What causes exhaust drone ?

Exhaust modifications

What causes exhaust drone ?

Postby scottb721 » Wed Oct 23, 2013 12:54 pm

I'm about to have my rear mufflers replaced for some extra sound out of the car.
Couple of quotes I've received are-
1. a pair of Hitech stainless steel dual tip mufflers $980
2. Cat back X-Force SS $850 or mild steel $475 (single tips I presume but I'd prefer duals. I'm not keen either on what some have said are 4" tips on their x-force)

I've read several times of x-force owners mention drone on the highway.
Would this be the result of the centre muffler being changed as part of the cat-back package ?

On my last Lib, an 03 2.5, I had just the rear muffler changed to a 'sports' one and it was great.

Would leaving the centre muffler stock reduce the likelihood of droning noise on the highway ?
I'd like to do this right the first time.

Thank you.
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Re: What causes exhaust drone ?

Postby SIMBAT » Wed Oct 23, 2013 3:05 pm

The stock centre muffler cuts out most of the droning if you just replace mufflers to sports mufflers you wont have drone issues, but as soon as you take out or change the centre muffler it will drone so much on acceleration and deceleration, you be praying for flat roads and flowing traffic all the time.

my opinion for you is for you to get some nice universal twin tip sports mufflers, (x force ones are great) get them made up to connect to the existing muffler flanges and you will have a great note and noticeable volume from out side the car and in the car i think you'll find there will be a perfect increase in exhaust note which will compliment the engine noises.

If you want it a little bit more aggressive than that i suggest getting your exhaust shop to put a flange join immediately after the centre muffler (i cant remember if there is one already) and he might as well put one on your stock set up so you can bolt it back on whenever you want. then from that flange go 3.5" to the Y pipes, then into 2" up to the flange for your sports mufflers. this will increase flow and give the exhaust a more aggressive/throatier tone without making it noticeably dronier. You can go mild steel or stainless depending on your budget and it would be probably cheaper than a cat back system.

For me i wanted it loud and unrestricted because i do occasional track days so I have just deleted my mufflers and had straight pipes made up with a flange so i can bolt on or off my mufflers whenever i want, it drones a fair bit but not intolerable.
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Re: What causes exhaust drone ?

Postby Smithy » Wed Oct 23, 2013 3:40 pm

Would highly suggest and recommend xforce Y pipe into TCP Auto Quad tip mufflers.

I get a little drone under load at lowish RPM, besides that she's all gravy! 8) Unfortunately 'drone' is all up to the owner though. I've got some friends cars who I think drone horribly but they don't seem to care/notice.

http://www.youtube.com/watch?v=t49GO9f6jB8
http://www.youtube.com/watch?v=VEvMdThhx70

Those video's are when the pipes were freshly installed and new (0-2 days old), it's slightly louder now.

Sorry for not answering your question properly however, I just came to preach the good word of the TCP :P
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Re: What causes exhaust drone ?

Postby Kekotic » Wed Oct 23, 2013 5:48 pm

Smithy wrote:Would highly suggest and recommend xforce Y pipe into TCP Auto Quad tip mufflers.

A few people (albeit with TCP TBE systems) ended up selling them because the drone was unbearable. They all had one thing in common, they had auto transmissions. I wouldn't recommend TCP/xforce to someone if their main concern is drone.

Scott the Hitechs sound great on their own on a 3.0, although for $1000 it's pretty steep. Second hand would be ideal if you can wait around for a while.
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What causes exhaust drone ?

Postby ndlibgt » Wed Oct 23, 2013 7:37 pm

My setup consisted of Tcp muffs, had a mid pipe 3" into 2.5" custom made by Barney from Hallam performance and phat dump on my auto with zero drone. Key is the muffler in the mid pipe IMO.
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Re: What causes exhaust drone ?

Postby scottb721 » Wed Oct 23, 2013 9:35 pm

I might go and talk to a couple of the x-force installers tomorrow as I'll be near enough to make the trip worthwhile. They might even suggest other brands.

I'm really not interested in having it done all the way up to the cat and and after reading the input here I will definitely leave the centre one stock.
I'd love the Hi-techs and money isn't really an issue however if I can save some I may as well plus it's a 3hr drive to Hi-tech.

Thanks
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Re: What causes exhaust drone ?

