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map sensors...


Cruez

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Ok gotta question..

 

I know about what map sensors are for..Basically they read manifold pressure...

 

but what is the main difference between 1, 2 and three bar sensors..?? besides reading above absolute pressure??

 

I have a N/A setup that I am running but the map sensor that came with it was for a turbo setup. It is a 3 bar sensor...I know I should have a 1 bar, but will it affect anything by using it? besides overkilll :?

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The main difference between the sensors is resolution. Assuming the sensors all have the same full-scale output, say 5V, a 1 Bar will have more output voltage change for a certain pressure change than a 3 Bar.

 

The one bar will effectively sense full vacuum to sea level absolute pressure. The 2 Bar will sense from full vacuum to approximately 15 psi, and the 3 Bar to approximately 30 psi. 1 Bar = 14.7 psi.

 

By using the 3 Bar over the 1 Bar, you will be reading only 1/3 of the full scale, so you may get rougher increments of pressure readable by your fuel computer, and it may not be as smooth in running or tuning.

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Gotcha...

 

Since the 3 bar has a higher scale.... the portion that I wil be using will have larger increments.... right???

 

For the 3 bar instead of the 1 bar, smaller voltage increments for the same pressure change, or conversely, the same output voltage change represents a larger pressure change.

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Guest the_dj

I might trade. I need a two bar, have a 1 bar. Three would work cause it's cheap and I'm cheap and can go 2 bar later. :)

 

Ok I'll trade you. :) When do you have to have it by?

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My intake should be finished tommorrow. Then I'll have to put it back together again...

 

I still have some brackets and whatnots to make for my new mods.

 

so I figure I'll need one in couple of weeks..

 

BTW what are the differences in map sensors... connection wise...??

 

I'll get a pic of mine and post it...

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Guest the_dj

Not sure, I'll try to send a picture of mine as well. I'm not sure when my fabricator/friend of my dad is going to be able to help me make my TT headers, but that's when I'll need it. I hope to have her back on the road in a month. :D

 

I already have the turbos, so I'm ready to get started but it will clearly take a while to finish a job like this. :)

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Guest jt240z

The 3 bar MAP sensor would work just fine for your NA engine. Keep in mind that a turbo engine has to run in the NA range too. If you want to trade, then fine. Don't think you HAVE to trade to get your NA engine to work correctly.

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  • 2 weeks later...
The 3 bar MAP sensor would work just fine for your NA engine. Keep in mind that a turbo engine has to run in the NA range too. If you want to trade, then fine. Don't think you HAVE to trade to get your NA engine to work correctly.

 

If he is never going to tubocharge, then the 1 bar sensor is much better for his application. If you assume an 8bit A/D converter in the EFI system, using a 3bar sensor for N/A is like going from 8 bit resolution (255 discrete steps) to a little more than 6 bit resolution (85 discrete steps).

 

btw,

1 atmosphere = 14.7psi

1 bar = 14.5 psi

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  • 1 month later...

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