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Ported Dart pro 1 pre platinum

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Re: Ported Dart pro 1 pre platinum

Postby groberts101 » Sun Jan 08, 2017 12:40 pm

randy331 wrote:How big is the Ex port now?

Randy


Dunno for sure, but based on the pic's down the end of that 1.75" od pipe.. I'd say he's in or close to the 1.5" X 1.5" size range. Definitely more flowz than the intake design will probably ever be able to make use of. lol

16 or 18 gauge? Would be nice to know what wall thickness that pipe is to better scale it.

The turbulence/stall issue would bother the hell out of me as the head left my bench. If it happens on a static flow bench it 'll sure as hell rear its ugly head even earlier in the lift and power range than you'd probably be happy with. Then again.. we used to live with the old Cleveland heads shortcomings by keeping the valve lift in check/within the stable flow range and they made decent enough power for what they were. Those ports actually howled! Might just be time to call it good enough for the task at hand.
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Re: Ported Dart pro 1 pre platinum

Postby Carnut1 » Sun Jan 08, 2017 12:56 pm

0108171244.jpg
After listening to some feedback I did some work to ssr and floor and a touch in the bowl. Turbulence is only noisy at .3" lift. Which is better and whole flow curve took a step up. Pitot airspeeds @ .8" lift and 239.3 cfm. Maybe that port bias thing is not so bad for the flow at the top of the port. 263 cfm @.8" lift 1 7/8" pipe.
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Re: Ported Dart pro 1 pre platinum

Postby groberts101 » Sun Jan 08, 2017 1:00 pm

where where those speeds taken from, Charlie? Exit or apex of short turn?

this is more along the lines of what I was talking about last night. Crude but shows how the ssr lays back on either corner of the ssr.

Charlies exhaust port 2.jpg


And after staring at it a bit longer.. I seriously think you may need to consider starting the layback of the floor corners much closer to the bottom of that seat. Think of them as small spillways for the excess volume/airspeed to migrate towards when the flow really picks up for the sizing of the ports choke.

Basically.. your choke is too long for what that current short turns angle and cross section sizing can handle. Dropping the floor width and squarish design all the way over the ssr and tying it into the choke will help tame that short sides speed to help flow reattach itself.

PS.. look at some of Chad's port designs. He digs in so deep on some heads floor corners to the point there is a hump left in the middle of the entire ssr. Don't remove the center hump.. the trench like reservoirs enable the center to better do its job more smoothly. Mostly done for the intake side.. but still illustrates the strategy he's using to coax the gas around the corners. And I'm sure I don't need to tell but you need to be a hell of a lot more careful with wall thickness on the exhaust too. Burr changes its pitch on the intake and you can just stop there.. does the same on the exhaust and you're already screwed.
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Re: Ported Dart pro 1 pre platinum

Postby Carnut1 » Sun Jan 08, 2017 1:25 pm

Carnut1 wrote:
0108171244.jpg
After listening to some feedback I did some work to ssr and floor and a touch in the bowl. Turbulence is only noisy at .3" lift. Which is better and whole flow curve took a step up. Pitot airspeeds @ .8" lift and 239.3 cfm. Maybe that port bias thing is not so bad for the flow at the top of the port. 263 cfm @.8" lift 1 7/8" pipe.

Exit airspeeds
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Re: Ported Dart pro 1 pre platinum

Postby groberts101 » Sun Jan 08, 2017 1:45 pm

Carnut1 wrote:
Carnut1 wrote:
0108171244.jpg
After listening to some feedback I did some work to ssr and floor and a touch in the bowl. Turbulence is only noisy at .3" lift. Which is better and whole flow curve took a step up. Pitot airspeeds @ .8" lift and 239.3 cfm. Maybe that port bias thing is not so bad for the flow at the top of the port. 263 cfm @.8" lift 1 7/8" pipe.

Exit airspeeds


ok.. what happens without a pipe?

And more importantly.. where were you reading 0" during full turbulence?.. still off the same spot/floors exit?

If so then that's not good either.. I assumed you were on or slightly past the apex with the pitot.

My best advice is this. Lose the pipe.. do it proper/pitot the apex and just beyond to find the problem area.. sneak up on the shape and fix it with a wider floor over the SSR.. put the pipe back on retest it and be proud of yourself. Pick that end of exhaust port floor speed up closer to what it needs to be and you have a solid 250+ cfm no-stall port right there. =D>
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Re: Ported Dart pro 1 pre platinum

Postby Carnut1 » Sun Jan 08, 2017 2:12 pm

0108171402.jpg
Sorry, I may not have been clear. Here are flows with and without pipe as port sits now. + shows noisy turbulence. Airspeeds taken about 1/8" inside from port exit. Exit size, 1.535" wide and 1.4480" high. Thanks, Charlie
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Re: Ported Dart pro 1 pre platinum

Postby cspeier » Sun Jan 08, 2017 2:43 pm

Here is something else to look at. Look at how deep the bowl is with the guides out.

Image
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Re: Ported Dart pro 1 pre platinum

Postby groberts101 » Sun Jan 08, 2017 3:04 pm

cspeier wrote:Here is something else to look at. Look at how deep the bowl is with the guides out.

Image


lol.. quit gloating with all these cool pic's(kidding.. keep em' comin') and hinting around here.. just tell the man where to best put his time and energy into that port. [-o<

Course learning what changes lead to what other changes is half the fun too. Nicest thing about exhaust ports is some shapes are more universally accepted by the atmosphere. :lol: Might not be as much power to be found there but it sure makes life much less complicated than the intake side. :)

Chad.. side note, the pic is blinding me with science.. did you cnc all the casting guide away and run straight guide into the port?

