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      02-01-2015, 10:26 PM   #1
Falafel Combo
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Why did they decide to go with a bolted rear subframe this generation around?
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      02-01-2015, 11:10 PM   #2
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Originally Posted by Falafel Combo View Post
Why did they decide to go with a bolted rear subframe this generation around?
M5 was the first ///M car that did that. In general, a solid connection of the rear tires to the frame gives less wiggle under cornering, making the trajectory more predictable. It also transmits more of the road to the driver's butt. Probably why most folks like the adaptive suspension on this car.
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      02-02-2015, 08:46 AM   #3
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The rigidly connected subframe acts as a stiffening element, similar to some of those bolt on units you see for sale on other vehicles. By rigidly connecting the rear end together, it increases the overall and torsional rigidity of the rear shell

Downside, of course, is increased NVH. The diff, usually bolted directly to the subframe, is isolated with bushings, so that helps some. But it does transfer more NVH since it still carries the suspension.
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      02-02-2015, 09:06 AM   #4
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M3 gts had this. Cool thing is the ride compliance is amazing on the f80 despite this which is cool.
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      02-02-2015, 09:44 AM   #5
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I love this aspect. Car feels more track oriented out of the box. I have the standard suspension. Wouldn't recommend that for the feint of heart...
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      02-02-2015, 08:56 PM   #6
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Quote:
Originally Posted by Falafel Combo View Post
Why did they decide to go with a bolted rear subframe this generation around?
Albert Biermann 'splains it all here (6:30 for the rear axel):

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He tries to draw people into inane arguments, some weird pastime of his.
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      02-02-2015, 10:24 PM   #7
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Quote:
Originally Posted by 8600RPM
M3 gts had this. Cool thing is the ride compliance is amazing on the f80 despite this which is cool.
Wouldn't have anything to do with ride compliance, more NVH.
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      02-03-2015, 04:15 AM   #8
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Quote:
Originally Posted by GrussGott View Post
Albert Biermann 'splains it all here (6:30 for the rear axel):

Perfect. Thanks Gruss!
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      02-03-2015, 06:57 AM   #9
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Quote:
Originally Posted by GrussGott View Post
Albert Biermann 'splains it all here (6:30 for the rear axel):

great video!!!!!! thx
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      02-03-2015, 07:11 AM   #10
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Originally Posted by FlagBonz View Post
great video!!!!!! thx
Every time I watch this video, I get a kick out of how passive the other watchers are. Some are checking their phones, no one is engaging with questions, they just stand there like statues. Were I in the presence of such a person and such a car, I guarantee that I would not stand there mute.
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      02-03-2015, 09:45 PM   #11
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Actually, it's only partly about stiffening the structure. Mostly it's about removing the lateral compliance from the rear suspension to improve the precision and directness of the rear of the car under lateral load and in transients. Less compliance laterally means the steering response of the rear matches the front better with less delay, and you have a better feeling of what's happening at the contact patches.

This also helps the drivetrain . . . the driveshaft has to first take up any compliance of the rear suspension before it can transmit torque to the rear tires. Less compliance means a more responsive powertrain, which allows the engine itself to be tuned for better response.
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      05-18-2019, 02:00 PM   #12
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Quote:
Originally Posted by GrussGott View Post
Albert Biermann 'splains it all here (6:30 for the rear axel):

Wish there were a similar video for the Comp package changes.
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