(EDIT) Changed Cobra to Cobalt
- My model of MX-5 is: 2011 NC
- I’m based near: Landgraaf, Then Netherlands
- I’m looking for technical help or recommendations on: Info regarding Cobra exhaust
Hi all,
I am looking for some Cobalt exhaust owners, and see if they had/have the same experience with their Cobalt exhaust.
A couple of weeks ago I installed the Cobalt exhaust from Moss Miata. The looks are exactly what I was looking for, and the sounds is also, as many say, how the MX5 should have sounded from facory.
Since I have installed the exhaust, I wasn’t able to drive the car a lot, so I do not think I have driven more than 80-100 miles or so with the new exhaust. So this could also be the cause for the things I have noticed so far.
What have I noticed.
Not always, and mostly when I am driving up a hill, the exhaust really drones a lot ( both on low and high rpm). Could this be because it hasn’t broken/ driven in yet ?
Another thing I see is that only 1 exhaust pipe ( the left one) gets black from the exhaust fumes ( see photo below), the other one is still “clean”.
Things I have checked :
- When the motor is running, both pipes give sound and have exhaust, so no blockage of any kind.
- Where the exhaust is connected to the mid pipe, there is no leakage
My question is, is this normal ? Do you also have experienced this on your exhaust ? Or could something else be wrong which I can check ?
Thnx in advance for your time and info
Below the photos of the exhaust pipes ( left is more black than the right one )
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Hi Ger, are you sure it is a Cobra back box , I have seen reports of one pipe getting blacker on the colbolt back box from moss , if it is a colbalt from previous posts on here I would say it is normal . But not seen this on cobra back boxes .
Hope this helps and if it is a colbalt could help others respond with advice .
Kind regards Kev
Hi Kev:roll_eyes: I am a stupid stupid man. I see now I wrote cobra but it should have been Cobalt 
will correct it
Thnx for your info
Ger
I had the Cobalt fitted to my 07 plate Sport. Lovely sound and not overly loud, sporty I say as it should had sounded from factory. Mrs A approved of that one, that was after I fitted one from Mx5parts and had to ditch it as too droney
As for the one side sooting up more, yes mine was exactly the same but it sort of evened itself out over time. It should really be discolouration rather than black soot, not running right if it’s a black sooty look.
The sound will mellow with the miles and get to sound nice and sporty, not tinny or droning.
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It looks like the design is the cause. The cobalt has one exit pipe from the rear silencer longer or more direct route than the other, could be that just like water or electricity the exhaust gas will take the path of least resistance…
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My Cobalt was fitted around 400 miles ago and I experienced the same. The higher rev drone disappeared quite quickly although I’m still getting some booming around 1600-1700 rpm, especially noticable when driving around town both off and on power but this is decreasing.
I was actually about to investigate the one side sootier than the other as I have it too, but according to the posts above it looks like this is normal.
I know my NC 1 does produce more soot than it should and this has highlighted the issue so I’ll try and sort that out now.
Take your Cobalt for a few longer drives to get it hot, with plenty of high revs and the sound should improve 
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Thnx all for your commends, I think Dean has a great point. I was checking the exhaust bushings yesterday, and did see that the design of the exhaust could cause the left exit pipe to be the more direct route.
Again thnx for your info.
I have the exactly the same experience as Andy. @Ger1971
I find it “soots” up after maybe 300-500 miles. I have similar suspicions of a nasty brewing in my NC1 @AndyGadget. Let me know if you find anything before I do!
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Mine also gets more soot on the near side pipe.
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