[mike leech]

Originally Posted by Stan Weiss

HIS,
Yes where someone measures and what it shows is very important. You would like all 9 points as close as possible.

Since fps / velocity is relative based on depression we need to say we are using 28" of water. Your 350 fps sounds about right as max in the MCSA and Johns 300 fps sound more like using an average CSA (like gotten from port cc's and port centerline calculation).

Stan

PS - Another common method used is CFM per sq. in. at different place in the port. Note this and the velocity also apply to the curtain area.

Curtains? That's a woman's area....

[Stan Weiss]

Originally Posted by mike leech

Curtains? That's a woman's area....

Mike,
Just where are you using your velocity probe?

Stan

[Half-Inch Stud]

Roger that CSA, average & peak fps.

i need re-educated on the fps relation to Valve curtain (area); sure a min valve curtain ( lift x pi x Dia ) CSA makes a match for air-handling capacity.

But I'm stuck at port fps needing a minimum valve lift area across piston position ( across RPM), that they both support the CFM; to support the piston peak velocity x displacement. Oh the math is time-based dynamic mass-air flow stuff.

I suspect a MAX engine RPM is assumed must be that Choke RPM calc.

[mike leech]

Originally Posted by Stan Weiss

Mike,
Just where are you using your velocity probe?

Stan

Outa the gutter. Meant like interior decorating type curtain area. Is there another?

[bad69bird]

Originally Posted by mike leech

MEAT Curtains? That's a woman's area....

Fix it for you Mike

[Half-Inch Stud]

What worse:

great Math skills and no dog in the fight"........or

having bought & 1/4 mile-Tested EVERY potentially competitive CYL Head in your proven racecar assembly, yet not sure why 1 head gave the slightly better results. intake & carb left the same? (naw)

some folks here may have a "super-power" on 1/4 mile combo insight! let's compare shall we:
http://m.youtube.com/watch?v=O4QVyETjYKM

[Stan Weiss]

Originally Posted by Half-Inch Stud

What worse:

great Math skills and no dog in the fight"........or

having bought & 1/4 mile-Tested EVERY potentially competitive CYL Head in your proven racecar assembly, yet not sure why 1 head gave the slightly better results. intake & carb left the same? (naw)

some folks here may have a "super-power" on 1/4 mile combo insight! let's compare shall we:
http://m.youtube.com/watch?v=O4QVyETjYKM

HIS,
Having talked to some very knowledgeable people, the next step is a very steep learning curve with a move to CFD. Not sure that is for me.

Stan

[cgeise]

Originally Posted by Stan Weiss

HIS,
Having talked to some very knowledgeable people, the next step is a very steep learning curve with a move to CFD. Not sure that is for me.

Stan

This is what I ment by one of my earlier posts -- The "Basic" math will not give the whole answer -- most of the time it works - when it dosent your left scratching something and wondering why -- There is a reasone they have developed wet flow benches and other specilized tools. I belive the CFD tech is why weather forcasting has goten better over the years. But it is just another tool - -crap in - crap out

[Tom Vaught]

Originally Posted by cgeise

This is what I ment by one of my earlier posts -- The "Basic" math will not give the whole answer -- most of the time it works - when it dosent your left scratching something and wondering why -- There is a reasone they have developed wet flow benches and other specilized tools. I belive the CFD tech is why weather forcasting has goten better over the years. BUT JUST ANOTHER TOOL -crap in - crap out

x 1,000,000,000 CFD is basically a "WET FLOW BENCH" test using Cartoons.

Tom Vaught

[Half-Inch Stud]

Originally Posted by Tom Vaught

x 1,000,000,000 CFD is basically a "WET FLOW BENCH" test using Cartoons.

Tom Vaught

adapco's STAR CCM+ CFD SW has a good ability to simulate (and optimize) an intake runner. Also decent engine sim ability for combustion products too. i sat in on the 4- hour mesh traing course. http://www.cd-adapco.com/products/star-ccm-plus

May take months rotting behind a monitor, but answers do come out of CFD trials.

So, Stan, that's why calcs along with Rules-of-thumb boundaries provides rapid design & refinement to get 95% of optimal. Would you believe 92%? 90%?

[Half-Inch Stud]

Originally Posted by Tom Vaught

x 1,000,000,000 CFD is basically a "WET FLOW BENCH" test using Cartoons. Tom Vaught

Uhm, I asked adapco PARTICULARLY about CFD ability to handle texture, surface finish & their response was....wait for it....

Quite disapponting: they said they're not sure, and would look into that and get back to me.

