10-06-2020, 09:14 AM | #1 |
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Exhaust details & undercarriage look from G82 M4 / G80 M3
![]() Featured on BIMMERPOST.com This is the X3/4M exhaust ![]() |
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10-06-2020, 09:57 AM | #3 |
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Hmmmm, interesting. I wonder if it is an attempt at making an equal length exhaust system.
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10-06-2020, 10:30 AM | #4 |
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does that make it easier to de-cat
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10-06-2020, 11:54 AM | #6 |
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Routing the downpipe under the transmission is very strange to me. It almost looks like the M5 midpipe setup. I wonder if they are planning for a V engine configuration down the road. I know that sounds farfetched but I do not see why else they would do it this way.
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10-06-2020, 02:34 PM | #7 | |
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10-06-2020, 02:43 PM | #8 |
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Looks like after-market exhaust suppliers will just need to tap in aft of item #9, which means much less metal/shorter piping than was required for the F80/82/83. Hopefully, that will translate into a less expensive exhaust mod.
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10-06-2020, 04:47 PM | #10 | |
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On the F8X, the exhaust gases of front manifold have to travel a longer distance that the ones of the rear manifold. Making a detour for the rear manifold balances the exhaust length.
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10-06-2020, 04:55 PM | #11 | ||
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Twin turbo straight sixes are not new, here is a picture of an RB26DETT front pipe to balance the lengths. You are talking 12" max to make up. |
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10-06-2020, 05:04 PM | #12 |
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The distance does nothing to efficiency. It just adds time, and therefore emissions, to the cold start. Once at operating temp in a few seconds the efficiency will be the same.
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10-06-2020, 05:17 PM | #13 |
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Can anyone explain what is going on in the original picture? The car looks like it is participating in some sort of circus trapeze act.
Just curious... |
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10-06-2020, 05:19 PM | #14 |
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Enables a lower profile of the exhaust resulting in less drag of the fast flowing under car air? Might not be enough space when routed one side to achieve the same?
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10-06-2020, 05:21 PM | #15 |
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I think BMW ran out of room to put both primary cats on one side ... so they used the unused space on the other side of the transmission for one of the cats and piped under transmission to that space.
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10-06-2020, 05:46 PM | #17 |
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Principles of thermal dynamics says largest temp difference from intake to exhaust mani equals largest power. Placing them closest to the manifold will equal more heat but to be honest I don't think that logic was used here looks like packaging but I didn't design the car. Also cats like to be heated up to function properly maybe the idea is to get into them and keep them heated. Or the all most important topic BMW topic NVH, BMW has started to make these M3/4 everyday cars with minimal NVH it's possible moving the cats closer helps eliminate some NVH topic the car tuners (me included) will remove those NVH nannies anyways!
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10-06-2020, 06:06 PM | #18 |
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See below aftermarket solutions for the F8X. They do add a fair bit of length.
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10-06-2020, 06:53 PM | #19 |
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https://g80.bimmerpost.com/forums/sh....php?t=1763157
In this Youtube video filmed by a german YouTuber, a BMW M employee states at around 8:20, that the exhaust and sound design team specifically engineered the exhaust to be equally lengthened to create the desired sound profile for the new BMW M3/M4. These undercarriage photos seem to confirm that. |
10-06-2020, 07:07 PM | #20 | |
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Porsche 911 turbo 2021 992 GT Silver
![]() Previous cars: M4cs 2019 F82 Limerock Grey / M4 2015 F82 Silverstone / M3 2008 E92 Silverstone / M3 2002 E46 Carbon Black Last edited by CanAutM3; 10-06-2020 at 07:59 PM.. |
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10-06-2020, 07:09 PM | #21 |
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