F80 M3 / F82 M4 ETK parts diagrams in detail: a quick analysis

[IND-Distribution]

     Featured on BIMMERPOST.com

Whenever BMW releases a new chassis and a new M car in particular, we watch for new information with anticipatory glee. All of us at IND have been working to gather info on the F8x M3/M4 daily, and today are happy to inform the BIMMERPOST community of that one of the biggest influxes of information in a chassis history is up and available for public viewing: all original BMW F8x M3/M4 parts diagrams are now live on RealOEM.com.

We'll take this opportunity to review some interesting parts diagrams, and comment on some of the unique aspects of the amazing F8x cars. The level of detail available in BMW's diagrams is uncanny, and F8x owners can discover the amazing engineering details that make their M cars special. While some of my notes on these components will be relatively pedestrian, I'm still excited at the opportunity to review these parts individually, piece by piece, before we really begin to tear in to our own M3 and M4 project cars.

Also see:

BMW M3 and BMW M4 Inside (part 1): The new M Servotronic.
BMW M3 and BMW M4 Inside (part 2): The Brake Systems.
BMW M3 and BMW M4 Inside (part 3): The new engine.
BMW M3 and BMW M4 Inside (part 4): Sound and Exhuast System.
BMW M3 and BMW M4 Inside (part 5): smartly light, rigid, precise.
BMW M3 and BMW M4 Inside (part 6): The new chassis.

The M3/M4 has two airboxes with two air filters, providing ample air flow to the S55's two turbos.

Charged air travels through the very short intercooler piping and to the air to water intercooler. As most of you have read in the BMW press releases, BMW's focus was to keep the charge piping as short as possible to improve response. Note that each turbocharger has its own unique flow path to the intercooler, and the intercooler merges the pressurized intake flow before it enters the manifold.

The water cooling system includes a heat exchanger for the engine's water, which removes heat from the block, along with an additional heat exchanger to cool the liquid for the air to water intercooler, and two auxiliary coolers. The hose diagram illustrates how piping is run directly from the air to water intercooler to the front mounted heat exchanger. This exposes cooling liquid to direct airflow, while keeping charge air contained in the top mounted intercooler for extremely short charge piping and excellent turbo response.

Two major oil coolers are also found at the front of the car- a flat mounted engine oil cooler, and a DCT transmission oil cooler for DCT equipped cars.

Finally, two water pumps carefully regulate coolant flow- one mechanical pump responsible for coolant flow through the engine block, and one electric pump responsible for coolant flow through the turbochargers. The electric water pump can operate independently of the engine even when the car is not running, cooling the turbos once you've deactivated the car to prevent coking of engine oil inside the hot turbos- a major improvement in reliability over older turbo charged cars.

BMW installed a host of chassis bracing on the new F8x cars to maximize chassis rigidity. A rigid body shell allows for the suspension arms only to control geometry change as the car navigates terrain, forcing the suspension arms to operate as intended.

The front and rear subframes are both extremely rigid fabricated pieces, with the rear being an especially impressive piece. Note the lack of space available for subframe bushings in the rear subframe- evidence of the rigid mounting that BMW has been promoting in their own literature. The rear subframe looks like something we are more accustomed to seeing in well engineered race cars than road going sedans! Additionally, the front skid plate acts as a chassis brace and is a stressed member, furthering the excellent rigidity of this car.

BMW's new front and rear uprights are also very impressive designs- both feature bolt-on wheel bearings for easy service, large diameter high strength hardware for wheel lugs, and a very rigid design. A rigid yet lightweight upright is critical for great performance as the upright locates the wheel bearing and therefore is directly in control of the wheel's position relative to the car.

