Does anybody know how the Hitachi MAF sometimes substituted in our car output differs from the Bosch? For example, for any given situation is the MAF outputting .5v less than the Bosch would or does it vary?

If it is a constant decrease throughout the range then I am thinking about a plug and play circuit that would allow me to use the MAF without tuning.

Anybody have the part number for the Hitachi MAF?

 

Quick research shows the Hitachi outputs a max of 5v and is at .5v with no air passing. I would assume the Bosch also has a voltage, probably .5v but that is just a guess, with no air passing over. From what I understand, and this could be wrong, both have the same maximum output voltage but the Hitachi sees more flow to get to max. If all of these statements are true then my original circuit idea won't work as I had hoped. The ECU calibration would be far easier than the circuit necessary.

 

would replacing the MAF pipe with a larger diameter unit and re-calibrating the tune allow us to see greater flow rates using the same MAF sensor? Assuming no turbulence is created when upsizing the pipe diameter, the accuracy level of the MAF should remain near the same, no?

 

From my research on MAF's I think you're right. I would be interested to hear what a tuner says.

 

our MAF pipe is already a pretty large diameter. i have not seen something this big used from a factory before.

 

for sure, but there's always bigger, could always just step up a section of the MAF pipe to ~5" too, as long as turbulence isn't created... think it's worth a shot for a tuner to try out

 

Part number is HTC AFH75-01A

Audi number 06 C 133 471 A

If u still wanted it ?

 

I believe keeping velocity up in that area is just as important if not more so than making a bigger volume pipe.
Then after that section would the rest of the intake plumbing benefit from it?

 

Would probably be a compromise solution, perhaps lacking some sensitivity at idle/very light throttle/flow but gaining the ability to read/not max at very-high power levels...think it's worth looking into for the guys that are having MAF issues and should be pretty easy for anyone with some light-fab skills and a datalogger/tuner to work with
Cheers,

 

Yes, that is how we typically do it. The Hitachi MAF does offer better drivability, and the larger housing allows for full resolution.

 

But as you said, with the Hitachi one.. Most like because that one can handle/read a bigger volume, lower velocity?

 

Yes, from what I've seen the Hitachi has better resolution than the OEM Bosch.

 

I think the Bosch uses an integrated IAT sensor. Does the Hitachi as well?