Ported Dart pro 1 pre platinum

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JoePorting
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Re: Ported Dart pro 1 pre platinum

Post by JoePorting » Tue Jan 31, 2017 8:20 pm

I'm sure you learned alot from this project, but an AFR #1068 227 SBC cylinder head with a 2.10 intake valve flows an honest 310 CFM @ .700 lift with an intake port that only measures 218 cc's. So the next part of your project should be to fill in the dead air zones with epoxy to get closer to a 225 cc port. I'd start with filling in the floor and raising the floor to around .950".
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Re: Ported Dart pro 1 pre platinum

Post by Carnut1 » Tue Jan 31, 2017 8:29 pm

JoePorting wrote:I'm sure you learned alot from this project, but an AFR #1068 227 SBC cylinder head with a 2.10 intake valve flows an honest 310 CFM @ .700 lift with an intake port that only measures 218 cc's. So the next part of your project should be to fill in the dead air zones with epoxy to get closer to a 225 cc port. I'd start with filling in the floor and raising the floor to around .950".
I do have a older AFR 210 that are ported and flow about 310 I need to reflow them and put them through the D.V. flowbench program and see how they do as far as port energy. I did quite a bit of flowball and Pitot work and they are not perfect ports but they really don't have any dead spots. If I wasn't chicken I would worl,the ssr even more and I bet there is more flow and port velocity there. AFR 227's are also a high port head that makes a difference. I have been thinking about some floor epoxy. Thanks, Charlie
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Re: Ported Dart pro 1 pre platinum

Post by Kbails » Tue Jan 31, 2017 8:36 pm

very nice time well spent. a lot of great info here, thank you for putting the time in to post.
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Re: Ported Dart pro 1 pre platinum

Post by Carnut1 » Tue Jan 31, 2017 8:46 pm

Kbails wrote:very nice time well spent. a lot of great info here, thank you for putting the time in to post.
I know you are just working on your next mill! Thanks, Charlie
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Re: Ported Dart pro 1 pre platinum

Post by David Vizard » Wed Feb 01, 2017 9:21 am

JoePorting wrote:I'm sure you learned alot from this project, but an AFR #1068 227 SBC cylinder head with a 2.10 intake valve flows an honest 310 CFM @ .700 lift with an intake port that only measures 218 cc's. So the next part of your project should be to fill in the dead air zones with epoxy to get closer to a 225 cc port. I'd start with filling in the floor and raising the floor to around .950".
Joe,
Strongly disagree with you here. Rather than doing time consuming fixes to ports that are now functional to the extent they will be capable of producing strong results I think the next serious porting job would be to rework some of those AFR #1068 heads you suggest. They look like they would be a great starting point for a set of really good heads. We can even incorporate your prior expert knowledge into the equation here. What say you??

DV
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Re: Ported Dart pro 1 pre platinum

Post by GARY C » Wed Feb 01, 2017 11:19 am

Without dyno testing before and after there is no way to know what gains you are getting, if any.
I would think that taking a head from 200cc's to 248 you would want to test them on the engine several times through out the stage of development to make sure you haven't gone to far.

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Re: Ported Dart pro 1 pre platinum

Post by groberts101 » Wed Feb 01, 2017 11:42 am

David Vizard wrote:
JoePorting wrote:I'm sure you learned alot from this project, but an AFR #1068 227 SBC cylinder head with a 2.10 intake valve flows an honest 310 CFM @ .700 lift with an intake port that only measures 218 cc's. So the next part of your project should be to fill in the dead air zones with epoxy to get closer to a 225 cc port. I'd start with filling in the floor and raising the floor to around .950".
Joe,
Strongly disagree with you here. Rather than doing time consuming fixes to ports that are now functional to the extent they will be capable of producing strong results I think the next serious porting job would be to rework some of those AFR #1068 heads you suggest. They look like they would be a great starting point for a set of really good heads. We can even incorporate your prior expert knowledge into the equation here. What say you??

