roadkill669

True, but I think i've figured something out. Jsut need to do some experimenting. Heres what I'm in the process of building.



Our AFM have a vaiable ouptut between 0V and 3.5V. Idle would be 3.5 and 100% would be 0V. A MAP sensor is the opposite. 0V is 0 psi and 4.5V would be 29 psi. I have been cruntching some numbers and I know the max my AFM will open is 80% at 15 psi. With all of my calculations, that is roughly 19 psi from a MAP, which is 2.64V and 0V from the AFM. So it has a 0 to 2.64V input with a 3.5V to 0 output. The problem with this is that the air flow varies with RPM and throttle, not psi. I know with my car, in 5th gear, I can floor it and make 15 psi by 3K and only be flowing around 30%, then it sky rockets after 4K to 80%. THis problem will be fixed wqith the use of a SAFC. SInce it is an Air Flow Corrector, we just need to tune it a little bit. But on Series 4 motors, the stupid TPS only reads the position of the primary butterfly to the opening of the secondary. So, i fixed this by creating a new pusher for the TPS that allows the full use of the 0 to 100% of throttle. Now, we can really tune the SAFC. In theory, it will work really well, but only if you have a piggy back, which most people do.



I am in ther circut designing process right now. But everything else is ready.

roadkill669

Whoops, 100% open(0V) would be 19 psi (2.64V) from the MAP, not 80%. Thought I would clear that up.

j9fd3s

well i looked in the shop manual and the afm signal and a 2 bar map sensor are the same except they are reversed from each other. (afm is 5-0v and map sensor is 0-5v) i have also put a volteter on the afm and watched the signal, and its close enough that it would work, but the map sensor signal is backwards. there are no reverse map sensors so what do you do?



mike

roadkill669

That would be great . A MAP sensor uses a silicon chip to meassure resistance. When there is pressure, it pushes on the chip, increasing the resistance, it then converts this change to an increasing voltage. The AFM is the same thing kinda. It uses the varying resistance, but not using a silicon chip, and is reversed output.



I can't wait to finish this project and test it. I have figured that I will use a 2 bar MAP since they are junk yard specials. I only need a few more psi to reach 19, so the SAFC will have to decrease the duty cycle since 100% air flow will be acheived earlier. I know this will work. As soon as I get the results, i'll post some directoins so other people can make them, or I can sell a kit.