, aftermarket hangers arent required. So i wouldnt think that would be an issue. I guess it is possible they could have been over-tightened, but a custom exhaust shop should know better.

Ill say this for the hundredth time lol.

I have Corsa Extremes.
Ran them with stock manifolds and resonators
Ran them without resonators and 3 inch mid pipes
Running them with long tubes and no resonators still 3 inch mid pipes

And NEVER any drone, anywhere.

But I didn't say they weren't loud with the long tubes lol
Yes haha i have seen you praising the Corsas. If this keeps up i might have to switch to the Corsa Extremes! I like the Borlas a hell of a lot, but this drone day-in and day-out is getting annoying.

Please feel free to call our customer service department and if there's anything technical they can advise you on etc. Those systems do NOT drone so if there's an issue like the shop suggested or an issue with our part - we will definitely help. We stand behind our million mile warranty and fully support our fans and customers. Thank you for your detailed posts and inquiries as well.
That sounds good...i think i will have to give you guys a call. Is there anyone i should ask for specifically?

The main reason i went with Borla was for the no-drone, in addition to their fantastic reputation for build quality. So hopefully i can get this resolved. I want to keep it!

Hi guys, again, this is the first report of our system having this kind of issue so i urge you all to call in if this is happening - thank you to beechkid for the explanation and everyone else chiming in that their system doesn't drone. let us know what can be done, our customer service department is here to help.
I/we really appreciate you posting. It shows that you guys stand behind your product. Please let us know if there is a certain specialist we might ask for when calling, or if we should reference your posts here on the forum. Thanks again!
 
#7 ·
Ill say this for the hundredth time lol.

I have Corsa Extremes.
Ran them with stock manifolds and resonators
Ran them without resonators and 3 inch mid pipes
Running them with long tubes and no resonators still 3 inch mid pipes

And NEVER any drone, anywhere.

But I didn't say they weren't loud with the long tubes lol
 
#8 ·
Please feel free to call our customer service department and if there's anything technical they can advise you on etc. Those systems do NOT drone so if there's an issue like the shop suggested or an issue with our part - we will definitely help. We stand behind our million mile warranty and fully support our fans and customers. Thank you for your detailed posts and inquiries as well.
 
#10 ·
Hi guys, again, this is the first report of our system having this kind of issue so i urge you all to call in if this is happening - thank you to beechkid for the explanation and everyone else chiming in that their system doesn't drone. let us know what can be done, our customer service department is here to help.
 
#14 ·
Another odd note:::
On cold starts when I drive away shortly after starting the engine and not allowing it to warm up completely, there is no drone/resonance at all?? Not sure I understand that.

But as soon as it warms up the drone is present.
I would check all clearances around pipes, mufflers, hangers etc. to be sure they are adequate. Especially check the over axle part of the pipes. All this stuff expands and changes as it heats up and if you have something that's close it could be making contact once heated causing the drone.
 
#17 ·
That is a really good point. I'm going to have to do that. It would explain why the drone isn't there when the pipes are cold, but when they warm up it is present. Great insight!

Slightly different application and combination of parts, but I experienced the exact same drone you are describing.

I had the Ford Racing Sport Mufflers which are supposedly very similar to the S-Types (they are both made by Borla) on my Boss with the factory (resonated) over axle pipes and they definitely had an annoying drone on the highway in the lower 2000 RPM range.

One of the main reasons I bought them was because they are advertised as being "Designed to eliminate exhaust drone at sustained RPMs".

I am currently running GT500 over axle pipes (no resonators) with GT500 mufflers and am now drone free.
I think this or Corsa Xtremes may be my end game if I can't get it solved. Thanks for the help! I love the sound of GT500 mufflers on the 5.0. I think what SteveGT said might be true...could be the clearances. Guess we will see.

If I was in this situation I would remove the Borla mufflers and put the stock ones back on and see if the problem goes away. If it doesn't , I would do the same thing with the x pipe. Just work one section at a time, go slow and sooner or later you'll find the issue. Good luck.
Very true. It has to be one of the pieces. I think doing what you said would pretty much have to yield results. Thanks for the input.

