R35 MAF in Legacy Skylines

[louis110]

So Vex's input is that the scaling in the software will be hard to work with. I had already ordered a couple of R35 MAF sensors from Feast, but haven't bought the housing yet. I'm planning on getting the HPI stock sized housing so it's a drop in affair, but according to Feast most of the other companies that sell the maf adapters are using a 80mm housing. What's the impact of using the stock sized housing? I'm guessing there shouldn't be any problems if HPI and other brands sell it, and a custom tune is a custom tune no?

[Skym]

There is documentation available on how to do the conversion and can compensate for the MAF differences with the way the tuning software is programmed (I gather some formula they use). With the maps, they could be more or less than ideal on some cells on fuel, ignition map, so like with any MAF change a retune is needed after conversion.

From what I understand, size of pipe is important as some MAF sensors are more sensitive to small changes in airflow that can upset them. You get that problem with Ford Racing Lightning MAF, etc.

I gather it has something to do with the sudden change in velocity and velocity is higher with smaller diameter piping, so sudden changes in airflow cause problems with the sensor. With bigger piping the velocity drops. That's with the same amount of air entering intake piping (engine, turbo sucking air in). Maybe a engineer on the forum could elaborate more on the subject of piping size, velocity, etc.

[louis110]

There is documentation available on how to do the conversion and can compensate for the MAF differences with the way the tuning software is programmed (I gather some formula they use). With the maps, they could be more or less than ideal on some cells on fuel, ignition map, so like with any MAF change a retune is needed after conversion.

From what I understand, size of pipe is important as some MAF sensors are more sensitive to small changes in airflow that can upset them. You get that problem with Ford Racing Lightning MAF, etc.

I gather it has something to do with the sudden change in velocity and velocity is higher with smaller diameter piping, so sudden changes in airflow cause problems with the sensor. With bigger piping the velocity drops. That's with the same amount of air entering intake piping (engine, turbo sucking air in). Maybe a engineer on the forum could elaborate more on the subject of piping size, velocity, etc.

Good points. Conveniently enough I have my B. Eng in aerospace engineering and fluid dynamics was one of my stronger areas. It's too bad I don't know **** about tuning a car lmao. But yeah you're right, with subsonic flows, smaller piping means higher velocity and lower pressure. I don't know what the 'ideal' condition for a maf sensor is, but I guess a more accurate reading can be taken when the velocity is lower due to a smaller pressure delta in the maf housing.

Have you come across any documentation you can share with us here?

[Skym]

Then there's the engineer we were looking for.

Also the calibration of the MAF sensor (airflow to voltage) is done in a certain diameter housing. I guess the MAF sensor (airflow to voltage) would need to be recalibrated to suit. I gather that's what a Z32 MAF sensor is. There's places that can recalibrate MAF sensors, but not sure who does it (I assume manufacturer).

This is the documentation for Nistune and R35GTR, etc slot sensors (page 5 onwards) -

http://nistune.com/docs/Nistune%20MAF%20Tech%20Notes.pdf

It's how the conversion works with the software and recommended piping size, etc. I was thinking of switching and running in blow through configuration instead of draw through as used by factory. But there might be temperature differences, as inlet temps drop after intercooler, so still on the fence about is it worth it.

The thing that puts me off a bit is the slot sensors seem to be known to fail earlier than normal MAF sensor (if cheap it doesn't really matter too much and would be part of routine servicing). But not sure if that's due to wet airfilters being used. Something that needs to be looked into for this type of conversion.

[racer986jec]

Run the z32 set up and give it time to run the R35 setup's

[louis110]

Run the z32 set up and give it time to run the R35 setup's

Probably the most logical way forward, since tuning on R35 mafs is still uncharted territory outside of Japan and Australia. I want to avoid switching back and forth between setups though you know? Get it right the first time kind of thing. It seems that taking the maf scale from a VQ sets up a good baseline and the tuner can dial in from there.