So if pressure difference is the only motivator worth considering, and the pressure in the cylinder doesn't come up to the pressure in the port until IVC, then VE is limited to the % of total cylinder volume that is available in the cylinder at IVC.

That's not how the world works either.

Also, show us some arithmetic verifying that the kinetic energy of the inflowing air is not sufficient to compress air that is already in the cylinder.

 

That depends on whether you use atmospheric air density or manifold as a basis for comparison. I think the majority of people in this thread think, and are speaking, about VE in relation to atmospheric.

 

Volumetric efficiency is simply the amount of air being pushed through your motor divided by the displacement and then multiplyed by 100 to give you a percentage. So if you are forcing more air/fuel through the same amount of cubic inches.....???????

 

Oh and I still need the volumetric effciency over the whole rev rang.

 

Here is some VE information on my 402 that I had dynoed on a superflow 902 a few weeks ago.

ls2-402 dyno.pdf

 

The 402 graph gives a good look at what a VE curve will look like. Remember ve is max at peak torque then diminishes with rpm always, you will never see a larger VE number after peak torque. Also a crude way to get an idea is to use a dyno graph of a sock engine, using the fact that it takes approximately 1 lb/min of air to make 10 hp you could approxiate the airflow over the rpm range. Also 0.069 x CFM = lb/min and (lb/min)/0.069=CFM So using a stock dyno chart you could calculate a very rough approximate airflow versus rpm because dynos aren't the most accurate measuring device. Then take these questimates and divide by the calculated theoretical airflow at the same rpm's at 100%VE then times that by a 100 to give you a percentage. Like I said this is rough but it is a way.

 

Stock engines, normally aspirated, probably hit VE in the 80% range at their best. No way is a stock NA engine hitting high 90s or over 100 VE.

 

I agree....97% seems a little high for stock.

 

my current setup (sig) sees 115 at peak tq and then down to 112.

I did a SD tune on a 00' z28 with a lid, ls6 intake, and no muffler that has peak tq at 96 and then down to 95

a stock 00' camaro has a ve map just like that, peak 95

a stock 02' camaro peaks at 99 and then drops to 89

a stock 02 z06 peaks at 99 and then drops to 90

these are all straight from efi live