Pretty sure I've read comments that the MAF sensor should be oriented in a relatively upright position. More specifically, pointing down into the housing.

Is this right? Is there a technical reason for it, or is this some kind of MAF myth? (Which is hard to say aloud, even when sober.)

 

Haha, wonder where this spawned from.

 

as long as it's not backwards i can't see it being an issue. I've installed the older ones offset by 90deg and didn't see any loss in performance. The only reason I can see for it being mounted straight up is for easy access.

 

^^^ That's what I'd wager as well. It's not like a wideband sensor that needs to be mounted pointing down due to moisture in the exhaust... Since there's no water in an intake, I can't see why it would matter...

 

Do I sense another "tuck and hide" write up from Rochester?

 

Ha ha! I don't think "Rotate your MAF" quite justifies a write-up.

I agree with you guys that common wisdom says it shouldn't matter. But "common wisdom" is kind of an oxymoron. (Guess who's not a Tea Party whack-a-doodle?)

Kind of want to hit up my local dealership's senior technician, and my mechanic. The downside to those inquiries is looking like a fool for asking, not that it's going to stop me. I'm proud about lots of things, but ignorance isn't one of them.

 

shouldnt affect it none chester, if it makes any consolation i had my TB upside down at maxus and im sure if positioning had something to do with it im sure the connector on the TB would be reading as if my intake was "up side down" get what im saying here???

 

if it makes you feel any better, when i custom made a CAI for my old M45 with the VK, i had to take a hacksaw to separate the MAF from the stock airbox and then relocate it towards the bottom of the engine where i had routed the duct to draw in fresh air.
never set off any codes or had any problems and those cars are SUPER sensitive to any aftermarket mods and are known to throw a CEL at the drop of a hat.

 

At the moment, the sensor is pointing down from the 10:00 position. If it were on the exact opposite side, in the 4:00 position, then it would be completely hidden by the MAF housing itself.

Still going to wait until next week, and have a conversation with my mechanic about this; (and tranny mount replacement.) It's been over a month since I'd talked with him, and he really enjoys mocking me... so this should make his day.

 

I believe that nmexmax once tested this out and found that it does matter as to what position the maf is oriented. I asked this question ages ago and I'm pretty sure it makes a difference.

 

^^^^ agreed. i had mine for the longest time in the 9 oclock position. A few weeks ago i read Nmex and put it back to the stock pos which is 12oclock. I did notice a difference. Nothing crazy but some throttle response and yes a couple points in gas mileage. Just picture the way air would flow in your intake and the see if it gets wacked with air or gets the hints of air. My intak has a curve to the right (looking from the bumper) so the air coming in hits the bens and sits more on the outside away from where i had the MAF. I positioned it at 12 and is more in the way of the incoming air now so i think it gets a better reading on the amount of air.

So in closing. i do believe it matters

 

You're attributing this requirement to the bend in your intake configuration. But mine is perfectly straight, so by that reasoning, it shouldn't matter... right?

 

My MAF has been installed in the 3 o'clock position since I've had my Injen intake. It has been so damn long ago I can't remember how it was installed stock on a 2k, but I think it was in the 12 o'clock position.

No issues for me....and if you think about it, really you should not see issues from the orientation, as long as it is faced the proper way for airflow. Hence the reason there is that handy little arrow on the MAF tube, right?

 

there are no issues at different orientation, but there are benefits.

 

Aside from ease-of-access, what benefits are you thinking?

 

I think you're right.

 

it benefits AFR. I'm not a guru or anything, but as I said, there are no issues by putting it at 3 o'clock or 6 o'clock or whatever. Your car will still run fine. But if you measure the amount of air going through the maf, which is measured as grams/cubic meter or something like that. It will measure the mass of air, NOT the flow, differently depending on the orientation. For stock applications this will not cause an issue. But for example If i tune my car a the 12 o'clock position, then decide to remove the MAF and put it on at 6 o'clock position the tune will be out by a bit. IIRC.


(waits for manny to jump in)

 

If you are overriding the ECU on the car tuning...otherwise the car's ECU should compensate as such.

 

I really want to rotate my MAF.

