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Old 01-27-2021, 07:05 AM   #1
pcampbell
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2005 2.5 SC OB

Default MAF pegged. Blow through MAF?

Can anyone tell me whether a blow through MAF is a good alternative for more bandwidth? I’ve pegged a 70mm MAF housing on my supercharged sohc 2.5.

Question is what to do next. I can go 76mm draw through which will require me to go 76mm then reduce to 70mm due to clearance issues.

or I can go blow through with a high quality aftermarket sensor , they say it is good for 800whp in a 3” tube. It also means I don’t have to recirculate my BPV which I believe is better for my supercharger (less restriction should mean less stress on it).

My BPV would go BEFORE my intercooler in the blow through setup — I don’t know if that is a problem.
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Old 01-27-2021, 07:07 AM   #2
pcampbell
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The aftermarket brand of MAF designed for blow through is called

https://www.pmas-maf.com/product-cat...ru-style-mafs/
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Old 01-27-2021, 07:17 AM   #3
pcampbell
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I should mention that my IAT sensor is after the intercooler so this has no bearing on my MAF readings.
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Old 01-27-2021, 09:23 AM   #4
motorbykemike
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How about just going speed density

Or hybrid maf/sd
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Old 01-27-2021, 11:49 AM   #5
pcampbell
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Quote:
Originally Posted by motorbykemike View Post
How about just going speed density

Or hybrid maf/sd


I would definitely consider that, but I don't really know how. There is not a lot of support for it (assuming we are talking about MerpMod?) especially on an NA ECU. Basically I would need someone to patch my rom for me (I think?) or I need to read more up about what exactly it is doing. I'm willing to pay someone to do it for me or show me.
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Old 01-28-2021, 12:46 PM   #6
pcampbell
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Does anyone know what a 76mm maf housing is good for in terms of Rough WHP?
it seems like it should be about 20% more than a 69mm? Which would be like...500whp????
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Old 02-09-2021, 03:14 PM   #7
pcampbell
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Double posting this but I have been reading about PMAS calibrated MAF sensors. They have one built for small displacement motors such that they will read 575 g/s at 4.7volts in a 2.5" ID tube. They are about $200 but you'll need a MAF housing and some wiring, plus presumably various elbows, clamps etc. to make it fit. About $400 total, I am considering this over just another bigger draw through MAF housing.

1 - I know I will not peg it. I don't know if I will or will not peg a 76mm draw through with the stock Denso.

2 - with it calibrated , in theory, it will be easy to tune. They provide g/s at every voltage point. I am not sure how well that will apply in a real life setting though.

3 - I can ditch the plumb back my bypass valve.


I wonder if anyone has any experience with these on a Subaru? Seems like more of a a Mustang thing!
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