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Discussion Starter · #1 ·
Whilst checking the MAF on my 115PD the other week I noticed that there are 2 screens between it and the airbox.

The first (closest to the MAF) is a very fine metal gauze, the other a quite thick plastic grid. Obviously both are designed to stop FOD from entering the turbo.

Now,

Back in the early 90's Yamaha restricted the power of their FZR 1000 EXUP sportsbikes by means of a large rubber grid between the airfilter and the carbs. This restricted airflow by 25%. All you needed was a stanley knife to restore power to what it was always designed to be.

Back to the present.....

Calculating the area within the maf inlet (60mm diameter opening) then adding up the surface area of the plastic grid (approx 1mm wide and 6mm squares) I figured that this on its own was restricting airflow by around 30% possibly more.

5 minutes carefull cutting with a stanley knife later and the plastic grid was gone.

It makes an instant difference. The engine Revs faster and doesn't feel as strangled anymore. MPG has also improved and it doesn't smoke. This is all on a standard car!

Warning!

Do not carry out this mod if when you take the lid off the airbox there is any debris on the engine side of the airfilter. Even though the metal gauze is pretty tough the plastic grid is designed to stop large objects. As I have never had anything on top of my filter I had no problems with doing this.

I don't know if this is a common mod or has been done before. Just had to share it with you guys as it makes a difference for no monetary outlay.
 

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Interesting, I might find a dead MAF from a scrappy to try this out.

I already have a smoothed OEM airbox with a 75mm cold air feed routed to the lower bumper grille.
 

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Discussion Starter · #3 ·
You've improved the airflow to the airbox over standard which is a very good thing but as you still have the restriction after this then go for it.

It'll be interesting to know your afterthoughts once it's done!

One thing to note....

The maf housing comes away from the airbox via 2 philips head screws and from the inlet pipe by a spring type clamp which you just squeeze with pliers to open up. Take the MAF sensor out CAREFULLY by removing 2 torx security screws, there is resistance to it being removed but that is just the rubber seal inside. Once the MAF sensor is out then you can start on the plastic restriction.

I tried cutting out the plastic 'squares' but this is quite difficult and would have ended up a mess so I removed the round plastic 'grid' completely but as this holds the metal gauze in place I have had to secure the gauze to the body of the inlet with a thin strip of araldite around the edges. Don't put it back together until this is completely set!
 

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I have done this some time ago without seeing any problems,  at the same time I modded the maf  with a diode and removed the bottom half , there is now no restriction at all and less smoke.    I will send pics if interested,  but don't know how to post
 

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I have done this some time ago without seeing any problems, at the same time I modded the maf with a diode and removed the bottom half , there is now no restriction at all and less smoke. I will send pics if interested, but don't know how to post
You can email me some pics to [email protected]

I'll post them up on this thread.
 

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Hmmmm this is very interesting, might have a go at this!
totaly agree it does sound interesting , but i think i would hunt down a maf from the breakers first check that it works then do the little mod , as i wouldnt wana end up screwing up the one i have already lol
 

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Hmmmm this is very interesting, might have a go at this!
totaly agree it does sound interesting , but i think i would hunt
down a maf from the breakers first check that it works then do the
little mod , as i wouldnt wana end up screwing up the one i have
already lol
lol yeah very true, but it's ok I have another maf. I took out my pd115 maf and replaced it with a pd130 one [Y]
 

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Guys, I would leave the fine metal gauze in place if I was you, it is
there to straighten air entering the MAF to provide a more accurate
reading for air flow by preventing turbulance.
 

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Guys, I would leave the fine metal gauze in place if I was you, it is
there to straighten air entering the MAF to provide a more accurate
reading for air flow by preventing turbulance.
I didn't think TDIMAN was talking about the fine gauze?? I thought it was the plastic grid he was talking about removing ?
 

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Guys, I would leave the fine metal gauze in place if I was you, it is there to straighten air entering the MAF to provide a more accurate reading for air flow by preventing turbulance.
I didn't think TDIMAN was talking about the fine gauze?? I thought it was the plastic grid he was talking about removing ?
Yes, he just removed the plastic grid.
 

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Haven't actually seen these bits so excuse me if this is a stupid question but...could it be that the plastic grid is there to keep the metal gauze in place under high flow conditions?  If you remove the plastic (which sounds as if it is only there for support) isn't there a risk of the metal bit distorting?
 

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I tried this mod yesterday on my existing MAF....called my local breakers first though just to check they had one available (which i'll pick up tomorrow) [;)]

Went for a short blast yesterday evening and I can feel a difference......smoke has been reduced also [:D]

......but this could all be because I cleaned the MAF before I put it all back together [:S]
 

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Discussion Starter · #16 ·
The plastic grid isn't there to support the metal gauze, it's there to prevent damage to it from large objects that have passed the airfilter. The plastic grid is on the airbox side of the gauze not the engine side

As I said in an earlier post, I have never found anything on the engine side of my airfilter before (in any car I've owned) so I was confident with removing the plastic which due to its construction is restricting the airflow.
 

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It's actually fairly simple to check out if any improvements come from this mod..just do some vag-com logged runs on the MAF before/after modding.
 
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