Anyone Running a Larger then OEM Maf Housing?
 

Hello,
as more and more folks begin boosting, and turning up the boost at some point the OEM maf is going to become a Limitation.

has anyone tried doing a 4" OD maf housing? Or anything larger then the OEM size?


I am nearing the Limit of the MAF(5v), at 4.88 volts I am not sure if a psi or two can be squeezed out of the remaining .12volts

I have done some searching and found nothing useful

I have done some playing around with a different MAF/housing setup

Seems to work OK...won't really know until I get the turbo back in the car :)

sub'd for interest

It's all in the scaling and even flow thru the tube and across the Maf, yes?

In theory you could use a 10" dia tube, no?
Or change the 5v value to something like 600 g/s

However I guess at some point you'll lose too much resolution in the Maf's ability to actual determine the correct amount of air flow.

Go to large and you ruin the Maf scaling resolution a idle and low rpm's.
Go to small and you reduce even more the ability for the Maf to scale WOT g/s readings.

Just thinking out loud ... guess that's probably a bad idea on the 8club

well since certain members are banned its fine :)

thanks Dan!

if the sensor could be placed in the middle of that 10" tube then I suppose it could.

you are right on both fronts, I have been thinking about trying a 4" with a .125 wall thickness so the ID would be 3.875 inches. so its would be about 13% larger, figure I could scale the maf 13% past the idle area and it should work. just finding a place to put this 4" housing is another issue.

The problems that I have had was trying to get the low end voltages high enough that they don't freak out the PCM.....and still have enough range to get the flow in the top end someplace that there is more resolution for higher flow. I have a unit to test...and I will see how it works when I get back to that :) It should allow me to measure up to 600g/s in the 5v scale if all goes well

what size did you try?

Lingenfelter 100 MM Mass Air Flow Sensor - MAF - GM Applications - Lingenfelter Performance

http://www.jbsautodesigns.co.uk/prod...-4-maf-housing

http://www.vmptuning.com/store/index...parent=99&pg=1


.

^ problem is you Need one that uses a voltage based sensor.....

Thanks Team, I can easily make a new housing for the OEM sensor, which I plan to do just seeing if anyone else has done this and see if they got good results,

Thanks Dan, your post are appriciated

The OE sensor won't be long enough once you exceed a 3.5" OD maf tube. The measuring part of the sensor has to be centered in the tube.

Racing Beats rev intake utilizes a bigger than oem maf tube, but it is not 4 inches!
How much air are you swallowing?
maybe this can be of help

REVi Intake System - FAQ


you never cease to fail me ....

I don't think its necessary to be exactly in the middle, air should be flowing in the pipe at the same speed everywhere.

^ Actually that is far from true...the air at the boundary layers at the walls move differently than the middle.

In a straight tube of only marginally different dia i'm sure it is well within the tuning allowances though

The premise of operation is based on it measuring at the center.

http://faculty.utpa.edu/abalogh/pipe_mix/pipepic.gif

A lot of Ford MAF's use an off center collector for the actual sensor...so it is possible to calibrate them that way. I think I might install the MAF I have and see if it will work OK NA...that might help me answer some of the questions

Yes, but we are discussing the OE sensor. In a turbulent flow situation the profile flattens out as the sidewall drag tapers off more quickly so in a turbo situation with high flow you may be correct in that it can be accounted for. My concern would be that compensation may not be consistent relative to the high vs low flow conditions.

This hints at a possible solution without going to a larger diameter: mount the OE sensor on a spacer to move it offcenter into a slower than fastest flow region, but not so far that it's in a turbulent zone. At low flows the velocity distribution as a function of radius won't be as large as at high flows, which is ok. But it does mean a simple scaling across the entire range won't work.

One could do it with a series of tests, first, stock location, recording MAF at WOT through say the full range of 2nd gear. Then space the sensor out some, do a second datalog, then change the calibration to match the first. Space out again, rinse and repeat. It should then result a lower voltage to Maf ratio.

It will impact Calc Load and a number of other variables but go ahead and knock yourself out

I wonder if I could sink the air flow sensor into the new 4" pipe, like have it recessed.
granted I will loose some space on the top, but the sides and bottom will have flow.

I have no need to knock myself out. Nor do I have any need or wish to do this myself. Pretty much any engine mod impacts "a number of other variables". Whether any of that impact has a significant detrimental effect varies. I'm sure that with your 1/2 million dollar test cell and associated equipment, you can make your mods while completely measuring all effects in a proper engineering environment. Don't have one? Then what seperates you from the other hillbilly (your word) tinkerers here? :scratchhe

concerning the RB maf pipe--I am well familiar with their statement--however if you install their maf pipe and do a run collecting the appropriate data, and then install the oem pipe and collect date --you will find that the data will suggest that the RB pipe flows like a bigger pipe. The oem maf pipe is more of an oval shape than the RB one. The RB maf pipe cross sectional area is larger than the oem.
I am surprised that Team took their statement without question. Did he really think that the RB Revi intake makes more power because it just flows better?
Sorry for the threadjack--its a mute point anyway.

If you are going to run a 4 inch maf pipe what are you going to do about the throttle body? Wont you need a larger one?

Yes - you have about 2 psi left and doing a bit of jiggery pokery should allow you another 1psi or so on top of that .

And if you aren't making 360-380whp by then , then you probably have other issues giving you a false reading.

The OE maf ovals because people over tighten the clamp. That doesn't make it flow less. It just skews the maf sensor reading because it is no longer centered in a uniform flow mass per the picture posted and as we have been discussing.

So you didn't actually measure it. You got some readings and just assumed that 1 + 1 = 3 again.

Thanks, I will give it a try.
that would be nice to see those numbers, but you could be right about other issues, the maf is probably just reading to high.