Re: Ported Dart 215's with port energy discussion 3.0

[Carnut1]

I must have misread ... I was under the impression this was going to be dual TBI throttle bodies; not carbs.
Oh well.

I will run dual throttle body tbi. The discussion wandered to poor low speed performance of the cross ram. Thanks, Charlie

AND, the low speed performance penalty surely is not from past experiences unless there is caburetor(s) relying on a vacuum signal being involved.
A TBI system does not share the same issues.

I guess I didn't misread and now understand you are totally against running any cross-ram manifolds for whatever reasons you may have, whether legitimate or not.
Sorry I even brought them up as any kind of alternative for what you intend to do ... I will be interested in reading about your finished product.

Sorry Walter, I don't mean to be confusing. I actually like cross rams and have wanted to build a dual four barrel tbi cross ram engine for a long time. I do believe a tunnel ram will out perform a cross ram. I was pretty set on a t ram. That may change. Thanks, Charlie

[randy331]

Will this see a dyno?

Compared to a well known head, like an AFR of same size.

Randy

Dyno is planned for this mill when finished. Are you saying I need to purchase AFR 235's and run these head to head Randy?

Your porting for pe.
To find out if pe is the thing to chase, you'd need to run them against something different. The afr heads are well known so it'd make a good baseline.
2 heads with same pe, but done differently, and one with less pe but similar size would be nice to see.

Randy

[Walter R. Malik]

Sorry Walter, I don't mean to be confusing. I actually like cross rams and have wanted to build a dual four barrel tbi cross ram engine for a long time. I do believe a tunnel ram will out perform a cross ram. I was pretty set on a t ram. That may change. Thanks, Charlie

Sure a tunnel-ram will out perform a cross-ram but, I don't see one ever getting under a Chevelle hood-line without a tall hood extrusion of some kind.

[groberts101]

20180329_210122.jpgNot much has been discussed about the shape and progression of airspeed through a 23 degree pinch. At this point I like a wide pinch with as smooth a arc as I can get. Input welcome. Thanks, Charlie

IMO, I'd never try and FORCE the flow to start going where I wanted it to that far out towards the entry. Especially considering that non-symmetrical runners turn, toss and bunch up flow and fuel where it wants to.. not necessarily where you want it to go at that point. The tunnel ram will probably help a great deal in that regard though.

Also keep in mind that velocity can be extremely high in the PR pinch areas(especially closer to the ports/pinches flow saturation point) so having a directive wing in that area might not be the best area to locate one. Would be like locating a swirl ramp or wing too far out into an area where the flow column is turning out of the manifold runner and still a bit confused as to where exactly it's supposed to be heading yet. Dry flow reactions to that wing on a bench is obviously going to be quite different than actual wet flow on the engine with the manifold in place. Just something else to ponder.

[Carnut1]

20180331_142006.jpg

Ok Greg, got me pondering so back to junk head and original fin. I will post a different pic later with a longer fin and we can compare. This pic was at .7" lift about 320 cfm. Thanks, Charlie

[Carnut1]

20180331_150731.jpg

Fin extended into pinch. Lowering the entire floor reduced flow to .5" over .5" lift gained a small amount of cfm. Apex came down a touch. Input welcome. Thanks, Charlie

[groberts101]

20180331_142006.jpgOk Greg, got me pondering so back to junk head and original fin. I will post a different pic later with a longer fin and we can compare. This pic was at .7" lift about 320 cfm. Thanks, Charlie

Sorry, Charlie.. wasn't trying to trip you up and slow your progress by rethinking things too much. I have absolutely 0% experience trying to run a vane that far out towards the entry, or anywhere on the floor for that matter, and could only speculate to the potential effect it may have based on previous pitot work out in that same area of the floor. Not that you could actually get the pitot in there without drilling holes up through the floor.. but you probably know very well what likely happens to the entry points speed profile once a manifold is bolted on and turning the mass right at that same juncture.

Curious.. is this just roughed in for now and you'll kill some of that wings sharpness.. more of a hump like Chad's designs, on final real port? Or do you intend on keeping the ridge very sharp like that? IMO, sharp is a big mistake that far out into the pinch entry when it comes to fuel shearing as the semi-gaseous flow goes where it wants to when crossing over the sharp ridge. We obviously try to bias what we can towards the inside/center of the cylinder but can only do so much and the rest just goes where the pressure differentials tells it to.

Also.. are you using the pitot to "see" what that extra long ridge is doing to the various locations atop the apex? And also what about the floors entry speeds?.. is that ridge changing the speed profile or consistency along the floor on either side of the pinch. IOW's.. if the ridge isn't changing dry flow speeds somewhere along the floor and leading up to the apex itself?.. why extend it out so far for fear of interrupting or even shearing actual wet flow within the real running port?

Just curious as to what your probe.. or string.. is seeing and reacting to. Never want to stop learning new tricks as long as these hands can still grind on stuff if you know what I mean.

[randy331]

most likely DV coscam design but that is not set in stone.

Is anything else in serious consideration ?

