DIY: OEM Exhaust Mod (my experience)

[aitacookie]

I wasn't sure if this should go in the media section but I did the OEM exhaust mod over the weekend and have pictures, videos, and comments to add. I realize this has already been done (as we used an established guide), but I figured some comments from my experience may be helpful!

Enjoy!

Just getting ready and cooling her off




Was going to use the lift but couldn't get the lift arms to match up where we felt comfortable so we just jacked it from the back - no problem there




Outlined where we were going to be making the cuts. **Note, we decided to cut the bracket off at the welds so that we could make clean cuts. We did not see how we could have done it without hacking stuff up if we did not take it off. This will be the absolute final weld once everything is put back up (see last picture and step).




Did one side at a time. Others may choose to do both sides at the same time but time was not a factor for us and we wanted to make sure we tackled each side as a separate mini project - just preference


Left side completely cut out - used both large and small blades to get into corners without hacking up the lines


The shell is made up of two very thin layers - this is important when it comes to welding back up. This photo has the top layer put off to the side and the shiny inside layer still on


Once removed you can see all the dirty fiberglass - we took it out to put back in later


The tube in question. The left sides tube is on the top so it has some angles (the right side's tube is on the bottom and is just a straight 5" or so piece)


Fiberglass off to the side


Sawzall worked best (although we went through a couple blades throughout the entire process). Cutting on the perforated piece is the easiest and makes most sense as one side has a gasket piece inside (and the perforated piping is a bit easier to cut through than the stainless base parts on the sides)


Taken out


Worked the angles and got it close enough to weld the differences




Weld completed. It is difficult to get underneath (as others have mentioned in their DIY writeups and such) so just get as much as you possibly can. It was perforated before so any holes are not a big deal. We just wanted to make them as small as possible.


Spot welded the first side so that nothing moved while we did the other side


Both sides spot welded and completed. I skipped taking pictures on the right side but it should be noted that the right side's pipe is on the bottom and although it is a straight piece so fitting is easier, it is a pain to cut the old piece out. It is hard to get a blade in there so we tackled it from both sides and took our time as to get the cuts as straight as possible. Straightforward though


Welded up and ready for grinding/smoothing. Im sure others have mentioned that the welding of the two thin pieces are a pain. We spot welded the two thin pieces together before spot welding them back on the muffler. We did this so that the two pieces would stay together (as one piece) when we did the spot welds back on to the muffler. We took our sweet sweet baby jesus time welding it back up. We were running hot and the pieces were thin enough to cause worry. A lot of stop and go took place but in the end it looks factory (not that it matters anyway since its all tucked up in the car once placed). Just wanted to make a note of it as its not thick stuff to work with.


Smoothing out


Coated with engine paint for safe measure


Final weld. Used cardboard to protect the paint while doing some quick and dirty welds to the last bracket that we had to cut off at the beginning. We put the entire exhaust together and took care of the bracket at the end so that we could assure everything was in the same place before we started. If you weld this piece back before putting everything together there is a big change the angles will be off (it was for us when we did a test spot weld before breaking those welds off and just going with the process above.


Here is a video of the end product. Cheers!!!

[Hurricane]

Great write up. The pics are fantastic and the sound is awesome. Are you experiencing any drone?

[aitacookie]

Originally Posted by Hurricane

Great write up. The pics are fantastic and the sound is awesome. Are you experiencing any drone?

Thanks man! You know, the exhaust really doesn't have any drone - which I was surprised about... only because I didn't know exactly what to expect. What I really love about it is that the sound is really the most enhanced when accelerating. When I am just sitting there it has a nice grumble, when I am on the freeway it has a nice grumble, but when I step on it - that's when it really opens up.

I couldn't be happier... and the money spent?! Who can beat that?

[thefox456]

One question:
what about the torque still good after this mod?

[aitacookie]

Originally Posted by thefox456

One question:
what about the torque still good after this mod?

Yeah man, noticed no difference at all. All we did was replace the perforated piping with the solid piping - doesn't affect anything in terms of performance I would imagine.

[blast1st]

this is an excellent DYI. Thanks

[Route 16]

What would have been the difference in sound if you bypassed the middle and just worked on the outside of the muffler (connecting pipe to exhaust tips).

Which shop is this?

[///M Power-Belgium]

Perfect and well done...
This is the best thing to do with our cars>>>http://www.m3post.com/forums/showthread.php?t=733817

[///M Power-Belgium]

Originally Posted by Route 16

What would have been the difference in sound if you bypassed the middle and just worked on the outside of the muffler (connecting pipe to exhaust tips).

Which shop is this?

About 10 % louder with bypass,but wil drone ,but sound is very personal

[RickTreat24]

Sounds really good, saw this in a different thread too and wanted to ask if in doing this mod, will it void factory warranty?

[M3@Apex]

Did you put the dead animal/insulation stuff back in?

[dparm]

Originally Posted by RickTreat24

Sounds really good, saw this in a different thread too and wanted to ask if in doing this mod, will it void factory warranty?

Not the entire car's warranty; they just won't warranty the exhaust system after you hack it up.

[///M Power-Belgium]

Originally Posted by M3@Apex

Did you put the dead animal/insulation stuff back in?

Yes..when not ...will sound to hollow !

[dparm]

Curious, is this louder when cruising around town at low speeds? What about on the freeway at a constant speed? (droning)

[///M Power-Belgium]

Originally Posted by dparm

Curious, is this louder when cruising around town at low speeds? What about on the freeway at a constant speed? (droning)

O drone here !

[dparm]

Originally Posted by ///M Power-Belgium

O drone here !

Thanks, I didn't think it would drone much since the Helmholtz chambers aren't modified.

[///M Power-Belgium]

Originally Posted by dparm

Thanks, I didn't think it would drone much since the Helmholtz chambers aren't modified.

Exactly ,///M BMW has doing a perfect job by the design of the Helmholtz chambers against drone !
Actualy the Helmholtz chambers are also designed to quied down the Oem exhaust so we can hear the amazing sound of the S65 intake sound and this is amazing !
Now from my experience i know...with another aftermarket exhaust or the Oem. exhaust mod. will kill this amazing intake sound because the exhaust sound is now louder !
And yes ...this is also the only downside of the Oem. exhaust mod. !
BUT......
When i have the choise.... of the intake sound or the Oem.exhaust mod....
Give me the sound of my Oem.exhaust mod. and that all day long...it sounds just perfect...actualy....it's amazing
For further questions about this feel free to shoot me PM.....

[Drift Unit]

What's the diameter of the pipes inside?

[Tewie]

Used this DIY to make the initial cuts. The welder I went to told me he could not perform the welds for the new straight pipes if he cut out the perf pipes : I ended up letting him weld sleeves over the perf. pipes instead (don't understand how that's any easier) mod sounds great though and very happy I did it.

[Spenary9]

Originally Posted by Route 16

What would have been the difference in sound if you bypassed the middle and just worked on the outside of the muffler (connecting pipe to exhaust tips).

Which shop is this?

I got this Mod done in the Dallas area at Eurauto Shop. Micheal has done several of them and it was quick and inexpensive. I love it! Sounds fantastic!!!