Converting MAF to MAP

[Lextreme II]

I just got a GM 3 Map Sensor. Currently i am using it as a tuning tool for boost reading for my Innovative LM-1 Unit. I am getting boost reading, RPM signal along with AFR and they all can be data log into my laptop and i can alter and tune split sec according.

Anyway, i have read in AEM forum showing how to convert MAF to MAP. Anyone have any experience with it?

A = Sensor Ground
B = Sensor Signal exist
C = +5v Sensor Power exist

Our MAF wiring
1- Brown, 0V.., Ground (BR) goes to E2 Key on
2- Yel/Black, 5V .. (Y-B) Goes to THA
3- Yel/Green, 5V.., (Y-B) Goes to KS
4- Blue/Red, 5V.. (Denote as L-R) Goes to VC
5- Brown, (BR) E Ground

So from the picture above how would i connect signal from map to maf? I am trying to eliminate MAF and use full MAP.

 

[MaxPower]

You cant use a MAP sensor on the stock ECU. The ECU is looking for a square wave signal that varies in frequency with respect to air-flow. The MAP sensor provides a 0-5V analog signal.

If the 1UZ didnt use a karmen vortex AFM but instead a VAFM that spits out a 0-5v analog signal it is possible to use a MAP sensor in its place, a small circuit to invert the sensor output is needed though. The ECU will then need to be re-mapped to suit the new sensor but even then it is very un-likely it will run properly as the algorithms that calculate fuel delivery are VERY different between a speed density (MAP) and MAF based system.

So looks like the AFM stays......

 

[Lextreme II]

Currently i am running a piggy back and perhaps this would help?

 

[Peewee]

I doubt it.

Converting to full standalone would enable you to run MAP

There is really no other reliable way.

 

[MaxPower]

Still no good Lex, the ECU is looking for a square wave input whose frequency is dependant on airflow, the piggy back modifies the ECU outputs after it has processed this signal.

U would be better of sourcing a larger MAF, if it is a restriction, and then tuning the ECU to suit or, like Peewee said, converting to aftermarket ECU that runs a MAP.

 

[Damien]

Have a look at the Map-ECU at http://www.performancemotorresearch.co.nz - does exactly what you want. It uses a MAP sensor to measure the load and spits out a square wave to imitate the output of a Karman Vortex AFM (or an analog signal if you currently have a MAF).

I tried to contact them through the form on their webiste but it doesn't seem to work. You can email them at [email protected] though.

 

[RvolvoR]

from what i have heard from some over on the volvo boards, is that the apexi S-AFC is able to do exactly what you are talking about and also act as a pretty good stand alone unit. you can put a MAP signal into it and it will spit out a MAF signal for you ECU to use

 

[SprinterTRD]

Maf to Map

You could use a voltage to fequency converter I think its a LM331 from memory available from national semiconductor

 

[MaxPower]

At say idle u will typically be pulling about 20kpa on a map sensor, the AFM will be registering a low air flow condition and spits out a frequency to indicate this. This is easy to emulate but its when u are driving that the relationship starts to become a problem. Lets take WOT @ 2000rpm as an example, the MAP sensor reads 100kpa but the AFM meter is still registering a fairly low air speed (larger than idle but still low), now at 6000rpm the MAP signal will still read 100kpa but the AFM will be reading a large airflow.

So u can see to emulate the AFM will require a MAP vs RPM table which is not a hard problem to overcome but there have been people who tried this, and in theory that is all u need to do, but they found problems with power enrichemnt (PE) due to the characteristics of the MAF that are allowed for in the ECU software. Nothing is impossible, just sometimes its not as easy as first thought.

 

[SprinterTRD]

Maf vs MAP

The Maf sensor also compensates for Air temp and Air density changes

 

[highlander]

Your best bet is to use a PRO-M maf where you can tune it with their own software.

 

[SCV8]

Doesn't the Apexi fuel controller come with instructions on how to use their unit with dual MAFs?
Thought I remembered seeing that in the user/installation manual a couple years back.

 

[R-Jay]

from what i have heard from some over on the volvo boards, is that the apexi S-AFC is able to do exactly what you are talking about and also act as a pretty good stand alone unit. you can put a MAP signal into it and it will spit out a MAF signal for you ECU to use

Can anyone verify this???? if so, this will be my choice of fuel control when i go twin/single (unsure which road i'll be taking) turbo when the time comes.... i'd go to my local Apexi dealer to ask, but alas, it's a sunday....

 

[R-Jay]

Well, i spoke to a local apexi supplier and he tells me the unit can't do what was said...

the MAP-ECU can be used to replace the karman vortex afm with a map sensor.
374 point mapping table, 30psi boost capable, windows based software....

looks to be the goods.... ESP made over 400rwkw with one of these on a 2jz.... shows you how tuneable it is... also done with pump fuel.

Well, looks like when the time comes, this is the one i'll be going with.

 

[1youZee]

The S-AFC can't do this. It has a setting for what type of meter it is, given a value of 1-6, MAP, KARMAN, Hot Wire,, so-on after you set that, you then adjust it to what typ of MAP or what type of MAF you have. for instance the MAF on a peticular engine may vary it's output for a certain amount of air, but another, possibly bigger/stonger, motor will allow for more air... at max output the weaker one will be flowing x amount of air where as the stronger will have the sam output but the ECU knows this means more air.. the S-AFC can adjust for this, but not signal type as the difference between MAF and MAP.

Standalone is the best way to go for this.

 

[Lextreme II]

How about this STM7

I emailed them already and ask for more info. Very interesting piece of electronic.

 

[R-Jay]

David, very good read there... seems like a good product... i don't know if it would be a good thing for us down under though... we have no support for products like that... price wise, it is quite decent, a little more than the map-ecu, but very good considering the features it carries..

one question, how popular are these units in the states? i know the version 7 isnt released yet, but what about the 6?

 

[Lextreme II]

I have never heard of them. From there website, they are still operating at home. That company started 2004 so they are very very new. They is why we didnt hear much from them. The price is very good and great features which i like. It has MAP conversion, timing both advance and retard along with extra injectors and other accessories control.

 

[SCV8]

A place named Horsepower Freaks has a Split Second product offered for the Mitsubishi 3000GT that uses a Karman Type of MAF.

 

[Lextreme II]

I am using Split Second right now and called up the owner asking the maf to map function. Right now they dont have anything will do that.