MAP sensor alternatives?

Ok, guys and girls, As we know the MAP sensor is key to fuel management. What alternatives do we have to our OEM sensor? I hear where they are changed when force induction is in use and I believe I read that there are remote mounted MAP's (ford) used. My basic thought is if one could be mounted to a vacum can of sorts to smooth the pulses found directly within the manifold that the output signal would be a more acceptable to our PCM. So lets do a little brain storming and share your thoughts about this.

Thanks,

I think I read somewhere that some guys use one from an srt4.

Second the Srt-4 sensor... I think they are calling it a 2 bar sensor. Let me try getting hold of Sean to share some info.

That would be great. Most manufacturers use MAF instead of MAP sensors so that should narrow it down some. I just haven't done any research yet. The 2 bar are for FI.

Greg shot him a link to see it to chime in on it.

Thanks, Sean is always a good source of information. I hope we hear from him.

Here is an example of what might be used. It would be easy to mount this sensor remotely.
http://www.summitracing.com/parts/FST-307007/

The srt4 map sensor is a 2 1/4 bar. Works great with forced induction. You only need this if using forced induction as it will never send a WOT signal on our n/a configs. There is a little tab to shave off the sensor and it's a direct plug up to the factory harness. On the '03 I had to remove some of the wire loom wrap on the map sensor bundle to allow the wires to come up a little. The srt4 map sensor has a 45 degree angle vs. the 90 degree factory one. Gotta stretch the wires a little

Thanks Sean, however we are not talking about FI, but ways to reduce cam reversion affecting the standard 1 atomospere MAP output signal.

So what exactly are you after? Are you trying to eliminate a surge at idle or trying to smooth out the idle via the MAP sensor?

truckin151 said:

So what exactly are you after? Are you trying to eliminate a surge at idle or trying to smooth out the idle via the MAP sensor?

Click to expand...

What I believe is happening is with the more aggressive cams especially with the tighter lsa (overlap) is they have a lot of reversion (pulses) corrupting the MAP signal to the PCM. If this signal can be smoothed out, the PCM can respond to this cleaner signal and then it is just a matter of tuning. But along with a smoother signal being generated we also need a higher idle which in turn also helps with smoothing the reversion pulses. I don't think it is difficult to get a usable MAP signal generated using the mods I have mentioned.

Edit: to have a quality idle that is totally streetable.

Sorry, I saw the srt4 map sensor mentioned above and wanted to make sure you weren't trying that w/o f/i. I don't know the details of how exactly, but I've seen somebody get a holley jet in the sensor to decrease the signal area.

hemifever said:

Sorry, I saw the srt4 map sensor mentioned above and wanted to make sure you weren't trying that w/o f/i. I don't know the details of how exactly, but I've seen somebody get a holley jet in the sensor to decrease the signal area.

Click to expand...

Sean, that is exactly in line with what I am thinking. A remote mounted MAF would have a vacum hose connected to it and the length/size of the hose could be varied to change the responsiveness of the MAP. Now using a vacum reservoir (can) in addition could possibly delute the vacum pulses to the point of making the signal too slow to be useable. So the key would be to find a point when the vacum pulses are smoothed out just enough to result in a steady MAP output signal. A restricting jet may be all that is really necessary. It is often stated that each 03's responds to mods differently, my thought is that it is the the individual MAP sensors that are reacting differently.

this stuff is admittedly way over my head. when you get this figured out, I'd like to see a write-up!! Sean has done amazing things with my truck to get it to run smooth. The problem is, smooth and efficient are two opposite spectrums. I run so pig rich its not even funny, but have to in order to run smooth. This would help things out a lot

Aaron, I'll try the restricter jet first as it is easy and cheap. I'm trying to install all my support mods before actually installing the cam. I got a tool box full of jets and will start reducing the size until the MAP fails to respond then backup a bit. If this doesn't feel right to me then I'll go with a remote MAP and keep experimenting.
The support mods being: PSC1 and window switch for the pwr steering mod.

Question to you aaron, what rpm are you idling at?

So how exactly are you going to be using the restricter jet on the map sensor? Just trying to figure out how or where I guess would be better, you plan on mounting it since from looking at it it id just a bulbe at the end where the air passes thru.

I am guessing here as I don't have the OEM MAP in front of me. But if I can't screw the jet into the inlet orfice I'll go with a MAF that I can manipulate/modify and use it to work with as there are plenty of remote MAPs I can come up with.

Redtruck-VA said:

What I believe is happening is with the more aggressive cams especially with the tighter lsa (overlap) is they have a lot of reversion (pulses) corrupting the MAP signal to the PCM. If this signal can be smoothed out, the PCM can respond to this cleaner signal and then it is just a matter of tuning. But along with a smoother signal being generated we also need a higher idle which in turn also helps with smoothing the reversion pulses. I don't think it is difficult to get a usable MAP signal generated using the mods I have mentioned.

Edit: to have a quality idle that is totally streetable.

Click to expand...

I did it with the PSC-1 on my brothers 03 Dakota with the 218 cammed 4.7 in it. Those cams usually idle pretty roughly, but with the PSC-1 in signal replace mode rather than modify it smooths out the MAP signal to the PCM and allows you to smooth the idle out. Look at the wiring diagram. I shifted my setup from Signal Modify to Direct Output. I realize that the instructions state not to do it this way, however you can adjust the map output to a fixed voltage around idle over several points of map sensor deviation. Basically the MAP sensor is going to jump all around at idle and lower engine speeds, but the map signal the PCM gets is coming from the lookup table on the PSC-1 and is stable.

I used a NO connection on a microswitch mounted to the throttle linkage on the 03 Dakota to control the P/S pressure switch. Idles about 700 in drive fully warmed up with the a/c off and NO codes. Truck doesn't even toss a random misfire code any longer. I would look at adding a microswitch into your APS that trips off the throttle cam inside of it. I believe you could squeeze a switch into that housing without it affecting the operation, run the two wires out of the case, and tie them into the pressure switch wiring. As soon as you touch the throttle it would close the circuit.