HELP... just put my finger through the MAF and killed it....

[Rusty]

I did a thread on AFR gauges a few weeks ago, Terrybullwon is the man to speak to there

[avants2turbo]

Get an RS2 MAF on first - running the wrong MAF is a BIG unknown and I don't wish to be implicated in anything orrible happening to your engine.

AFR guages generally use a 'wideband' O2 probe in place of lambda probe... The best ones provide a simulation of the Bosch lambda signal into the ECU so its doesnt get confused without it.


Paul

makes sence, ill get the RS2 MAF ordered from VAG parts tomorrow, as for the homefry, when i send you my ECU will i get the old chips back? I only ask as its already got a MTM remap, or chip or whatever they do..

Cheers,
Keith

[S2central.net]

Get an RS2 MAF on first - running the wrong MAF is a BIG unknown and I don't wish to be implicated in anything orrible happening to your engine.

AFR guages generally use a 'wideband' O2 probe in place of lambda probe... The best ones provide a simulation of the Bosch lambda signal into the ECU so its doesnt get confused without it.


Paul

[avants2turbo]

Nah - get an AFR on it for a bit of scientific fun.... But I'd put an RS2 MAF on it masel'

AFR = ?

Air/Fuel ratio?

where do i get me one of them, and how/where does that fit? is it like a lambda sensor that just measures the burnt mixture and displays it?

Paul, also, is the "spare" homefry available yet for me to test and send you my ECU to do? (as per our PM correspondance a couple of weeks ago)

[S2central.net]

Nah - get an AFR on it for a bit of scientific fun.... But I'd put an RS2 MAF on it masel'

[avants2turbo]

I didn't come here for an argument... I came here for abuse

S2 MAF and RS2 MAF are identical electrically. Mechanically they can be swapped in/out of S2/RS2 airboxes. The only physical difference is the much talked about screens - tight metal mesh on S2 - much less restrictive plastic mesh on the RS2.

I don't have data for that VR6 MAF but the scaling on it will be very different from the S2/RS2 item. Lets say the RS2 MAF gives a 5V output at 40lbs of air per minute (just a nominal number here)... The VR6 MAF will be scaled such that 5V is for a lower air mass - so when using it on the S2/RS2 the MAF is telling the ECU that a much higher amount of air is being ingested than reality... Its saying the load is higher for any throttle position than reality - consequently the ECU provides more boost and fuel. All sounds good until you realise that if you max the MAF voltage too soon (and I feel you will with this MAF) that after a certain point the ECU just uses throttle position to determine load - cos you get no more info about air mass after it exceeds 20lbs/min... So this is probably OK iduring cruise conditions if lambda adaptation stays within limits.... But at WOT you run the risk of running direct off the maps without accurate MAF inputs....

To cut a long story short, I reckon you'll be running more lean (and with more advance). More lean produces more power - but TOO lean can cause knocking and high EGTs.

Its an interesting one - get some wideband AFR measurements on cruise and WOT to find out for sure.....


Paul

If you think the VR6 MAF will make it run more lean, will the fact that my thermostat is stuck open even things up a bit?

(by stuck open i mean it stays low temp on the motorway, but in traffic sits just above the 90 deg, then back on the motorway it cools right down again)

would that make it run more rich?

i know it was very thirsty before i killed the S2 MAF, not sure if its better/worse as havent really driven it since last night...

[BRY]

I think MAFS are crap and anybody who likes using one is a ****.

Is that enough abuse? :mischeif:

[S2central.net]

I didn't come here for an argument... I came here for abuse

S2 MAF and RS2 MAF are identical electrically. Mechanically they can be swapped in/out of S2/RS2 airboxes. The only physical difference is the much talked about screens - tight metal mesh on S2 - much less restrictive plastic mesh on the RS2.

