JasonS4+Festicle

So, I'm running home brew stage III. Was using an 85mm MAF from VAST mated to an open element filter. Anyone that has used a set-up like this knows it is a bit louder than using a stock airbox. I was hoping to get rid of the noise so went back to the same MAF housing mated to a stock airbox top.

Apprently, the way the MAF housing is mated makes a big difference in MAF readings and consequently fueling.

So, I put the MAF to stock box in and immediately was running rich - like 10.0 on my wideband (that's as rich as it goes).

Tried pulling fuel with Lemmi - no better.

Mike2KS4 suggested I change how the MAF was mated since any turbulent airflow can really mess things up.

Here are some before pics:

<img src="http://img.photobucket.com/albums/v294/jasons4/maf-before1.jpg">

<img src="http://img.photobucket.com/albums/v294/jasons4/maf-before2.jpg">

Again A/F pinned at 10.0 on my wideband. This is with greentops and -22% primary fuel pulled.

Notice the blue epoxy areas that seem to cause a tiny narrowing before the MAF.

Thanks to WindyCityS4 for his help and Mike2kS4 for his suggestions, as well as Piggie who mentioned opening up this area. I dremmeled away (and used a die grinder) some of the extra "stuff". I then used an epoxy paste to fill any new holes I created.

The result:

<img src="http://img.photobucket.com/albums/v294/jasons4/maf-after1.jpg">

<img src="http://img.photobucket.com/albums/v294/jasons4/maf-after2.jpg">

A/F ratio now mid 11's to 12's. No other changes - just made sure the opening in front of the MAF had no areas that could cause turbulence.

Our MAF sensors are very sensative and even this little bit of abnormal flow was apparently causing bad readings.

My g/s went DOWN after opening up that area. I think I was getting a falsely elevated airflow reading causing my car to give more fuel than it needed.

Hopefully, this will help anyone who might be having odd fuel issues.

ModifiedA4

pics work now...(edited)

Arcteryx::Stock Rods

thanks for the post....when/if i get my car, i'll make a mental note to check it out.

2000s4biturbo::Uli

is it glued directly to the maf?

Audeye A6

pictures worky now.

lemieux@curbside

and build jb weld all around it .. it would be perfect if you can find a bell mouth 4"
i was thinking about doing that for the next summer.
btw i have the exact same MAF.

ModifiedA4

i wonder if a short velocity stack at the maf/airbox junction would be a good idea.

WindyCityS4

The MAF housing is "glued" to the airbox, but the MAF sensor can be removed.

Todd/A.W.E.

our MAF housing design.

That is why the straightener was a necessary part for us.

The turbulence is from the airbox, not from the "step" in our housing.

Captain Matt, I be

i have some interesting ideas about rigging something up, i need to find a spare airbox cheap.