Randy

[Carnut1]

most likely DV coscam design but that is not set in stone.

Is anything else in serious consideration ?

Randy

I know what is in the 383 now and how it performs. I have numbers rolling around in my mostly empty head, Coscam is great but I think it will recommend a larger cam than I want for the street. I am sure I will start a 40 page thread on just speccing the cam. I will install what I want anyway. Thick headed that way. Thanks, Charlie

[Carnut1]

20180331_142006.jpgOk Greg, got me pondering so back to junk head and original fin. I will post a different pic later with a longer fin and we can compare. This pic was at .7" lift about 320 cfm. Thanks, Charlie

Sorry, Charlie.. wasn't trying to trip you up and slow your progress by rethinking things too much. I have absolutely 0% experience trying to run a vane that far out towards the entry, or anywhere on the floor for that matter, and could only speculate to the potential effect it may have based on previous pitot work out in that same area of the floor. Not that you could actually get the pitot in there without drilling holes up through the floor.. but you probably know very well what likely happens to the entry points speed profile once a manifold is bolted on and turning the mass right at that same juncture.

Curious.. is this just roughed in for now and you'll kill some of that wings sharpness.. more of a hump like Chad's designs, on final real port? Or do you intend on keeping the ridge very sharp like that? IMO, sharp is a big mistake that far out into the pinch entry when it comes to fuel shearing as the semi-gaseous flow goes where it wants to when crossing over the sharp ridge. We obviously try to bias what we can towards the inside/center of the cylinder but can only do so much and the rest just goes where the pressure differentials tells it to.

Also.. are you using the pitot to "see" what that extra long ridge is doing to the various locations atop the apex? And also what about the floors entry speeds?.. is that ridge changing the speed profile or consistency along the floor on either side of the pinch. IOW's.. if the ridge isn't changing dry flow speeds somewhere along the floor and leading up to the apex itself?.. why extend it out so far for fear of interrupting or even shearing actual wet flow within the real running port?

Just curious as to what your probe.. or string.. is seeing and reacting to. Never want to stop learning new tricks as long as these hands can still grind on stuff if you know what I mean.

Greg, it is my first wing design so anything could happen. I like it sharp. I want to do more smoke testing on it but I need to find smoke that does not leave residue or damage the bench fans and blades. The Pitot airspeeds over the apex are interesting If I get some time I will draw it out and we can discuss it. Thanks, Charlie

[GARY C]

most likely DV coscam design but that is not set in stone.

Is anything else in serious consideration ?

Randy

I know what is in the 383 now and how it performs. I have numbers rolling around in my mostly empty head, Coscam is great but I think it will recommend a larger cam than I want for the street. I am sure I will start a 40 page thread on just speccing the cam. I will install what I want anyway. Thick headed that way. Thanks, Charlie

I'm not sure how that would be possible considering it would based on the intended application, if all of the components are matched correctly DV's cams tend to be smaller than most and has been the center point of what he has written about for his entire career. A good example would be the 600 hp 600 tq 468 BBC with a 268 flat tappet hyd cam.

[Carnut1]

Is anything else in serious consideration ?

Randy

I know what is in the 383 now and how it performs. I have numbers rolling around in my mostly empty head, Coscam is great but I think it will recommend a larger cam than I want for the street. I am sure I will start a 40 page thread on just speccing the cam. I will install what I want anyway. Thick headed that way. Thanks, Charlie

I'm not sure how that would be possible considering it would based on the intended application, if all of the components are matched correctly DV's cams tend to be smaller than most and has been the center point of what he has written about for his entire career. A good example would be the 600 hp 600 tq 468 BBC with a 268 flat tappet hyd cam.

I wrote that after I read a coscam recomendation on a similar mill.

[GARY C]

I know what is in the 383 now and how it performs. I have numbers rolling around in my mostly empty head, Coscam is great but I think it will recommend a larger cam than I want for the street. I am sure I will start a 40 page thread on just speccing the cam. I will install what I want anyway. Thick headed that way. Thanks, Charlie

I'm not sure how that would be possible considering it would based on the intended application, if all of the components are matched correctly DV's cams tend to be smaller than most and has been the center point of what he has written about for his entire career. A good example would be the 600 hp 600 tq 468 BBC with a 268 flat tappet hyd cam.

I wrote that after I read a coscam recomendation on a similar mill.

If your goal is max power and or max rpm you will get a different recommendation then if your goal is idle quality and driveability but you will rarely if ever get both.

[Erland Cox]

20180331_150731.jpgFin extended into pinch. Lowering the entire floor reduced flow to .5" over .5" lift gained a small amount of cfm. Apex came down a touch. Input welcome. Thanks, Charlie

I would grind the common wall opposit the bulge.

Erland

[Carnut1]

20180331_150731.jpgFin extended into pinch. Lowering the entire floor reduced flow to .5" over .5" lift gained a small amount of cfm. Apex came down a touch. Input welcome. Thanks, Charlie

I would grind the common wall opposit the bulge.

Erland

It will be. At 1.16" now