So I was looking around and found the Omni Power 7 bar Map sensor. Is it worth it? Does anyone have one installed? I know Evos come with a stock one, but according to the description it does not work as well as the aftermarket one. I ask since, I moved from Texas to a screaming 4,600ft above sea level and crappy 91 octane gas. Tune coming soon for crappy 91 octane.

 

First of all, the stock sensor is an MDP (manifold differential pressure) sensor as opposed to MAP (manifold absolute pressure) sensor. This is a similar difference to narrowband/ wideband o2 sensors. The reason why the inferior sensor doesn't make a difference usually is when you use a MAF, it's the primary reference for AFR.

if the car runs well, then why would you think it would make much of a difference?

7 bars is ~102.9 lbs/in^2 ... minus 1" per 1000 feet above standard. So you're only loving 4.5"mg. 2.036 "Hg = 1 psi, so in short the difference is 2psi below standard. If you were going to change the sensor, 4 bars should be enough.

Of course, correct me if I'm wrong.

 

7bar??? i think a 4 bar will be plenty

 

^ +1
7 bar is 101psi. I think you'll be ok with a 4 bar.

 

Since it is measuring absolute pressure does a 3 bar MAP sensor only read up to 28.8psi rather than 43.5psi?

 

You have it backwards.. That's 28.4 psi differential pressure (from 14.2 psi ambient), 42.6psi absolute (3 bars)

 

Hmmm now I'm a little confused...1bar = 14.5psi. 3 bar =43.5psi. Therefore does a 3 bar map sensor have the ability to read 43.5psi? It was my understanding that the first bar was the ambient pressure.

To dumb this question down to make sure we are on the same page here my question is what is the max PSI a 3 bar map sensor reads? Does my JDM 3 bar map sensor have the ability to log with Evoscan a max of ~29psi or ~43.5psi?

 

Absolute being the key word in all of this, it is local pressure + boost = absolute pressure in the manifold. So in evoscan you will only be able to log the 29psi, maybe a little more depending on altitude.

To the op, 4 bar is probably all us mortals will ever need to log boost or run sd.

 

Double post

 

Thank you for the explanation. That is exactly what I was looking for and what I originally thought was the case. I think I phrased the question poorly.

I've been using a JDM 3 bar but I may swap it out for an Omni 4 bar now...thanks for your help!

 

No problem heel2toe

 

So is it worth buying?

 

If you want to log boost via Evoscan or are planning to convert to SD in the future then yet an upraded MAP sensor is necessary. Now depending on how much boost you plan to run should determine whether you will be fine with a 3 bar or 4 bar. Realistically anything greater than a 4 bar is not necessary unless you're planning to push your car over ~43psi

 

If you're going to bother buying a MAP sensor, you might as well buy one that will fully accommodate any future plans. Get a 4-bar and be done with it. Mod right, mod once.