Ve ?

[Taylorman]

So a NA unless very tricked out does not reach 100% VE right? Blowers are used to get the motor to 100 and above 100% VE right. How much boost is required just to get the motor to 100%? The more boost the hight the VE right?

[steelcomp]

So a NA unless very tricked out does not reach 100% VE right? Blowers are used to get the motor to 100 and above 100% VE right. How much boost is required just to get the motor to 100%? The more boost the hight the VE right?Plenty of NA motors running past 100%VE.
Your question needs a lot more info to be answered. Each motor is diferent and will have different requirements.

[TurboNova]

Let's look at what VE actually is.
"The actual amount of air the engine ingests compared to the theoretical maximum is called volumetric efficiency (VE). An engine operating at 100% VE is ingesting its' total displacement every two crankshaft revolutions.
Volumetric Efficiency, For contemporary naturally-aspirated, two-valve-per-cylinder, pushrod engine technology, a VE over 95% is excellent, and 100% is achievable, but quite difficult. Only the best of the best can exceed 110%, and that is by means of extremely specialized development of the complex system comprised of the intake passages, combustion chambers, exhaust passages 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.), as well as the allowable tolerances for components in high-volume production.
For a known engine displacement and RPM, you can calculate the engine airflow at 100% VE, in sea-level-standard-day cubic feet per minute (scfm) as follows:
100% VE AIRFLOW (scfm) = DISPLACEMENT (ci) x RPM / 3456"
This equation is theoretical VE and not the actual VE of the engine.
I have tuned quite a few turbo engines in the 95% efficiency, but have yet to even see an engine that makes 100% and I don't think over 100% is truly achievable. Even when you have a boosted engine it will not make your VE higher it will just make the air charge more dense, the engine can only still pump out a maximum volume of air. Most of the engines I see even the boosted ones are in the 80%-90% range.

[Morg]

Let's look at what VE actually is.
"The actual amount of air the engine ingests compared to the theoretical maximum is called volumetric efficiency (VE). An engine operating at 100% VE is ingesting its' total displacement every two crankshaft revolutions.
Volumetric Efficiency, For contemporary naturally-aspirated, two-valve-per-cylinder, pushrod engine technology, a VE over 95% is excellent, and 100% is achievable, but quite difficult. Only the best of the best can exceed 110%, and that is by means of extremely specialized development of the complex system comprised of the intake passages, combustion chambers, exhaust passages 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.), as well as the allowable tolerances for components in high-volume production.
For a known engine displacement and RPM, you can calculate the engine airflow at 100% VE, in sea-level-standard-day cubic feet per minute (scfm) as follows:
100% VE AIRFLOW (scfm) = DISPLACEMENT (ci) x RPM / 3456"
This equation is theoretical VE and not the actual VE of the engine.
I have tuned quite a few turbo engines in the 95% efficiency, but have yet to even see an engine that makes 100% and I don't think over 100% is truly achievable. Even when you have a boosted engine it will not make your VE higher it will just make the air charge more dense, the engine can only still pump out a maximum volume of air. Most of the engines I see even the boosted ones are in the 80%-90% range.
Excellent post,
The problem is, reality sucks. And motor builders have goals promissed to customers.
This may get interesting.

[steelcomp]

Let's look at what VE actually is.
"The actual amount of air the engine ingests compared to the theoretical maximum is called volumetric efficiency (VE). An engine operating at 100% VE is ingesting its' total displacement every two crankshaft revolutions.
Volumetric Efficiency, For contemporary naturally-aspirated, two-valve-per-cylinder, pushrod engine technology, a VE over 95% is excellent, and 100% is achievable, but quite difficult. Only the best of the best can exceed 110%, and that is by means of extremely specialized development of the complex system comprised of the intake passages, combustion chambers, exhaust passages 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.), as well as the allowable tolerances for components in high-volume production.
For a known engine displacement and RPM, you can calculate the engine airflow at 100% VE, in sea-level-standard-day cubic feet per minute (scfm) as follows:
100% VE AIRFLOW (scfm) = DISPLACEMENT (ci) x RPM / 3456"
This equation is theoretical VE and not the actual VE of the engine.
I have tuned quite a few turbo engines in the 95% efficiency, but have yet to even see an engine that makes 100% and I don't think over 100% is truly achievable. Even when you have a boosted engine it will not make your VE higher it will just make the air charge more dense, the engine can only still pump out a maximum volume of air. Most of the engines I see even the boosted ones are in the 80%-90% range.
How many examples of an NA engine exceeding 100% VE would you like?

