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View Full Version : MAF to MAP conversion?



JMoney
09-18-2006, 01:35 AM
Anyone done this? I think that I'd like to do a MAP conversion to reduce the problems associated with an intake and possibly a turbo in the far, far future.

rougeben83
09-18-2006, 03:06 AM
Ugh...of the top of my head, probably the whole intake manifold, ECU for a MAP car, probably part if not all of the wiring harness.

Too much trouble for what it's worth IMO. Easier to just clean the MAF every now and then...

MAF cars can be turbo'ed too. The PP6 engine management does better on MAF turbo'ed cars than MAP based on experiences by GC imp owners...

Wiscon_Mark
09-18-2006, 09:23 AM
I think he's more referring to the moddability of the MAP vs. the MAF.

But yeah, I don't think so without swapping ECUs. I doubt the signals are the same (although it'd be sweet if they were!!). But even so, the fuel delivery would be off if you were to position the MAP anywhere else besides where the MAF is.

ivwarrior
09-18-2006, 09:38 PM
But even so, the fuel delivery would be off if you were to position the MAP anywhere else besides where the MAF is.

And it'd be REALLY screwed up if you put a MAP sensor (which reads "vacuum") in the intake piping where the MAF sensor is, which never sees much "vacuum".

Even though the both essentially do the same thing (measure the amout of air coming into the engine) they do it in two totally different ways, and at the very least you'd need the ECU reprogrammed or replaced to get it to work.

It's not worth the headache now to do it for a turbo project that may never happen.

rougeben83
09-18-2006, 10:19 PM
Hence why I suggested using the whole intake manifold so he can just plop the MAP at the TB like us MAP guys :grin:

Anyway, yeah. Skip it, get a PP6 with your turbo and go go go. :evil:

mranlet
10-30-2006, 09:01 PM
I'm working on this for the sake of open element ITBs.

I already have a 2.5RS MAP computer and a Phase II intake manifold (which will needed to be modified to fit my Phase I engine). Are the harnesses the same? Where could I find a pinout of the MAP computer? Any idea what I would need to do wiring-wise to have the MAP computer and MAP sensor work with my MAF wiring harness?

Thanks for the help, hopefully I can be helpful to others soon!

SammyDaFish
04-09-2007, 03:58 PM
But even so, the fuel delivery would be off if you were to position the MAP anywhere else besides where the MAF is.

And it'd be REALLY screwed up if you put a MAP sensor (which reads "vacuum") in the intake piping where the MAF sensor is, which never sees much "vacuum".

Even though the both essentially do the same thing (measure the amout of air coming into the engine) they do it in two totally different ways, and at the very least you'd need the ECU reprogrammed or replaced to get it to work.

It's not worth the headache now to do it for a turbo project that may never happen.


you guys are not understanding how this whole thing works. The ECU needs to know how much air is entering the engine. It reads this is mass, usually something like g/s^2. A MAF reads air mass itself (which is a measure of volume and density). a MAP sensor measures only one thing, manifold absolute pressure. This alone is worthless to the ECU since it tells the computer nothing about how much air is entering the engine. So even if the voltage ranges were the same (they are actually). just wiring a MAP sensor wouldn't work. The ECU needs a measure of air mass entering the engine and of cars without a MAF that use a MAP sensor the ECU uses the speed density algorithm to calculate air mass. It does this by using reading of manifold pressure, intake air temperature and fixed values of volumetric efficiency that are programed into the ECU. Without all of those pieces of information the ECU can not calculate the remaining operating parameters to run the engine.

There are products that do this and usually have laptop programmable VE tables to tune with. More and more sophisticated piggy back units are adding this type of feature as well, so it surely can be done, but you need to understand what you're trying to do before you can figure out what you'll need to do it.


oh, and the MAF is always under vacuum in the stock location.

backpack09
04-09-2007, 04:31 PM
^not when the car is off :lol:

ProdriveDreams
04-09-2007, 06:15 PM
...It does this by using reading of manifold pressure, intake air temperature and fixed values of volumetric efficiency that are programed into the ECU....

The computer also needs to know the engine's RPMs to use its predetermined tables for volumetric efficiency, but essentially yes you are right.

ivwarrior
04-09-2007, 07:15 PM
And it'd be REALLY screwed up if you put a MAP sensor (which reads "vacuum") in the intake piping where the MAF sensor is, which never sees much "vacuum".

Even though the both essentially do the same thing (measure the amout of air coming into the engine) they do it in two totally different ways, and at the very least you'd need the ECU reprogrammed or replaced to get it to work.


you guys are not understanding how this whole thing works.


oh, and the MAF is always under vacuum in the stock location.

1. I do understand there are major differences, hence why I said the ECU would need to be reprogrammed or replaced to hope to make it work.

Second, I said the MAF never sees MUCH vacuum, nothing compared to what the MAP sees when the throttle plate is closed. If you think they're always close to the same, get a vacuum gauge, connect it somewhere close to the MAF sensor and watch it from idle to WOT. Then, pull a line off the manifold and connect the gauge there, and do the same thing and see the differences for yourself.

SammyDaFish
04-09-2007, 10:16 PM
^not when the car is off :lol:

lol, you've got me there