Descreening The Maff

[wild willy]

I recently replaced my maff with a new unit and was pleased to reach 246g/sec, this was a little aggressive boost wise in the mid range so i made adjustments with my mbc and limited peak boost to produce 237 g/sec.
i have run a non screened oversized maff housing in the past that always produced good results but obviously under read. So i descreened a stock maff housing to see what the results would be.

Standard maff housing.
RPM Mass Flow Load
TIME
STAMP /min g/s %
150.96 2920 80.53 93.7
151.67 3280 138.47 100
152.27 3760 171.19 100
152.88 4200 186.39 100
153.48 4640 193.42 100
154.08 5080 210.69 100
154.69 5480 224.39 100
155.29 5840 231.19 100
155.89 6160 234.11 99.6
156.5 6440 235.94 99.6
157.11 6720 237.78 99.6

RPM Temperature Load Absolute Pres.
TIME
STAMP /min °C % mbar
150.66 2800 24 67.1 1330
151.37 3120 24 95.3 1790
151.97 3480 25 79.6 2490
152.57 4000 24 83.5 2540
153.18 4440 24 82.4 2530
153.78 4880 24 86.7 2510
154.38 5320 24 95.3 2400
154.99 5680 24 95.3 2350
155.59 6000 24 95.3 2300
156.19 6320 26 95.3 2310
156.8 6600 27 95.3 2220

Descreened Maff

RPM Mass Flow Load
153.4 3440 172.25 100
154 3920 190.11 100
154.71 4480 205.11 100
155.31 4920 216.36 100
155.91 5360 235.06 100
156.52 5720 241.53 100
157.12 6080 250.64 100
157.72 6360 253.36 100
158.33 6640 255.89 99.6

RPM Temperature Load Absolute Pres.
153.7 3680 24 5.1 2540
154.4 4240 23 5.1 2540
155.01 4720 23 5.1 2530
155.61 5120 24 5.1 2490
156.21 5520 24 5.1 2440
156.82 5880 24 5.1 2420
157.42 6240 26 5.1 2310
158.02 6520 27 5.1 2320
158.64 6720 27 0 2340

Descreened maff housing gives 255g/sec which is a nice gain. The cynical part of me says that since the meshing is there to straighten air flow into the maff, all i have done is messed with calibration. However when you see how much of a restriction the plastic and meshing is in the intake system it can be seen that air flow has simply increased. This is proved by the increase in turbo boost generated. More in = more out.
With further boost adjustments and an alteration to the intake system i'm looking for 270g/sec provided that the maff doesn't get maxed out.

 

[ibizacupra]

Descreened maff housing gives 255g/sec which is a nice gain. The cynical part of me says that since the meshing is there to straighten air flow into the maff, all i have done is messed with calibration. However when you see how much of a restriction the plastic and meshing is in the intake system it can be seen that air flow has simply increased. This is proved by the increase in turbo boost generated. More in = more out.
With further boost adjustments and an alteration to the intake system i'm looking for 270g/sec provided that the maff doesn't get maxed out.

I wonder what effect to flow across the sensor vs its calibration is happening also.
agree with the fine mesh screen also looking like it woul dbe nicer flowing without it

some great airflow thru it tho

 

[Stu_pot]

Great results Willie, think I might do this with the spare housing I have while everything is in bits

 

[jake]

how are you altering fueling perametres etc ?

 

[wild willy]

how are you altering fueling perametres etc ?

I always log with vagcom and make any adjustments with Lemmiwinks.

@ Stu... Do it, your turbo will boost better for it.

@ Bill... Cheers mate, any restrictions removed from the intake can only be good. You would think that someone could release a sports version of the maff sensor itself whereby most of the heating circuit and other electronics could be located outside of the maff tube and only the sensing element is left in the tube with a much streamlined profile, minimising airflow restriction.

 

[Stu_pot]

I always log with vagcom and make any adjustments with Lemmiwinks.

@ Stu... Do it, your turbo will boost better for it.

Aye aye Captain!

Consider it done

 

[ibizacupra]

I always log with vagcom and make any adjustments with Lemmiwinks.

@ Stu... Do it, your turbo will boost better for it.