And to clarify here.. you're talking about all that newfound ceiling space alleviating some of the constriction coming around the ssr? Would raising the roof, maybe slightly smaller radii around the guide-roof transition, pushing the walls slightly.. be enough area change to help that short side settle down a fairly substantial amount?
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Re: Ported Dart pro 1 pre platinum

Postby cspeier » Sun Jan 08, 2017 3:08 pm

The casting doesn't have any guide wing. If I had a clean sheet, I would add it. However, it has never caused any issues. This is a Pro-Filer casting.

He's doing the right thing by working it. Only way you find it. Three sides to this. Someone telling you what to try, Actually applying it in your own terms, Then seeing the result.
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Re: Ported Dart pro 1 pre platinum

Postby groberts101 » Sun Jan 08, 2017 3:16 pm

cspeier wrote:The casting doesn't have any guide wing. If I had a clean sheet, I would add it. However, it has never caused any issues. This is a Pro-Filer casting.

He's doing the right thing by working it. Only way you find it. Three sides to this. Someone telling you what to try, Actually applying it in your own terms, Then seeing the result.


Thanks for the reply.

And no, I get it.. tough to help anyone port a set of heads over the computer.
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Re: Ported Dart pro 1 pre platinum

Postby Carnut1 » Mon Jan 09, 2017 7:56 pm

0109171936.jpg
After more Pitot work I decided to try the small radius and flattening of ssr. No difference of flow or turbulence but worth a shot. Tried smaller radius burr on guide boss, no gains. Tried three different exhaust valves, 1st radius edge 1.6 pro flo Manley short 30 degree back cut. 2nd unknown 1.6 short square margin, 3rd REV 1.625 small 30 degree backcut deep square margin. All flows have had leakage subtracted. All flows without pipe. Flow with 1 7/8" pipe 263cfm @ .8" The radius edge helps the 1.6 valve but the 1.625 is a clear flow leader. Notice the shape of the valve made a difference where the turbulence ruined the fun. The 1.625 had least turbulence. Comments welcome. Thanks, Charlie
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Re: Ported Dart pro 1 pre platinum

Postby groberts101 » Tue Jan 10, 2017 11:31 am

When you get time to breath can you post another couple current design pics?

A nice sharp close up picture looking through the chamber to see up and over the apex would be killer. Might help others who pop in to see a pinch point or shape concern. Tricky part is getting that damned auto-focus to pick up/lock onto something deeper into the port while you're up close, flashlight helps the camera and the guide is a good sweet spot to lock before panning back out about 3 inches to take the shot. Should help dial in the autofocus right around the turn a little better.

And apologies up front if I may seem too preachy and teachy, not trying to act the know-it-all just sharing the few tools and experiences rolling around my old rusty tool boxs, sincerely trying to add some perspective. Plus, it's too damned cold outside to heat the garage enough to enjoy the work.. and I have motive too. Maybe there's some little tidbit I might find that helps my personal kasse highport conversion. Getting kinda hyped to start welding and cutting. Sure as hell wish the internet existed when I was doing a few complicated max-effort sets long ago. I think 335 and 385 series intake and exhaust mod's might'a left a little lasting scar tissue in the lungs AND the brain . #-o I'd have easily killed to get a nice port like you have at this point! =P~

More pic's please! [-o<
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Re: Ported Dart pro 1 pre platinum

Postby groberts101 » Tue Jan 10, 2017 11:57 am

PS. I like buying oversized exhaust valves just so I can cut them down and have both features.. a bit more cash thicker/heavier helps compression and durability.. using thick margins and broke top radius edge usually helps stabilize the flow cone around the valve. Whereas squashed intake ports with layed SSR typically seem to prefer thinner margins and sharp top edge. Helps with anti-reversion a tad bit too.

Am hoping that Chad or Knight or some other proven port designer might pop in eventually who has an inkling why the flow picked up so hard with same smaller valve combo's same seat size? Possibly helped "fix" something going on further downstream?

Also makes me wonder if that choke size and/or seat design might prefer the larger seat matched to that bigger valve?

PSPS.. brains starting to work again on the reread.. if that port didn't lose much peak flow and turbulence settled down a bit?.. I'd seriously be looking at running a better port matched primary size like a 1-3/4" pipe shaped/squashed to the heads port and then step up to the 1-7/8" pipe out where Calvin/Exhausted (I know you know.. but for any others that are new) typically recommends.. around 9"-12", IIRC. Also been LOTS of cases where a smaller flange/primary pipe size helped stabilize a port without killing power in the real world too. You may also remember that there are some who have successfully shrunk primaries even to the point of blocking some of the ports exit size and still picked up power. I myself wouldn't get too carried away on that ports peak numbers or you might have to kill the exhaust side of the cam too much(reverse split on lift AND duration). As Calvin always says.. keep the velocity up longer/further away from the ports exit to help minimize the back doors size on the way back in. Just might end up with fewer cam design compromises that way too.
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Re: Ported Dart pro 1 pre platinum

Postby Carnut1 » Tue Jan 10, 2017 4:30 pm

0110171601.jpg
More pics due to popular demand. It is not out of focus but not perfect either. I was unhappy with my blending with smaller radius cutters on ssr so I did a light polish just to even out the high spots that may have developed.
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Re: Ported Dart pro 1 pre platinum

Postby Carnut1 » Tue Jan 10, 2017 4:31 pm

0110171600.jpg
Cylinder wall side.
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