# Replacing MAF sensor with a MAP sensor - my experience



## 2kjettaguy (Dec 24, 2000)

Well, after lots of thinking I tried it. I studied the wiring and voltages on the stock MAF and was able to put a 0-5v 3 bar MAP sensor in place of the MAF sensor. Using my Split Second PSC1-001 I can tune the sensor's signal voltages into what the ecu needs to see for proper fueling. 
I had it idling 14.7 and mapped out within the threshold of what the ECU considers appropriate MAF voltage. I wasn't getting any MAF low or high voltage codes. 
Here's where the hard part comes in. The MAP sensor is a 0-5volt device. at 29" of vacuum the sensor will shut off, or show 0 volts. At 30psi it shows 5volts. 
The MAF sensor works based on volumetric airflow. Map these 2 out and a comparison of the voltages are very different. There's enough range in the PSC to make the voltages of the map sensor = that of a MAF sensor, but it's *very* difficult. 
For instance, I was adding fuel in the hard vacuum ranges to make up for the drastic drop in voltage. In the low vacuum ranges to atmospheric pressure things were "close." In boost, voltages were way too high. 
As rpm increases you need to increase voltage from the MAP to mimic increased airflow. This is not too bad, but you need to work every column from 29" to 16psi while also accounting for the difference in the sensors. 
I messed with this for 2 hours w/ the wideband and laptop. I came to the conclusion that though this is possible, it's not worth the time. You need to completely remap the entire voltage range of the sensor. I took some very educated guesses and laid out some base maps in the PSC assuming I'd be increasing voltage with rpm to mimic increased flow, and I was lowering voltage as values increased to account for the function of the MAP sensor. 
If I had like 5 hours on a dyno where I could go all out safely and also mimic street driving, it could be done. Worth 5 hours dyno time to me? Nah. I've got so many months of fine tuning in my current map that I'm actually satisfied with the way it drives - less the BOV.
So there, MAF beats MAP in one (and only one) situation!








Evan


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## mrkrad (Nov 9, 2000)

*Re: Replacing MAF sensor with a MAP sensor - my experience (2kjettaguy)*

logically using both can be a best of both worlds..


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## Holy Piston (Oct 24, 2003)

*Re: Replacing MAF sensor with a MAP sensor - my experience (mrkrad)*

Programmable speed density system is what you want.


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## [email protected] (Aug 25, 2001)

*Re: Replacing MAF sensor with a MAP sensor - my experience (mrkrad)*


_Quote, originally posted by *mrkrad* »_logically using both can be a best of both worlds..


i.e. 1.8T
btw, holy piston... i think SDS would be a great choice for evan


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## 2kjettaguy (Dec 24, 2000)

*Re: Replacing MAF sensor with a MAP sensor - my experience (Anand20v)*

I'll probably go for a system when I get my new shop constructed and most importantly paid for.


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