RS4 MAF Modification

[Sonic]

Ok so i think we want to come up with something at a decent quality and price that's going to fit the new MAF's which Dmitri can source to the more stock ABY/RS2 setup.

A set of 2 alloy reducers between the airbox/MAF and MAF/intake hose sounds ideal if the length isn't going to be too much.

[prj]

Reducers on both ends are pointless, as the flow will just go through the center pretty much, and the MAF won't read high enough.
You can't have a reducer on the inlet, and you don't NEED a reducer on the inlet.
You can cut the airbox and glue it in, or bolt it.



























This is on AAN, I haven't tried on ABY/ADU.

[Sonic]

That's similar to how my current RS2 MAF was modified to bolt into my RS2 airbox (it needed a bracket to fit after the turbo modifications).

What about the inlet hose? Do you have a source for ones that will replace the samco and fit directly onto the new MAF?

[prj]

No, I don't.
Make one out of metal with the necessary bungs, then use silicone hoses.

OR get some company to make you a MAF-Turbo hose with the correct openings. That would be the optimal solution.

[Rusty]

In terms of what I've already had made - the pipe MAF blank could be machined and have a suitable receiver welded to it. I paid ~£40 for the 1 off alloy tube with the beading and limit stops at one end and a piece replicating the flange at the other (very simple and designed to replicate the OE MAF that fits to the airbox and then to the MAF - Turbo hose without any modification). I'd expect to add £40-60 for a machined piece welded to that pipe and the pipe machined to receive it, so something in the region of £150 for a 1 off with an RS4 element, going by the 60 euros quoted above.

To machine the whole housing from Alloy or Delrin (or another non-hydroscopic plastic), you would have to tweak the design to minimise operations and keep the costs down but it would be an all in one design and total cost would be something akin to the welded effort and the cost would definately benefit from being made in a larger batch for sure. I guess the question is whether people want to pay a little less and do some DIY airbox mods or pay a little more and have something that is designed from teh outset to fit.

What bore do you need for the MAF housing, or can it be the 76mm of a 2mm wall, 80mm OD pipe?

[Sonic]

For a bolt-on job £150 sounds absolutely fine... hell the RS2 MAF is about £250 from memory, and Ross's just died after a few thousand miles!!

I'd far rather have a decent, bolt-on solution without having to extensively replace parts, cut expensive and rare airboxes and samco pipes any day, even if it costs a bit more.

[prj]

Rusty, do you realize that sticking the sensor into the smaller tube will limit the amount of air it can read?
It can do 550-600 in the big tube. It'll max out at like 400 in the small one.

Not to mention calibrating this from scratch will be "fun" and I'll have to charge extra, as it'll take a LOT longer than usual.

[Lloyd]

How do you tell when the MAF is on the way out? What are the symptoms?

[Rusty]

Rusty, do you realize that sticking the sensor into the smaller tube will limit the amount of air it can read?
It can do 550-600 in the big tube. It'll max out at like 400 in the small one.

Not to mention calibrating this from scratch will be "fun" and I'll have to charge extra, as it'll take a LOT longer than usual.

I don't realise anything, that's why I asked what ID was required. If it's far larger, then it's a bit more difficult to package and still fit the OE airbox.

How does having the OE inlet trumpet inside the airbox affect things then? That's the same ID as the OE MAF at 72mm or so (from what I've just measured).

[Sonic]

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?

[Sonic]

Rusty, do you realize that sticking the sensor into the smaller tube will limit the amount of air it can read?
It can do 550-600 in the big tube. It'll max out at like 400 in the small one.

Not to mention calibrating this from scratch will be "fun" and I'll have to charge extra, as it'll take a LOT longer than usual.

It's a difficult call though, on one hand you have some Frankenstein car which looks anything but stock, and on the other you have something that fits as stock but which is going to time consuming and more difficult to map.

[Ross]

@Lloyd, I would have never known my MAF was on its way out if Dmitri had not been taking values, what the side-effects are I do not know but it would be interesting to know as I now have my old MAF fitted again...

You'll know if the wire snaps, you get a fault code 2324 and the car will idle and drive like sh*t and hesitate like mad if you try and go on boost.

@Rusty, I think for the direct-fit Dmitri's chinese housings are probably the way to go - he's working on a bolt-on solution so I don't think there's much point in replicating his efforts. What I do think should be investigated is getting an RS4 MAF fitted... modifying airboxes should be for ABY only, not RS2 - they are too rare Can we get these posts into a separate 'RS4 MAF Fitment' thread and clean up Andy's?

[Rusty]

I'm just offering to help with the design, not to replicate or compete.

[Sonic]

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.

[prj]

I don't realise anything, that's why I asked what ID was required. If it's far larger, then it's a bit more difficult to package and still fit the OE airbox.

How does having the OE inlet trumpet inside the airbox affect things then? That's the same ID as the OE MAF at 72mm or so (from what I've just measured).

The ID on the RS4 MAF is 82mm.
The OD on the RS2 MAF is 80mm.

Do you now see the problem?

I don't know how the trumpet affects things, didn't have a problem with that...
The housing that is needed is 0 280 217 531, from the Alfa MAF.
There's a chinese knockoff CH-XX009.

The problem is, I haven't ever held this in my hand, and while from all the measurements and the ID and OD it's a perfect match, in real life there could be some game breaker!

You can get all the dimensions for it here:
http://www.guzzimental.com/documents...%20Sensors.pdf

This info is not exactly top secret, and I am not worried about sharing it.