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Cylinder Volume, skew performance??

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Old Jul 13, 2005 | 06:42 PM
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Default Cylinder Volume, skew performance??

I just noticed this field in my HPTuners software. Since I have a 393ci engine, the cylinder volume isnt correct. I dyno'd the car and the power is abnormally low on motor and Im wondering what affect the cylinder volume will have on my car, if any.

The car is tuned to a perfect 12.3 afr with around 29* timing.

Any input it greatly appreciated!
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Old Jul 13, 2005 | 06:49 PM
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It affects fueling IIRC
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Old Jul 13, 2005 | 06:54 PM
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So if my tune is perfect AFR wise then it wouldnt matter, no?
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Old Jul 13, 2005 | 07:11 PM
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Right it doesn't matter since the fueling is right. It doesn't matter past 4000 rpm where the maf takes over completely anyway. It could be making you go lean at part throttle/low rpm but you won't see it on the dyno.
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Old Jul 14, 2005 | 02:04 PM
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Cylinder volume messes up speed density. Speed
density still matters at higher RPM, when you have
unsteady-MAP conditions. Maybe not on the dyno.
You should put it right.

If the speed-density and MAF airflows disagree
too much you may see a MAF performance code.

12.3:1 is somewhat fat for NA and you would probably
see some improvement from a leaner setup. If you
need to keep it fat for power adder and have no
slicker way of bumping fuel only when needed, you
may just have to tolerate detuned NA performance.
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