It looks like PMDmustang and I are going to meet up this weekend and see what we find. Then on Monday i'm going to call Borla tech and see what they have to say and go from there.

Everyone on this thread has been incredibly helpful. I want to thank everyone for the advice so far! When I figure out the problem I will be sure to post back on here with an update.
 
#15 ·
Slightly different application and combination of parts, but I experienced the exact same drone you are describing.

I had the Ford Racing Sport Mufflers which are supposedly very similar to the S-Types (they are both made by Borla) on my Boss with the factory (resonated) over axle pipes and they definitely had an annoying drone on the highway in the lower 2000 RPM range.

One of the main reasons I bought them was because they are advertised as being "Designed to eliminate exhaust drone at sustained RPMs".

I am currently running GT500 over axle pipes (no resonators) with GT500 mufflers and am now drone free.
 
G
#16 ·
If I was in this situation I would remove the Borla mufflers and put the stock ones back on and see if the problem goes away. If it doesn't , I would do the same thing with the x pipe. Just work one section at a time, go slow and sooner or later you'll find the issue. Good luck.
 
#20 ·
I have the Borla S-Type Axle back's on my 14 GT and I get a very noticeable drone at right around 2k RPM. I notice it more when in higher gears (5th and 6th) and if i give it gas its annoying. I don't know if the exhaust drowns out the drone in lower gears or what the deal is. But borla is not drone free at all RPM's/Thottle level's.
 
#21 ·
UPDATE:::

I just got off the phone with Borla a little bit ago. I talked to Chris Baas and he said that the 5.0 has issues with water collection in the muffler chamber. It is only on the 5.0 mustang because of the unique design of the mufflers, he said. The water causes a drone/resonance. He says that there have been many owners who have fixed their drone issue by drilling small drain holes in their mufflers to let the water out.

Some batches of the S-type had drain holes from the factory, and some did not. They did not notice the issue immediately, which is why this is the case. So he told me to check my mufflers and see if there are drain holes, and if there are not, he will send me specs for drilling them. The holes only go into the outer chamber and will not effect the sound of the muffler (he says). Before he troubleshoots with me further, he wants me to do this.

So thats the scoop. I'm at work so I haven't checked to see if there are drain holes or not. I will update everyone once I find out.

Thanks everyone! rwavey.gif
 
#22 ·
I guess hopefully you don't have the drain holes or the drain holes are plugged. And that you get the condensation water to come out of the mufflers and the drone goes away. Sounds like an easy fix if that is what is causing the drone. Wear some goggles when you drill from below.
 
#24 ·
Thanks for the tip, I'll remember that.

I knew about the water condensation part before buying the mufflers but did not know they were associated with drone. When I first installed them I broke 2 drill bits (Borla reccomends a very small size bit for these holes) and they were not the highest quality bits either but still I got frustrated and just threw them on. 6k miles later they still ring like a bell when I knock on them. And I do not think its coyote only issue. My neighbor has catback Borla S-type for his 3.7L 2013 V6. His had about a half gallon of water in them in a month and had to drill them right away for risk of interior damage. They did not ring like a bell when you knocked them with your knuckles lol. In any event I do not think there is any residual water in my mufflers causing drone but other then the hollow sound they make when you knock them I have no way to prove it. I will buy some higher quality bits and drill the holes soon and report back.
That sounds like a good plan! Let us know if it helps at all and if any water comes out.

UPDATE:::::

Checked my mufflers. No drain holes. Need to find some time to call Borla (they close at 4!) and get the specs for drilling the holes. Will update once they have been drilled to let everyone know if it made a difference.
 
#23 ·
I knew about the water condensation part before buying the mufflers but did not know they were associated with drone. When I first installed them I broke 2 drill bits (Borla reccomends a very small size bit for these holes) and they were not the highest quality bits either but still I got frustrated and just threw them on. 6k miles later they still ring like a bell when I knock on them. And I do not think its coyote only issue. My neighbor has catback Borla S-type for his 3.7L 2013 V6. His had about a half gallon of water in them in a month and had to drill them right away for risk of interior damage. They did not ring like a bell when you knocked them with your knuckles lol. In any event I do not think there is any residual water in my mufflers causing drone but other then the hollow sound they make when you knock them I have no way to prove it. I will buy some higher quality bits and drill the holes soon and report back.
 
