CSF 7071 97-02 Audi S4 (B5) Radiator

CSF’s MQB cooling package
High-performance all-aluminum, triple-pass engine water radiator (CSF #7084)

CSF HQ worked with CSF Europe manager Ash Stewart, who is the owner of a highly modified Mk 7 Golf R and experienced driver, to develop the MQB cooling package. The word came across to CSF that there was a tremendous gap in the marketplace for an easy to install / economical cooling solution to control DSG transmission temperatures during heavy track use in automatic transmission vehicles. As the cooling system experts, CSF was there to meet the challenge.

Before installing the upgraded CSF DSG heat exchanger, Ash was not able to push his car after several laps on the track because of high transmission oil temperatures. The transmission in his Golf R would start to feel sluggish, and he was forced to start  (well below optimal shift points) to keep his car out of transmission limp mode and out on the track longer. He was  sacrificing faster lap times, for longer track sessions and to avoid the risk of damaging his transmission. After installing the CSF upgraded DSG heat exchanger + CSF engine water radiator, Ash reported back the following after a competitive track day at Donnington race circuit in the UK.

Observations from driving:

• Oil temperature seems to be consistently much lower by around 10-15°C (50-59°F), allowing me to use all of the revs all of the time without a care for oil temp. It sits at around 125°C (257°F) max now and I’ve never seen it go above 130°C (266°F) (this used to happen after around 2-3 “fast laps” with OEM set-up).
• Oil temperature now peaks and flat lines throughout the sessions. Before it would slowly grow to around 130°C (266°F) and then rise uncontrollably, very quickly and then not be able to cool down. Every time you would jump back on the throttle to drive fast, the oil temperature would spiral out of control again (talking 14°C+ (284°F with EASE). 

Observations from logs:

• Engine coolant temperature does not go above 100.5°C (212.9°F)

What we can say for sure:

• Engine Oil Temperatures are reduced and maintained consistently during full load/rpm 
• Engine coolant temperatures are maintained in the optimum range 
• DSG oil temperatures rises and falls in line with the engine coolant temperature (well within ideal operating parameters)

The MQB platform  of vehicles which have a unique cooling system in that all of the major engine and drivetrain fluids are water cooled (engine water, engine oil  transmission oil). For many of the higher ranging / highest performance models (Audi 8X S1, Audi 8V S3, Audi 8S TT (2.0TSi), Volkswagen MK7 Golf R, and 5F Leon Cupra) there are additional small radiators (heat exchangers) located at the corners of the front bumper underneath the headlights. Used on the left side of the vehicle as the DSG transmission heat exchanger, and on the right side as an auxiliary water radiator.

In these vehicles with 3 upfront water radiators (Center (Main radiator) Left, Right (DSG/Aux radiators). The coolant flows from the engine into the main water radiator. The coolant then splits into a Y piece, going into two auxiliary heat exchangers (small radiators). The right side auxiliary radiator is dedicated solely as a secondary means of lowering coolant temperature to maximize efficiency. The left side auxiliary DSG heat exchanger cools the automatic transmission fluid that is contained in an oil-to-water transmission cooler. 

For best performance to both engine temperatures and transmission performance CSF recommends upgrading the main water radiator (CSF #7084), and the DSG heat exchanger (#8132). For maximum  and heavy track use, CSF recommends upgrading the auxiliary radiator on the right side of the vehicle with an additional CSF #8132 heat exchanger.

Radiator Comparison