I have an NC2 with one of those Sound Tubes, its a 2.0 2010 sport tech.
I’d like to hear the car without the piped in slightly iffy induction noise.
I can see that it is removable with a few bits added, is there not a far simpler way to silence what is coming into the cabin, by possibly blocking the sound hole with some foam?
I might try, but would this do any damage, before I get bodging?
Cheers,
R.
I wondered about trying something similar so I can see if there is any difference. Might have a look over the Christmas break.
On the ND before I did the full delete I put a thick grommet in line, not sure if the plumbing is the same on the NC though can’t imagine it’s massively different.
I’ll see if I can find my post and if the pictures still are linked.
I think a solid solution would be better as you would not want to risk foam particles getting into the induction system.
https://forum.miata.net/vb/showthread.php?t=666268
Iirc, 2CVs had similar tubes running into the cabin but they were for practical reasons, ie ducting heat into the cabin from the air cooled cylinders and they were made of felt in order to minimise sound transmission which I thought was rather clever.
Why oh why are the Mazda sound tubes not switchable???
I just found a very tight fitting black bottle top and blanked it off. Free and easy. Then removed the pipe work once I realised how much better it was without the tube.
Have you got a pic of the finished job - And is it really worth it from a sound point of view? Because at the moment I don’t really care about the excess plumbing?
An pictures of how to blank this off would be very helpful
Cheers
I’ll take a picture in a minute…
Ok so I’ve been to look and i remember how I did not now. Leave the first bit of the concertina pipe from the induction tube in place and pop a bottle top of the correct diameter in there. I managed to find a top hat shaped one that was perfect but a normal top would do. IIRC 29mm is the size. Rip out the rest of the pipe work and pop a 20mm blind grommet into the hulk head hole. Job done.
You see the grommet in the green circle in the picture.
The end of the induction tube is in the red square. I tucked it under a bracket as seen and used a black cable the to keep it from rattling around. I think I had to rotate it at the end where is comes out of the dome looking union. It works beautifully and only cost me, NOTHING. I don’t see the point wasting £50 on a delete kit.
And yes I need to finish detailing the engine bay I know!
Found my ND post.
Odd that people mention a resonator in-line. I cut mine open and it is actually more of an amplifier. It actually amplifies the engine induction sound and sends it into the cabin. After removing it mine is incredibly quiet in the cabin now. It isn’t even a small difference that could be missed, it’s night and day quieter right thru the whole rev range. And I don’t like droning noise, that’s why I fitted a Cobalt exhaust and removed it after less than 50 miles lol.
I wanted my ND to look standard, so I detached the rubber flexible bit and secured a plastic bung into the hole. I then injected expanding foam into the pipe end that goes into the bulkhead before refitting the sound tube, slid over the plastic bung. The car is now without the piped induction noise but appears to be as built.
Thanks for that - so the difference in sound is significant then - and you can enjoy the exhausts noise and engine without the drone. I like the sound of that. I might just pull the bulkhead tube out and stuff it with insulating foam and put it back it back together. As long as the tube is blowing into the bulk head and not sucking, I wouldn’t worry about induction contamination then.
So 3 bolts off, bulkhead end of tube in my hand, wedged a large dense sponge in (ain’t no way its going to move anywhere), and the sound of the car is transformed. I am delighted, no drone sound, much more satisfying mechanical sound is present and next week a Japspeed rear box goes on to put the cherry on the top.
Thanks for all you help, job done.
What a stupid oem addition that sound tube, considering all the ‘gram theory’ of the whole MX-5 ethos?
I’m loving my 5!!
I bought the replacement part from “MX5 Parts” prior to the arrival of my ND 30AE and I removed and replaced the “sound tube” assembly as soon as I got the car home - 15 minute job, could be quicker but I’m useless with those sort of tasks!
Just saw this again. I blocked mine with a brass insert I use for blanking 22mm compression fittings (plumber). Rolled for 3 months with it in, removed it and found no difference in the noise levels in the cabin. I actually have the delete kit I bought to do it properly but will sell it on at some point.
I deleted my post asking about this sound tube, it was pretty obvious what needs to be done once I’d taken a second look at it.
I’ll have go today if it stops raining.
The tube seems an awful lot of effort and materials for noise that seems most can do without. TBH I haven’t a clue if it does anything, only had the car a couple of months, got to block it off to feel any difference I guess.