#25 ·
#26 ·
UPDATE ::::::::

So I just got off the phone with Steve Williams at Borla. He sent me the PDF specs for drilling the holes (Thanks also to PMDmustang for posting them up here on the forum). And he also gave me a next step to do after I drill the holes.

Steve wants me to talk to my Ford dealer and ask them about any TSB's (Technical Service Bulletins) and current ECU re-flash for my car. He said that sometimes a car can roll off the assembly line with a slightly different tune than the rest. Where the timing might be off half a millisecond or something to that effect. In these cases, all that is required is a re-flash from the dealer to the updated spec.

He asked me what gas mileage I am getting (17 city and 27 highway) and he said that my higher than average gas mileage is some evidence that my ECU could possibly use a re-flash.

We talked for about 15 minutes, so that's all the info in a nut-shell from what I remember.

If Ford gives me the run-around (likely), and drilling the holes doesn't fix anything, then a BAMA tuner may be the only fix left.

I will update with any new developments!
 
#27 ·
Our systems for the 2011+ Mustangs don't drone. If you are experiencing drone there's something wrong and we need to make it right for you.

Please contact me directly if you are having drone issue with a Borla setup on a 2011+ Mustang. My email address is davidb@borla.com and my phone number is 805.246.6067.

I cannot stress enough that we have tuned the drone out of our systems for 2011+ Mustangs. They should not drone in any gear, at any RPM, under load etc. If for some reason you have drone issues it's important you let me know so we can make it right for you.
 
#28 ·
Our systems for the 2011+ Mustangs don't drone. If you are experiencing drone there's something wrong and we need to make it right for you.

Please contact me directly if you are having drone issue with a Borla setup on a 2011+ Mustang. My email address is davidb@borla.com and my phone number is 805.246.6067.

I cannot stress enough that we have tuned the drone out of our systems for 2011+ Mustangs. They should not drone in any gear, at any RPM, under load etc. If for some reason you have drone issues it's important you let me know so we can make it right for you.
David,

Thank you for standing behind your product, that is really important to all of us in the Mustang community.

I firmly believe what you are saying is true; the exhaust isn't suppose to drone. So I'm sure we will figure out why it is doing so.

I will contact you directly on Monday so that we can works towards a solution.
 
#29 ·
UPDATE:::::

I had the holes drilled in the mufflers. About 2 cups of water came out of one muffler, and none came out of the other. This didn't fix or change the drone in any way unfortunately.

I was inspecting my exhaust, and noticed that inside one of the mufflers the steel had split!

Looking inside the tip about 5 inches in, just before the honeycomb pattern starts inside the muffler, the steel was split and there was a gaping opening about 1/2" wide and about 3 inches long. So this may be my drone issue.

At any rate, I called the website I purchased the exhaust off of, and they are sending me a complete new system free of charge.

After I install the new system I will report back with an update.
 
#30 ·
i have done a lot on research also on drone and some are saying that different cars would react differently on parts specially the muffler. i installed a muffler delete on my 2014 GT while at 2000miles on the odometer. drone was like a tuning fork at 1900 - 2100 rpm at 6 speed. installed a K&N blackhawk CAI at 2500miles and I'm at 7600miles now and drone level has go down significantly like 75%. the car now is drivable a long drives. maybe after 5000miles the honeymoon stage is over and the engine part has adjusted to the car already. just a thought
 
#32 ·
Water collection inside my Borla S axle backs became evident because their sound had changed somewhat.... still sounded deep and the resonance was there, it just suddenly became muffled somewhat. I had poised the question in the forum and someone pointed me to check for drain holes.......there were none, through Borla's site I downloaded the pdf, drilled the holes... and was seriously blown away by the amount of water that came out; from both mufflers! I filled 2 med sized coffee cups, one from each!
No sooner the water emptied out, there was a sudden improvement in the overall sound, just like when they were freshly installed. since then, never had an issue at all.
I'm hoping Borla, as a matter of manufacture, is now adding the weep holes to all their exhausts. There has to be an escape route for water than gets inside the mufflers!
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top