Volumetric Efficiency

[Desertrunner]

The blue line waves are from the air rushing down the intake to catch up with the engine on the intake stroke then bouncing back when the intake valve closes. There would be very little difference on a running engine with the blue line.
The yellow pressure reading would be 4 to 5 times higher if it was a running engine and have a totally different shape.

[Warp Speed]

Interesting

[Firedome8]

You are correct, Stan. Actual VE is a theoretical calculation based on the amount of air ingested into the engine. With correct valve events, the more air going into the engine, the more that will be "trapped" in the cylinder/combustion chamber. I don't believe that it is possible to get a VE of much over 105% without the aid of supercharging, turbocharging, etc.. As far as valve events are concerned, there is a very fine line between closing the exhaust valve at the exact correct time and scavenging intake fluid into the exhaust system.
To answer a question posed in a previous post, very high exhaust temperature (red/glowing headers) can usually be attributed to very lean intake mixture.

On the glowing headers, does the lean mix burn slow and then continue burning in exhaust? Or ?

[Warp Speed]

Max VE is all about the correct intake, Diameter (so you get Velocity) and Length ( so you get Mass). When you get inertial to work for you you will get the highest VE. Its not about harmonics at all.
Below are two pressure traces, the blue line is a pressure transducer reading just before the intake valve, the yellow line is the in cylinder pressure transducer. The engine is not firing so we can get a clean trace. Both traces are at the same rpm. If you look down the bottom under the yellow "1" you will see the first has 4.56V the second has 5.74V. The second is 126% of the first so if this was a 500 hp engine the second would 630 hp extra. This is the same cam and lift etc in both traces . As I said the only difference is the design of the intake and using inertia, it is of course a NA engine.
Enjoy,
TEST A 4,000 rpm LS Head No Pipe.jpg
TEST A 4,000 rpm LS Head and 29.5 by 350L.jpg

Maybe I'm missing something in your post, but what is the difference in set up between the 2 graphs?

[David Redszus]

You are correct, Stan. Actual VE is a theoretical calculation based on the amount of air ingested into the engine. With correct valve events, the more air going into the engine, the more that will be "trapped" in the cylinder/combustion chamber. I don't believe that it is possible to get a VE of much over 105% without the aid of supercharging, turbocharging, etc.. As far as valve events are concerned, there is a very fine line between closing the exhaust valve at the exact correct time and scavenging intake fluid into the exhaust system.
To answer a question posed in a previous post, very high exhaust temperature (red/glowing headers) can usually be attributed to very lean intake mixture.

On the glowing headers, does the lean mix burn slow and then continue burning in exhaust? Or ?

Glowing headers can result from any of three conditions, all of which result in a LATE (not necessarily slow) burn.
Excessively lean or excessively rich mixture, or retarded timing will result in glowing headers.
Engine misfires are another cause of glowing headers.

[Erland Cox]

Torque will peak when BMEP peaks. Which may, or may not, be when VE peaks. BMEP is IMEP minus FMEP. FMEP losses include pumping losses, accessory losses and also mechanical friction losses.



Erland

[Ken_Parkman]

Just a note that steel will glow red if heated to egt of a good engine. The color is a result of the time the metal has to heat and the various heat transfers. Sustained load at high power makes a pretty good heat transfer to the headers from the exhaust.

[Desertrunner]

stuffed up

[Desertrunner]

Max VE is all about the correct intake, Diameter (so you get Velocity) and Length ( so you get Mass). When you get inertial to work for you you will get the highest VE. Its not about harmonics at all.
Below are two pressure traces, the blue line is a pressure transducer reading just before the intake valve, the yellow line is the in cylinder pressure transducer. The engine is not firing so we can get a clean trace. Both traces are at the same rpm. If you look down the bottom under the yellow "1" you will see the first has 4.56V the second has 5.74V. The second is 126% of the first so if this was a 500 hp engine the second would 630 hp extra. This is the same cam and lift etc in both traces . As I said the only difference is the design of the intake and using inertia, it is of course a NA engine.
Enjoy,
TEST A 4,000 rpm LS Head No Pipe.jpg
TEST A 4,000 rpm LS Head and 29.5 by 350L.jpg

Maybe I'm missing something in your post, but what is the difference in set up between the 2 graphs?

Don't feel to bad it goes over most peoples heads as the data is a lot to understand. At least you are asking.
So the two graphs are of a single cylinder motor driven by a electric motor. The motor is running at 4,000 rpm.
In the head of the motor I have a number of pressure transducers.
One in the combustion chamber,
Second in the intake port of the head just behind the intake valve.
Third not shown in the graph on the exhaust just after the exhaust valve.

So every thing is identical in both graphs except the first has no intake just the head open at the inlet, no manifold nothing.
The second graph has a intake pipe 29.5 mm ID and 350 mm long with a bell on the end.

What the two graphs show very clearly that having a intake pipe you can create inertia which then leads to a higher VE.

[swampbuggy]

I would say the same inertia is created by the proper design of an excellent exhaust system, such as a NASCAR CUP SYSTEM. Only difference is it is the back door. Mark H.

[Desertrunner]

I would say the same inertia is created by the proper design of an excellent exhaust system, such as a NASCAR CUP SYSTEM. Only difference is it is the back door. Mark H.

Cigar to you Mark,
On a exhaust the pressure waves are a lot higher then with the intake.

[engineguyBill]

I would say the same inertia is created by the proper design of an excellent exhaust system, such as a NASCAR CUP SYSTEM. Only difference is it is the back door. Mark H.

Cigar to you Mark,
On a exhaust the pressure waves are a lot higher then with the intake.

i.e. early exhaust valve opening, which enhances "blowdown" which reduces pumping losses and results in higher VE and the resultant maximum horsepower output at high RPM. (in a properly designed/engineered engine combination)

[Warp Speed]

I believe we are mistaking pressure waves and inertia as being the same.......?

[Desertrunner]

I believe we are mistaking pressure waves and inertia as being the same.......?

I know exactly what is going on there is no confusion. But you have reminded me why I hate forums so much so I will spare you any more comments from me as I shouldn't have wasted my time posting the R&D data. I thought people might learn something but I was wrong.

[Warp Speed]

I believe we are mistaking pressure waves and inertia as being the same.......?

I know exactly what is going on there is no confusion. But you have reminded me why I hate forums so much so I will spare you any more comments from me as I shouldn't have wasted my time posting the R&D data. I thought people might learn something but I was wrong.

Didn't mean to get your feathers in a ruffle that's for sure, but not really sure what I said that warranted that response. Was I supposed to just say "ooh, awww, wow, amazing"?
I do a little of this type of testing myself, and was just trying to get your meaning clearified.
Sorry.......