BMW's shift consoles have always isolated noise and vibration well, but the bushing design leaves a bit to be desired with respect to shift feel. The bushings at the front of the console (part number 2 in the diagram) and the rear bushing (part number 15) allow for the console that supports the shifter to move slightly, pivoting the shifter as the driver moves the car through its gears. Fortunately many manufacturers produce short shift solutions for BMWs, and changing these bushings to more rigid pieces is one of the most important gains of these kits (more so than the reduced throw, in my opinion).

There has been much ado about the new carbon driveshaft found in the F8x cars. This excellent piece will reduce rotating mass and improve engine response even further. As you can see BMW spared little expense in optimizing this car! Interestingly, the tail end of the driveshaft does not have a bolt flange like most older BMWs- here BMW M opts for a direct splined connection to the differential, allowing for the driveshaft to slip over the differential's input shaft splines. This driveshaft is of course also constructed from a single piece as opposed to the two piece construction of most BMW cars, eliminating the need for a center support bearing.

Finally, we reach the famous M differential with its servo controlled locking mechanism. The servo can be clearly seen at the top of the differential case, toward the rear. You'll note that the lower differential pan has an array of cooling fins like most M differentials, but the arrangement has been improved a bit when compared to older M cars. Fins have been placed along the length of the lower cover, allowing for more cooling surface area while also giving the bottom of the differential a far lower profile than the previous M3, preventing expensive damage to the differential cover. This was not possible on previous M cars as the differential housing was a large one piece cast unit, as opposed to this F8x version which has a bolt on lower cover.

One other item of interest is the nose mount of the differential- the differential interfaces with its nose mount with some bushings, and the nose mount itself bolts to the subframe with more bushings. This is BMW's way of controlling noise, vibration, and harshness from the differential now that the subframe is solid mounted to the car.

I hope you’ve had as much fun looking at these images as I have. The new F8x M3/M4 is truly an incredible car. I'm honored to be at IND at a time when we can study and dissect this work of M engineering art, and I am excited to keep the BIMMERPOST community updated as we continue with technical analysis, data gathering, and general obsession over the new M!

[Money2536]

Thanks Ilia!

[Boostin FD]

Where's the blow off valve so I can vent it outside and make a swooooshhhh sound ;-). Ha!

[mic_crispy]

Originally Posted by Boostin FD

Where's the blow off valve so I can vent it outside and make a swooooshhhh sound ;-). Ha!

I know youre probably joking but i believe in sport+ it is meant to remain closed to stay in boost.
In other modes it isnt. I know if i put mine in comfort i can hear a blow off.

[Caelric]

Thanks for the parts diagrams. Good to know that the electric water pump continues after engine shut off, to cool down the turbos.

Also, wondering how much the intake airflow piping can be improved. Not much, it looks like from the pictures.

[kitw]

Awesome, thanks for sharing! The exposed bracing is beefy but man, the rest of that bracing is seriously beefcake!

[GOLFFRR]

[Dawko]

Thanks for the info and write-up!

[metrickid]

Nice info.

[rubber_ducky]

Great stuff. Thanks for posting

[thebigcheese]

Any carbon fiber cold air intakes in our future? lol

[Suave]

Awesome information, Thanks!

[Boostin FD]

Originally Posted by mic_crispy

I know youre probably joking but i believe in sport+ it is meant to remain closed to stay in boost.
In other modes it isnt. I know if i put mine in comfort i can hear a blow off.

But where is it? I didn't see it in the diagram nor was I able to locate it by quickly looking at the engine bay at the dealer.

[CanAutM3]

Thanks, that was an enjoyable read

[0-60Motorsports]

Very Interesting. Thanks for posting this Ilia.

[Park2670]

Very cool stuff to look over. I am glad I am not the only one spending too much time on that site!

[DieGrüneHölle]

This info has been up on realoem for awhile.

[Sean@PSI]

Great post.

www.Realoem.com is a great resource for any BMW owner looking for Part #s and information on their BMW.

[Evan@Tischer]

[Dackelone]

Very nice job from the IND crew!

[Maz335i]

Great info!

[W///]

Great post Ilia!