So, the ability to CFD model-simulate, say a propeller for Thrust & Drag (HP) vs RPM where the windward/leeward blade surface finish gets varied would not be caught by even the fine mesh because the models are not matured. So, unless you know-for-sure, CFD by anybody using any suite of algorithms is about X2 as a wet flow bench

my opinion: a fella still has to experiment with textures to find out what the CHANGE in performance shows. Then asign Rule-of-thumb factors for said performance changes.

[LiL Jack]

ETSLIPTTFMF

THAT IS ALL!

[Half-Inch Stud]

If a fella had a "really good port" with a smooth tape film inside, then replaces the tape film with films having "textures-under-test"(think 220 grit, 120, 80, 60 grit & CNC bit step patterns), then the TUTs evals could occur more quickly than CFD could provide such answers.

Revealing PERF results are related to the smooth in terms of Rules of thumb for each texture. I figure.

oh and ETs slip-based evals puts ya back at POST 286 (cue it up and play it loud)

[3fastgtos]

Wow, how many pages now of computer racing BS? All I know is my ports are big x huge and they work pretty good.

[Half-Inch Stud]

Originally Posted by 3fastgtos

Wow, how many pages now of computer racing BS? All I know is my ports are big x huge and they work pretty good.

it's COLD OUT dude, so Half of us gotta bench race for awhile. Oh, but South Dakota's having aheat wave..

Wish i could say: "But I'lll be back for you jack, and let the machine speak. that's right." but my only ride is slow, and will continue to be slow for my forsee-able Street/Strip future.

[john marcella]

Originally Posted by Half-Inch Stud

If a fella had a "really good port" with a smooth tape film inside, then replaces the tape film with films having "textures-under-test"(think 220 grit, 120, 80, 60 grit & CNC bit step patterns), then the TUTs evals could occur more quickly than CFD could provide such answers.

Revealing PERF results are related to the smooth in terms of Rules of thumb for each texture. I figure.

oh and ETs slip-based evals puts ya back at POST 286 (cue it up and play it loud)

In my humble opinion, any fuel that is on the port walls, I consider to be dead and a lost cause. I also don't think there is any texture that you could apply to the surface to keep fuel from adhering to it or to reintroduce it to the air stream with out hurting that air stream.

JMO

[Matt Meaney]

Originally Posted by Half-Inch Stud

it's COLD OUT dude, so Half of us gotta bench race for awhile. Oh, but South Dakota's having aheat wave..

Wish i could say: "But I'lll be back for you jack, and let the machine speak. that's right." but my only ride is slow, and will continue to be slow for my forsee-able Street/Strip future.

are you saying, not even a "coon tune" could get it there? I don't believe it.

[Half-Inch Stud]

Originally Posted by john marcella

In my humble opinion, any fuel that is on the port walls, I consider to be dead and a lost cause. I also don't think there is any texture that you could apply to the surface to keep fuel from adhering to it or to reintroduce it to the air stream with out hurting that air stream.

JMO

100% agreement on your 1st Sentence. 2nd sentence conflicts with 1st Sentence.

Suppose there was a Runner/guide texture that improved fuel atomization, then a fella would need to lean-out their combo to correct the EGRs, revealing a gain. Do Piston & Chamber coatings work? Id so, then why did they work?

Suggest textures be tried for HP-dyno, not Flow-bench results.

[Half-Inch Stud]

Originally Posted by Matt Meaney

are you saying, not even a "coon tune" could get it there? I don't believe it.

"That's right. That's right! THAT's RIGHT! eh eh eh" - ZZT

here's a story: Certain engine was delivered. Fella tears that NEW engine apart and polishes the runners, puts it together and the engine spits, farts and has trouble with loaded acceleration. Calls the builder & says hey I did so-&-so polish, Builder says " there is no ability to undo the polish to restore the texture, engine is ruined". Fella bought a new engine, and is enjoying a very responsive state-of-art HP/CID carb'd engine.

We hope fuel injection will be as-good.

[john marcella]

Originally Posted by Half-Inch Stud

100% agreement on your 1st Sentence. 2nd sentence conflicts with 1st Sentence.

Suppose there was a Runner/guide texture that improved fuel atomization, then a fella would need to lean-out their combo to correct the EGRs, revealing a gain. Do Piston & Chamber coatings work? Id so, then why did they work?

Suggest textures be tried for HP-dyno, not Flow-bench results.

I don't believe there is anything that conflicts with what I said.

So you think coating the chamber and top of the pistons makes hp, try it and test it. I will bet the dyno can't measure the difference. The coating will reflect heat, the chamber is the only place I want heat unless its a N2o or boosted app and as long as it does not limit me on the timing on a NA app. But if I have the cam close it wouldn't on a NA app.

I think coatings are BS. IMO they don't work. At least for NA 10,000 rpm and below.