Some of us want to push it just a hair past the stock 17 psi sensor or want a little more overhead in case the car overboosts with the stock MAP sensor. We all know you loose some resolution on the mapping with the 3 bar MAPs too. I was screwing around looking for a 2.5 Bar map to fill the gap and ran across this one:
http://www.audiworld.com/tech/pix/mpx4250.pdf
Part number is MPX4250AP for the one with the port, mounts, and pins on the bottom.
You can get it from http://www.newark.com/ for $23.41 shipped.

It has the same old connections...5V in, Ground, and 0-5V linear out increasing with pressure. Should be good up to a max of 21.56 psi.

Some of you may want to go with this if you still have the stock MAP and you're playing in the 15.5-17.5 psi range or have picked up a 3 bar but are never going to see the high side of 20.5 psi. I'm not condemning people with 3 bars (there's alot of you after all! ) but it just takes away from your ability to fine tune. This MAP sensor would make things a little less granular if you're not using a 3 bar to its full ability.

 

good find!
Im surprised no one has thought of that before, it does make a lot more sense as the standard range for a lot of people is right around 15-20 Psi

and th price is right also

 

You can also find the MSD 3 bar for around $50, which is cheaper than the standard GM part.

 

Do you have to buy a harness for use with that one Trevor?

 

Looks like it just comes with some raw pins...you'd need to do some soldering.

I didn't pick one up. As you know there's no reason to run more than 16 psi with stock sequential twins so the stock MAP is still OK. Not much overhead though...

 

You lose no resolution with the 3bar map sensor if you are referring to the p-rows calibration. You have the control over what values are used for each p-row value and if you want you can leave the stock PFC p-row values untouched and be mapped to around 20 psi.

Now if you are suggesting the GM 3-bar sensor output has less resolution vs some other sensor I guess you have some data that we need to see. I have no clue how accurate and consistent any of these map sensors are but the rough testing I did with the stock MAP and the GM MAP indicated no obvious flaws, we're talking rough testing to calibrate the p-rows to my desired boost values.

 

Its no secret that you can re-assign P-rows.

You loose resolution because you're not using the full range of the sensor.

23.7 InHg (vaccum)
2.5 Bar: 0.25V
3.0 Bar: 0.33V

20 psi o' boost
2.5 Bar: 4.62V
3.0 Bar: 3.96V

Range of operational output=
2.5 Bar: 4.37V
3.0 Bar: 3.63V

The 2.5 bar has 16.9% more resolution between those two pressure points. Not a huge difference but it is there. If you're running more than 15.5 psi but never plan on exceeding 20.5 psi this is a good way to go.

 

2.5 bar? Why mess with the girly hardware........

How about a 4 bar

 

...says the man who puts around town on ET Streets and skinnies.

You're nuts man...but in a good way!

 

 

Not significant, YMMV.