ANYONE w/12v & 24V Ported Head Flow #'s???

lenahan05 said:
lets get this thread back on track guys. we all understand a better head will be more efficient. the fact is all your talking about 100% VE is irrelevant because none of the diesels will ever be near 100%VE. the most efficient diesels on earth are 2stroke diesels and their only 54% efficient at their best. so lets get back to the head flow numbers and stop trying to show whos the smartest. if you wanna argue that stuff start a VE thread. i don't mean to come off as a smart*** but that's not what this thread is about. thanks guys
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Dude.... my 100% required volume numbers are about 1/3 of the reported flow rate numbers given in this thread....

And yes, the 100% value is damn sure important, because it tells you the cylinder's requirements. Without that knowledge, you have no goal. After all, unless you've forgotten, the whole point of the head ports/valves is to fill that cylinder as close to (and in rare cases in excess of) 100%.

And no, VE in the 50's is not practical. I would say something in the 70's to 80's+ is more realistic over a practical rpm range with these engines.

At 2800rpm a 5.9 would be displacing 291 CFM at 100% VE. At 54% VE you'd be moving 157 CFM.

You honestly think that engine is only ingesting 157 CFM at 2800 rpm?

Are you sure you're thinking about VE correctly?
 
i guess your right my fault. were talking air an not air/fuel like i was thinking. cubic in wise your numbers are correct for effciency of air in the cylinder.
 
So what are the specifics for a stock 5.9 cam, 12v or 24v?

If we had a graph of the lift vs crank angle we could see the exact airflow requirements of the ports for any given rpm.
 
Are VE's for atmospheric air different than VE's for boosted air?
 
keeping flow numbers a secret is usually done by guys who are running full blow race cars/ race trucks and they do not want anyone to know what is done to there engine and cylinder head. most respected cylinder head machinist would not have a problem releasing cylinder head flow numbers and specs. the thing they will not release what how they got the head to flow so good, every machinist has his own way to port a head. why would you hide good flow numbers on cylinder head?
 
lenahan05 said:
lets get this thread back on track guys. we all understand a better head will be more efficient. the fact is all your talking about 100% VE is irrelevant because none of the diesels will ever be near 100%VE. the most efficient diesels on earth are 2stroke diesels and their only 54% efficient at their best. so lets get back to the head flow numbers and stop trying to show whos the smartest. if you wanna argue that stuff start a VE thread. i don't mean to come off as a smart*** but that's not what this thread is about. thanks guys
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Dude with that two stroke comment you are up in the freaking night. A two stroke is more MECHANICALLY EFFICIENT however, not more thermally and therefore not necissarily more efficient all together.
 
Piers stage 2 12v head says it flows 163cfm on the intake and 185cfm on the exhaust.
 
j-rod said:
If you are asking if VE is different on an engine with forced induction vs. a naturally aspirated engine, yes.
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It is, but probably not for the reason you think.


The effect forced induction has is in increasing the density of the air charge, which increases it's inertia, making it possible to take better advantage of port scavenging.

And even this is relatively modest in magnitude. Probably negligible.
 
I just pick a place that has a good reputation, ship it, and be done with it. You are going to have to take their word on the numbers(if they actually flow it) anyway. I've got a head going out next week and I didn't even ask him what it would flow. The flow number is just that... another number.
 
The CFM I speak of is at standard Atmosphere. A better term is pounds of air. As you increase boost the ability of the engine to be volumetric efficient at the increased atmosphere becomes more difficult. That is swept volume, divided by 2, times bar

I would go with less the 50% volumetric efficiently on the poorly designed ports. . Remember the Cummins ports were designed, for around 300 hp at a relatively low RPM. The cam timing and the small port only give a very short time for air to flow in to the engine.
Then answer is to open the valve higher, and for a longer amount of time at the maximum lift. This requires very aggressive lobe acceleration rates, and big ratio rocker arms.
 
RonA said:
I just pick a place that has a good reputation, ship it, and be done with it. You are going to have to take their word on the numbers(if they actually flow it) anyway. I've got a head going out next week and I didn't even ask him what it would flow. The flow number is just that... another number.
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Where's that at Ron? Willy Wonka's Chocolate Factory?
 
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