MPI: MAF-2-MAP conversion

I

igdrasil

:
12psi Protege5
All updates will be ALSO posted in this 1st post

This week I will be starting the MAF to MAP conversion. This means Im going to replace the MAF for a 2.5BAR MAP sensor. I know this involves a lot of tunning, first starting with logging voltages on both the MAF and the MAP.

Im still on the brainstorming, trying to find the best way to log both sensors output at the same time, then work on the analog map to do the necesary corrections so the MPI output thru the MAP matches the stock MAF output.

Any ideas, suggestions, comments are welcomed. good or bad, pros and cons, doesnt matter..all of em help.


UPDATE JAN. 30, 2005 -CAR IS RUNNING WITH NO MAF!!!
Idle is perfect, acceleration thru all the rpm band is great. Normal Driving is fantastic considering there is no tunning at all, only some numbers on the analog map. Some stumbling building boost, but the rest is smooth. And finally...no stalling issue so far, still need to vent the BOV more and see if its stalls or not

fuelcal.gif


analog.gif
 
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i think kooldino would be the person to ask on this subject, no? i only say this as i know he has done the change on his mpi
 
Captain KRM P5 said:
i think kooldino would be the person to ask on this subject, no? i only say this as i know he has done the change on his mpi
Click to expand...

I dont know for sure...but I think he still have the MAF controlling stock injectors and MAP sensor for boost reference to control extra injector and ignition control.
 
StuttersC said:
Why are you switching?
Click to expand...

Couple of reasons.

1. Tunning ability for up to 21psi on the 2.5BAR MAP
2. Remove MAF restriction.
3. BOV Stalling issue will be gone.
 
that seems like a lot of work for decent results.

Good luck. I think for most people it would be more economical to upgrade to the 80mm MAF. BOV's, on the one hand I think they are rice, but on the other - they do serve a purpose, I just hate the "ricer hard-on"'s that people get when they hear it vent to atmosphere. Admittedly, I myself (shame) admit it's pretty kewl sounding.

Then again - up to 21psi...... good golly miss molly. I can't wait to see how things progress.
 
I think you should just run the 80mm MAF(its massive) and screw the atmoshphere bov and just recirculate...
 
igdrasil said:
This week I will be starting the MAF to MAP conversion. This means Im going to replace the MAF for a 2.5BAR MAP sensor. I know this involves a lot of tunning, first starting with logging voltages on both the MAF and the MAP.

Im still on the brainstorming, trying to find the best way to log both sensors output at the same time, then work on the analog map to do the necesary corrections so the MPI output thru the MAP matches the stock MAF output.

Any ideas, suggestions, comments are welcomed. good or bad, pros and cons, doesnt matter..all of em help.
Click to expand...

You can use something like the Innovate LM-1 with the AUX cable and log up to 6 inputs at the same time, up to 44 mins.
 
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Update Jan. 30, 2005

CAR IS RUNNING WITH NO MAF!!! (placed on my backseat)(naughty)

Idle is perfect, acceleration without load thru all the rpm band is great. I would love to take a video but my cam is dead.
 
igdrasil said:
CAR IS RUNNING WITH NO MAF!!! (placed on my backseat)(naughty)

Idle is perfect, acceleration without load thru all the rpm band is great. I would love to take a video but my cam is dead.
Click to expand...

A How-To would be nice to read.
 
Update...this is anyway a PM i sent to focus:

Its very very very easy to at least start the car and make it idle.

The fun starts as you go into 0 vac.

I found the best way to do this (if you can handle issues) is to 1st start the car with the MAP and make it idle having the MAF only connected to the EngTemp wire and monitor BOTH the Analog Output and EngTemp voltage.

Normally when the car Idles the MAF is sending about 1.9v-2.2v, the map will send about .30v-.80v so you just have to rise the fuel zero calibration to XX number, until itl sends around 2.0v-2.4v out of the map voltage on idle.

Now having the car idle fine, the fun part starts. Now we separate men from children. Its not easy, but its fun and a challenge.

The easiest way is to monitor both voltages on the graph and try to keep both drawings nearly equal, to mimic each other. I will post a pic in a few minutes and a log file.
 
This is how it looks

Check this...you will see the voltages differences, this is how it will start, you need to get both lines nearly identical, check voltages at the left corner, this is what you most likely want to see all the time (refering to voltage, notice the green bar) unless you want to do corrections when you want to behave different. If you want near stock feel, both lines should mimic one other:

display4.gif


More of the same, you need to correct these peaks, differences:
display5.gif



Getting better:
display6.gif



And better....
display3.gif
 
WOW...that sensor readout is nothing short of SICK...Good work man damn...Im Impressed

It would really be appreciated if you wrote something up on this..like a REAL good writeup going into the tuning alterations that have to be made..Then we could put it in the MPI Library Sticky so all of us could use it...

Please?
 
igdrasil said:
I dont know for sure...but I think he still have the MAF controlling stock injectors and MAP sensor for boost reference to control extra injector and ignition control.
Click to expand...

Yeah, that's how I'm set up. Why are you switching to all MAP? I thought you were happy with the MAF setup?
 
igdrasil said:
Couple of reasons.

1. Tunning ability for up to 21psi on the 2.5BAR MAP
Click to expand...

If that was your only concern, you cuold go with a big MAF. Just playing devil's advocate here.

2. Remove MAF restriction.
Click to expand...

I don't think that would gain you too much. Just my opinion.
 
Kooldino said:
Yeah, that's how I'm set up. Why are you switching to all MAP? I thought you were happy with the MAF setup?
Click to expand...

Yeah, MAF is ok, I just wanted to add some pepper to my car. Car is running fine, but I just got a MAP sensor and I wanted to see If I could get this to work without the MAF.

Let me tell you, if you though that MAF tunning the stock injectors was a PITA, try a 2bar MAP!!! Not easy ok! ITS VERY VERY DIFFICULT but its fun. I been discovering a lot of things and one is...that maybe MAF voltage output has a lot to do on ignition timing or injector cycle difference thru RPM.

This is only a thought, i just have to read total timing while building boost...

I believe this because, (remember im running FMU) when I modify the output to send less voltage than usual, and the FMU is pushing fuel, instead of going leaner, it will go richer to the point that it missfires, then if I decide to put more fuel on that same range (higher voltage), it wont missfire and feel it faster....

This is weird.
 
the tunning is almost done, car is doing very fine. I even tested with my girlfriend driving it.
She likes to kick the ass of my car, shes a low rpm driver with high boosts, imagine the car in 5th gear, 2800rpms and 10psi climbing uphill...
Lots of load changing situations, lots of shifting and also a fast response car and reliable.

Car is not stalling, power curve is almost linear, at least thats how it feels. Still needs some fine tunning on idle because my manifold has leaks.

Will try take videos as soon as I repair my video cam
 
Awesome to hear! I have a similar conversion planned for my Celica All-trac using the SMT6. My conversion would be AFM-->MAP, but the same principles apply in general.

What wire on the MPI did you use to monitor the MAF signal voltage?

Yes I know I'm just a lurker here...just come in and check out the stuff you guys do with your MPI's every once in a while, since the Celica community has only just begun to see what these things can do.

:)

Chris
 
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