Thread: DIY Map/Maf enhancer / manipulator

Don't know what is in the tuning boxes, but hopefully the tuners are doing a bit more than that.

The "problem" with the sensors is the output is run into an analog to digital convertor, and to maintain resolution the maximum value is set to something less than 5V. When you hook up a VNT or a big tune the airflow measure by the MAF exceeds the maximum value coded in to the ECU, and the ECU sees this as a fault.

If you hook up a pot as shown you are simply attenuating the signal across the board. While it will reduce the output of the MAF/MAP so it avoids a fault condition, it also introduces an error that effects all readings from the sensors.

A better solution might be to look for a voltage limiter that clamps the maximum output to a value that avoids faults.

I think justfishing may have done something like this after finding a boost box he purchased was non functional.

cheers
Paul

Hello,
I have been down the track you are going in many times. I did make a volt switch and post it here explaining how to make it, any problems PM me. There are many very good tuners on this forum. Fooling sensors is great but not to trip the ECU at maximum possible volts without limp mode is the way to go not to limit across the whole range as Offtrack already said. The best way to make the MAF not go to limp mode is to make the diameter of it bigger you do not even have to have do any electronic tricks. At low RPM you want all the volts you can get form the MAF not to reduce it, you want that VNT to SPIN.
Ian

Originally Posted by justfishing

Hello,
I have been down the track you are going in many times. I did make a volt switch and post it here explaining how to make it, any problems PM me. There are many very good tuners on this forum. Fooling sensors is great but not to trip the ECU at maximum possible volts without limp mode is the way to go not to limit across the whole range as Offtrack already said. The best way to make the MAF not go to limp mode is to make the diameter of it bigger you do not even have to have do any electronic tricks. At low RPM you want all the volts you can get form the MAF not to reduce it, you want that VNT to SPIN.
Ian

Thanks for the info

I came across these guys

Split Second

they make VC2-5

Adjustable Voltage Clamp for 5V operation
and
Modifier
Dual Channel Universal Signal Modifier

prices are reasonable compared to what the LR tuners are selling similar products for.

I might give these ago.

There is a different problem - the output volage can be modified, but there is a limit of the MAF, and if you are over this limit, the MAF is no more working correctly (not measuring) and the output of the sensor is not chaging with the input air mass. To do it correctly, you have to use a proper MAF, capable to measure the increased quantitie of air, and then modify the maps in TD5 ECU to accept the different range of the MAF. The 5V (or 4,5V practically) is limited by power supply for the sensors and by the input range of AD converter in the ECU (look into datasheet of the CPU used in ECU).
If you just scale the output voltage down, you will get false reading in lower range and limit in upper range. Without modifiing of the map in ECU, the work will not be correct.

Originally Posted by madtom

There is a different problem - the output volage can be modified, but there is a limit of the MAF, and if you are over this limit, the MAF is no more working correctly (not measuring) and the output of the sensor is not chaging with the input air mass. To do it correctly, you have to use a proper MAF, capable to measure the increased quantitie of air, and then modify the maps in TD5 ECU to accept the different range of the MAF. The 5V (or 4,5V practically) is limited by power supply for the sensors and by the input range of AD converter in the ECU (look into datasheet of the CPU used in ECU).
If you just scale the output voltage down, you will get false reading in lower range and limit in upper range. Without modifiing of the map in ECU, the work will not be correct.

The ADC on the CPU has a 0-5V range which is referenced to the sensor earth, and the MAF can use full range.

cheers
Paul

Hello,
I built my Volt switch for about $40 I am looking at improving it making it smaller and easier to setup this can be used either on MAF or MAP no limp mode ever. Do not get me wrong it is great to experiment. This the reason I made mine as I did buy a boost box form one of the vendors on your list it NEVER worked always had limp mode and over boost.... lost the plot and made my own never a fault since, mine works it is normal volts till it hits a pre-set mine is 4.4volts the switched to a regulator set at 4.8 volts then resets once the volts go below 4 volts.
I did take the brought one apart and found 6 diodes in reverse which is a classic slow bleed of volts over the whole range not just when you want it at the peak. They cost about 50 cents it cost me about 150 pounds !!!!!!! from the UK what a ripoff....
Ian

I was thinking of ordering this unit from Split Second

http://www.splitsec.com/products/dat...odifier_ds.pdf

what do you guys think?

Mick

Guys I made my own adjustable voltage reg for my MAP. Just fixed the input 5v to 4.75v it drops the output maxx to 4.75v

It stoped the over boosting from the MAP. but when I turn my tubo rod up even more it hits over boost agian. I think its from the Maf sensor limits?

I would like to know more about the IRB 2 stage voltage box for the MAF option?

As the MAF is 12 volts in but 5 volt max out I dont think my trick for lowering the 12v to 4.75v in.

Does anyone know if the IRB cuts the power supply to the maf to a lower volt? or does it lower the signal out to less then 5volts?

Im after a DIY option.