Jump to content

Calculating VE


Recommended Posts

Volumetric efficiency is basically comparing how much air your "air pump" (engine) is actually pumping per 2 revolutions, compared to its total displacement.

 

There isn't really a formula to find out volumetric efficiency, since it has SO many variables/ incalculable items.

 

Its just like a guesstimate, factory engines run like at ~80% tuned up performance engines can get up around ~95%, and all out race motors can get up to and around 110%. Those are all naturally aspirated motors.... of course boosted engines run waaay higher because they are forcing the air in, instead of just relying on air pressure differences.

 

Edit: Hatch, good luck finding those numbers if the factory never released them. If someone has put them on a flow bench, it was for their personal knowledge, and more than likely they aren't sharing it with others without a cost.....

Edited by Pyrorocketeer
Link to comment
Share on other sites

Edit: Hatch, good luck finding those numbers if the factory never released them. If someone has put them on a flow bench, it was for their personal knowledge, and more than likely they aren't sharing it with others without a cost.....

 

yea i realized that. however i think i'm gonna get a b-series head from a junk yard just to get a base idea.

Edited by Hatch92
Link to comment
Share on other sites

to see what, head flow numbers? They don't really mean all that much/ tell the whole story. They don't say much about port velocity, they can just tell you flow at certain lifts, under WOT. Which most engines don't spend all their lives in this range.

Link to comment
Share on other sites

to see what, head flow numbers? They don't really mean all that much/ tell the whole story. They don't say much about port velocity, they can just tell you flow at certain lifts, under WOT. Which most engines don't spend all their lives in this range.

 

 

i would like to find out just so it will help me out a little more later when i start to build the turbo setup using that GT35r

Link to comment
Share on other sites

well even then, all you need to be concerned with is exhaust flow. Intake is going to be forced down its throat, regardless of what the port looks like. Honda heads flow pretty damn well from the factroy, and there isn't much that one can do to 'open them up' to be able to flow a little more

Link to comment
Share on other sites

It can be done, roughly, but I would need so much information as far a cam profiles,how the cam is degreed, chamber volume, piston dish volume, bore, stroke, rod length, deck height, compressed gasket thickness, etc. Most of that would go into SCR and DCR calculation and then a VE could be estimated with intended operational range.

 

 

Oh...and that would be just for naturally aspirated. For a turbo I'd need a detailed compressor map, physical specs, and a lot of other stuff. For the record VE's are often calculated AFTER the engine is put together as then it is a simple matter of measuring mass flow across the engine and making adjustments accordingly.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

Terms of Use | Privacy Policy | Guidelines
We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.