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what all affects Kpa in a tune??

Old 07-17-2007, 07:41 PM
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Default what all affects Kpa in a tune??

I hope this is a ok question. I dont know that much about tuning but I wanted to know what can affect Kpa?

thanks
Old 07-17-2007, 07:43 PM
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not much in tuning affects your map reading. Its usually mechanical parts ie camshaft, intake, vacuum leaks that affect your map readings.
Old 07-17-2007, 08:56 PM
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KPA is just a measurement from the map sensor that the pcm uses to determine several things in the tune. If you are getting odd readings, As Foff667 says, it could be from bad sensor, vacuum leak, pinched/damaged wiring, Not plugged in, ect..
Old 07-17-2007, 09:09 PM
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As stated, for the most part it's the mechanicals of the motor that play a role in kPa (or absolute manifold pressure, which is atmospheric minus manifold vacuum). HOWEVER, you can see changes in kPa at idle by changing the desired idle speeds, base spark, and fueling. As absolute manifold pressure (kPa) increases at idle, idle quality decreases...
Old 07-17-2007, 09:44 PM
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could a bad map sensor cause the Kpa to read normal from idle to 5000 rpm then drop down after 5000 rpm's?
Old 07-17-2007, 09:47 PM
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No, i would say a massive intake restriction.
Old 07-17-2007, 10:16 PM
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Originally Posted by wait4me
No, i would say a massive intake restriction.
As of now Im running a Volant twin cone cold air intake, into a descreened 85mm MAF into a 90mm TB and 90mm FAST. I think the induction setup is pretty good.
Old 07-17-2007, 10:29 PM
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at wot, the KPA should read close to what your kpa is with key on engine off.


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