DV
I can't say for sure here, but I believe what joe was eluding to is that the overall port size of this head is not necessarily indicative, or maybe better to say.. not as optimally matched to the actual cfm results. And to some extent I would have to agree that this head seems kinda back towards old school where extra size was often substituted for idealized shape.

IMHO, aside from sizing the cross section accordingly, if you can get the short side speed to settle down and stay attached really well.. your job as a porter is pretty well done at that point. I myself highly subscribe to the theory of faster roofs(roof/long side easily tolerates it) and slower floors(bent ports generally need all the help they can possibly get). Try and trick the valve curtain into thinking the roof floor distance has been equalized/better idealized to promote filling in the curtains short side. Once you reach the specific castings floor corner size limit then the rest of the work is in layback angle and shape. Easier said than done and to better achieve this on 23° bent ports ALWAYS requires proper floor and short turn width and layback.

Ideally, Charlie makes a mold of the port to better visualize any of these potential "dead spots".

As many here probably very well know, much of this stuff is highly subjective and port volume numbers can really throw you off when comparing different cylinder heads. Bigger/deeper bowls can really add volume quick even when the pinch and port entry gasket size would be considered small by most standards. Hell, lots of guys can sleeve the PR pinch, dig troughs around long side/hairline the guides and end up at a specific volume/flow number but that doesn't mean the head is gold because the short side is completely fixed. It's not and that's where the biggest pot o' gold is located on these kinda heads.

Personally speaking, and I'm not trying to bust Charlies balls on this to keep the man continually obsessing over a single set of cylinder heads, those speed differentials(although not terrible) would have me working the short side. IMO, still too fast(370 in the corner?) and needs attention to make these heads be all they can possibly be. This is dry testing.. what happens around the valve when you add fuel mass into the equation? :-k

Then again, my projects can sometimes take nearly forever and/or I end up giving free labor away because I continually nitpick and drag projects out far too much trying to sweat the littlest details. Money changes everything.. and that's when shape rules most. I remember being very naive when I was a teen, getting irritated when the very first set of ported heads I bought only had about 40% of the port touched with a grinder. I felt betrayed and kinda ripped off that everything wasn't big and shiny until I started doing my own stuff. Perfectionism can lead towards some awesome looking and performing port work but it's hard as hell to make money off it when you add up all the obsessive hours. :D

Irregardless of where this port design(and conversation) ends up I would like to thank Charlie, David and any other contributors for sharing their time and resources with the greater community. Highly commendable.. wish we could have more threads like this. =D>
Last edited by groberts101 on Wed Feb 01, 2017 11:53 am, edited 1 time in total.

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Re: Ported Dart pro 1 pre platinum

Post by FGaspare » Wed Feb 01, 2017 11:49 am

Chad, Where's the best places to send cast iron heads to get brazed up like your fill on your superstock exhaust ports ?

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Re: Ported Dart pro 1 pre platinum

Post by cspeier » Wed Feb 01, 2017 11:56 am

FGaspare wrote:Chad, Where's the best places to send cast iron heads to get brazed up like your fill on your superstock exhaust ports ?

I was using a guy in KC but I think I wore him out. :)

I will find his contact.

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Re: Ported Dart pro 1 pre platinum

Post by cspeier » Wed Feb 01, 2017 11:59 am

Personally I think the floor is the most critical area in the port at the apex. I'm not so much concerned with the speeds, just that the gradient across it, and up and down is tight. If you can manage the air, and it makes the turn, the pushrod pinch is along for the ride. In a velocity limited head, meaning pushrod area the restriction, I don't think the CSA at that area can be used to determine peak.

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Re: Ported Dart pro 1 pre platinum

Post by groberts101 » Wed Feb 01, 2017 12:18 pm

cspeier wrote:Personally I think the floor is the most critical area in the port at the apex. I'm not so much concerned with the speeds, just that the gradient across it, and up and down is tight. If you can manage the air, and it makes the turn, the pushrod pinch is along for the ride. In a velocity limited head, meaning pushrod area the restriction, I don't think the CSA at that area can be used to determine peak.
Good stuff, Chad. Do you bias the corner speeds at all?.. ie; drop one corner/slanted floor.. or work to maintain consistency?

