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Cobb Turboback exhaust Drone

9.1K views 26 replies 7 participants last post by  Miko79  
#1 ·
Hi All

I originally had the Cobb Turboback exhaust and it was just too droney, ok at idle and nice sound at Wot but just daily commuting was too much, so went to exhaust shop with my stock muffler and res delete cat back and the guy just welded a flange on stock muffler and put it back on axle back with the Cobb 3" still in place, it is way too quiet now, spoke with him again and he said he can cut out the Cobb large resonator and put a pipe there res delete and leave the second resonator and stock muffler on, will there be some more sound with the large resanator removed from the Cobb??
Thanks

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#3 ·
Yes - your exhaust will get louder than it currently is if you remove the resonator from your exhaust.
 
#5 ·
Hi

Thanks for the reply much appreciated, ended up cutting the large first 3" resanator off the cobb and putting a 3" pipe in its place and leaving the second one in place and then the stock muffler, sounds better but wish i never wasted money on the Cobb exhaust as it was too boomy/droney especially just crusing around, the biggest problem with the Cobb system is it is basically straight pipe after axke back which caused tge drone/boomy sound, they should of just had one resanator in place instead of 2 and had a muffler at rear would of been heaps better, thanks [emoji106]

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#6 ·
same design as my Greddy so I don't agree with that at all (the Greddy is no loud at all compared to COBB). the difference is the mufflers/res

you could have just cut one res out and replaced with a muffler and been good. Can't imagine out Frankenstein it looks under that car.

Waste to chop up such a nice system, oh well.

The COBB system is WAY to loud for me as well. kids like it LOL
 
#7 ·
Hi

Thanks, i know it wasnt the best idea to hack the cobb exhaust but kept the 3" for possibly big turbo later, or i might even put the cobb axle back on again and then put a vibrant ultra quiet resonator where the cobb resanator was removed, but ideally the cobb turboback system needs a muffler after axle back to avoid the drone or possibly add a catless down pipe for a bit of extra sound and performance later for the moment it sounds ok especially with pops crackles, when i bought the car only really drove it for a about 2 weeks before doing exhaust but actually enjoying the quieter ride after having the full cobb exhaust was just getting into my head and not good for my 5yr old son, and also for my older aged ears [emoji106]

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#8 ·
Hi

Am thinking of putting the cobb axle back exhaust pipe back on as its a liitle quiet with the stock muffler, as the first Cobb resanator has been taken off, will adding a Vibrant ultra quiet resanator tone down the drone? Or would it be better to put the original cobb resanator and also add the vibrant resenator on as well?

Thanks

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#9 ·
Hi All

Went back to exhaust shop today and had the Cobb first resanator welded back on followed by a Vibrant 3" Ultra quiet resanator just after it and the cobb axle back exhaust pipe/tips, its still loud, the drone is still there, has a different exhaust note but still has the boomy sound when going down in gears around 2500-3000rpm and also under WOT is quiter at idle,

what to do? Has anyone had success with some sort of sound deadining in boot area? At this point thinking of getting a couple of old blankets and putting them under spare wheel?? Please any help would be appreciated especially someone who has the Cobb turboback exhaust fitted to there Focus ST thanks

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#13 ·
Hi All

Went back to exhaust shop today and had the Cobb first resanator welded back on followed by a Vibrant 3" Ultra quiet resanator just after it and the cobb axle back exhaust pipe/tips, its still loud, the drone is still there, has a different exhaust note but still has the boomy sound when going down in gears around 2500-3000rpm and also under WOT is quiter at idle,

what to do? Has anyone had success with some sort of sound deadining in boot area? At this point thinking of getting a couple of old blankets and putting them under spare wheel?? Please any help would be appreciated especially someone who has the Cobb turboback exhaust fitted to there Focus ST thanks

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Sorry, forgot to quote. This should have been with my message above.
 
#10 ·
I'm running a downpipe and resonator delete with stock muffler and tailpipe. That's plenty loud enough for me... I would suggest putting the stock muffler back in, as someone else mentioned.

Other than that, I can't think of what else you could try... How big/wide is the piping on that COBB system vs the stock pipes?

I do have slight drone, but only under acceleration/on the freeway. Nothing during normal driving conditions.
 
#11 ·
If I am correct, the system you are running has no muffler? Straight piped? That'll cause drone no matter what you do to it. Look at getting the stock muffler back in there.
 
#12 ·
Without a muffler, these will hardly make any difference in terms of stopping the drone/quietening the car down.
 
