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-   -   OBD0 MAP sensor (https://www.homemadeturbo.com/engine-management-10/obd0-map-sensor-17957/)

EastSideRider 03-26-2004 07:53 PM

OBD0 MAP sensor
 
How do I get the OBD0 MAP sensor of a ZC to allow me to push more than 9.5 psi? I have been reading the FAQ about all the "hacks" and such.........but I am still a bit confused. I am not worried about the strength of the engine, seeing as how it will be a fully built ZC.......I would like to hit 12-15 psi.

TurboEF9 03-26-2004 09:58 PM

Re:OBD0 MAP sensor
 
There is a common misconception about "how much boost" MAP sensors can "handle".

You physically *can* run more than 9.5psi on your stock MAP sensor. The problem is, your ECU will not KNOW you're running more than 9.5psi. Get what I'm saying?

Now the long version for the nerdy want to know it all types.

There is a diaphram inside the MAP sensor that moves, based on how much pressure is being generated in the manifold. These movements are translated into voltage readings betweeen 0 and 5 volts. Mid point, ~2.9-3.2 (or so) volts, you start hitting "boost". Due to the resolution (the amount of movement that registers an increase in voltage, this all based on the design of the MAP sensor) and the physical construction of the MAP sensor, the diaphram can only move so far. This totals about 4.8-4.9 volts. How much press does it take to get it to read that much? Around 9.5 psi. :D

How does a 3bar MAP sensor work? Exactly the same. However, the resolution is smaller. BAsically, they fit a larger scale in the same space. Still 0-5 volts, but there is more space between incrementation points.

So, to finally finish answering your question. Get a bigger MAP sensor, or fatten up the last column of your fuel map.

leed 03-26-2004 10:50 PM

Re:OBD0 MAP sensor
 

or fatten up the last column of your fuel map.
I have done this before as well, and it will work. There is a point where the diaphram may rupture, but I can vouch for it holding up to 14psi.

Say your last column on TE is 8.6psi, well just tune it for 14 or whatever your running on the column. You will just have a fat spot when transitioning from say 8.3psi to your target psi. Not really a big deal.

turbohf 03-27-2004 02:21 AM

Re:OBD0 MAP sensor
 
i run 10-12psi on turboedit and a stock Honda MAP...i always have an eye on the A/F's though...


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