 

as I said the MAF measures the mass of air in g/m3. At stock position it might be 100% efficient.(doubtful, but lets assume 100 hypothetically.) Rotate to a non stock position and maybe it drops to 90% efficient. It still works. But for someone who cares how efficient the MAF is at WOT it makes a difference to them. You want the MAF to read as high as possible in g/m3.

 

It's been at 10:00 for a long time. Knight is saying I should rotate it straight up to 12:00, rather than all the way around to 4:00, which is what I want to do. I don't understand enough about physics to even guess one way or the other. Hence the question.

Jury is still out.

 

I have an answer on this question.

Spoke with the senior tech at one of our Nissan dealerships. He's a long-haired old dude who's been servicing Nissans for 30 years. Usually, he just glowers at you with his patented, "It's there for a reason" response. But this was the first time he'd been asked the question about MAF Sensor Orientation.

He paused for a long time, then nodded his head and gave me an answer. The MAF sensor is (predominately) in a vertical orientation to reduce risk of condensation build-up, which is really unlikely considering how enclosed the sensor is, but this accounts for that risk, however slight. He said I could probably put it at the 4:00 position and never see any adverse effect, but it's intended to be vertical.

And there it is. I'm done.

The sensor is staying in its upright-ish position.

 

Rochester is gonna add the "rotated MAF mod" to his mod list

 

Hmm. You're going to have to work on your reading skills.

 

I was just thinking... Orienting the MAF in different ways may affect WOT performance (however slightly), but if you have a AFC unit and WB, you could manipulate MAF voltage and thereby eliminate possible inefficiency of the MAF while in a 4 o'clock position. I suppose you might still get reduced performance in part-throttle driving, because most people don't attempt to tune AFR at anything but WOT. I dunno, just my musings...

 

 

Myself and SR20DEN have noticed differences in AFR when the it is turned 30º or more in either position, and no, neither one of us has a long white beard and I'm not even 30 years old yet, so take that as you may.

 

Thanks for weighing in, NmexMAX.

You're a fine, young man. Keep up the good work.

 

http://forums.maxima.org/1671793-post14.html
http://forums.maxima.org/1896224-post61.html

Mine is actually lying flat right now flipped 90º, so the sensor is essentially lying flat on it's side, parallel to the ground. Of course, every time I change my intake configuration, the AFR tends to go wack until I AFC it back to where I want it.

 

This is correct. It will make a difference for sure. But during closed loop mode in a car with stock injectors and stock sized MAF, the ecu will compensate for the difference in A/F ratio based on the primary O2's feedback. But the difference in A/F ratio shouldn't be that much to effect drivabilty much at all.

By the way, most of you newer members might not remember this from back in the day but....

http://forums.maxima.org/3696238-post1.html

I understand that this was for a 4th gen with a z32 MAF and 370cc injectors, but the idea of the MAF is pretty much the same. Basically with that specific setup, you need to turn the MAF 90 degrees for the car to run correctly.

 

I rotate my maf every 5,000 miles































Why do you want to do this anyway?

 

Just something else in his quest to clean up his engine bay.

 

Bingo. It's a Quest.

 

we have found a witch...!!! May we burn her?

 

That depends... does she weigh as much as a duck?

But seriously, I'm glad to have started this thread. It puts to rest (for me, at least) nagging questions about MAF orientation.

 

There's a camel's hump in the AFR that occurs when the OEM Helmholtz resonator is removed and a straight pipe is put in its place. The gains are minimal for power and undesirable. One way to alleviate, or at least remedy this slightly is to clock the MAF in either direction 30º. But that's the old way to do it, we all know the 'real' way to fix it these days.

 

Guess I'll be rotating my MAF back to where it's supposed to be. I rotated it for the same reason you wanted to Rochester...to make it a bit more pleasing to the eye.

 

 

Although entirely unintentional, that's where I'm at, Manny. And that's where I'll stay.

Thanks!

So I'm not the only passenger on the crazy bus. Good to know.

 

Sorry for the grainy pics .. they look better when not cropped... Anyhow, there's a better picture that sorta shows the entire 'field'.

BTW, I have a new filter.