Maf seeing turbulent air, any idea on causes?

[slowcoach3]

I've been doing some research and can't find much in the way of information, so wondered if anyone has any experience or knowledge on what causes a maf to see turbulent air? So far I've changed the maf as this needed doing anyway, swapped cone filters around, tried a short run wth no filter, changed the maf plug all to no avail. Both mafs were genuine bosch ones and have always been correctly supported by a heat shield on the end of my b5 TIP. Does anybody have any ideas?
Cheers

 

[jojo]

How do you see/measure turbulent air going through the MAF ?!

 

[jimmcgee]

How do you see/measure turbulent air going through the MAF ?!

X 2

 

[<tuffty/>]

If the MAF tube is screened and has a straightener then it shouldn't see turbulent air... has seen idle and part throttle issues with de-screened MAFs before and even though it shows more airflow it actually makes less power

<tuffty/>

 

[slowcoach3]

When you log airflow on vcds, when the rpm is the same normally aaround 4k in 4th for example and you look at throttle position-always on light part throttle- and rpm whilst the throttle and rpm is exactly the same the maf readings are all over the place! Sorry if that's a convulted answer! When this turbulence occurs it shows itself as a pulsing which is felt in the cabin as it feels like it rocks the engine

 

[slowcoach3]

The screen ia intact and I believe the maf is all in the correct position, sounds dumb but what do you mean by straightener?

 

[<tuffty/>]

The screen ia intact and I believe the maf is all in the correct position, sounds dumb but what do you mean by straightener?

The plastic matrix thats typically covering the mesh... flow straightener...

<tuffty/>

 

[slowcoach3]

Thanks tuffty, should have realised lol Yup all is present and correct as bosch intended. ****** car.

 

[jimmcgee]

typed [h=2]Maf seeing turbulent air[/h]into google and most of the answers say pod filter problems How do YOU smooth AFR with the MAF table...
Laminar flow at the MAF or turbulent?

 

[slowcoach3]

Thanks dude, I appreciate that, I have given that a bash but I have tried pretty much everything, different brand new bosch mafs, filters no filters etc but it still persists. Weirdly its something that appeared overnight one day not there then bang. Doing my head in. Cars 100% fine on WOT though

 

[jimmcgee]

no problem lol , you have me wondering now , so going to log maf v rev on my torque app that i use every time in the car :thumbsup:

 

[badger5]

perhaps lambda playing silly buggers
narrow band on yours yea?

try disconnecting it and seeing how it fares

 

[slowcoach3]

It is narrowband yes, disconnect the lambda? I'll give it a shot I'm going to be up with Phil tomorrow so I might bring something to bribe you with and try and pick your brains for a minute or two...

 

[aragorn]

You could try a velocity stack on the end of the MAF. Most factory installations have a velocity stack, and they're often binned when you fit a cone filter.

That said, i cant see why it could just appear randomly one day. Might make sense if it appeared after you'd fitted the cone.

 

[slowcoach3]

As you say it's random and that's what's annoying me! If something had been changed I would go back over everything but it doesn't seem to be that easy!