I don't have data for that VR6 MAF but the scaling on it will be very different from the S2/RS2 item. Lets say the RS2 MAF gives a 5V output at 40lbs of air per minute (just a nominal number here)... The VR6 MAF will be scaled such that 5V is for a lower air mass - so when using it on the S2/RS2 the MAF is telling the ECU that a much higher amount of air is being ingested than reality... Its saying the load is higher for any throttle position than reality - consequently the ECU provides more boost and fuel. All sounds good until you realise that if you max the MAF voltage too soon (and I feel you will with this MAF) that after a certain point the ECU just uses throttle position to determine load - cos you get no more info about air mass after it exceeds 20lbs/min... So this is probably OK iduring cruise conditions if lambda adaptation stays within limits.... But at WOT you run the risk of running direct off the maps without accurate MAF inputs....

To cut a long story short, I reckon you'll be running more lean (and with more advance). More lean produces more power - but TOO lean can cause knocking and high EGTs.

Its an interesting one - get some wideband AFR measurements on cruise and WOT to find out for sure.....


Paul

[UrS4boy]

It will fit, regardless of what they say on there website.
Its cheaper then the S2 one ( if your buying from them or dealers anyway )
It has less airflow restriction, but if yo take the mesh out from the S2 one its even better

As long as you aren't ham-fisted and put your finger through the wire. (Another reason for the RS2 mesh).

While the airflow through the RS2 MAF is better than the stock AAN (ABY) MAF (with the screens in), the electronic outputs are virtually the same. Mihnea found this out some time ago, IIRC, and started tuning the AAN so the RS2 MAF was NOT required. Follow this link for data (a graph):

http://forums.audiworld.com/s4s6/msgs/190502.phtml

Hope we're all friends again. Otherwise we'll have to go to the Monty Python School of Arguments.

"That's not an arguement, that's just contradiction"

"No it's not!"

etc.

[Rusty]

[s2_bo]

It will fit, regardless of what they say on there website.
Its cheaper then the S2 one ( if your buying from them or dealers anyway )
It has less airflow restriction, but if yo take the mesh out from the S2 one its even better

[avants2turbo]

just been on VAG parts website, i was under the impression that the RS2 MAF was a direct fit with the S2 airbox but the VAG parts description is;

RS2 MAF
MAF for engine code ADU, larger diameter compared to normal S2, this is not a direct swap for the S2 as you will need to change the air box due to the size increase


so, does the RS2 MAF fit or not?

[avants2turbo]

now u got a reason to buy an rs2 maf lol

whats the difference between the RS2 MAF and the ABY S2 MAF?

whats the advantage to going with the RS2 one?

whats the part no. and any one got a price?

[Rusty]

Cos of course a sarcastic tone transmits well via text... (that was sarcasm too by the way )

Why is there mesh at both ends then if it's sole purpose is to steady the flow? Why does it then enter a smaller diameter tube with no mesh, to minimise the turbulence of the flow the mesh should be on the smaller tube also? Why does my Slovenian MAF make my car feel faster?

[UrS4boy]

Whilst I know nothing about you, you also know nothing about me so I suggest that you accept that there are different opinions in the world and stop being so rude. I think it's telling that you have resorted to abuse rather than showing me evidence or studies that support your arguement rather than suggesting that I do an experiment that has rather different parameters to the situation we are discussing.

I have had a quick look around and accept that a fine mesh gives a laminar flow but the mesh on the front of the MAF is quite large and this is the reason I am doubtful that it makes any real differece. However, the open weave also thankfully minimises the pressure difference and thus loss.

Finally, if this effect is so important then why did Porsche replace the mesh with a large plastic grid?

You must have missed the link to the VAG info on the mesh and what the factory says the purpose was/is:

http://forums.audiworld.com/s4s6/msgs/140143.phtml

I presume that Porsche thought that the screen was restrictive to flow and decided to go with a more open grid (but notice, they didn't eliminate the grid entirely).



You might want to check out this post and the link out of it as well:

http://forums.audiworld.com/s4s6/msgs/203180.phtml

Oh, yeah, and that wasn't abuse. That was sarcasm.