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Volumetric efficency

EFI Tuning Fundamentals

Discussion and questions related to the course EFI Tuning Fundamentals

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Does a stock engine work at 100% volumetric efficency? Lets say we have a 5.0L v8, would it be working at 100% or less because of the intake restrictions etc.

No. There are many factors that come into play with VE. While VE is basically a measurement of how much air is getting into the cylinder, intake design, head design, intake restrictions, the floor and roof of your exhaust and intake ports, how well they flow etc. all play a major factor in how much air gets inside the cylinder itself. Majority of factory engines will be anywhere from 85% up to around 95%. Nascar built engines even though naturally aspirated, have whats called a supercharger effect and actually can flow up to about 105% (hence the super charger effect). This just means it is super efficient and actually gets more air cramed into the cylinder than it's supposed to at 100%.

Hope this makes sense.