RS4 MAF Modification

[prj]

is that 400hp? The RS2 MAF can cope with >400 (although clearly for not very long) so surely a pipe with the same diameter as that would be ok?

The RS4 MAF is at 5.67V, which is maximum before 390 hp.
After that the ECU is going blind.

On Ross' car the MAF was maxed by 5000 rpm, the rest was last cell mapping.

[Ross]

Excellent

I appreciate a couple of reducers are not the most ideal, but as rusty pounted out there is a trumpet already in the airbox so another 2.5mm radius surely shouldn't cause a problem with airflow in the MAF and disrupt readings. It would need to have a tapered increase in bore with no sharp angles, like a bottle kneck, IIRC. JP has a good handle on fluid mechanics so perhaps he can confirm. Hell, perhaps he can do a port & polish on a reducer too

Perhaps the way to go is a housing with the bore of the RS4 MAF, but a design that can be fitted to the airbox without modification? The MAF does have a fat O-ring between it & the airbox, so that has to give some room to play with...

I think the first step is get an RS4 MAF to take measurements. Perhaps I need to give TPS a call....

[prj]

You already have a matching housing. If you have money to blow, go buy that housing and see if it fits. After that I will tell you the code of the RS4 sensor and you can buy that from Bosch.

Hell, buy two of them and I'll take one off you:

http://www.aliexpress.com/store/301124/210332855-380322261/Mass-Air-flow-meter-OEM-0-280-217-531-.html

Aliexpress is safe to use.

[Rusty]

The Alfa MAF housing does indeed have the same measurements as the OE, excluding the ID, which is 72mm on the OE MAF I've just measured.

Is the next part along the RS4 MAF? The quoted ID is 78mm, which could be worked with quite nicely, as the silicon hose and rubber O ring would allow for a little extra thickness on the inlet and outlet and thus a wall thickness of 1.5mm could be used

[prj]

Im just trying to work out if its a case of just having you over with an RS4 MAF Dmitri, to fit and remap, job done, or whether i need to head to a garage to let them work out how to modify the car to fit an RS4 MAF before you get over here.

Yes, you should be able to have a really good idea on how to get it fitted before I get there.
I'll do the electrical work, but the rest...

[prj]

The Alfa MAF housing does indeed have the same measurements as the OE, excluding the ID, which is 72mm on the OE MAF I've just measured.

Is the next part along the RS4 MAF? The quoted ID is 78mm, which could be worked with quite nicely, as the silicon hose and rubber O ring would allow for a little extra thickness on the inlet and outlet and thus a wall thickness of 1.5mm could be used

I posted the RS4 measurements already in this thread, but It's the one on the right side.

[Rusty]

Ah yes...

What are your plans for that Alfa housing then? Are you going to fit an RS4 element to it and scale it? If you wanted an OE fit housing capable of larger air flow than that one (due to a bigger ID) then that's very possible and gives you a bolt-in solution for a few more ponies and the RS4 MAF for the big boys. The RS4 MAF is a little more difficult to fit to an OE airbox and would require some gentle internal tapering to get to the larger ID...

[prj]

I am looking to move entirely to the Alfa china housings with a RS4 sensor.
And for higher horsepower cars where the turbo does not fit anymore anyway with the aribox in place, I am looking to use the Pro-M pressure side solution, which is good for 800hp.

It's a bitch doing all the plumbing. Sticking the MAF on the pressure side simplifies lots of things.

I got this figured out pretty well, I just need some time to finalize all the solutions.
I actually even have the PCB design of the converter, and the software, I just lack time to test everything.

[Sonic]

gentle internal tapering

[Rusty]

Something like that!

About 5 degrees or so.

[Ross]

This afternoon was really dragging till this thread cropped up. Don't tell my boss

Alpha housing... so it fits stock, but does it have a bigger ID, to support bigger HP? Or is it the same with the ~390hp limit?

I guess I'm just trying to work out if I should go for this option, get the RS4 MAF and make it fit, or try my luck with my old MAF until Dmitri has the big HP version ready....

[Sonic]

Something like that!

That's how i imagine my airbox is feeling right now

[Rusty]

Something for discussion - a housing with 5 degree internal tapering to go to 82mm ID.

The left end (inlet) could be tapered down to the size of the internal trumpet on the airbox and thus avoid the step change.

[europeanme]

my rs4 MAF is within 'grabbing' distance...what do you want to know?.....

You watch someone will come up with a genius idea after I took the plunge and brought the MAF...

[prj]

Alfa version will still be 400 hp limit.
The idea behind that thing is to provide a good replacement for the stock MAF, as they seem to be getting more and more expensive.

The whole idea is a plug and play solution.