 
     |
| 2-Bar MAP sensors. Any preference for brand/source? (Page 1/1) |
|
Raydar
|
OCT 09, 12:56 PM
|
|
I need to replace the MAP sensor on my project car. (2.8 Miller Woods turbo)
The one I removed is a 2 bar sensor. It's written right on the bottom of it, in Sharpie.  It's what I would have expected anyway, given the installation.
Since this is not my car, and is boosted, I don't want to take any chances on the usual chinesium stuff.
Reliability is more of a consideration than price. Can anyone recommend a good source or brand to look at?
There are tons of them on eBay and Amazon. Most of them are un-pronounceable brand names. Pricing is all over the... map. Not to be punny.
Thinking about going to Rockauto and finding a Delco/Delphi one for a 3800SC. That crosses over to a 2 bar MAP, in several places I've looked.
Thoughts?
Thanks!
|
|
|
Vintage-Nut
|
OCT 09, 01:41 PM
|
|
I replaced my original Manifold Pressure Sensor with GM 12569240 / ACDelco 213-1545
------------------
Original Owner of a Silver '88 GT
Under 'Production Refurbishment' @ 136k Miles
|
|
|
|
olejoedad
|
OCT 09, 03:02 PM
|
|
| quote | Originally posted by Vintage-Nut:
I replaced my original Manifold Pressure Sensor with GM 12569240 / ACDelco 213-1545
|
|
VN, wouldn't that be a 1 BAR MAP?
Raydar is looking for a 2 BAR MAP for a boosted application.
|
|
|
Vintage-Nut
|
OCT 09, 10:58 PM
|
|
|
|
|
82-T/A [At Work]
|
OCT 10, 08:20 AM
|
|
Can I ask a dumb question... what is the difference between these MAP sensors, technically? Is the analog range of the potential signal wider compared to the lower bar sensors? Is that essentially what they're doing? They're just able to measure a larger range of atmospheric pressures?
If I was to upgrade a totally stock Fiero with a 2-bar sensor, does the ECM have the proper programming to (on the office chance the signal goes out of the BAR 1 threshold) appreciate the larger number?
|
|
|
|
1985 Fiero GT
|
OCT 10, 08:25 AM
|
|
| quote | Originally posted by 82-T/A [At Work]:
Can I ask a dumb question... what is the difference between these MAP sensors, technically? Is the analog range of the potential signal wider compared to the lower bar sensors? Is that essentially what they're doing? They're just able to measure a larger range of atmospheric pressures?
If I was to upgrade a totally stock Fiero with a 2-bar sensor, does the ECM have the proper programming to (on the office chance the signal goes out of the BAR 1 threshold) appreciate the larger number? |
|
Both sensors output something like 0-5v signal, or 0.5-4.5v, 1 bar, the highest voltage represents atmospheric pressure, lowest voltage a perfect vacuum, 2 bar sensors, atmospheric pressure will be 2.5 volts, 14.5 psi boost is the highest voltage, perfect vacuum is still the lowest voltage, plugging in a 2 bar map will make a stock ECM think the engines getting half the air it really is, because the signal will never go above 2.5 volts (half vacuum)
|
|
|
|
82-T/A [At Work]
|
OCT 10, 09:57 AM
|
|
| quote | Originally posted by 1985 Fiero GT:
Both sensors output something like 0-5v signal, or 0.5-4.5v, 1 bar, the highest voltage represents atmospheric pressure, lowest voltage a perfect vacuum, 2 bar sensors, atmospheric pressure will be 2.5 volts, 14.5 psi boost is the highest voltage, perfect vacuum is still the lowest voltage, plugging in a 2 bar map will make a stock ECM think the engines getting half the air it really is, because the signal will never go above 2.5 volts (half vacuum) |
|
Ah, ok... that makes perfect sense then. Thanks!
|
|
|
|
Dennis LaGrua
|
OCT 10, 04:41 PM
|
|
| quote | Originally posted by 82-T/A [At Work]:
Can I ask a dumb question... what is the difference between these MAP sensors, technically? Is the analog range of the potential signal wider compared to the lower bar sensors? Is that essentially what they're doing? They're just able to measure a larger range of atmospheric pressures?
If I was to upgrade a totally stock Fiero with a 2-bar sensor, does the ECM have the proper programming to (on the office chance the signal goes out of the BAR 1 threshold) appreciate the larger number? |
|
A one BAR MAP sensor operates at 0-4.9 Volts on manifold vacuum proportional to the voltage. This is for a stock Fiero ECM.
A Two BAR MAP sensor operates at 0-2.5V for manifold vacuum and 2.6V - 4.9L Volts for manifold pressure proportional to the voltage. They are not interchangeable unless the MAP table in the ECM/PCM is assembled to work with either sensor. If you are programming and want ECM comparability with the 2 BAR MAP; for a Fiero ECM, the MAP table in the program must be scaled by a factor of two. This is done in a modified editor before you can program for engine control under boost.
Blend this in to what 85 Fiero GT has said and you have the entire answer.
------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE " [This message has been edited by Dennis LaGrua (edited 10-10-2025).]
|
|
|
|