Volumetric Efficiency

Phil · Posted: Thu Jan 10, 2002 7:38 pm Post subject: Volumetric Efficiency

Does anyone know any way of calculating the volumetric efficiency of any given engine??

Turbo_Gem · tinkerer Joined: 10 Jan 2002 Posts: 50

there is a set formula to do it, or there r a couple of computer programs available such as engine analyser to calculate very accurately what an engine will put out.you`ve gotta know cylinder head flow,combustion chamber size & type,engine capacity,length of the inlet tract from valve to open air,full camshaft specs including lift,overlap,duration,lobe centres,exhaust length ie port length, header primary & secondary length, not to mention exhaust system size & length, also in most cases the engine owners perceived penis size plays a part in how much power they think their engine will put out. in other words its pretty involved. i`ve got the formula somewhere,just gotta find it. the programs r available i believe from any speed shop dealing with hi tech stuff(in other words not a V8 shop)

Phil · Posted: Fri Jan 11, 2002 2:58 am Post subject: Re: Volumetric Efficiency

Jeez, sounds like its a bit much, but if you have the formula handy could you post it up?
I'm just interested because I was reading an article on tuned length intake runners and the VE is needed to calculate the runner diameter. It's only for efi engines as far as I know, and I'm planning on getting efi as soon as I have the cash.
Thanks.
Phil

LOK15 · Posted: Sat Jan 12, 2002 11:08 pm Post subject: Re: Volumetric Efficiency

i`ll try and find it tonite.. if u go efi on an aspirated gem engine, go for quad throttle bodies,dont use a plenum type manifold such as those on the import g180 & g200 engines.i have tried that myself, and the thing ran out of puff at 6000 rpm(peaked at 5500) even tho the engine was designed to make peak power over 7000 rpm(yep everything possible was done to it),however it did pull 140 hp on the rollers.. i`d use injection perfection quads or something similar,either 40 or 45 mil depending on what kind of use u want it for.if ur just going down to the shops & back then a plenum manifold will do.for arguments sake the manifold i used was from an import g200 from a very early aspirated piazza single cam,ported out and using a 62mm vs commodore throttle body.u can actually see my car at willowbank on our website (geocities.com/isuzumotorsports)its the green one doing a skid in the events section.. it pulled a 15.10 at 90 mph in full street trim,would have been better if it hadve revved harder or was geared differently,as i had to pull 4th just b4 the line..
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Turbo_Gem · tinkerer Joined: 10 Jan 2002 Posts: 50

whoops sorry phil it was me there i just forgot to logout lachy..

Turbo_Gem · tinkerer Joined: 10 Jan 2002 Posts: 50

jeez i put my foot in it..i got the formula out,i cant fucking understand it,is more to do with horsepower potential and , all i can suggest is to get the engine analyser program,this formula needs deciphering by someone.. i`ll put some of it here anyway.. intake runner length = 132000/peak hp engine revs(answer in inches)132000 is the constant for the 2nd harmonic. the rest of this shit is gobbledygook..

Phil · Posted: Tue Jan 15, 2002 6:46 pm Post subject: Re: Volumetric Efficiency

Do you reckon you could scan it and send it to me? Just for interests sake. I like reading about stuff like that... call me a nerd if you will.