@ Bill... Cheers mate, any restrictions removed from the intake can only be good. You would think that someone could release a sports version of the maff sensor itself whereby most of the heating circuit and other electronics could be located outside of the maff tube and only the sensing element is left in the tube with a much streamlined profile, minimising airflow restriction.

i have a motorsport MAF - it lives in a box on the shelf where it can do no harm, and the DTA ecu managed nice without it - hehe
{joking}

On a more serious note, I would expect upstream things like filters, pipes etc to have more of a disturbance effect on a descreened MAF.

wondering if logs of steady state cruise control speeds logging MAF variation before and after would indicate any flow turbulance

 

[Matt S!]

Willy - some good results there!

How have you took the screen off the MAF? Cut it off?

Cheers!

 

[wild willy]

Willy - some good results there!

How have you took the screen off the MAF? Cut it off?

Cheers!

Cheers, removing it is a PITA but easy enough.
Before you start, remove the maff element from the housing to avoid any unnesscessary vibrations and bits of debris, use a TS25 bit to remove the security screws.
The end of the maff nearest the turbo comes away from housing very easily, just use a small screw driver to gently lever it off or a set of long nose pliers.
The air filter end is more secure but it is not glued as it appears. Use a hole saw to make a 10p hole size in the plastic meshing. Whilst looking at the face of this maff housing you can see that the edge of the maff housing is reinforced at various points around its perimeter. Use a small screw driver to gently prise the plastic mesh away from the housing only at these reinforced points whilst using using your finger in the 10p hole to pull the plastic mesh forward. It will eventually leave the main housing and the wire mesh will just fall out.
Congratulations.... Job Done.

 

[Matt S!]

Sounds good!

Keep the thread updated on how the car runs without the mesh...

May get a spare housing to attempt the job !?

 

[kineticz]

Going to give this a go today

 

[Stu_pot]

Going to give this a go today

Nice one, looking forward to the results!

Can I log in VAG-COM using the old v309 ?

Sorely tempted to buy it but spent loads recently.

 

[paul-murphys]

im getting my car mapped to my hybrid once i fit it an the 3" downpipe an decat so could i descreen my maf then get the mapper to adjust the fueling. would this make more power or smooth out boost an is a mbc a must ? thanks

 

[wild willy]

Going to give this a go today

Just do it and have fun.

 

[wild willy]

Nice one, looking forward to the results!

Can I log in VAG-COM using the old v309 ?

Sorely tempted to buy it but spent loads recently.

Yep, the freeware version is all you need.

 

[kineticz]

Well the plastic screen is a nightmare to get off! Those clips that hold it in are difficult to get underneath to wedge it out. But it's done so time for a test drive.

 

[wild willy]

im getting my car mapped to my hybrid once i fit it an the 3" downpipe an decat so could i descreen my maf then get the mapper to adjust the fueling. would this make more power or smooth out boost an is a mbc a must ? thanks

If you do all the mods at the same time, the remap will be at its optimum for your set up. The LCR has a wideband sensor for automatically adjusting the fueling to maintain it within safe limits for the car. Its always best though to log after any modification to check that all is well. I use lemmiwinks which is great but if your not confident i'd pay someone like Bill to log the car for you and make minor adjustments using freeware software. Anything major though a custom remap would always be recommended.
If you go custom remap then a mbc should not be needed for a hybrid but i'm a belts and braces sort of person who likes the extra security the mbc affords. Until your car is remapped i'd definately run a mbc as your just as likely to kill your engine / turbo driving to the mapping agent as you are going flat out up the M5. Remember peak torque is not high up the rev range.

 

[jamiebennett81]

hmmmm

meshy things on an intake pipe to me says "extra safety measure"

I know the idea of the air filter is to filter out all the dirt, but is the mesh there in the first instance as a safety net, for what ever reason other items of dirt could get in etc?

just my over safety type mind doing overtime?

if not, then I will look at removing this also when I replace my MAF finally

 

[kineticz]

Well I found no dirt or pieces of crap on my screen so not needed IMO

 

[Feel]

Trust your air filter, and service it regularly (to check it) and it'll be fine.

I did mine (stage 1 LCR) and don't recall that much difference - but mine never had high g/sec figs like some others.

With a free flowing filter, it's entirely possible that a screened MAF becomes the next restriction. Not sure that a descreened MAF would be beneficial with a less free flowing induction system, and let's not foget that your setup can obviously pull more air - so it is restricted by a screened MAF (a St1 or St2 with OE turbo might not be able to flow more).

Good results though, you must be pretty happy with your setup, now :