G80 M3C Underbody

ashiifi · 07-24-2021, 08:30 PM

Everytime a new car comes out, I always struggle finding good/clean underbody photos. Once my M3C came in, I thought I'd throw it on the lift and take some photos for anyone that needs them. Not the best quality but better than nothing I suppose. Good reference to see the extent of the midpipe and all of its restrictions. See anything interesting worth calling out? Now that I have access to a lift, anything else worth taking a photo of under here?

Motorat · 07-24-2021, 08:50 PM

Nice! Thanks

Patton250 · 07-24-2021, 08:53 PM

Really cool. Thanks

LukeM15 · 07-25-2021, 01:36 PM

Awesome. Thank u!

_E90S65_ · 07-25-2021, 08:05 PM

Beauty in the beast.

BMWEM3 · 07-25-2021, 09:07 PM

Doing the same here on mine!

Limegrntaln · 07-25-2021, 10:42 PM

Blew my mind when I saw they flattened the factory exhaust.

zmicke · 12-31-2021, 04:08 AM

Some countrys dont have twice resonators, they have Opf.
https://g80.bimmerpost.com/forums/sh....php?t=1764118

Snt282 · 12-31-2021, 06:04 PM

I'm not familiar when it comes to parts of an exhaust. Can someone take the original underbody pic and annotate it with the different parts?

NightWriter · 12-31-2021, 06:36 PM

Quote:

Originally Posted by Snt282

I'm not familiar when it comes to parts of an exhaust. Can someone take the original underbody pic and annotate it with the different parts?

Sure... I'm about 94.4% certain about these

iviegatron · 12-31-2021, 08:11 PM

Quote:

Originally Posted by NightWriter

Sure... I'm about 94.4% certain about these

[IMG]https://i.ibb.co/3khGyTF/g80.png[/IMG]

Pretty close. The flap/valve controller is further to the left and right of the exhaust.

Also the catalytic converter are the secondary cats. The primary cats are on the downpipes which are not visible in the pic.

Snt282 · 01-01-2022, 11:26 AM

Quote:

Originally Posted by iviegatron

Pretty close. The flap/valve controller is further to the left and right of the exhaust.

Also the catalytic converter are the secondary cats. The primary cats are on the downpipes which are not visible in the pic.

Also where the different sections of the pipe?

Is the stuff between the secondary cats and the first set of resonators part of the downpipe or is that not visible?

What's the piece of pipe between the two sets of resonators called?

After the second of resonators down to the flap controllers, is that the mid pipe?

After what part is considered the tail pipe here?

Raider_G80 · 01-01-2022, 12:07 PM

very helpful post and thanks SNT for asking the questions, I also had been wanting to educate myself about these parts

iviegatron · 01-01-2022, 04:05 PM

Quote:

Originally Posted by Snt282

Also where the different sections of the pipe?

Is the stuff between the secondary cats and the first set of resonators part of the downpipe or is that not visible?

What's the piece of pipe between the two sets of resonators called?

After the second of resonators down to the flap controllers, is that the mid pipe?

After what part is considered the tail pipe here?

Elaborating on what NightWriter posted. Hope this helps.

Also where the different sections of the pipe?
See attached picture

Is the stuff between the secondary cats and the first set of resonators part of the downpipe or is that not visible?
It is not visible. They connect to the secondary cats and go up to the engine.

What's the piece of pipe between the two sets of resonators called?
No special name, just a pipe that extends from one resonator to another.

After the second of resonators down to the flap controllers, is that the mid pipe?
The midpipe includes both resonators and secondary cats.

After what part is considered the tail pipe here?
The four tips after the muffler are the tail pipes.

Raider_G80 · 01-01-2022, 04:14 PM

Quote:

Originally Posted by iviegatron

Elaborating on what NightWriter posted. Hope this helps.

Also where the different sections of the pipe?
See attached picture

Is the stuff between the secondary cats and the first set of resonators part of the downpipe or is that not visible?
It is not visible. They connect to the secondary cats and go up to the engine.

What's the piece of pipe between the two sets of resonators called?
No special name, just a pipe that extends from one resonator to another.

After the second of resonators down to the flap controllers, is that the mid pipe?
The midpipe includes both resonators and secondary cats.

After what part is considered the tail pipe here?
The four tips after the muffler are the tail pipes.

appreciate you taking the time to do that thanks v much

iviegatron · 01-01-2022, 04:31 PM

Quote:

Originally Posted by glissco27

appreciate you taking the time to do that thanks v much

Yup, no problem.

NightWriter · 01-01-2022, 04:45 PM

Quote:

Originally Posted by iviegatron

Yup, no problem.

Thanks for the updates. Does the X-Pipe actually cross the two? I believe some have cut out the resonators and had their exhaust guy apply an X or H connector...

iviegatron · 01-01-2022, 05:00 PM

Quote:

Originally Posted by NightWriter

Quote:

Originally Posted by iviegatron

Yup, no problem.

Thanks for the updates. Does the X-Pipe actually cross the two? I believe some have cut out the resonators and had their exhaust guy apply an X or H connector...

It does. Some have gone straight pipes, eliminating the X and others have added an X or H when cutting out the resonator.

spicoli024 · 01-01-2022, 06:41 PM

Quote:

Originally Posted by iviegatron

It does. Some have gone straight pipes, eliminating the X and others have added an X or H when cutting out the resonator.

Thanks Omer. Very helpful.

Snt282 · 01-01-2022, 08:22 PM

Quote:

Originally Posted by iviegatron

It does. Some have gone straight pipes, eliminating the X and others have added an X or H when cutting out the resonator.

