Charge Cooling Study

Aftermarket intercooler upgrades are a common bolt-on part for the newer BMW S55/B58 platform. They are an easy sale for vendors due to their bolt-on ability, seemingly low price, and propensity for the stock units to leak.

After thousands of datalogs we are able to compile enough data from track testing to provide a conclusive solution for our clients. This is a very different approach because 1) we don’t sell these parts and 2) our data is a compilation of information from around the entire world, including varying scenarios, conditions, and environmental factors.

The simple answer without reading further is the "Wagner Tuning Competition Intercooler Kit". This offers the best cooling performance.

Here is a recent back to back test on a PS2+ car that we identified during the initial calibration stages as having extremely poor intercooler performance. Thankfully the customer elected to have the shop install a Wagner TMIC at our recommendation and the results speak for themselves. Same car, same day, same dyno.

First picture:
VRSF 5th Gear Dyno Pull 22'C Temp Increase through a single pull
Wagner 5th Gear Dyno Pull 3'C Temp Increase through a single pull

Second picture: Here's the direct swap of the intercoolers showing a 20whp and 20wtq improvement. Temps were significantly improved! Starting temperatures were the same. There are a few reasons we made more power: 1) Reduced IAT = cooler, denser air. 2) Cooler air = reduced detonation levels allowing for more power in the calibration 3) A larger core flows air more easily reducing pumping losses.

So what design is the best between a Bar/Plate or Tube/Fin? Do you want 1 pass, 2 pass or 4 pass? Do you want top/bottom flow or rear/front flow? The correct answer is the one that removes the most heat…

Based on our data, we definitely want to avoid intercoolers with the top/bottom flow arrangement. Regarding passes, the single pass just isn't capturing as much heat, the 4 pass option we recently tested was almost as bad as the VRSF.

How do other intercoolers fare? While most of them are not as bad as the VRSF, if you’re going to make an upgrade, make sure it's an upgrade!

Above you can see coolant from the commonly failing OEM charge cooler in the chair air pipe (which should not have any fluid in it). This can lead to engine failure.