GR86 Cobra Resonated suddenly got ridiculously loud

N

nlanks

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Jun 27, 2023
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Hi, I’ve had the Cobra resonated exhaust fitted for a few months now (done by Fensport).

At first it was perfect - definitely an upgrade over stock noise but not overbearing. I’m 42 after all and don’t want an ASBO.

However a few weeks ago when starting up it was embarrassingly loud on cold start, then dropped a bit but still much louder than before. It seems to have stayed like that and honestly now I’m embarrassed to drive it.

Has anyone else had this?
 
Cobra systems are always very loud on cold start for GR86, so not sure why yours was any different. Pretty subdued after the cold start though, so if yours remains very loud you probably have an issue somewhere.
 
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Alistair31 said:
Cobra systems are always very loud on cold start for GR86, so not sure why yours was any different. Pretty subdued after the cold start though, so if yours remains very loud you probably have an issue somewhere.
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Yes it was always louder on cold start, but now it’s genuinely terrifyingly loud. I think there must be an issue. I’ll get a video up tomorrow
 
Some things that can make an exhaust suddenly get much louder.
  • Exhaust leak somewhere.
  • Sound absorbing packing material (fiberglass, etc.) got blown out (from resonator, muffler, etc.).
  • Catalytic convertor's internal media broken or blown out. You'll sometimes see honeycomb-like material fall out.
 
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I’m just about to pull the trigger on a cobra exhaust. Hope you get it sorted
 
My non-resonated has had no issues so far and is still more than gentle enough for around town driving despite the colder weather; your resonated version should be even more so.
If the noise from the cold start isn’t dropping off to a modest hum after 30s or so maybe it could be a mapping issue? If it does noticeably drop off and the system is still throaty, maybe check that there isn’t an air gap somewhere, perhaps where it joins the second Cat?
There’s not much that can go wrong with a cat-back system, but from their website: “Cobra Sport exhaust systems come with a lifetime warranty for the original purchaser”, so if it turns out that something has gone awry with the Cobra Resonator, just give them a call and I’m sure they’ll help out if they can.
 
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What does it sound like when you are driving around with it warmed up?

The cold start is loud, nothing out of the originally for an aftermarket exhaust though. Now the ambient temps are in single figures the cold start is more aggressive and lasts longer than it does in the summer.
 
ZN8 said:
What does it sound like when you are driving around with it warmed up?

The cold start is loud, nothing out of the originally for an aftermarket exhaust though. Now the ambient temps are in single figures the cold start is more aggressive and lasts longer than it does in the summer.
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Still much louder than it was when driving around
 
Sounds like one for Fensport/cobra! If it was just cold start I'd definitely say it was the weather but not whilst warm.
 
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ZN8 said:
Sounds like one for Fensport/cobra! If it was just cold start I'd definitely say it was the weather but not whilst warm.
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Thanks, yeah that’s what I’ve concluded too. Email sent. Thankfully I kept the standard exhaust
 
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My OEM pipes used to throw out water like that. When I removed the backbox it had about a litre of water in it (from ingress and/or condensation). I think your current system may have developed a leak and the silencer wadding has got soaked, reducing its effectiveness so everything is louder. Only an opinion of course. The experts at Cobra/Fensport will get to the bottom of it. Good luck! 🤞🏻
 
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That sounds very similar to my non-resonated Cobra in fairness. Mine has certainly gotten louder as the temps have dropped. The noise reverberating against the fence won't be helping it but if it's much louder whilst driving too then maybe a problem with an internal baffle etc 🤷‍♂️
 
I think its just a case of they carbon up and get louder the more miles you do, the engine is pretty efficient so it takes a while, I purposely bought an IL Motorsport for my MX5 as it was quiet but after 5 or 6 K miles it was just right, same again on the GR, went for the legamax premium which is one of the quietest options out there, put 15k into that it sounds spot on, nice deep tone.
 
Sonic said:
@nlanks any response yet from either service provider?
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Sorry completely forgot to update.

Fensport agreed to take a look, so I dropped in whilst travelling down there. They agreed the sound wasn’t right and something must have happened, so swapped it out there and then from stock and said they would claim back in Cobra warranty.

Didn’t charge me anything and sorted it.

As always, pays to use specialists. Great job and service Fensport.
 
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