Thanks for the diagram. How is it possible to tell there is an x-pipe and straight-pipe in those resonators? Is it only possible to tell after cutting it open?

m.dreamin · 01-01-2022, 08:49 PM

That's why this forum rocks, folks like you sharing stuff for everyone else to learn. Much appreciated.

Am I wrong in thinking that the underbody is flat enough where a rear difuser actually does seem to be a helpful component of the G8x cars? My understanding of difusers is that they really don't matter if the underbody isn't flat, but this seems pretty clean in terms of airflow.

iviegatron · 01-01-2022, 08:57 PM

Quote:

Originally Posted by Snt282

Thanks for the diagram. How is it possible to tell there is an x-pipe and straight-pipe in those resonators? Is it only possible to tell after cutting it open?

Exactly. From the surface you can't tell. People found out by cutting them.

07-24-2021, 08:30 PM	#1
ashiifi f82_s55 93 Rep 94 Posts Drives: F90, G80, F82, E92 M3 Join Date: Aug 2020 Location: Chicago iTrader: (1)	G80 M3C Underbody Everytime a new car comes out, I always struggle finding good/clean underbody photos. Once my M3C came in, I thought I'd throw it on the lift and take some photos for anyone that needs them. Not the best quality but better than nothing I suppose. Good reference to see the extent of the midpipe and all of its restrictions. See anything interesting worth calling out? Now that I have access to a lift, anything else worth taking a photo of under here? Attached Images
	Appreciate 41 evilalien450.50 Patton2502938.00 AndroidRobot4328.00 ks74.50 chicagofan0019077.00 FITM3NT540.50 vampire81434.50 bri10425904.00 akkando5863.00 xantdieselx410.50 DavidXJ663.00 mzcp2660.00 ando2000.50 DecemberStorm590.50 SG82JP148.00 heavyD^23688.50 Keishune173.50 2011ninja3377.50 Dhillon63141.00 psylovibe1030.00 S@v3f3rris72.50 RichardGM4515.00 HTTP 4102141.50 BMWRacer5232519.00 SimsimmaM3172.00 m.dreamin1608.00 m4ml1814.50 3some!15.00 RockinPA4848.00 OneSlickM240.50 Icealicy94.00 TK3pedal386.00 Tall Tom Cruise1001.50 F82G82AND149.50 Paula0.00 DocWeatherington2932.50 Llarry15478.00 Tweet Quote

07-24-2021, 08:50 PM	#2
Motorat Private First Class 115 Rep 103 Posts Drives: BMW Join Date: Sep 2014 Location: East Coast iTrader: (0)	Nice! Thanks
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07-24-2021, 08:53 PM	#3
Patton250 Colonel 2938 Rep 2,538 Posts Drives: BMW X3,M5,Turbo S Join Date: May 2021 Location: Tampa iTrader: (0)	Really cool. Thanks
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07-25-2021, 01:36 PM	#4
LukeM15 Captain 560 Rep 991 Posts Drives: M3 G80 Comp Xdrive Join Date: Nov 2016 Location: Maryland iTrader: (4)	Awesome. Thank u!
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07-25-2021, 08:05 PM	#5
_E90S65_ Captain 736 Rep 674 Posts Drives: 2021 M340i Join Date: Dec 2020 Location: Pluto iTrader: (0)	Beauty in the beast.
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07-25-2021, 09:07 PM	#6
BMWEM3 Enlisted Member 105 Rep 46 Posts Drives: BMW F80 M3 CP Join Date: May 2018 Location: San Diego iTrader: (0)	Doing the same here on mine! Attached Images
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07-25-2021, 10:42 PM	#7
Limegrntaln Major General 13413 Rep 6,933 Posts Drives: 2022 DG/BLk xDrive M4C Wk 34 Join Date: Mar 2008 Location: Sacramento Area iTrader: (3) Garage List 2022 G82 M4 Competi ... [9.23]	Blew my mind when I saw they flattened the factory exhaust. __________________ 2022 DravitGrau /Black Full Merino M4 Competition M xDrive / Production Week 34/ Delivered 10/19/21/ IG: dravit_m4_comp YT: G Dubyou
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12-31-2021, 04:08 AM	#8
zmicke New Member 0 Rep 7 Posts Drives: M2 Competition Join Date: Sep 2021 Location: Sweden iTrader: (0)	Some countrys dont have twice resonators, they have Opf. https://g80.bimmerpost.com/forums/sh....php?t=1764118
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12-31-2021, 06:04 PM	#9
Snt282 Private 20 Rep 55 Posts Drives: None Join Date: Nov 2020 Location: South Carolina iTrader: (0)	I'm not familiar when it comes to parts of an exhaust. Can someone take the original underbody pic and annotate it with the different parts?
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01-01-2022, 12:07 PM	#13
Raider_G80 Private 83 Rep 75 Posts Drives: '22 M3Cx Join Date: Dec 2021 Location: NJ iTrader: (0)	very helpful post and thanks SNT for asking the questions, I also had been wanting to educate myself about these parts
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01-01-2022, 08:49 PM	#21
m.dreamin ///M 1608 Rep 296 Posts Drives: 2022 M4 Competition xDrive Join Date: Aug 2021 Location: San Francisco iTrader: (0)	That's why this forum rocks, folks like you sharing stuff for everyone else to learn. Much appreciated. Am I wrong in thinking that the underbody is flat enough where a rear difuser actually does seem to be a helpful component of the G8x cars? My understanding of difusers is that they really don't matter if the underbody isn't flat, but this seems pretty clean in terms of airflow.
	Appreciate 0 Quote