Darin Morgan-PS Heads & Swirl

[PSFAN]

Darin, you are probably the most experienced here with PS Heads. The question I have is regarding swirl. The port I just tested had no swirl until the .550" lift point(dead still), once the valve is opened to .600" the swirl takes off to 1560rpm and increases to 2540 by .950" lift.

Is this good for making power in a Pro Stock engine? I have never paid much attention to the swirl numbers before but I am now trying to narrow down what makes a good intake port.

Any opinions are more than welcome.

Thanks in advance.

[Darin Morgan]

Darin, you are probably the most experienced here with PS Heads. The question I have is regarding swirl. The port I just tested had no swirl until the .550" lift point(dead still), once the valve is opened to .600" the swirl takes off to 1560rpm and increases to 2540 by .950" lift.

Is this good for making power in a Pro Stock engine? I have never paid much attention to the swirl numbers before but I am now trying to narrow down what makes a good intake port.

Any opinions are more than welcome.

Thanks in advance.

If you can attain more mixture motion without increasing area, slowing down velocity or decreasing flow in the process, I cant see that as being a negative but then again, the three types of Pro Stock heads out there right now have almost ZERO swirl especially the DRCE3 or the Mopar hemi heads.

[phoenix]

Darin you tease! Why almost "ZERO" swirl? Is it RPM related? How do these heads keep the fuel from seperating? Is this the end result of wet flow testing. I WANT MORE MAN! By the way, are the DRCE3 heads finally starting to out perform the DRCE2's? Thanks. Shane

[SchmidtMotorWorks]

Darin,

Any chance of you posting images of a DRCE3 head in any state of development?

[Motorman 407]

Its about time. To pack as much as you can into the cylinder within the time frame the valve is open. When the air goes in a swirling motion it takes more time for the air to get into the cylinder than if it falls straight down therby not filling the cylinders as much. The lesser mixture quality is less of a loss than the gain of getting more in there. Swirl is good for emissions but an all out race engine can care less. The Hemi head for example don't swirl it tumbles but that happens after the charge is already in the cylinder. The swirl meter is used to make sure there is no swirl in an all out race head. This is nothing new it has been out there for several years.

[Robert Kane]

Darin,

Any chance of you posting images of a DRCE3 head in any state of development?

I agree. I would love for you to takes us on a start to finish of a set of heads, even if you don't post the pics. Of course we'd love to seem some pics though.

Do the DRCE3's resemble the "Hemis"?

Robert

[phoenix]

PLEEEEEASE!!!

[Ron E]

We’d all love to see that, Darin. (I do realize it may be getting a bit personal, though)

I think a major reason for the lack of swirl in the “new-age” P/S heads is the valve to bore-wall relationship. With the bore so close to the short-side flow, it greatly reduces the need of horizontal flow paths (I.E. swirl). The “swirl” flow is necessitated by the pressure equalization that naturally takes place, as the flow leaves the organized confines of the port and equalizes into the much larger chamber. A more wedge-like valve location demands much more swirl, as the S/S flow essentially dumps into a huge void., creating a “dynamic vacuum (the velocity pulls, or entrains air on the short-side of the chamber, near the deck to “follow” it.) The S/S flow either has to fill this void itself (huge expansion loss due to the immediate loss of organization in the S/S flow) or the pressure must be equalized from other quadrant(s) of the valve. A well developed wedge offers up this support-air in the form of what is usually referred to as swirl. Usually, slower moving air (OD, or flow that’s near the valve seat, as opposed to ID flow tucked around the valve head) with less inertia is more easily influenced by the huge pressure imbalance in the short-side of the chamber. This horizontal flow tucks up around the S/S flow and essentially creates a dynamic diffuser shape that allows the S/S flow to expand more gradually, and prevents the S/S flow from degrading as quickly. One reason that distinct valve angles work well on intake valve-jobs, as they “peel” a little velocity from the OD of the flow-path, which helps get the pressure equalization process going. If you’ve ever tried radiused valve-jobs on intakes, you realize that they flow great….up to a point, and then they back up HARD. As long as the S/S flow can handle the void (lower lifts) all is well. But, with the smoothie valve job, the signal to “go short” is ignored due to higher velocity around the valve-seat, and at a easily defined point, the S/S flow path loses it’s organization (direction) and it gives up the hunt. This essentially shuts down short side flow up into, and above the seat area, and all is lost. It’s common, in this condition to see flow reverse from the chamber up past the valve head, and re enter the chamber out the long half of the valve. And, no points are given for flowing the same air twice.

But, back to the new-age P/S heads, I think seeing a dramatic change in your swirl numbers may be showing at that particular lift, you’re losing some stick somewhere. Old H-D guys have been using swirl meters for years to know when something is going wrong. Swirl means it’s ripping somewhere, in their case. (at least with the early traditional chambers).

