Thread: How to completely get rid of MAF on de-EGR'd TD5

I presume cos the tachosoft map is more air flow dependant and with this mod the MAF signal is linear along the throttle travel and the original reading is not as the higher(not dangerous though) readings were in the middle range not at full throttle

The recent comment on the MAP calculating (actually allowing calculation of) air mass used/cyl would only be possible IF you had a comparison of air mass entering engine (can anyone tell me which device provides this?), inlet air temperature and ambient pressure of inlet air.

THEN, the MAP would have to calculate the pressure drop per cylinder inlet cycle (the usual suspects in the MAP sensor field are NOT sensitive enough to sense in the frequency range of the engine cycle frequency). At the MAP level it will also need to account for a difference in temp post turbo and take these figures to the ECU and then it will need to calculate a comparison between MAF and MAP figures and establish an actual "boosted" air mass (again, based on inlet temp, pressure, post turbo temp and pressure). The ECU is more than capable of performing the functions but the MAP sensor is not really that sensitive. In fact in an NA application I had to place the MAP sensor attached to a reservoir separated from the plenum. All because of changes in pressure and slow response due to cam profiles (but that happens when you add 8mm of weld to a cam tip).

THEN there is the issue of pulse reversion in addition to basic plenum design (not getting into laminar flow properties around the sensor) causing all sorts of funky things happening inside with the air mass.

Ahh time to resurrect this great thread.

Has anyone done Sierrafery's MAF isolation mod to an EU3 auto?

If so what results were achieved?

Regards Philip A

Originally Posted by PhilipA

Ahh time to resurrect this great thread.

Has anyone done Sierrafery's MAF isolation mod to an EU3 auto?

If so what results were achieved?

Regards Philip A

Maybe read this...

http://www.aulro.com/afvb/discovery-...ml#post2189106

It's a pity this thread is based on almost entirely fallacy and misinformation - on both sides.

To clarify the purpose of the MAF on Td5's:

- EU2's use the MAF/RPM primarily for EGR, MAP/IAT for calculating airmass, and MAP/AAP for boost.

- EU3's use MAF/RPM for calculating airmass, MAF for EGR and MAP/AAP for boost. If the MAF fails or is disconnected the ECU falls back on the MAP/IAT to calculate airmass and a simplified fuelling strategy.

On the EU2 the "mod" is essentially pointless, and on the EU3 it will cause mis-fuelling (which might be interpreted as "better" performance).

In other words: it's an idea that should have taken around the back of the farm shed and put out of it's misery at post 2.

Paul, it's known that a bad MAF on an Auto impacts the transmission behaviour- do you have the exactly link between the two?

I've often wondered if it's ECU torque calculation / demand or a direct feed to transmission CU.

Offtrack , great to see you back.

I have done quite a few mods to my 02 EU3 auto D2.

They are , cleaned up airbox, complete removal of EGR, 18.5-19 about PSI (Nanocom and gauge agree) boost, Remap, decat, free flow muffler, ceramic coated exhaust manifold, and turbo blanket . The car also has a snorkel.

I have an EGT gauge just in front of the turbo. it will show about 720C if kept pretty flat at 115Kmh up a big hill, say Moonie Moonie hill southbound. I usual like to keep it to 650C

My MAF is about 3.5 Years old VDO.

The car goes really well but I tested it out last night and it gave the same symptoms as when I had a crook MAF when I first bought the car.
No faults.
Symptoms are stuttering at 4000RPM at full throttle full load in 3rd up a hill accelerating back up to 110Kmh from the inevitable night roadworks 40Kmh zone.
I think the MAF is OK but the air flow is now taking it over 650 and back to zero..

It is no big deal as I seldom use full throttle full revs, and the car goes REALLY well with otherwise perfect driveability but it would be nice if there was a cheap fix, like a high output MAF available, or the bypass worked.

I have done a lot of research but there doesn't seem to be any uprated MAFs available except for IRB and they seem hard to contact.

Any comments on this perennial topic?

Regards Philip A
.

Originally Posted by PhilipA

It is no big deal as I seldom use full throttle full revs, and the car goes REALLY well with otherwise perfect driveability but it would be nice if there was a cheap fix, like a high output MAF available, or the bypass worked.

I have done a lot of research but there doesn't seem to be any uprated MAFs available except for IRB and they seem hard to contact.

Any comments on this perennial topic?

Regards Philip A
.

Funny you should ask....

I've been working on a recalibration for the stock MAF which extends the range quite a bit.
It should read virtually the same as stock to 680, but theoretically extends usable range to 840ish.