Postby chanham » Wed Oct 23, 2013 11:23 pm

Smithy wrote: Unfortunately 'drone' is all up to the owner though. I've got some friends cars who I think drone horribly but they don't seem to care/notice.


this.

I think it's dependant on the owner. What sounds shit to some may sound fine to others.

I'm running ultrex quads and a xforce y + center pipe all in stainless on my 3.0. When at speed, its a very SLIGHT 'hummm' drone, but its absolutely bearable. You only realy notice when you pay attention to it. When putting more load on the pedal to get up to speed, its a tad more droney, but it doesn't bother me too much!
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Re: What causes exhaust drone ?

Postby chanham » Wed Oct 23, 2013 11:27 pm

But in my opinion its totally worth doing to really hear the h6 sing!
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Re: What causes exhaust drone ?

Postby alexeiwoody » Thu Oct 24, 2013 7:27 am

Drone is when at certain rpm, usually 2000-3000, the exhaust is louder inside the car than it is outside. If it's not annoying the hell out of you, then it's not drone. You won't get it by just changing mufflers.

If you decide to do the whole catback - drone is caused by not having a middle muffler. Aftermarket systems usually only have a 'resonator' in the centre pipe, which doesn't do squat. Put a straight through muffler in there and no drone even with a full 3" TCP tbe. Tcp quads sound good, look the same but cost a lot less than hi techs. No need to waste money or driving :) Goodluck
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Re: What causes exhaust drone ?

Postby scottb721 » Thu Oct 24, 2013 12:34 pm

Went to a couple of joints in Newy. $500 for a pair of X-force rears in stainless plus $150 for different tips. They're 1-2 Y tips look too long though, and wide probably.
Another tip option I'd be happy with are the double tapered ovals. These follow the bumper curved both horizontally and vertically.

If the TCPs are a simple bolt-on job I'll see how much they are shipped. I've had mine off before.
Are the TCP genuine duals or just Y tips ?

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Re: What causes exhaust drone ?

Postby alexeiwoody » Thu Oct 24, 2013 12:59 pm

scottb721 wrote:Went to a couple of joints in Newy. $500 for a pair of X-force rears in stainless plus $150 for different tips. They're 1-2 Y tips look too long though, and wide probably.
Another tip option I'd be happy with are the double tapered ovals. These follow the bumper curved both horizontally and vertically.

If the TCPs are a simple bolt-on job I'll see how much they are shipped. I've had mine off before.
Are the TCP genuine duals or just Y tips ?

Cheers all


The tcp are proper quad tips and look nice like a factory exhaust should, performance but stylish. Same as hi techs. The x force are probably the more obnoxious ones out there, although you can't fault their performance exhaust systems.

The tcp and the hi techs and the phat quads are all made for the lib so they'll bolt on nicely onto stock pipes. The trick with any brand quads is to try and get the quad tips to align properly, so it looks like sex and not like an aftermarket botch job.
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Re: What causes exhaust drone ?

Postby scottb721 » Thu Oct 24, 2013 1:31 pm

alexeiwoody wrote:
scottb721 wrote: The trick with any brand quads is to try and get the quad tips to align properly.


Is this problem negated by going to something like the TCPs that bolt straight in ?
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Re: What causes exhaust drone ?

Postby shav » Thu Oct 24, 2013 3:23 pm

Is the centre pipe in a stock exhaust system restrictive? If you were to replace just the mid and Y piece with a 3" mild steel system and 'better' flowing centre pipe, and kept the stock mufflers, would there be drone as well as a performance increase once tuned?
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Re: What causes exhaust drone ?

Postby alexeiwoody » Thu Oct 24, 2013 9:59 pm

The stock mufflers are massive compared to most aftermarket brands, shouldn't have any drone.

Regarding alignment, might be good with any of the top brands, just something to be aware of if you're DIY. The reason I brought it up is quad tips make even slight crookedness apparent.

You better post some pics up so we can all scrutinise and if it's bad - laugh? :D Nah, just kidding the mufflers will bolt on fine, I bought crooked muffs once and it was nearly impossible to tell.
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Re: What causes exhaust drone ?

Postby scottb721 » Thu Oct 24, 2013 10:04 pm

Just waiting on a shipping quote from TCP then will choose. Probably be about a $280 difference between them and the hi-techs.
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