[92562]

How many examples of an NA engine exceeding 100% VE would you like?I wouldn't mind seeing one.
Since an engine is nothing more than an air pump, just looking at the VE equation tells me that due to little things like blow-by, etc. you'll never reach theoretical VE. Maybe a good rotary? Unless I am oversimplifying things, teach me something here.

[steelcomp]

For starters, Here's a single four barrel 427" SB Chev.ETAVBWIN.ZIP
looks like you are "Trapping" at least 117.0 VE % or more
without wasting too much out of exhaust or rings
CID= 427.445 --- Fuel Consumed in Lbs/Hour ---
CFM @ 12.5:1 13.2:1 14.0:1 14.7:1 16.0:1 Fuel Engine
Engine 117.0 A/F A/F A/F A/F A/F Heat Friction
RPM Ve % Lbs/Hr Lbs/Hr Lbs/Hr Lbs/Hr Lbs/Hr HP HP
5700 824.8 258.2 244.5 230.5 219.6 201.7 1835 129.3
5800 839.3 262.7 248.8 234.6 223.4 205.3 1867 134.3
5900 853.8 267.3 253.1 238.6 227.3 208.8 1899 139.5
6000 868.2 271.8 257.4 242.7 231.1 212.3 1931 144.7
6100 882.7 276.3 261.7 246.7 235.0 215.9 1964 150.0
6200 897.2 280.8 266.0 250.8 238.8 219.4 1996 155.4
6300 911.7 285.4 270.2 254.8 242.7 222.9 2028 161.9
6400 926.1 289.9 274.5 258.8 246.5 226.5 2060 168.5
6500 940.6 294.4 278.8 262.9 250.4 230.0 2092 175.2
6600 955.1 299.0 283.1 266.9 254.2 233.6 2125 182.1
6700 969.5 303.5 287.4 271.0 258.1 237.1 2157 189.1
6800 984.0 308.0 291.7 275.0 261.9 240.6 2189 196.2
6900 998.5 312.6 296.0 279.1 265.8 244.2 2221 203.5
7000 1013.0 317.1 300.3 283.1 269.6 247.7 2253 210.9
7100 1027.4 321.6 304.6 287.2 273.5 251.3 2286 218.8
7200 1041.9 326.1 308.8 291.2 277.3 254.8 2318 226.8
7300 1056.4 330.7 313.1 295.2 281.2 258.3 2350 235.0
7400 1070.8 335.2 317.4 299.3 285.0 261.9 2382 243.2
7500 1085.3 339.7 321.7 303.3 288.9 265.4 2414 251.7
7600 1099.8 344.3 326.0 307.4 292.7 269.0 2447 260.2
7700 1114.3 348.8 330.3 311.4 296.6 272.5 2479 268.9
CID= 427.445 --- Fuel Consumed in Lbs/Hour ---
CFM @ 12.5:1 13.2:1 14.0:1 14.7:1 16.0:1 Fuel Engine
Engine 117.0 A/F A/F A/F A/F A/F Heat Friction
RPM Ve % Lbs/Hr Lbs/Hr Lbs/Hr Lbs/Hr Lbs/Hr HP HP
7800 1128.7 353.3 334.6 315.5 300.4 276.0 2511 278.0
7900 1143.2 357.8 338.9 319.5 304.3 279.6 2543 287.3
8000 1157.7 362.4 343.2 323.6 308.1 283.1 2575 296.9
8100 1172.1 366.9 347.5 327.6 312.0 286.6 2607 306.5
8200 1186.6 371.4 351.7 331.6 315.8 290.2 2640 316.4
8300 1201.1 376.0 356.0 335.7 319.7 293.7 2672 326.3
8400 1215.5 380.5 360.3 339.7 323.6 297.3 2704 336.4
8500 1230.0 385.0 364.6 343.8 327.4 300.8 2736 346.7
8600 1244.5 389.6 368.9 347.8 331.3 304.3 2768 357.5
8700 1259.0 394.1 373.2 351.9 335.1 307.9 2801 368.5
8800 1273.4 398.6 377.5 355.9 339.0 311.4 2833 379.7
8900 1287.9 403.1 381.8 360.0 342.8 315.0 2865 391.0
9000 1302.4 407.7 386.1 364.0 346.7 318.5 2897 402.5
9100 1316.8 412.2 390.3 368.0 350.5 322.0 2929 414.2
9200 1331.3 416.7 394.6 372.1 354.4 325.6 2962 426.0
9300 1345.8 421.3 398.9 376.1 358.2 329.1 2994 437.9
9400 1360.3 425.8 403.2 380.2 362.1 332.7 3026 450.1
9500 1374.7 430.3 407.5 384.2 365.9 336.2 3058 462.3
9600 1389.2 434.9 411.8 388.3 369.8 339.7 3090 474.8
9700 1403.7 439.4 416.1 392.3 373.6 343.3 3123 487.4
Note=> Air/Fuel Ratio will shift towards 12.5:1 to 13.2:1
for non-acceleration Steady-State type Dyno test.
Air/Fuel Ratio will shift towards 14.0:1 to 14.7:1
for 600 RPM/SEC or faster acceleration type Dyno test
Fuel in Lbs./Hour at various Air/Fuel Ratios may differ from
actual Dyno Data due to Fuel Specific Gravity and Temperature
Fuel Heat HP = the amount of Energy per Lbs. of Fuel converted into HP
Friction HP = the amount of mechanical and fluid friction losses,
along with Pumping Losses ... based upon research
by GM , Honda , SuperFlow equations , and others.
at 300 RPM/SEC its =>
427.445 Cubic Inches @ 8200 RPM with 117.0 % Volumetric Efficiency PerCent
Required Intake Flow between 396.1 CFM and 420.6 CFM at 28 Inches
Required Exhaust Flow between 244.9 CFM and 284.9 CFM at 28 Inches
300 RPM/Sec Dyno Test Low Normal Best
Peak HorsePower 965.1 980.1 995.1
Peak Torque Lbs-Ft 667.2 674.1 681.0
HorsePower per CID 2.258 2.293 2.328
Torque per Cubic Inch 1.561 1.577 1.593
BMEP in psi 235.4 237.8 240.2
Carb CFM at 1.5 in Hg. 1187 1320 1454
Target EGT= 1118 degrees F during 4 second 600 RPM/Sec Dyno accel. test
Octane (R+M)/2 Method = 115.1 to 115.0 Octane required range
_________________

