Coupe exhaust issues

AlZ4M

Member
Not so much an issue but I couldn't think of a better word...

You may have seen my gauging interest thread re selling my Rogue Engineering exhaust and thought I'd ask for some real world experiences here.

The exhaust sounds awesome, not too loud at tickover and with a real howl at the upper-end of the rev range. However, I'm finding it boomy at low speeds and I think it's down to the lack of trim between the exhaust itself and the cabin.

Now I know that with a sports exhaust you will get drone if you labour the engine with a gear that's high for the engine speed but I seem to be getting an acoustic effect from the sound presumably coming up from beneath the boot floor and then being bounced around the cabin.

Outside it's obviously a fair bit louder than standard but nothing too dramatic but inside it sounds a bit Max Power for my liking and just wondering what I can do about that. The system is brand new so has probably about 30 miles on it at the moment and even when taking it out for a spin this evening it does seem to have become less intrusive.

So has anyone with a coupe fitted an after-market exhaust and then sound-proofed underneath the boot carpet and if so did that make a dramatic difference? Or is it just a case of getting a few miles on it and letting it settle?
 
I've got the same exhaust and it's only boomy and resonant when cold. 30 minutes into a hoon and it mellow/smooths out into a cruising grumble and a howl when pushing on.

On a cold start it was 91dB at Oulton on Friday.
 
That's good to know, thanks.

I'll just see how I get on with it I guess- although I probably do very few trips longer than 30 mins so maybe an after-market exhaust isn't really for me.
 
Now not wanting to put you off selling them to me :thumbsup: but you could get hold of a roll of dynamat and line the boot floor. Alternatively - as I have done - get hold of a roll of compressed foam carpet underlay and go to town in the boot area.

Mine has quietened down a lot
 
Would adding some lead weight (wheel balancing weights) to the exhaust help change the harmonics? It's something I've been meaning to try on the wife's X3.
 
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