What calculations affect the VE.

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Mr DOHC
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What calculations affect the VE.

Post by Mr DOHC »

I have installed a new dual plane and 1000cfm on my 355 and while trying to get it to idle right, I can see the VE all of a sudden climbs up from the idle valid of approx 40 up to 80-90, while it does this it slowly dies as it leans right out.

The car is sitting there in park, idling around 1200-1300. What would cause the VE to rise like that?
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antus
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Re: What calculations affect the VE.

Post by antus »

VE is a measure of how filled the cylinder is, in a table with the axis of MAP and RPM. Are you saying MAP is changing as it warms up, or RPM to use a different VE call on the VE table or something else?
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charlay86
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Re: What calculations affect the VE.

Post by charlay86 »

VE comes directly from a lookup table with axes of MAP and RPM that you need to calibrate to match the efficiency of your motor.
pman92
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Re: What calculations affect the VE.

Post by pman92 »

Sounds like as the engine is stalling the MAP value is going up due to the reduced RPM causing it to move to a different VE cell
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Mr DOHC
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Re: What calculations affect the VE.

Post by Mr DOHC »

pman92 wrote:Sounds like as the engine is stalling the MAP value is going up due to the reduced RPM causing it to move to a different VE cell
Yeah I think the car may be starting to stall for some reason first. Then the VE looks like it goes up. I’ll grab the log and see whether it shows anything. I can’t remember if it was logging.
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Re: What calculations affect the VE.

Post by Charlescrown »

Post a log so we can have a look.
Mr DOHC
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Re: What calculations affect the VE.

Post by Mr DOHC »

i THINK this issue was caused by my MAP signal being too one-cylinder-dependant.
i moved the signal line from a single cylinder to under the throttle body.
i'll see how that goes.
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