why do so many of ya'll Mega squirt vets go with a MAP (manifold pressure) instead of MAF (mass air flow sensor) ?

I would guess it's cheaper and easier....to be confirmed

the MAP is dependent on VE tables and temp sensor calc for density. the MAF is a direct measurement of flow.

you are correct. i didn't stated that MAP is better over MAF, I just think it will be easier and cheaper.

as you might now, MAF has a heat source and a heat sensor that measures the air being passed through it. very accurate, however, it's more sensitive to environmental impacts than a MAP sensor.

just to make it clear, this is just my theoretical bla bla / 2 cents and are open to be educated.

i’m working on collecting all the parts and info for my MS conversion (2056cc and std. intake). But based on my industrial experience with MFC ( a type of MAF for gasses) I would go with the MAP sensor…..it think it will be easier and cheaper.

I would say it goes back to the early days of MS. Speed density was all that was offered. The MAP sensor was soldered on the board. It was simple and straight forward. As things have progressed, there remains a bias that favors a MAP sensor because less modifications to the hardware and software are required. I've used MS off and on since 2004 (I had a little episode with SDS for a while) and I still don't know how much would be required to run MAF. In my case it boils down to why change something that works.

Dave

As GM found out in the late 80"s MAF are a pain in the a$$.Thet get dirty, break. and otherwise fail. The MSII Map is a little unit that is right on the board, pre calabrated, and for my experance works great. I am thinking about adding or changing to the baro sensor one since I live on one side a mountian and work on the other.I have about 2500 mile on mine and so far so great. I'm using MAP, IAT, OIL temp, and TPS. Gordon

I completely agree with draganc. MAP sensors are cheap, plentiful, dead simple to hook up, and fairly robust. MAF sensors, while more accurate, are expensive, more complicated to hook up both mechanically and electeically (I though I'll admit I haven't looked into that part explicitly), and somewhat delicate. I seem to recall something about Boxsters burning up MAF sensors when people installed oiled K&N air filters.

As other people have implied/mentioned, MAP is proven effective, so what is the benefit of hassling with MAF?

But that being said, I thought about playing with MAF on my turbo project just to learn something new.

One other thing to note...

I think if you're going to run boost, you need to go with MAF. I think that's because a MAP sensor can't read vacuum (a reading of 0 on a MAP sensor means the sensed pressure equals atmospheric pressure).

But that's no concern because everyone knows you can't turbo a Type 4.

Cause the megasquirt came with a map....

I'm afraid that's not true. The map sensor used on MS is accurate to 30" mercury on the vacuum side and over 2 bar on the positive side. If you need more, upgrade the MAP.

MAF is easier on the processor, but harder on the installer:)

My kit car needs to pass emission testing here in Georgia. I running MS1 extra the
car would not pass with a MAP, the trouble was the vacuum signature was the same with no load (1000 RPM's) and at 2500 RPM's. I then installed a Ford MAF sensor drove the car around using Tuner Studio to tune the VE table and then pass
the emission test on the first try. I also notice that the engine was smother at idle and did not have any hesitation while driving. I would say MAF is the way to go.

this all makes sense.
904svo: can you share some links to guide teh conversion to MAF?
so you run MS1 extra or did you do the MS2 upgrade? the MS versions confuse me still

what's your point?

His post count is low so I'll break it down for him.

megasquirt is an aftermarket fuel injection system popular with the do it yourself crowds like us. it can be configured to use various combinations of readily available OEM sensor inputs.
most people choose the MAP sensor but most modern EFI systems use MAF. i posted here to seek input and guidance on this issue prior to commencing my next EFI project

JMKnight:
typically the quality of the question defines the quality of the answer but i'm feeling generous today

doesn't MAF use enable closed loop wide band O2 tuning?

My ms2 will with a map as well. I'm just not sure why megasquirt didn't put the drivers in for wide band. According to my documentation, you still need the wb controller interfaced to the ms. While I think mas is a more precise way, they are a lot more finicky to air leaks/ dirt, and especially kn filter oil!

yes, I read that you need the wide band controller like an Innovate LC1
I think MAF, like L Jet is intolerant of vacuum leaks. same goes with any modern car. emission control requires us to account for all air flow, even the crank case vapors.
the anti K&N tip is greatly appreciated.

I used the information from MS to install the MAF on X7. People forget that the
914 had a Trap Door style MAF installed on latter versions. A lot of documentation
says the MAF is too much of a air restriction, this is true with the trap door style
but a hot wire type does not have these problems. The only problem I had was
to set the VE table for WOT voltage then scaled it down to match the MAF output.

Then using Tuner Studio with a WB O2 sensor and my AFR tables set to the AFR
I wanted. Tuner Studio did the rest of the work to correct the VE table.

Its not that hard to do. All the information is in MS documentation whether it be
MS1, MS2 or MS3

Nope. Any load-measuring system can be used with closed-loop O2 adjustment. Wide-band or narrow-band don't really matter in principle, just as long as you can get the outputs and the inputs to match correctly.


The 1.8s were the ones with barn-door air flow meters.

--DD

MAF is more accurate because it measures the amount of air going into the engine. This is why most modern cars use one.

MS can easily be set up to use a Ford Mustang MAF and it works great. I sold my MS to Series9 already setup for a MAF. As long as the ECU knows the callibration of the sensor, tuning is a breeze.

You can still set the target lambda for more fuel where you need it. setting up a MAF is far les difficult than creating a VE table from scratch.

I have never heard of anyone running a maf sensor on what i would consider a premium ECU unless completely stock and even these are few and far between. The low vacuum signal can be easily accounted for with combination of tps and map and high quality components.
Map is a great system for use in turbo charged cars as it gives direct feedback to the ECU for boost pressures and has no dramas with the type of plumbing and relief used.
Having said all this i have just spent all night pulling hair out of my head and setting fire to airfilters as i try to start my engine for the first time since converting to fuel injection
Cheers
Edwin