The BMW S55 intercooler and heat exchanger debate is a touchy subject. Not many debate that the factory S55 cooling system is capable. Especially when compared to the N54 or N55. However, some believe there are still gains to be had from aftermarket upgrades. Others believe it's a waste of money. In this guide, we will break down the pros and cons of upgraded S55 intercoolers and heat exchangers and list a few popular options on the market.
S55 Air-to-Water Intercooler
BMW's approach to intercoolers drastically changed since the early days of mass producing turbo engine. The N54 and N55 utilized air-to-air intercoolers, often referred to as front mount intercoolers (FMIC's). However, the S55 engine receives an air-to-water intercooler. The below video is a great reference:
In summary, a top mounted air-to-water intercooler shortens the intake tract and reduces lag. Water is also more efficient at cooling the charge air. However, water is tougher to cool down once it's hot (as compared to air). Therefore, the S55 is tougher to cool down once things are too hot.
We should note - again, the S55 system is effective and rarely suffers heat soak. This is especially true on bone stock S55's. There simply isn't enough heat to overwhelm the factory intercooler and heat exchanger. However, all else constant, more boost and more power creates more heat. As such, modded, aggressively driven, or tracked S55's may benefit from an upgraded intercooler and/or heat exchanger.
S55 Upgraded Intercooler & Heat Exchanger Performance
As noted - the S55 stock cooling is very effective. It is unlikely stock S55's see any notable benefits from an upgraded intercooler or heat exchanger. Modestly tuned S55 engines should also hold up well with stock cooling. The true benefits are mostly reserved for those pushing stock turbos to the limit, running upgraded turbos, or aggressively tracking their cars. Even then, don't expect peak power gains on glory runs.
We understand this sounds very vague so far, and it is. There really isn't a ton of data out there. At least - not enough concrete data to make us comfortable saying, "these are great upgrades that we highly recommend". We do believe effective aftermarket options should provide slightly cooler temperatures for those pushing well beyond 600whp. We did find a few logs supporting the claim that upgraded intercoolers and heat exchangers will lower IAT's. However, it mostly seems to be 10-15° temperature differences. Those tests may also be conducted under different circumstances. For example, the stock cooling parts may have been logged after an hour long track session. Whereas, the upgraded parts may have been tested on the first or second pull after warming up.
So Upgraded Intercoolers & Heat Exchangers Aren't Worth It?
Truth be told - probably not. The few percent willing to push the S55 platform to its limits may find value in upgraded intercoolers and heat exchangers. We would like to see vendors and aftermarket companies proving their products. We suspect there is a reason there isn't too much visible data. Testing likely hasn't shown any notable or promising results.
A lot of tuning and performance parts companies popped up after the N54's release. We believe many of them are used to simply manufacturing and stuffing in intercoolers with larger cores and surface areas. It worked well for the N54 and N55 with their FMIC designs. However, it seems a lot more engineering, thought, and design work is needed to significantly improve the factory S55 system. There simply isn't THAT much room for improvement. That's just our opinion. Again, some may still find value in aftermarket upgrades.
Additionally, some have experienced cracks and leaks from the OEM S55 intercooler. If you run into this situation and no longer have warranty then it may be worth considering an upgraded intercooler.
S55 Upgraded Intercooler Options
All that said, we will list a few popular options on the market for those who are still sold on intercoolers and/or heat exchangers. This is certainly not an exhaustive list as there are many options available.
1) VRSF S55 Top Mount Intercooler
We recommend a lot of VRSF's products. We believe they make quality products at an excellent price point. Additionally, their products come with a lifetime warranty to back the quality claims. The VRSF S55 intercooler has a 62% higher capacity than the OEM design. It's also equipped with a high density, dual pass bar & plate core. With a price of only $549.99 this intercooler may be worth a shot for those pushing their S55's hard.
S55 VRSF Intercooler Price: $549.99
Buy Here: VRSF S55 Top Mount Intercooler Upgrade
2) Wagner Tuning S55 Intercooler
The Wagner Tuning intercooler comes in at a totally different price point when compared to VRSF. However, we've decided to include this option since they show significant IAT improvements with their product. To note - as stated on the chart - this test was done on a 775whp S55. We also cannot comment as to the circumstances under which the data was gathered. We're assuming these results also include the installation of their heat exchanger upgrade. It definitely seems to be a notable improvement that will definitely result in better performance. Again, a 775whp S55 is a great example of having enough power to overwhelm the OEM system. The results certainly would not be as promising on a 600whp stock turbo S55.
S55 Wagner Tuning Intercooler Price: $1,990.00
Buy Here: Wagner Tuning S55 Intercooler Upgrade
BMW S55 Upgraded Heat Exchanger Options
Moving onto heat exchangers, we'll provide a few options as we did with the above intercoolers. Once again, this is not an exhaustive list.
1) S55 VRSF Front Mount Heat Exchanger Upgrade
The VRSF upgraded heat exchanger features a high density dual pass bar & plate core, as with the intercooler. Additionally, it also comes at a great price point along with lifetime warranty and satisfaction guarantee. The good price point may make it a product worthwhile to test out.
VRSF S55 Heat Exchanger Price: $399.99
Buy Here: S55 VRSF Heat Exchanger Upgrade
2) Masata S55 Front Mount Radiator/Heat Exchanger
Masata's heat exchanger upgrade increases cooling capacity by 89%. While this is one of the more expensive options on the market, the quality and cooling capacity improvements make it a fantastic upgrade despite its price tag. Additionally, it comes with a lifetime warranty and is a direct OEM fitment.
Masata Front Mount Heat Exchanger Price: $1,000
Buy Here: Masata S55 Heat Exchanger Upgrade
3) S55 Wagner Tuning Front Mount Heat Exchanger
Sticking with the brand trend, Wagner showed great results with their intercooler upgrade. We assume those results also included the heat exchanger upgrade. It's an expensive product as with the intercooler. Therefore, this may not be for the faint of heart. Additionally, results likely won't be as impressive on stock turbo cars.
Wagner Tuning S55 Heat Exchanger Price: $990.00
Buy Here: S55 Wagner Tuning Heat Exchanger Upgrade
BMW S55 Intercooler & Heat Exchanger Summary
We really apologize for the vague nature of this post. It was tough to write as we prefer (and find it easier) to provide concrete data that we truly believe in. That simply isn't the case with the S55. It's an impressive engine that came from the factory with a great overall design, including the cooling system. As boost and power are added the OEM system certainly doesn't keep up as well. However, most stock turbo S55's should hold up well on the factory design.
For those pushing the limits or running upgraded turbos, you may find value in upgraded intercoolers and heat exchangers. As Wagner Tuning showed in their chart - the S55 IAT's remained much cooler with their products. Though, the testing was shown on a 775whp S55 with Pure Stage 2 turbos. Don't expect the same results on stock turbo engines.