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  #1  
Old 09-04-2013, 09:05 PM
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Smile Gutted Exhaust S50

Seen this done on lots of e36 and 46 M3's with varied results. With 2nd hand back boxes now only costing about £100 punds I had to give it a go, picked up a set of a member and got hacking.

Started by marking out were I wanted to cut, in order to create a little door for me to get the different tools in.


Cut along the lines with a huge grinder, and then bent the double skin casing back.


Wearing gloves I pulled out the fibre glass, packed in very tight, take a while to remove.


Decided not to fuss around and just take out the lot. Used grinders and hand saws to do the bulk of the cutting but due to having no space I have to resort to cold chiseling the last bits through.


Hours later they both were complete gutted.


Had them welded up and put them on.
Very happy with the result, best and cheapest mod on the car!
Great sound really raspy and no drone when cruising.

Little sound clip
http://www.youtube.com/watch?v=ts0MsxpEkWQ
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Old 09-04-2013, 09:13 PM
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Nice wheels!

How about a drive with the camera on the passenger seat or something! Might try this for myself at some point as the back boxes are nice and easy to remove and fit to go from a quiet to loud set, especially if you say there is little drone!

I know Exdos has done a few of these but unsure if it's the same thing or he has left some pipework in place.

Last edited by c_w; 09-04-2013 at 09:15 PM.
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Old 10-04-2013, 08:05 AM
JuhaV JuhaV is offline
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Nice pics ! This is good info.

Question : The two output pipes coming out from the back, do they have closed ends inside the resonance chamber ? The final camber looks very clean and carbon free ...

If so, then one potential quick mod could be using one of these http://www.kegoutlet.com/15-16-hole-...drill-bit.html (choosin suitable size) attached onto a long rod and drilling it through those closed ends inserting the whole drill setup into the silencer via the output pipes.

I have done this for a few some motorcycle silencers and with a drill saw having the center drill bit in place (and the drill bit being long enough), you have > 95 % change that you can extract the piece of the metal sheet out from the silencer after drilling just by pulling the set up out carefully.

If lucky, this way it will be a 10 min job and will not require removing or opening up the silencers.

Would be interested to hear if somebody has tried this out and how it affected the roar.

- JuhaV
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Old 10-04-2013, 03:00 PM
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There were some pictures on the forum of what Exdos had done to his oem back boxes but I cannot see them anymore? John have you still got a link to the pictures?
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Old 10-04-2013, 04:48 PM
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Love the sound.

How do you get on with the supersprint decat?

Mine gave a pretty noticeable hesitation around 3k, but always wondered if it was just a combo of my other mods that caused it.
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Old 10-04-2013, 05:59 PM
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I've been doing this mod to the MC silencers since 2006 and posted quite a lot about on this forum in the past. It is the single-most effective performance mod that you can do, and I say that with lots of datalogging to prove it.

I've also done the same gutting to the OEM silencers on my Z4MC and, again, it gives verysignificant performance increase. I've also further developed my air intake mods and in conjunction with gutted silencers the results are very impressive.
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Old 10-04-2013, 06:28 PM
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Quote:
Originally Posted by c_w View Post
I know Exdos has done a few of these but unsure if it's the same thing or he has left some pipework in place.
I've done various configurations but the silencers I've had on my MC for the past 6 years are completely gutted and with flat bottoms which I've incorporated into a rear diffuser design that occupies the full back end. You'll have seen this if you looked underneath when you were at Gaydon a couple of years ago. I've still got my OEM silencers in store and the silencer/diffuser mod simply uses existing fittings and unbolts and can be removed to revert to OEM with absolutely no damage to the car.

Quote:
Originally Posted by Dave P View Post
There were some pictures on the forum of what Exdos had done to his oem back boxes but I cannot see them anymore? John have you still got a link to the pictures?
A lot of my photos that were linked to my threads "disappeared" but here's a few.





Here are a couple of video clips so you can hear what they sound like inside the car.http://www.youtube.com/watch?v=CK_qqogGCRo
http://www.youtube.com/watch?v=lms43vxfz30
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Old 10-04-2013, 06:29 PM
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Quote:
Originally Posted by exdos View Post
I've been doing this mod to the MC silencers since 2006 and posted quite a lot about on this forum in the past. It is the single-most effective performance mod that you can do, and I say that with lots of datalogging to prove it.

I've also done the same gutting to the OEM silencers on my Z4MC and, again, it gives verysignificant performance increase. I've also further developed my air intake mods and in conjunction with gutted silencers the results are very impressive.
Even with standard map?

I thought it sounded a bit 'tinny' - is there a half way house that might prevent that? Thanks!
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Old 10-04-2013, 07:05 PM
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Quote:
Originally Posted by breezer View Post
Even with standard map?

I thought it sounded a bit 'tinny' - is there a half way house that might prevent that? Thanks!
The OEM maps can cope with a lot of modding to the air-intake and exhaust systems. I've been datalogging the mods for most of the time I've been messing with the intakes and exhausts and the ECU has been able to cope with everything that I've thrown at it. My Z4MC's ECU yields considerably more information than does the MC, including Air:Fuel ratios, and it doesn't matter what I do, the AFR's just accommodate the increase air flow that my mods create.

My "gutted" silencers are not completely empty: I have some sound deadening in them and, as my videos show, they don't sound tinny at all.
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Old 11-04-2013, 12:23 AM
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Quote:
Originally Posted by topgeartom View Post
Love the sound.

How do you get on with the supersprint decat?

Mine gave a pretty noticeable hesitation around 3k, but always wondered if it was just a combo of my other mods that caused it.
Mine seems fine with the de-cat, not noticed any hesitation. Coupled with the gutted cans Iv noticed a much stronger sense of urgency to the lower revs. Not sure if this is just a placebo effect from all the racy sounds and expectation, but seem to have a lot more get up and go.

Will do a inside the car vid soon to give those wondering what it sounds like.
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