Integrated MAF pipe

[prj]

The HotFilm MAFs don't suffer from wires ripping off, but I recently learnt that they do suffer from potentially serious drift (inaccuracy) issues over use which give rise to lean running

Incorrect information. This only happens when it is contaminated with oil, and affects the standard MAF just as much.

Have plenty of cars with RS4 MAF fitted for 3 years without any mixture issues.

[S2central.net]

Interesting... are the running with or without the factory crankcase ventilation system that blows oil vapour around to the MAF location ?
Totally agree the OE hotwire MAF is not immune to such contamination over time, but at least it has the 'burn off' sequence on shutdown to purge any oil droplets that may otherwise be clinging onto the wire... the HFM devices have no such defence that I know of.

[prj]

It is not needed if your dump valve is adequate, as the air does not go backwards out the inlet if that is the case.
Burnoff is not the be-all end-all either.

Plus, it's easy to clean should the need arise.

[Thuppu]

+ That you can get at least three RS4 mafs with the same money as one stock maf.

[S2central.net]

That is a very important point too, but the main thing is you cannot just swap to the RS4 MAF (with a suitable remap) and forget about it... you need a WBO2 monitor to identify if/when the MAF needs cleaning or replacing !

[Error404]

Won't the ECU throw. Mixture adaptation code long before it gets dangerously off piste?

[prj]

That is a very important point too, but the main thing is you cannot just swap to the RS4 MAF (with a suitable remap) and forget about it... you need a WBO2 monitor to identify if/when the MAF needs cleaning or replacing !

Incorrect information once again. I don't know where you are getting this from and how many cars with a RS4 MAF you have monitored.

I have many cars running these, I have retuned a few with hardware upgrades and the mixture was exactly the same 2 years later.

Please state source. There is no use spreading misinformation - the HFM5 is used on millions of cars around the world and it does just fine without any "signal degradation".

Won't the ECU throw. Mixture adaptation code long before it gets dangerously off piste?

It will.

[S2central.net]

I got this info from a reputable source - very well known UK tuning company and yes I too was surprised at what I heard. Maybe it was just some FUD that he wanted to justify his decision to keep the S2 MAF in use. He claimed to have seen them degrade over time and cause lean running. I didnt ask why the ECU didn't raise a fault code on mixture.

[nesshead6]

I have been meaning to replace my potentially faulty stock S2 MAF for some time... If switching to an RS4 one is a more cost effective solution, what would be needed to do this?

[S2central.net]

Currently the ecu software to run that is only available from prj.

[nesshead6]

Yeah I've just been reading his thread about making a stock MAF replacement. Hasn't been updated for a while though.

[prj]

I got this info from a reputable source - very well known UK tuning company and yes I too was surprised at what I heard. Maybe it was just some FUD that he wanted to justify his decision to keep the S2 MAF in use. He claimed to have seen them degrade over time and cause lean running. I didnt ask why the ECU didn't raise a fault code on mixture.

Since there is no one else offering the RS4 MAF on the S2 engine besides me, then how could that company seen the HFM5 MAF's on the S2 degrade over time? Right, they could not have.
Sounds like FUD to me alright

I recently changed the MAF on my RS4 as a precautionary measure. The AFR changed less than 0.1 lambda and this MAF has been on the car for an eternity.

Not to mention the millions upon millions of other cars on the road using hot film technology. Let me guess, they are all running mega lean?!
Maybe a letter to Bosch would be a good idea, let them know their MAF's are all degrading and showing lean, I am sure they will appreciate it. Okay, enough now

The problem is oil contamination. No oil contamination, no degrading. And even when SOAKED in oil completely (oil dripping from it), it's still only about 1 point AFR difference on WOT.

[prj]

Yeah I've just been reading his thread about making a stock MAF replacement. Hasn't been updated for a while though.

I have a working prototype of the solution, but no interest to develop it to an end product, as not financially viable.

[S2central.net]

Since there is no one else offering the RS4 MAF on the S2 engine besides me, then how could that company seen the HFM5 MAF's on the S2 degrade over time? Right, they could not have.
Sounds like FUD to me alright

I recently changed the MAF on my RS4 as a precautionary measure. The AFR changed less than 0.1 lambda and this MAF has been on the car for an eternity.

Not to mention the millions upon millions of other cars on the road using hot film technology. Let me guess, they are all running mega lean?!
Maybe a letter to Bosch would be a good idea, let them know their MAF's are all degrading and showing lean, I am sure they will appreciate it. Okay, enough now

The problem is oil contamination. No oil contamination, no degrading. And even when SOAKED in oil completely (oil dripping from it), it's still only about 1 point AFR difference on WOT.

They did not say they had seen HFM5 degradation on S2 application - just on some other OE applications.

[nesshead6]

I have a working prototype of the solution, but no interest to develop it to an end product, as not financially viable.

How many units would you need to sell to make it viable? Maybe worth starting a 'group buy' thread?