Next Level Performance
August 8, 2026 • 9 min read
Our Verdict
The CSF #8178 Twin Charge-Air-Cooler Set is the single best heat-soak fix for the BMW M5 F90 and M8, running liquid-to-air cores that are 100% larger than factory per side.
If your S63-powered M car pulls timing on the second flat-out pull, CSF’s drop-in charge-air coolers keep intake air temps down and power up — and they cut 60–130 mph times by roughly 0.3 seconds. At $2,799 for the pair, it is a proven, install-and-forget upgrade.
Shop Our Top Pick →The BMW M5 F90 intercooler upgrade from CSF — officially the #8178 Twin Charge-Air-Cooler Set — is a bolt-in cooling system that replaces both factory liquid-to-air charge-air coolers on BMW’s S63 4.4L twin-turbo V8. It fits the 2018–2023 M5 (F90), including Competition and the 627-hp M5 CS, plus the M8 (F91/F92/F93) in coupe, convertible, and Gran Coupe form. On paper the S63 makes 600 to 627 horsepower, but on a hot day or a second track pull, that number quietly evaporates as intake air temperatures spike and the ECU pulls timing. At NLP Performance in Tampa, FL, cooling is the first upgrade we recommend for these cars, and the CSF charge-air coolers are the part we reach for. Here is exactly what they do, what they cost, and whether they are worth it.
Why the S63 V8 Heat-Soaks Under Boost
Heat soak is what happens when the factory charge-air coolers can no longer pull heat out of the compressed intake charge, so intake air temperatures (IATs) climb and the ECU retards ignition timing to protect the engine. The S63 is a hot-vee twin-turbo design — both turbochargers sit inside the V of the block — which packs enormous heat into a tight engine bay. BMW cools the boost with a compact liquid-to-air (water-to-air) intercooler system rather than a front-mount air-to-air unit. That system is excellent for instant response and packaging, but its small cores saturate quickly under sustained load.
The symptom is familiar to every F90 M5 and M8 owner who has run back-to-back pulls: the first launch feels violent, and the second feels soft. Track laps have long, high-load runs with short breaks, so the coolant and cores never get time to recover, and thermal saturation sets in. In stop-and-go summer traffic the same thing happens at low speed, because there is no airflow to reject heat. Once IATs climb far enough, the S63 pulls power — and in the worst case, drops into limp mode and ends your session early. A larger charge-air cooler is the most direct way to keep intake temps in a safe, consistent window.
CSF’s liquid-to-air cores are the largest that fit the factory M5 F90 / M8 location.
What Is the CSF F9X Twin Charge-Air-Cooler?
The CSF #8178 is a direct-replacement pair of high-performance liquid-to-air charge-air coolers (intercoolers) engineered specifically for the BMW M5 F90 and M8 S63 engine. CSF used CFD analysis and real-world testing to build the largest core that fits the OEM location, then integrated the charge pipe into a single-piece design for the strongest, lowest-restriction system possible. The result is a drop-in upgrade that installs in the factory location with no modifications — you keep the OEM look and packaging while roughly doubling core capacity per side.
Core Design: 100% Larger Than Factory
Each CSF core is roughly 100% larger than the factory unit per side, which directly increases the system’s capacity to absorb heat from the hot charge air leaving the turbos. CSF replaces the weak OEM crimped-on plastic end tanks with larger, CFD-analyzed, 100% TIG-welded cast aluminum end tanks — the same construction philosophy that keeps their coolers alive on the highest-horsepower S63 builds. The single-piece design integrates the charge pipe, eliminating a factory joint and adding strength where boost pressure is highest.
CSF also machines dual 1/8-inch NPT ports into the outlet-side air tanks, placed directly in the post-intercooled charge stream, so owners running water/methanol injection have a clean, correctly located injection point. The set ships in a crinkle-black finish, and CSF notes the coolers are currently running on the top five fastest S63-powered M cars in the world — a strong signal that the cores hold up when the power climbs well past stock.
Key Specifications — CSF #8178
TIG-welded cast aluminum end tanks replace the failure-prone OEM crimped plastic.
CFD-designed cores maximize surface area within the factory M5 F90 / M8 footprint.
Performance Gains: What the CSF Coolers Actually Do
In independent testing the CSF charge-air coolers improve 60–130 mph times by approximately 0.3 seconds, which is the real-world signature of lower, more stable intake air temperatures. A charge-air cooler does not add peak horsepower on a single cold dyno pull the way a tune or downpipe does; instead, it protects the power the S63 already makes. When IATs stay in a safe window, the ECU stops pulling timing, so the second, third, and fourth pulls feel as strong as the first. On a big-power tuned car, denser, cooler charge air also lets a calibrator run more aggressive timing safely.
Think of it as consistency insurance. A stock F90 M5 can trap a strong number when everything is cold, but a tuned car making 700-plus wheel horsepower will heat-soak almost immediately without a cooling upgrade. That is why CSF’s cores are the baseline mod on the quickest S63 cars in the country — they turn a peaky, heat-limited setup into one that repeats its best pull all day.
The single-piece design integrates the charge pipe for a stronger, lower-restriction path.
The complete CSF #8178 pair replaces both factory S63 charge-air coolers.
