The F90 M5 and the M8 family share an engine bay that is full. The 4.4 litre twin-turbocharged V8 is wide, the cooling pack is deep, and the pipework has to find a route through a space that was never designed with aftermarket parts in mind. That is the real constraint on intake work for this platform, and it explains why so many owners find that a part which looks right does not actually sit right.
M5, M8, M850i and M550i models do not share an engine, but they share enough of the front end that a single intake system can be developed to cover the family. That is how the intake system for the F90, F91, F92 and F93 models was approached here.
This article looks at what changes when you move from the six-cylinder cars to this V8, and what to check before ordering anything.
A V8 with two turbochargers has two inlet paths, and they are rarely symmetrical in the engine bay. One branch is usually shorter and straighter than the other, and the two have to be balanced well enough that neither side is starved.
On the road this shows up as a car that feels stronger on one side than the other under part throttle, or as an intake that sounds busy without going anywhere. It is a fitment problem rather than a tuning problem.
The intake system for the BMW M5, M8, M850i and M550i F9x models was developed around that need: two branches that reach the same place without adding an unnecessary number of joints along the way.
Every coupler is a place where the air slows, where a clamp can loosen, and where a leak can develop. On a boosted engine a small leak on the intake side costs more than most owners expect, because the turbos then have to work against a path that never quite seals.
Fewer joints is the reason a welded metal tube run usually beats a stack of adapters, even though the adapter route is easier to sell. It is also the reason the routing should be planned before the parts are ordered rather than after.
Where joints are unavoidable, silicone does the work. The hose has to absorb the movement of the engine, and it has to keep doing that after several seasons of heat cycling.
The intake on this engine starts at the filter housing, passes the airflow meter and feeds two compressor inlets. Most of the restriction sits in the bends rather than in the filter, so a tidy path with gentle transitions is worth more than a larger filter element.
Cool air is the second consideration. A filter drawing from the front of the car sees cooler air than one sitting in the engine bay, and cooler air at the compressor inlet leaves less work for the charge cooler downstream.
Materials follow from position. Titanium suits the tube runs and the parts that see heat but have to stay light. Silicone suits the connections. Aluminium suits the larger formed shapes that would be uneconomical to make any other way.
The charge coolers on this engine sit in the valley between the two banks, which is why the intake pipework has to pass them on the way to the throttles. It is a compact arrangement that works well, and it also means there is very little room to add anything around it.
That makes charge cooling a judgement call rather than an automatic upgrade. Intercooler work on other platforms shows what is possible when there is space to work with, and the same thinking applies here: solve the airflow path before changing the heat exchanger.
Behind the turbos, the F90 owner has options that do not exist on a four-cylinder car. Titanium downpipes for the S63-engined X5M and X6M F95 and F96 use the same material logic on a closely related engine, and titanium exhaust work for the F90 4.4T follows the same route at the back of the car.
Titanium keeps its strength where an exhaust gets hottest and adds little mass at the same time. Stainless steel remains the more repairable choice, and for many owners that matters more than weight.
The exhaust on this platform is also the part owners notice most in daily use, because it is the section they hear rather than see.
Custom work here starts with a negotiation and then the project starts. There is no useful quote without either a drawing or a sample, because the mould has to be made from something.
Mass production starts only after the customer confirms the sample. That is the sequence that keeps a two-branch intake honest, because any imbalance shows up in the sample rather than in the shipment.
Owners often describe their car by model year, but the parts follow the chassis code. F90 is the M5, and F91, F92 and F93 are the three M8 bodies, and the M850i and M550i share most of the same front-end space.
You can see what is already produced on the BMW, Audi and Porsche page and read about this kind of work under titanium exhaust system and exhaust pipe. Intercooler work sits under intercoolers, and anything based on your own file or sample is handled through customization. You can also reach the workshop directly at tigindustry@fupower.com.
The plant covers roughly 53,819 sq ft and employs more than 50 people, which is why a sample can be measured, tested and returned to you before production is agreed.
