Why is my mountune cat back droning?

[lx93]

So I just installed my mountune cat back, and I am on the stock downpipe and everything else. The car drones quite a bit over 3k rpm after the install. Is this how the mountune cat back is? Or something went wrong with my system?

 

[NJBooST]

I had a lot of resonance with both the Mountune and Cobb exhausts. I greased the exhaust hangers and it went away for me.

 

[CanadianGuy]

So I just installed my mountune cat back, and I am on the stock downpipe and everything else. The car drones quite a bit over 3k rpm after the install. Is this how the mountune cat back is? Or something went wrong with my system?

Make sure it is not touching anything else. I have it and Cobb exhaust hangers. If I WOT the sound is rich and loud, under cruise the sound is no more than a little louder over the stock, I don't consider it drone as it is a lounder exhaust.

I had a lot of resonance with both the Mountune and Cobb exhausts. I greased the exhaust hangers and it went away for me.

Curious stock hangers or Stiffer?

 

[lx93]

I didn't install the gasket between the flexi pipe and the exhaust because the stud on the flexi pipe snapped off and not long enough to grab with the gasket in between. Could it be a leak causing the drone too?

I will check again and lube the hanger as suggested.

 

[frankiefiesta]

Yes an exhaust leak will make your car sound terrible

 

[CanadianGuy]

I didn't install the gasket between the flexi pipe and the exhaust because the stud on the flexi pipe snapped off and not long enough to grab with the gasket in between. Could it be a leak causing the drone too?

I will check again and lube the hanger as suggested.

The exhaust came with 2 bolts for the flexipipe. Just need to press out the stock ones to use them.

 

[Bonesaw]

I know the Mountune is a "deeper" sounding exhaust and it seems those freq's transfer more in the deeper/bass side of things. I just deleted my stock muff for a straight-through type muffler and the tone is SUPER deep. It sounds great but it def resonates/drones under certain conditions... decel being the worst but EASILY controllable. When I drive smooth its almost stock like, but if I drive aggressively its loud. But yeah, check the obvious things like fitment/contact and hangers first.

 

[NJBooST]

I didn't install the gasket between the flexi pipe and the exhaust because the stud on the flexi pipe snapped off and not long enough to grab with the gasket in between. Could it be a leak causing the drone too?

I will check again and lube the hanger as suggested.

Don't bother greasing the hangers. Install a gasket and get your DP to mid pipe sealed correctly. Probably sounds like your running a straight pipe!

 

[lx93]

What tool is used to press the studs out? Do I need to take that off of the car to do that?

 

[hquakers]

What tool is used to press the studs out? Do I need to take that off of the car to do that?

Torch and a BFH (Big F-In Hammer). Heat up the hole, cherry red, and whack it out. Yes, I'd recommend taking it off the car unless you like your FiST roasty-toasty.

 

[Kip2MyLou]

Make sure it is not touching anything else. I have it and Cobb exhaust hangers. If I WOT the sound is rich and loud, under cruise the sound is no more than a little louder over the stock, I don't consider it drone as it is a lounder exhaust.

That's how I would describe it also. Just louder.

 

[jayrod1980]

I have the MAP exhaust installed on mine... I get the boom/loudness as well around 3K RPM. That spot is where the exhaust is the loudest. I used the supplied gasket and some nuts and washers to connect the DP to the exhaust since I stayed with stock DP. How will I know if I have an exhaust leak? I notice I peak now at 23PSI on the AccessPort instead of 21 like before.

 

[CanadianGuy]

Easiest way to find a leak is examine your coupling. If there is any carbon like the exhaust tips you have a leak.

 

[jayrod1980]

Easiest way to find a leak is examine your coupling. If there is any carbon like the exhaust tips you have a leak.

Thanks, how long do you think it would take to produce that buildup of there was a leak?

 

[CanadianGuy]

Thanks, how long do you think it would take to produce that buildup of there was a leak?

How long does it take for your tips to have carbon? Clean them and when they are black your leak would also be.

 

[J2FoRS]

I have the MAP exhaust installed on mine... I get the boom/loudness as well around 3K RPM. That spot is where the exhaust is the loudest. I used the supplied gasket and some nuts and washers to connect the DP to the exhaust since I stayed with stock DP. How will I know if I have an exhaust leak? I notice I peak now at 23PSI on the AccessPort instead of 21 like before.

You must have super sensitive ears or our exhausts may be from different builds or something. I see no drone or boominess at all with mine unless your truly punching it through the gears it's pretty loud in cabin at about 4000 RPM but I think there's a huge difference between loud or boomy/drone. But everyone has their own tastes too.

 

[lx93]

okay so i installed the correct bolt and gasket, but the mountune exhaust still sounds drony around 3000 rpm while not on the throttle. its a really low tone and might not be considered drone by others, but it is a significant cabin noise level increase compare to stock esp. at highway speed. i personally prefer the stock exhaust, it has a very OEM quality to it

 

[bobjob]

i personally prefer the stock exhaust, it has a very OEM quality to it

haha, from the office of redundancy, I got mine ordered for black friday and ordered the cobb hangers. Hopefully its not an issue for me

 

[CanadianGuy]

haha, from the office of redundancy, I got mine ordered for black friday and ordered the cobb hangers. Hopefully its not an issue for me

Same set-up. It is loud but not a resonant drone. One thing is cap off the Sound Symposer. The Symposer works great with the OEM but is off frenquency with an after market CBE. Once I did that the Mountune was nice, deep, rich and burbly. And sounds Angry when you WOT. Sweet love.

 

[jayrod1980]

My MAP exhaust makes very loud booming noise around the same 3K RPM but I think that is a result of the engine and transmission. I'd bet any exhaust will do the same. I've had the symposer capped off for all but a week of ownership and I couldn't believe how loud the exhaust is stock on this car... It's not quiet and you can hear some very boomy sound at the same 3K rpm.