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Discussion Starter #1
Hi i have found the following table showing map sensor voltage against psi for chrysler turbo, would these figures be the same for all map sensors/turbos?

Manifold Pressure
(relative sea level / absolute) 2 Bar
MAP Output
14.31psi / 29.01psi =4.90V
14.00psi / 28.70psi = 4.84V
13.00psi / 27.70psi = 4.67V
12.00psi / 26.70psi = 4.50V
11.00psi / 25.70psi = 4.33V
10.00psi / 24.70psi = 4.16V
9.00psi / 23.70psi = 3.99V
8.00psi / 22.70psi = 3.82V
6.00psi / 20.70psi = 3.47V
4.00psi / 18.70psi = 3.13V
2.00psi / 16.70psi = 2.79V
0.00psi / 14.70psi = 2.45V
5.00inHg / 12.24psi = 2.03V
10.00inHg / 9.78psi = 1.61V
15.00inHg / 7.33psi = 1.19V
20.00inHg / 4.87psi = 0.77V
25.00inHg / 2.41psi = 0.35V
29.10inHg / 0.40psi = 0.02V

the map sensor used is 2 bar and the info is taken form the following source

http://minimopar.net/ecu/map_se.html

cheers
chris
 

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Discussion Starter #2
wait a second lads ive just had a thought,

surely the max voltage(around 5v) will be whatever the boost is set to at max?

so i now need an accurate way of working out how the boost will decrease as the throttle is closed to plot against the volts on the map sensor but id assume i can only do this by taking readings directly from the car?

can anybody help?

cheers
chris
 

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Discussion Starter #5
so does this mean the only way for me to get the data i need is to put the car on the rollers and measure the readings throught he range?

surely theres a calculation for this data based on the map sensors specs as the ecu uses the given info to calculate fueling so somewhere i must be able to find out the readings without actually having to read them off on a rolling road

cheers
chris
 

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They are only manufactured to a certain tolerance, so personally the only way i would be happy even if you got the spec would be to put the car on the rollers to check whats really happening not make assumptions about what should be happening, but obviously its a good way to get things into the right ballpark so you are on the rollers for less time if you can get the specs.


Chip
 

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PS

Get a spare wheel, hook a manual pressure guage and the MAP sensor up to it with the output to a volt meter, that way you can get the exact values that your specific sensor is giving out at different pressures.

Start at 30psi and just gradually deflate the tyre back to zero.

You still want it on the rollers though.

Chip
 

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Discussion Starter #8
chip you wana run that last bit again please,

i get a spare wheel, inflate it to 30psi, wire up the map sensor, put a voltmeter to the map sensor then slowly let it down and record the readings? i take it this would be right for giving me ballpark readings? would these readings mirror the pressure produced by a turbo?

cheers
chris
 
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