The picture I'm finally arriving at in my later years of porting is that the inlet size is often way overblown for what the short side can handle. Unless it opens up a fix for some cockamamie manifold runner exit angle, I rarely ever gasket match the pinch side of the port any more. Just turns it into a bigger wall rather than a simple protrusion.

Meaning I would rather have huge bowls with heavily streamlined guides along with more generous short side volume combined with smaller inlet port sizes. This keeps head/manifold runner velocity higher and the short side is better set up to handle the extra speed coming over the apex. Best with wider powerband street heads though.. not max flow effort.

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Re: Ported Dart pro 1 pre platinum

Post by cspeier » Wed Feb 01, 2017 12:41 pm

groberts101 wrote:
cspeier wrote:Personally I think the floor is the most critical area in the port at the apex. I'm not so much concerned with the speeds, just that the gradient across it, and up and down is tight. If you can manage the air, and it makes the turn, the pushrod pinch is along for the ride. In a velocity limited head, meaning pushrod area the restriction, I don't think the CSA at that area can be used to determine peak.
Good stuff, Chad. Do you bias the corner speeds at all?.. ie; drop one corner/slanted floor.. or work to maintain consistency?

The picture I'm finally arriving at in my later years of porting is that the inlet size is often way overblown for what the short side can handle. Unless it opens up a fix for some cockamamie manifold runner exit angle, I rarely ever gasket match the pinch side of the port any more. Just turns it into a bigger wall rather than a simple protrusion.

Meaning I would rather have huge bowls with heavily streamlined guides along with more generous short side volume combined with smaller inlet port sizes. This keeps head/manifold runner velocity higher and the short side is better set up to handle the extra speed coming over the apex. Best with wider powerband street heads though.. not max flow effort.

It just all depends, I follow my pitot tube. I want the floor the same across..

Here is my 23º 265cc port. Hardly a flat floor..

Image

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Re: Ported Dart pro 1 pre platinum

Post by Amilcar » Wed Feb 01, 2017 3:18 pm

cspeier wrote:
groberts101 wrote:
cspeier wrote:Personally I think the floor is the most critical area in the port at the apex. I'm not so much concerned with the speeds, just that the gradient across it, and up and down is tight. If you can manage the air, and it makes the turn, the pushrod pinch is along for the ride. In a velocity limited head, meaning pushrod area the restriction, I don't think the CSA at that area can be used to determine peak.
Good stuff, Chad. Do you bias the corner speeds at all?.. ie; drop one corner/slanted floor.. or work to maintain consistency?

The picture I'm finally arriving at in my later years of porting is that the inlet size is often way overblown for what the short side can handle. Unless it opens up a fix for some cockamamie manifold runner exit angle, I rarely ever gasket match the pinch side of the port any more. Just turns it into a bigger wall rather than a simple protrusion.

Meaning I would rather have huge bowls with heavily streamlined guides along with more generous short side volume combined with smaller inlet port sizes. This keeps head/manifold runner velocity higher and the short side is better set up to handle the extra speed coming over the apex. Best with wider powerband street heads though.. not max flow effort.

It just all depends, I follow my pitot tube. I want the floor the same across..

Here is my 23º 265cc port. Hardly a flat floor..

Image
Curious, this bias looks like something I found that worked better on my trials.
Just wondering , on David Vizard book, seems like opposite? At least for me, roof higher on center of cylinder helped.
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Re: Ported Dart pro 1 pre platinum

Post by Amilcar » Wed Feb 01, 2017 3:56 pm

How ´s looks like on yours Charlie? I agree that a port mold would be nice.

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Re: Ported Dart pro 1 pre platinum

Post by cspeier » Wed Feb 01, 2017 7:28 pm

The first photo is a 23 degree, the second photo is my 13 degree.

Image

Image

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