BMW B58 Intercooler & Heat Exchanger Upgrade Guide
Yes, the B58 engine does have an intercooler. However, it is not the common intercooler setup you would see on most turbo vehicles.
While most forced induction engines use "direct" air-to-air cooling, the B58 intercooler uses an "indirect" water-to-air cooling system. The B58 intercooler is integrated into the intake manifold. Compressed air flows through the intake manifold, through the intercooler, which has coolant flowing through its plates.
The indirect cooling system creates a lower volume of air between the turbocharger and intake valve, which increases intake pressure. Additionally, it results in more even temperature distribution within the intake ports. All resulting in a more efficient cooling system and turbocharger, and nearly zero turbo lag.
Can you Upgrade the B58 Intercooler?
On forced induction vehicles, the intercooler is usually an essential performance upgrade. While an intercooler doesn't necessarily create more power, it prevents power loss from excess heat. Additionally, it's an important reliability mod for tuned cars as heat kills engines.
On the B58, the stock cooling system is actually very good. From what we've seen so far, there is little need to upgrade the cooling system unless you are frequently tracking the car or slapping a bigger turbo in the engine. This is good news because, as of right now, there are no intercooler upgrades for the B58. And there likely won't be many in the future.
Because the B58 intercooler is integrated into the intake manifold, upgrading it would require you to replace the whole manifold. Ultimately, you'd be looking at upwards of three or four thousand bucks just to get the parts to replace it. Given the cost, there isn't enough of a market for any tuning companies to mass produce an intercooler upgrade.
With that being said, if you need additional cooling power on your B58, keep reading below!
B58 Heat Exchanger
Mounted directly in-front of the B58 radiator is a heat exchanger. Because the B58 intercooler is water-to-air, there is a need for a cooling system to cool the water that flows through the intercooler. Otherwise the intercooler would turn into a heater.
This heat exchanger mounted to the radiator serves that function. Water circulates from the intercooler to the heat exchanger, then back. The heat exchanger uses an air-to-water design, where ambient air flows through the fins on the heat exchanger, cooling the water inside, before being circulated back to the intercooler.
The OEM heat exchanger has a 1-row core that is 27mm thick. The OEM exchanger uses a "single-pass flow" structure, meaning the water only flows through the heat exchanger once before being circulated back to the intercooler.
Upgrading the B58 Heat Exchanger
Because we can't upgrade the B58 intercooler, our next best alternative is upgrading the heat exchanger.
One of the first and most notable products is the B58 CSF Upgraded Heat Exchanger. The CSF exchanger has a 2-row core that is 68mm thick, drastically increasing air volume and cooling effect. Additionally, it uses a "triple-pass flow" structure where the water is circulated through the heat exchanger three times before being circulated back to the intercooler.
The net effect is cooler water being sent back to the intercooler, therefore increasing effectiveness of the intercooler and reducing intake temps.
As you can tell from the results, intake temps slightly decrease from 4300 to 5900rpms, compared to increasing from 95 to ~112 degrees.
Our Pick: CSF Upgraded Heat Exchanger
CSF's results look great and it appears to be the most widely used on the market today. The heat exchanger bolts directly up to the factory location, with no modification needed. Direct bolt-on applicated and relatively easy to DIY.
Do you Need to Upgrade your B58 Heat Exchanger?
As we briefly mentioned previously, the B58 charge air cooling system is very efficient. With the integrated water-to-air intercooler and supplemental heat exchanger, it is extremely capable of handling tuned and modified B58's.
We would normally always recommend an intercooler if you are going FBO with a more aggressive tune. However, on the B58, the stock cooling system is plenty adequate for FBO/tuned cars. Replacing the heat exchanger will be most beneficial for people who frequently track their cars, or are looking to upgrade their turbocharger.
It might also be more appealing for those individuals who live in very hot climates. While we might not say its a necessity, at $550, its a great reliability and power-retention mod for those who want the additional cooling power or who like to drive their cars hard on the streets.
This B58 Intercooler / Heat Exchanger Guide is Applicable For:
All B58-powered BMW's
1-Series:
- F20/F21 M140i
2-Series:
- F22/F23 M240i
3-Series:
- F30/F31/F34 340i
- G20 M340i
4-Series:
- F32/F33/F36 440i
5-Series:
- G30/G31 540i
6-Series:
- G32 640i
7-Series:
- G11/G12 740i/Li
8-Series:
- G14/G15/G16 840i
X-Series and Z-Series:
- G01 X3 M40i
- G02 X4 M40i
- G05 X5 40i
- G06 X6 40i
- G07 X7 40i
- G29 Z4 M40i
**NOTE: The CSF Upgraded Heat Exchanger only fits the M140i, M240i, 340i, and 440i, in addition to most non-x-series B48 engines.