Bosch MAF Housing Upgrade Diameter – Product Codes

May 30, 2025 Off By RICHARD

Sometimes the diameter of your Bosch MAF housing may not be enough for the power you are running. The information below summarises the Bosch part numbers and the corresponding MAF housing dimensions/diameters. So you know what codes to look for, to get X diameter.

Bosch HFM5 MAF sensor and housing specs.

Code	Outer Dia mm	Inner Dia mm	Temp Sensor	Range kg/h	Power Estimate bhp
0280217123	60	50	Yes	8-370	153
0280218019	70	62	Yes	10-480	199
0280217531	71	80	Yes	12-640	264
0280218008	86-84	78	No	12-850	350
0281002421	92	82	Yes	15-1000	415

Bosch MAF sensor codes with housing information from this data sheet

Plug Housing	Contact Pins	Gaskets	Wire Cross Section
1 928 403 836	1 987 280 103	1 987 280 106	0.5-1 mm3
	1 987 280 105	1 987 280 107	1.5-2.5 mm3

MAF sensor accessory/connector information

Where to Find?

Your local Bosch auto part dealer is the obvious choice.

But if you just want the housing or you are happy to take the risk with a non-branded MAF sensor you can try the usual auction sites.

Case Study

In our case we only needed the housing for a VAG 1.8T 20v motor running 300+bhp.

We ordered the largest MAF sensor from Aliexpress. The supplied MAF sensor was removed from the housing and replaced with the Bosch MAF sensor that was already on the engine. This gave the accuracy of the Bosch sensor with the much bigger flow capability of the large housing.

Difference

Originally the MAF sensor was close to 4.5 volts before full boost and full RPM which seemed liked the MAF signal might have been pegged. (Original housing was 80mm outer diameter).

With the 92mm outer diameter MAF housing, peak MAF signal was down to 3.6 volts, well within the measuring range of the MAF sensor element.