im bored....and this goon keeps e-mailing me about how well his 'e-boost' is working, so i thought i;d clear this all up for anyone who might think its true, feel free to input any information, etc:


Ok before I go into this e-boost stuff, let's look at the concepts of turbocharging/supercharging/boosting in general


we all know that an engine digests air that, when combined with gasoline, is used to make the powerful explosion inside an internal combustion engine. The more air = the more fuel that can be added which in turn, makes a higher pressure inside the combustion chamber resulting in a higher power stroke and in turn creating torque to the crank. Now, as you may or may not know…horsepower is only a measurement of torque at a given RPM, and a higher torque at a given rpm = more power.

this explains that more combustion pressure during the power stroke in turn makes more power. But we have a 4 stroke engine now, so what about the other 3? Before the engine can make power (power stroke) there is the compression stroke. And before that, there is the intake stroke. And after compression is the exhaust stroke. During the intake stroke, the piston moves down in the bore, creating a lower than atmospheric pressure. The pressure outside of the cylinder (atmospheric) is now higher than the pressure inside the cylinder so in turn, air flows into the cylinder to fill it. Contrary to what some of you may think about the workings of an internal combustion engine, the piston itself DOES NOT suck air into the chamber. It does not happen. Skrilla made a post about this a while back. I actually got it wrong, and since then….learned up. Like I said ^^^ the greater the amount of air that fills the cylinder, the higher the pressure inside the combustion chamber will be (after the compression and power stroke that is), ok so now that all that nonsense is out of the way…let’s move on:



im sure you might be familiar, or have at least heard of the term ‘volumetric efficiency’ volumetric efficiency (VE) is used to describe the amount of fuel/air in the cylinder in relation to regular atmospheric pressure. If the cylinder is filled with fuel and air at atmospheric pressure (14.7psi) then the engine is said to have 100% volumetric efficiency. In a 2 liter four cylinder like our 420a, each cylinder has a volume of 499.18cc. ok this is how I got that:

Our engine = 121.8cu in

1cc = 0.061 cubic inches

121.8 cu in divided by 0.061 = 1996.72cc, so truly not in “fact” a 2 liter yet.

the 420a being a 4 cylinder means 1996.72cc/4cylinders = 499.18cc of air per cylinder (at 100% VE)


if one cylinder breathes in 424cc on the intake stroke, the engine is said to have an 85% volumetric efficiency (typical of most 420a’s) ( 424cc/499.18cc = 0.849 or 85% rounded up). Volumetric efficiency will change with a lot of different things such as how good the intake ports flow, how large they are, cam profiles, valve timings, etc. lets just say a 420a has a 85% VE. If a 420a 2 liter revving to 7200 rpm WOT, redline, this means that it eats 7188.2L of air per minute (one intake stroke to every two rpm), or 119.8 liter per second. Another way to look at it this flow is in cubic feet per minute and, and since 1cc = 0.061cu in and 1 liter = 1000cc each minute this engine consumes a approximately 254 cubic feet of air per minute. now….. a little 60mm diameter PC cooling fan flows only about 18 cubic feet per minute. Think about it this way….it would take over 14 60mm fans working hard just to feed this 2 liter, and that’s not even creating any boost.


*People confuse BOOST with AIRFLOW, if you don’t ever go above 14.7psi, you are not boosting. You might only see power because of the increase in VE, a vivid example is vtec (variable valve timing focused on scavenging principles and different rockers and lift durations)


so whats some ways to improve an VE? The best way is ‘forced induction’, causing a VE of OVER 100%, a variable valve timing like vtec does the same thing to a certain extent. But who cares about vtec? I wont go into it. Point is, If you have more air in the engine than it can even can consume, you have a boost pressure. Increasing VE to 120, 180, 200% means that much more fuel which means that much more power



now…..e-boost:
it connects and runs off the 12 volt on the battery. As you know…supercharging robs some power from the motor, and a highly efficient supercharger takes about 14.5kw to run. It steals this from the power generated to the crank due to the power stroke. On the other hand…to have an electric motor that runs off the 12 volt battery generating that many watts (14000+) we'd need a current flow of at least 1000 amps (14,000+ watts/13.8 volts = 1050 amps. So for this to even work….you’d need like 10 alternators!!! Let alone a serious fuckin compressor, not a fan

So remember kids…airflow does NOT equal boost, e-turvo can die a healthy death now, k thanks.

