I bought a Cobalt stainless steel Backbox a couple of months ago which I love, but I found myself recently wanting a bit more noise.
Not wanting to get involved with removing the catalytic converters/MOT failures etc I decided to look from this point backwards.
The centre pipe on MK3’s runs from the secondary cat all the way to the Backbox, but a common failure point is the centre silencer as they often rot through and are subsequently replaced with one similar to the image below… Easy fix, cut the old one off just before the muffler and slide the new piece in… Fanny’s your uncle, job done.
But, while I was at MX5 City the other week I was chatting to them about this… And they’ve been able to source for me the exact same piece of pipework, minus the silencer…
As easy to fit as you’d imagine, here is the result…
I’ll be honest, the video doesn’t really do it justice, probably because it was recorded on my phone… But please believe me, if you want a bit more out of your lovely stainless steel backbox then this is the way to go… The noise is really deep and throaty and it sounds like a proper sports car!!!
There’s also a gorgeous burble on the overrun, you get the occasional subtle pop/bang and overall its just miles better.
It also doesn’t drone at motorway speeds at all… Give them a call, it’s the best £75 you’ll ever spend!!
Thanks for this Chris great idea … and takes the number of youtube videos of MX5 nc exhaust sounds i have watched to a higher number than should be normal … been trying to decide on exhaust upgrade for months now at some point, I will just have to decide …
The cobalt backbox is widely regarded as being one of the best ones you can get for a variety of reasons, but for most people they want the noise without the ridiculous vibration or droning on the motorway… The quality of the exhaust note is also lovely… More of a deep rumble than a raspy whine…
Interestingly, I don’t have that box on mine.
It goes from the header to the mid cat, resonator box and then the rear box.
Whether the NC1 is different from the NC2, 1.8, 2.0 etc?
Nope not at all - the emissions systems (both cats, all sensors etc) are all fully present and intact… The exhaust is also not really loud enough to be a problem either!
Yes I think I understand, do you mean replace the mid pipe with the one shown above and keep the OEM back box?
I don’t see why not.
Don’t know what the sound will be like, I notice in the video it looks like a Cobalt back box.
Question to help me with my analysis paralysis or make it worse …are the cobalt tail pipes fixed ? if so do they extend more than std nc1 ? do you have any side profile pics ? been a real rabbit hole trying to choose a backbox. thanks for any help
If the oem system has the extra silencer and you want to get a louder, deeper sound at minimal cost, replacing the silencer and pipe with this pipe at £75.00 might be just the ticket.
… been trying to decide on exhaust upgrade for months now 
at some point, I will just have to decide …
