Difference between bad MAF housing design or too large MAF housing?

shadow

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Thanks ! This explains it better for me.So could you say that a good designed maf doesn't jump in fuel trims drasticly but goes up smoothly ?
Not quite.

What should go up smoothly is the MAF Flow vs MAF Voltage table. This should be after it has been adjusted using the results of the STFT vs MAF v. graph in my post above.

This is the MAF Flow vs MAF Voltage table:
Honda Civic 10th gen Difference between bad MAF housing design or too large MAF housing? 1610429376120


STFT VS MAF v. should be within +/- 5% (straight line at 0% is theoretically ideal, but not achievable).
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shadow

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I just wrote a long response in agreement with you. Then I thought of PRL's race maf design and deleted my response. PRL's race maf entry is much more abrupt than his smooth funnel design but it works perfectly fine. Thoughts?

Race Maf.jpg
My guess is a wide entrance is not a problem for high boost. The problem will be at idle and low rpms where there isn't enough velocity to get an accurate reading.

Turbulence comes in not from the diameter, but from what comes before it. It may be caused by an ill designed bend (corner, sharp radius, wrong bell mouth, etc.)

I have no idea how much improvement the race MAF will have (with the OEM turbo) because it still bottle necks now to the turbo intake tube. It will help (with an large aftermarket turbo) so MAF voltage doesn't exceed the sensor's capability.

For reference, my 2011 STI's OEM MAF housing had air straighteners before the sensor. They were just vanes that straightened air flow. That of course detracts from the housings flow area.
 
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Hondanickx

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It's a velocity stack so there's should not be any turbulence .Others like eventuri and sprint filter also have their Velocity stack right before the maf so i don't think it Will be bad.
Honda uses a simple radius with a Angle on the maf housing.
Sta in this link you see some differences.There are also CFD examples of what a different flow does to the shape of the flow towards the maf sensor.That is the most important part afaik.
 
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It's a velocity stack so there's should not be any turbulence .Others like eventuri and sprint filter also have their Velocity stack right before the maf so i don't think it Will be bad.
Honda uses a simple radius with a Angle on the maf housing.
Sta in this link you see some differences.There are also CFD examples of what a different flow does to the shape of the flow towards the maf sensor.That is the most important part afaik.
This is the point I was trying to make. If PRL's design works fine and doesn't cause any turbulence, then yours with the velocity stack should not as well. Incoming air crashing against PRL's flat surface at the maf sensor housing's entry would be a problem before your velocity stack, since your velocity stack actually gradually guides the air in through diameter reduction before entering the maf sensor housing.

I like your design. :thumbsup:

@shadow I realize turbulence is not by maf sensor diameter but some of the things you mentioned above. I'm specifically talking about his funnel/velocity stack design.
 
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Hondanickx

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The OEM design also uses a Velocity stack but in a simple radius form and a Angle to guide the flow towards the maf housing ( i think).
A larger more designed Velocity stack just Guides more air into the housing.Difference is 2-3% VS a regular radius.When i'm home i can post more pictures and info.
 


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Hondanickx

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someone needs to get a smoke machine to find out hahaha
I'm trying to get it into a CFD program and get a cfd simulation done.
Ones this works i can simulate both OEM and any aftermarket maf housings and see how the air Flows around the maf sensor.
 
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So it took a lot of effort for me since i'm new into using these programs .But i finally got some results from a CFD program.
What i learned from this is (i think) :

The oem MAF housing is designed for or around the MAF sensor.All the tapers and angles inside are there for the flow true and around the maf sensor.
These tapers and angles need to remain if the MAF housing is close to the stock size or slightly larger .
If going much larger (like a race maf) there's no point keeping these angles /tapers.


The first maf housing (short one) is a oem style maf housing (much like the prl street)
The oem MAF housing has a radius with a angle as a air entrance.You can see it guides the air towards the MAF sensor.

Second one is my design with a velocity stack and i kept the angle to guide the air towards the MAF sensor.Which doesn't do as much as on the oem style housing.

Air velocity on both test is 25 M/s .
I'm still doing some other test to see how it affects flow.
The MAF housing is not straight but actually has different tapers inside which you might not see on these pictures.

Honda Civic 10th gen Difference between bad MAF housing design or too large MAF housing? OEM style MAF test 02


Honda Civic 10th gen Difference between bad MAF housing design or too large MAF housing? 2021 MAF Flow test 01
 


 


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