_________
96 talon esi-t
san clemente, ca


as needles of ice
are the ill winds' talons
the coldest of shadows
they seep unto the bone

silent souls leave .308 holes

i agree w/ everything you said except for this:

"It steals this from the power generated to the crank due to the power stroke."

power is not "stolen", youve just increased the efficiency of the system. power is (in your words) "stolen" by means of an elctronic turbo because there are so many steps used to transform that power. everytime you change "power" (mechanical, electrical, heat, light, etc..) you waste a little bit. w/ an e-turbo, you arent increasing the efficiency of ANYTHING, you are just sucking on resources and wasting them to produce next to nothing.

edit: i just realized that what i wrote makes next to no sence. hope you can understand it, lol.

that was way to fuckin much to read...



Nick
97RS

turbo8u> shut your SUCK
ZAO684: NIPPLE warning...maybe>?
turbo8u> yea i was a window licker on the short bus in junior high

Originally posted by SPL_Eclipse
"It steals this from the power generated to the crank due to the power stroke." power is not "stolen

the additional weight on the rotating assembly would cause power loss, yes. (superchargers are powered by belts) i wasnt talking about e-turbos robbing power, they just rob amps, and dont do jack shit.



_________
96 talon esi-t
san clemente, ca


as needles of ice
are the ill winds' talons
the coldest of shadows
they seep unto the bone

silent souls leave .308 holes

^^yeah, we are saying the same thing, i was just being nitpicky, lol. this will go into the "things weve seen before section", if for nothing else the description of VE and how it works. :bowdown

save me from rereading all that (I did read it..)

if I don't run at least 14.7 psi by 7200rpm I'm not really boosting?

I think you're misusing the word boost, because ANY increase in airflow will, by your theory be INCREASING the volumetric efficiency (more horsepower) ... but anyway

Originally posted by turbo8u
*People confuse BOOST with AIRFLOW, if you don’t ever go above 14.7psi, you are not boosting. You might only see power because of the increase in VE, a vivid example is vtec (variable valve timing focused on scavenging principles and different rockers and lift durations) so whats some ways to improve an VE?

Are you referring to 14.7 psi on a boost gauge?? If so, then this statement is way off. Boost gauges are calibrated to read 0 vac at 1 atm. When the gauge reads 14.7 psi, you are way over 100% VE.

I agree though that e-turbos and all equivalents are made strictly to make money off of suckers. The scary thing though is that I'll bet they make a lot of money hahaha.

B.T.W., You calculate Volumetric Efficiency by dividing the mass of air inducted into the cylinder between IVO and IVC by the mass of air that would fill the cylinder at atmospheric pressure (with the piston at BDC). Typical values range from 0.6 to 1.2, or 60% to 120%. You can't really calculate VE by HP, RPM and displacement. You might be able to get close, but it doesnt take into account variables like pumping losses, parasitic drag, thermodynamic efficiency and a few other things. It isn't that uncommon to get over 100% VE with a NA motor.

Originally posted by Matt_95tgs
Boost gauges are calibrated to read 0 vac at 1 atm.

Just becuase I'm a no0b in training...

atm = atmosphere, right?

^^yes

turbo8u is assuming this in the entire discussion. its s simplified version, but really hits on the main points. great job, IMO (or at least as i understand things, lol).

No you guys are misunderstanding him.

Atm pressure is 14.7 psi, meaning for your boost gauge to read 1 psi, the ACTUAL pressure in your system is 15.7 psi @ sea level.


