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The actual amount of air the engine ingests compared to the theoretical maximum is called volumetric efficiency (VE).
For the things that I like to say about volumetric efficiency...

It's a good way to make some power... AIRFLOW (scfm) = DISPLACEMENT (ci) x RPM ÷ 3456 :p

More air it's not always better.

The air-to-fuel mass ratios at best power mixture is typically around 12.5 to 1. If you work through the arithmetic, you find that the airflow required at that mixture (12.5 to 1) is:

For Honda naturally aspirated engine, the theoretical maximum amount of air that each cylinder can ingest during the intake cycle is equal to the swept volume (displacement) of that cylinder (0.7854 x bore x bore x stroke). Since each cylinder has one intake stroke every two revolutions of the crankshaft, then the theoretical maximum volume of air it can ingest during each rotation of the crankshaft is equal to one-half its displacement.

There are many factors which determines but I like the fundamental determinant is the mass of air it can ingest

into the cylinders For contemporary naturally-aspirated, Only the best of the best can exceed 110%, and that is by means of extremely specialized development of the system comprised of the intake passagies, combustion chambers, exhaust passagies and valve system components.

Generally, the RPM at peak VE coincides with the RPM at the torque peak. And generally, automotive engines rarely exceed 90% VE. There is a variety of good reasons for that performance, including the design requirements for automotive engines (good low-end torque, good throttle response, high mileage, low emissions, low noise, inexpensive production costs, restrictive form factors, etc.......... :wink: as well as the allowable tolerances for components in high-volume production.

Knowing a claimed power and fuel-flow for a given engine, you can calculate an estimate of the VE required and use all these yardsticks for estimation of reasonableness.

Engine airflow at 100% VE, in sea-level-standard-day cubic feet per minute (scfm)



But the sea-level -standard it's hard to go base on...


We claim power in real life.


Beacuse when elevation rises, oxygen levels are reduced, reducing an engine’s volumetric efficiency. The typical drop in horsepower at any rpm level is approximately three percent per 1,000 feet of elevations.
 

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It seems like increased plenum volume might be good for turbo but that's not really my area... as far as for all motor just by looking at it I'd be surprised to see it make more power but maybe someone can post dyno charts and prove me wrong??
 

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taqman15 said:
there was no tuning.. 2 base runs before and 2 after.. this is in 4th gear.
k20a motor with -k-pro untuned..
91 octane
stock motor with the cat and stock civic muffler(haha). it kind of killed the performance but it's all relative.

p.s thanks to Casey at Modacar for the dyno time.. if you need to check if this a real deal, you can call him at modacar..
Looks pretty good man... so it fits k20a manifold?
 

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import_trung said:
only reason i ask for a group buy is cos i noe ppl on this forum are probably interested in one. and supplied bolts would be sweet. saves hassle in having to look for ones that fit.
it's probably easier to get the bolts here as they are Metric and not exactly common in the states
 
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