This post is going to feel a bit odd to write. We typically like to throw in some technical data and analysis. Nonetheless, there are some minor different between the B46 and B48 engines. Let's dive in and discuss the BMW B46 vs B48.
B46 vs B48 Emissions
Emissions standards are really the only difference between the B46 and B48. For the consumer there are no important changes between the two engines. The B46 is a SULEV engine, and is the primary engine available in the US. Some other parts of the world also receive the B46. The B48 doesn't meet the stricter emissions requirements.
It's basically the same as the N20 vs N26 comparison we wrote about here. Unfortunately, we can't track down the exact technical data of the B46 vs B48. However, we have a few reasonable assumptions.
What's Likely Different
This is pure speculation and likely isn't an exhasutive list. We do know the N20 and N26 make the same power and torque. That also applies to the B46 vs B48. If you're leaving the car stock then the emissions stuff is pretty irrelevant as there isn't a noticeable impact to performance. Anyways, we suspect a few differences include:
- Sorted fuel injectors
- Stainless steel fuel lines
- Extra HC fleece filter
- Minor software changes
- Catalytic converter
Again, this is speculation and probably isn't an exhaustive list. Point is - these updates are mostly irrelevant.
The stock B46 and B48 have the same power and torque output. If you're modding the engines then downpipes, intakes, and software (tunes) are 3 of the best basic bolt-on mods. That addresses the primary differences of the engines that could potentially affect performance when modded.
B46 vs B48 Summary
The BMW B46 and B48 are basically the same engine. B46's meet SULEV emissions standards and are the primary engines in the US market. We wish we had more technical data to share. However, B48 is the widely accepted engine code for the B46 and B48.
Power and torque from the two BMW engines are identical. The B46 likely has slightly more restrictive parts like catalytic conveters and air-boxes. However, these are among the best starting bolt-on mods regardless of whether it's a B46 or B48.
Please feel free to drop a comment and share any technical data. Or just throw in any comment - we love to hear from our readers!