Installation & Fitment (F90 M5 / F91–F93 M8)
The CSF #8178 is engineered as a true drop-in fit that installs in the OEM charge-air-cooler location with no cutting or modifications required. It replaces both factory coolers and their integrated charge pipes, so most experienced technicians complete the job in a few hours as part of a front-end service. Fitment covers the 2018–2022 M5 base, 2019–2021 M5 Competition, 2022 M5 CS, and 2020–2023 M8 in coupe (F92), convertible (F91), and Gran Coupe (F93) body styles — every U.S. S63-powered M car of this generation.
One important note before you buy: CSF lists this set as not available for shipment to California because it is not CARB-exempt. For customers in the other 49 states it is a straightforward performance upgrade. At NLP Performance we recommend pairing the install with a fresh coolant service for the low-temperature circuit so the new cores start with clean, full-strength coolant. If you are not comfortable working on the front end of an M5 or M8, have a qualified shop handle the swap.
Dual 1/8-inch NPT ports in the outlet tanks are ready for water/methanol injection.
Pair It With the CSF S63 Oil Cooler
The CSF #8317 High-Performance Engine Oil Cooler is the natural companion to the charge-air coolers, addressing oil temperature the same way #8178 addresses intake temperature. The factory S63 oil cooler is an all-metal design with several known weak points; CSF reinforces those areas with stronger materials, a rugged bar-and-plate core, cast end tanks, and 100% TIG-welded construction. It was developed with CarBahn Autoworks specifically to survive the extra heat of their S63 stroker kit, so it has huge headroom for a street or track car. Each unit is individually leak- and pressure-tested and backed by a 2-year limited warranty.
The bar-and-plate CSF oil cooler was co-developed with CarBahn for S63 stroker heat.
How the two CSF coolers compare
Both CSF cooling upgrades target a different heat source on the S63: the charge-air coolers control intake air temperature, while the oil cooler controls engine oil temperature. Here is how the two products line up side by side so you can decide whether to start with the charge-air set, the oil cooler, or both.
| Product | Cools | Core / Build | Fitment | Price |
|---|---|---|---|---|
| CSF #8178 Twin Charge-Air-Cooler SetTop Pick | Intake air (IAT) | Liquid-to-air, 100% larger cores | F90 M5 / M8 (S63) | $2,799.00 |
| CSF #8317 Engine Oil Cooler | Engine oil temp | Bar-and-plate, TIG-welded | F1X & F9X M5/M6/M8 | $719.00 |
On a tuned F90 M5, the first two pulls used to feel completely different. After the CSF charge-air coolers went in, the car repeats its best pull instead of falling on its face when it gets hot — that consistency is the whole point of the upgrade.
— NLP Performance Install Bay | Tampa, FL
CSF Charge-Air-Cooler Pros & Cons
What We Like
- + Cores 100% larger than OEM per side for big IAT reduction
- + True drop-in fit in the factory location, no modifications
- + TIG-welded cast tanks and integrated charge pipe for strength
- + Dual 1/8-inch NPT ports ready for methanol injection
Things to Consider
- – Not available for shipment to California (not CARB-exempt)
- – Protects power rather than adding peak HP on a stock car
- – Premium price; front-end labor recommended for install
Frequently Asked Questions
Does the BMW M5 F90 need an upgraded intercooler?
Any tuned or track-driven BMW M5 F90 benefits from an upgraded intercooler, and even a stock car improves in consistency. The factory liquid-to-air charge-air coolers are small and heat-soak quickly under sustained load, causing the S63 to pull timing and lose power on back-to-back pulls. CSF’s #8178 set roughly doubles core capacity per side to keep intake air temperatures stable.
How much larger is the CSF charge-air cooler than the OEM unit?
Each CSF core is approximately 100% larger than the factory charge-air cooler per side. That extra volume dramatically increases the system’s ability to transfer heat out of the compressed intake charge, which is why intake air temperatures stay lower and more consistent during repeated wide-open-throttle runs.
Will the CSF charge-air cooler fit my BMW M8?
Yes. The CSF #8178 set fits the 2020–2023 BMW M8 in F91 convertible, F92 coupe, and F93 Gran Coupe form, along with the 2018–2022 M5 (F90), 2019–2021 M5 Competition, and 2022 M5 CS. All of these share the S63 4.4L twin-turbo V8 and the same charge-air-cooler location.
Do the CSF coolers add horsepower?
The CSF charge-air coolers protect horsepower more than they add it. On a stock car they mainly restore power lost to heat soak, keeping the second and third pulls as strong as the first; independent testing shows about a 0.3-second improvement in 60–130 mph times. On a tuned car, cooler and denser charge air lets a calibrator safely run more aggressive timing for real gains.
Is the CSF charge-air cooler a drop-in install?
Yes, the CSF #8178 is a drop-in fit that installs in the OEM location with no cutting or modification. It replaces both factory coolers and their integrated charge pipes, and most experienced technicians complete the job in a few hours. If you are not comfortable working on the front end of an M5 or M8, a qualified shop can handle it.
Does the CSF charge-air cooler ship to California?
No. CSF lists the #8178 charge-air-cooler set as not available for shipment to California because it is not CARB-exempt. Customers in the other 49 states can purchase and install it as a standard performance upgrade.
Kill Heat Soak on Your S63 M Car
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