#14 ·
Hi

Thanks for that, yeh i know i originally took the Cobb axle back pipe/tips off and then put back on original muffler, then was too quiet so took of the first resanator of the Cobb catback which made it a little louder, the stock muffler is so good and being quiet so thought i would go back to exhaust shop and what i had done was take off stock muffler and put back on cobb axle back pipe/tips welded both cobb resanator and a Vibrant ultra quiet resanator as well thinking it would help but its still quite loud to be honest just can get in your ears, its all 3" all the way through with Cobb catted downpipe, Cobb exhaust is really good quality but they should of added a muffler towards the rear instead of just 2 resanators, because from axke back its just straight piped, ime hoping some dynamat or other sound deadining material would help under spare wheel and around boot area, hopefully someone can comment if they have gone down the route of doing the sound deadining thing to reduce the drone/frequency of the Cobb exhaust

Thanks [emoji3][emoji106]

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#16 ·
Well, your problem has helped me solve mine... Couldn't decide whether to remove my muffler or not, but decided about 2 weeks ago to leave it as is.

For what it's worth, at least you've helped a fellow Focus driver know that he made the right decision.
 
#17 ·
Hey Bu$ka mate

No problem thats what the forum is for hey [emoji3][emoji106] yeh wouldnt recommend doing muffler delete as well as resanator delete will drone for sure, thats the biggest problem with the Cobb system first its the placement of the resanators and secondly not having anything in line after the axle back part its just a straight pipe and thats where the loudness/drone/frequency is coming from i will leave it for now see if it settles down with the new Vibrant ultra quiet resanator in place as its only been 1 day, dont get me wrong sounds mean as has a different exhaust note with the Vibrant but still has that ****ty drone boomy sound[emoji344][emoji350]



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#18 ·
Yeah, noise is great when you want it, but not constantly or while travelling for hours. Good luck, keep us posted.
 
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#19 ·
Mike- just trying to think practically- the Cobb exhaust is a desirable / premium product (in my estimation, anyway). The drone will be acceptable to the right buyer, and there may be other benefits to the Cobb over other products, but it seems the Cobb exhaust is the wrong product for you.

Have you considered putting the Cobb exhaust back to stock and removing it from the car, selling it as a complete Cobb exhaust, (and getting most of your money back) and purchasing something a bit more mild? I recently installed a Borla Cat Back (PN 140504), and all of the reviews state that there is no drone, and I can confirm that that is true. It's definitely louder than stock at cruising speeds, but not by much, and it's WAY louder than stock when you put your foot down, but it's the best of both worlds, in my opinion. I know it seems like a bunch of bent pipes, but there is substantial engineering that goes into stuff like this, and I bet you get a better overall outcome by purchasing a system that was designed to work with your car and provide the experience that you are looking for.

Just my 2 cents, as someone who also just installed an exhaust.
 
#20 ·
Mzadrati makes a great suggestion, in my opinion... For a daily driver/some performance bonus, stock exhaust with downpipe and resonator delete is enough.

But that's for me... Now... When I was 18, that COBB pipe would probably have been exactly what I was after.
 
#23 ·
Mzadrati makes a great suggestion, in my opinion... For a daily driver/some performance bonus, stock exhaust with downpipe and resonator delete is enough.

But that's for me... Now... When I was 18, that COBB pipe would probably have been exactly what I was after.
So true when you younger your ears can handle it

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#22 ·
Hi Mzdrati

Thanks man, will leave it on for now but that would most likely be my next option is to take the whole cobb exhaust off and sell it put factory exhuast which has resanator delete and factory muffler and then look around for another one [emoji106][emoji3]

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#24 ·
Miko, I had exactly this problem as my car had a cobb CAI and catback installed from the dealer. I couldn't handle the drone as a daily driver and ended up installing an AWE Touring Non-res system instead. I installed Hushmat in the rear area initially and it helped a bit ( dropped it about 8 dB), but swapping the exhaust made the difference for me. I'm pondering installing the Cobb resonator section to the AWE to take it down just a little more if I can't sell it. Old ears...
 
#25 ·
Hey mate,

Yeh its that drone that gets to your ears, i switched map today to Stratified progressive crackles far out like a shotgun, i think the Vibrant ultra quiet resanator made it louder but different exhaust note, i might try put some sound deadener under spare wheel and then some sort of sound mad under on top of spare wheel to see if it helps but if it doesnt may just take the whole cobb catback exhaust off the car and put on the stock one which already has resanator delete done on it will see, the Cobb really needed to have sort of rear muffler in place, thats where all the drone is coming from, the resanators work uo until axle back then just straight pipe = Drone [emoji106]

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#26 · (Edited)
#27 ·
Hi all

Follow up the exhaust has quietened down a bit with the Vibrant ultra quiet resanator in place, its a bit more tolerable now, still a bit of drone but no where near as before, sounds crazy with the pops and bangs, still kept my stock exhaust system in garage in case my ears get old can put it back on at somepoint, but for anyone looking to get a 3" exhaust system cat back and with downpipe would highly recommend a system which has proper resanators in place as well as a muffler at rear, without a muffler its pretty much straight piped [emoji106]

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