# Volume Efficiency



## jbrewton (Apr 13, 2007)

Does any one know the normal volume efficiency % for a 2001 Nissan Frontier 3.3L VG33E?


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## BTF/PTM (Oct 19, 2006)

jbrewton said:


> Does any one know the normal volume efficiency % for a 2001 Nissan Frontier 3.3L VG33E?


do you mean the volumetric efficiency? It's virtually impossible to calculate it accurately because valve timing, cam lobe profile and variable intake functions all change the way air enters the cylinders.

In general, volumetric efficiency of a naturally aspirated engine is right around 1.0, sometimes it gets a little better than 1.0 (perfect fill) because of the stuff I mentioned above. I'll dig out my old thermodynamics book and see if I can help further.


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## jbrewton (Apr 13, 2007)

BTF/PTM said:


> do you mean the volumetric efficiency? It's virtually impossible to calculate it accurately because valve timing, cam lobe profile and variable intake functions all change the way air enters the cylinders.
> 
> In general, volumetric efficiency of a naturally aspirated engine is right around 1.0, sometimes it gets a little better than 1.0 (perfect fill) because of the stuff I mentioned above. I'll dig out my old thermodynamics book and see if I can help further.


Yes, volumetric efficiency. Using a scan tool I was able to calculate based on RPM's, MAF, Air intake temp and size of engine. It's probably not accurate, but my results were .78 at the higher RPM range 3500-4000 and a little above .80 in the 2500-3500 range. At idle VE was closer to .28 I just wanted to know if this was normal.


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## azrocketman (Oct 5, 2005)

jbrewton said:


> Yes, volumetric efficiency. Using a scan tool I was able to calculate based on RPM's, MAF, Air intake temp and size of engine. It's probably not accurate, but my results were .78 at the higher RPM range 3500-4000 and a little above .80 in the 2500-3500 range. At idle VE was closer to .28 I just wanted to know if this was normal.



Seems like you're applying rocket science where it's of no value. A simpler indicator (in my opinion) is horsepower per liter (or cubic inch). The normally aspirated VG33 is rated at 170 horsepower or 52 horsepower per liter. The 2.4 liter four cylinder is rated at 143 horsepower or 60 horsepower per liter (about one horsepower per cubic inch). The VG33 is generally acknowledged to be a relatively low output engine optimized more towards torque for truck applications.

Steve


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## BTF/PTM (Oct 19, 2006)

azrocketman said:


> Seems like you're applying rocket science where it's of no value. A simpler indicator (in my opinion) is horsepower per liter (or cubic inch). The normally aspirated VG33 is rated at 170 horsepower or 52 horsepower per liter. The 2.4 liter four cylinder is rated at 143 horsepower or 60 horsepower per liter (about one horsepower per cubic inch). The VG33 is generally acknowledged to be a relatively low output engine optimized more towards torque for truck applications.
> 
> Steve


actually horsepower isn't in units that are compatible with liters, you'd have to use cubic inches instead. It's not rocket science, just basic engineering. 

.78 sounds kinda low, but then I've seen the 3.3L engine and the intake manifold looks like very little thought was put into it other than "ok, how can we make things fit?". I would venture to say that the 4.0L V6 has a much higher volumetric efficiency since it produces more horsepower than the standard 4.6L Ford V8 and a lot of other engines and has a much more contoured manifold design. Interesting stuff, glad to see there's at least one other nerd here on the forum


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## azrocketman (Oct 5, 2005)

BTF/PTM said:


> actually horsepower isn't in units that are compatible with liters, you'd have to use cubic inches instead. It's not rocket science, just basic engineering. )


It's power per displacement. While the units are SAE over metric, relative comparisons are valid. 

Steve


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