With such a near ideal (left-to-right, and close to S/S bore-wall) valve location, the main reason that swirl happens is greatly lessened. With this necessitated swirl out of the equation, you’re freed up to investigate how, or if you can purposely induce swirl to serve an intended result.

Ya'll can shoot any, or all of my thoeries down. No way you can hurt my feelings as bad as some of these damn cylinder heads have, in the past.

[Ron E]

BTW, this is a great site. I never thought I'd see such a free exchange of ideas from such qualified people. And without the normal personal-attacks and insults so many others degrade in to. (ya'll remember that when you start killing my post)

[SBC]

Good post Ron E.
Just when I was going to unplug my flow bench and resort to a flashlight for "valve head visible". HaHa.

Gary

[cboggs]

Ron,

Welcome to the forum, .. but I must say, .. when you make clear, intelligent
posts, . . . . and participate in the "free exchange of ideas", . . .
it's great, .. .. but if you use the word "ya'll, .. you'd better be ready for the
personal attacks ( joking )

Good post, .. very good, ..

Curtis

[Darin Morgan]

Darin,

Any chance of you posting images of a DRCE3 head in any state of development?

I agree. I would love for you to takes us on a start to finish of a set of heads, even if you don't post the pics. Of course we'd love to seem some pics though.

Do the DRCE3's resemble the "Hemis"?

Robert

The jury is still out or should I say confused when it comes to swirl, twirl, tumble, twumble,stwirl, swumble and all the other definitions floating around. Mixture motion has never been detrimental from what I have read and learned on my own but I have never seen a case in which it made a major difference in power either. I have measured swirl and tumble for two decades now and I can find no correlation between power and swirl intensity, angular velocity or TQ/Swirl measurements in unlimited engines. I am not alone in my opinion. I have had discussions with some of the greatest engine builders in the world on this subject and one thing is evident. We just don't know because we cant find an instance where varying the swirl intensity made a significant difference. If someone can show me a case where it has happened I am all ears and eyes because I want to know. If you want to point to cases where the fuel economy was increases or the part throttle power, low air speed power was increased with a corresponding increase in swirl, save your breath. We already know it works in that instance but where has it ever help unlimited engines, open engines like Pro Stock, F1 or any other engines that operate at high VEs and extreme RPM. I have yet to find one that I can believe. I find cases of guys saying that it happened but they didn't log there efforts or keep track of any other variables in there testing so the end data is worthless in my opinion.

If you want over all good fuel economy, part throttle fuel economy and acceleration then swirl is a very powerful aid. In engines with extremly high inlet velocities from TQ peak to HP peak and beyond, I see no benefit.

I will try and post some picks of the DRCE III in transition. I have no heads here right now due to various reasons but I should have some of the Proto types back here in a couple weeks. No it does not resemble the Hemi at all.

[Ron E]

Ron,

Welcome to the forum, .. but I must say, .. when you make clear, intelligent
posts, . . . . and participate in the "free exchange of ideas", . . .
it's great, .. .. but if you use the word "ya'll, .. you'd better be ready for the
personal attacks ( joking )

Good post, .. very good, ..

Curtis

Curtis,
Thanks, and I’ll try to keep my “regional speak” in check. I’m sure you’ve already had to answer this, but, on you site (very nice BTW), the head without a chamber. What does it fit?

[cboggs]

Curtis,
Thanks, and I’ll try to keep my “regional speak” in check. I’m sure you’ve already had to answer this, but, on you site (very nice BTW), the head without a chamber. What does it fit?

yo, yo, yo, .. wazzz up, .. ( DC area regional speak )

Ron, .. the "chamberless head" is a Ford 1600 "kent" head used
in forumla ford open wheel cars. They are run in Canada, Australia,
New Zealand and the US. .. won all 4 championships.
Funky little thing to work on.

I do a fair amount of road racing work.

And you? what is the primary work you do?

Oh, .. thanks for the compliments on the web site, .. built it myself.
< sticks chest out with pride >

Curtis

[SWB]

This doesn't necessarally relate to Pro stuff, but it relates to engines in general and may be of value to someone here.

In private conversation with an engineer at Jaguar, I found out some interesting things about the May "fireball" heads used on the later V-12 jaguar engines. It was stated that the whole design contributed to excellent burn stability. Apparently by introducing the swirl and most specifically, biasing the charge to the exhaust side (for confinement with the hot exhaust valve and spark plug at TDC), the heads were able to tolorate very lean mixtures as well as significant amounts of EGR and still not mis-fire.

Sometimes it makes me wonder what NASCAR engine builders would be doing nowdays if there were no compression ratio rules to deal with?....

SWB