Measuring Volumetric Efficiency.

Anyone know a formula for that, how to measure it?


[Modified by vtec.dc2, 1:26 PM 11/25/2002]

 

trying to figure out the airflow of type r engine

one formula I found:

AIRFLOW = 0.5 x Engine Size x RPM x % V/Efficiency

 

anyone?

 

damn.. thats outa my league..

you lost me at Volume

 

I would say it gets right up to around 100% if not more at the higher rpms.

 

There is no one volumetric efficiency for a give engine. It varies throughout the rpm range, and will match the torque produced by the engine. Max VE occurs at peak torque. Depending on the car VE may be anywhere from the 80's to just over 100 in an NA car at peak. Intake tuning and scavaging can cause VE to exceed 100% for short periods in the range.

From what I know, only car manufacturers have the instruments to give the true VE for an engine.

 

Normally you'd measure the airflow and use that to determine the VE, not the other way around. You can make a venturi-style airflow meter that will give you decent results. It's kind of a lot of work, though, with about half of the work being the math.

It'll probably be a lot easier to find the numbers online, though. If you just need a decent approximation, you can assume 100% VE and use the above formula.

As others have noted, VE varies throughout the RPM range due to intake and exhaust tuning. Since the ITR engine is highly tuned, it probably stays in the area of 100% in a large part of its RPM range.

 

thats correct, i should of stated my question better (going to edit on top)

my question would be on how to calculate volumetric efficiency of an engine.. I found this calculator from
https://honda-tech.com/zerothread?id=248299

not sure if hp you enter is whp or at the crank.

 

is there a formula to measure airflow without the meter?

 

Don't know of one/can't think of one off-hand, but then I'm a bit out of practice. Try a Google search for "measure airflow"

 

yep.. will try that.. thanks

 

As has been noted, VE matches or is tightly related to the torque produced by an engine. There's probably some way then to figure out VE based on the torque, then...but it seems like a hell of a lot of work finding the exact relation between VE and torque in the first place.