So turbo8u, are you saying I should buy 14 turvos? :D The turvo guy is gonna redesign it, making the whale **** looking intake just a row of turvo's.

Originally posted by WickedESi
No you guys are misunderstanding him. Atm pressure is 14.7 psi, meaning for your boost gauge to read 1 psi, the ACTUAL pressure in your system is 15.7 psi @ sea level. So turbo8u, are you saying I should buy 14 turvos? :D The turvo guy is gonna redesign it, making the whale **** looking intake just a row of turvo's.

ahhhhhhhhhhh ok now i get it

Originally posted by Matt_95tgs
Are you referring to 14.7 psi on a boost gauge?? If so, then this statement is way off.

no, thats not what i meant at all. lol.

Originally posted by Matt_95tgs
When the gauge reads 14.7 psi, you are way over 100% VE.

i know, you're at 1 bar, aka...double the atmospheric pressure. exceeding VE by FAR, afterall...VE doesnt mean shit to a forced induction car under 1+ bar of boost, or any boost for that matter.

Originally posted by Matt_95tgs
B.T.W., You calculate Volumetric Efficiency by dividing the mass of air inducted into the cylinder between IVO and IVC by the mass of air that would fill the cylinder at atmospheric pressure (with the piston at BDC).

i was wondering about that, someone told me once 420a's have better than normal VE, im pretty sure thats true too. its based on environmental conditions too though, it'd be hard to be exact, buy you can get close.

Originally posted by Matt_95tgs
You can't really calculate VE by HP, RPM and displacement. You might be able to get close, but it doesnt take into account variables like pumping losses, parasitic drag, thermodynamic efficiency and a few other things. It isn't that uncommon to get over 100% VE with a NA motor.

i didnt calculate VE by HP, RPM and displacement at all. i said lets assume VE is 85%, typically on a NA car, VE is not exceeding 100% though, i beg to differ with you there. with some 4-2-1 headers and some intake mods, maybe closer and maybe over...but stock? i dunno. i'd like to know of a motor without any valve timing that exceeds VE. ours sure doesnt. a s2000 for example exceeds VE because of the holding open of the exhaust valves, the resulting effect is that the exhaust pulse actually helps draw air into the next cylinder during its intake stroke (works on the principles of scavenging)

airflow in most engines is only about 80% efficient. at normal running speeds, the cylinders are only filled about 4/5ths. there are lots of restrictions to airflow though....air filter, throttle plates, bore sizes, ledges from the manifold to the head, bends in the manifolds, intake and exhaust valves, and the exhaust system all slow airflow into the cylinder.

:thumbsup
_________
96 talon esi-t
san clemente, ca


as needles of ice
are the ill winds' talons
the coldest of shadows
they seep unto the bone

silent souls leave .308 holes

heh

the NA guys can say .."Yeaaahp. I'm givin her 14.5psi... Stock internals...:afro"

Originally posted by GhEttOrAiD
heh the NA guys can say .."Yeaaahp. I'm givin her 14.5psi... Stock internals...:afro"

exactly :beer

109whp at 14psi, thats so good! lol

edit: skrillas told me of a guy who boosted 13psi on stock internals for a year :bowdown


_________
96 talon esi-t
san clemente, ca


as needles of ice
are the ill winds' talons
the coldest of shadows
they seep unto the bone

silent souls leave .308 holes

Ya I think Josh was missunderstood, he was refering to atm pressure not boost pressure. Every car in the world will breathe from 1 Bar or less of nature's pressure (depending on elevation or a lack thereof)

Ya the guy that was running 13 lbs was Joe (Joe P. I think and not the guy who made the manual boost controller either) I almost bought his CF hood like 4 yers ago - before I learned to make my own fiberglass hoods at 25% the cost LOL

Haters. My electric trubo runs 10s all day long. You guys don't know what youre' talking about. Plus, with my electric BOV, I get lots of poon. You don't know what you're missing!