B48 & B58 Charge Cooler Water Radiator AKA “Heat Exchanger” – Now Available!
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B48 & B58 Charge Cooler Water Radiator AKA “Heat Exchanger” – Now Available!

Stage 1/2’d, or even big turbo’d your B48 or B58 powered BMW? Let’s fix your ridiculously high and power robbing charge temperatures with the CSF Charge Cooler Water Radiator, also known as the “Heat Exchanger”


Let’s jump straight in…

Proven Performance

  • Drops Charge Air Temps ✅
  • Drops Charge Air Temps Consistently ✅

Independently proven to drop Charge air temperatures by 10C vs. the OE heat exchanger. The car tested was a B58 engined car with Pure Turbos Stage 2 Turbo Upgrade!

*Testing conducted in the heart of winter. The tempertature delta will be higher with higher ambient temperatures.

The Low Down

The tuning potential for the charge-cooled M1/240i, 1/2/3/420i and 1/2/3/425i is huge. However, once boost levels are increased the charge air temperature increases which is due to compressed air heating up. The stock cooling system works okay on a stock car but once boost levels are increased and more heat is introduced it begins to struggle.

Increased heat robs power in several ways, the main being that hotter air is less dense and results in less oxygen which is key for power and with the hotter air the risk of knock is also increased, to counter this the ECU will introduce its safety protocols to reduce power until the air is cool again.

You can see in the above testing that during repeated runs the stock charge temperatures begin to spiral, with sustained hard use the stock charge temperatures can run away and due to the efficiency of the stock cooler, it will struggle to decrease them.

The only way to maintain and improve performance is to reduce the temperature is by improving the cooling performance.

The CSF Solution

  • Featuring a super thick 68mm dual-row core which maximises the space available with zero cutting.
  • The Triple Pass design means that coolant passes through the core three times before the outlet for the coolest temperatures.
  • Another feature which you will not find in other designs is CSF’s unique B-Tube technology which uses a uniquely shaped tube, this allows CSF to use a thinner material whilst maintaining strength for an incredibly lightweight core which also improves heat transfer; it’s around 15% more efficient than regular O-Tubes in the same space.
  • Matched with a rock guard, just like the OE part. The CSF Charge Cooler Water Radiator/Heat Exchanger is the ultimate cooling upgrade for the B58/B48 powered motors.

Feature Overview

  • Worlds largest 2-row core 68mm (unique) // Stock is 27mm
  • CSF’s B-Tube technology (unique) // Stock is O-Tube
  • Triple Pass (unique) // Stock is Single Pass
  • Removable Rock Guard – Just like the origonal
  • CNC machined quick connect fittings
  • Fitting requires ZERO modifications
  • Available in Polished Silver or Black

We have many fitments confirmed right the way from the 120i, M140i all the way through to the 440i. Take a look at the below to view


  • 15-18 BMW 120i, 125i, M140i(x) (F20)
  • 15-18 BMW 120i, 125i, M140i(x) (F21)
  • 15-18 BMW 220i, 230i(x), M240i(x) (F22)
  • 15-18 BMW 220i, 230i(x), M240i(x) (F23)
  • 14-18 BMW 320i(x), 330e, 330i(x), 340i(x) (F30)
  • 14-18 BMW 320i(x), 330i(x), 340i(x) (F31)
  • 15-18 BMW 320i(x) GT, 330i(x) GT, 340i(x) GT (F34)
  • 15-18 420i(x), 430i(x), 440i(x) (F32)
  • 15-18 BMW 420i, 430i(x), 440i(x) (F33)
  • 15-18 BMW 420i(x), 430i(x), 440i(x) Gran Coupe (F36)

OEM PART #: 17118741830

How to Order

The first batch of Polished Silver radiators will arrive before the end of February with the Black coolers arriving towrds the end of March.

You can buy the coolers from a CSF dealer who you can find by clicking here or directly via the CSF Europe store below

New release




New Release