[steelcomp]

I wouldn't mind seeing one.
Since an engine is nothing more than an air pump, just looking at the VE equation tells me that due to little things like blow-by, etc. you'll never reach theoretical VE. Maybe a good rotary? Unless I am oversimplifying things, teach me something here.
A quick look at an engine as an air pump in a static state may give you that impression, but under dynamic conditions, things aren't as they seem. Optimizing airflow into, and out of an engine, and the combustion process that takes place during that period, has become very sophisticated...to a level that is difficult to understand without a physics and engineering degree.
Trust me...100%VE is commonplace.

[92562]

Thanks,
I have the physics degree, but it's geared toward nuclear medicine, not engineering! It just seemed to me that the only way to get more out than you put in is to consider that the heated gases take up more volume than the cool intake gases. I've only dynoed a handful of the engines I've built and frankly, never paid that column much attention. Thanks for the education!

[steelcomp]

Thanks,
I have the physics degree, but it's geared toward nuclear medicine, not engineering! It just seemed to me that the only way to get more out than you put in is to consider that the heated gases take up more volume than the cool intake gases. I've only dynoed a handful of the engines I've built and frankly, never paid that column much attention. Thanks for the education!
Air can be compressed. A moving column of air can be accelerated, then suddenly stopped in the front, yet continue to move in the rear, packing the molecules together, and compressing. Then, at the proper moment, the door is shut from behind, trapping that compreessed column of air. This is called ram effect, and in an oversimplified manner, can "overfill" a given volume. Port shapes, intake runners, exhaust, cam timing can all effect this ram effect to the point of exceeding the calculated volume of an engine at a given rpm.
Volumetric effeciency isn't letting out more than you take in, rather, it's the ability of the engine to take in near, or above it's calculated volume. What goes out is another story all together.