Pinch point debate 2

[user-9274568]

OK, here is my challenge to you.
1. Post your best explanaion of what pinch does to the air flow in a manifold and port combination of your choosing.
2. Send me a scanned copy the parts. I will simulate it and provide an explanation of what happens.
3. Then the readers can decide which observations are more useful.
Sound reasonable?

Honestly, I have no desire to spend anymore time on this with you.

Maybe someone else has the desire but I find your approach cumbersome.

[SchmidtMotorWorks]

OK, here is my challenge to you.
1. Post your best explanaion of what pinch does to the air flow in a manifold and port combination of your choosing.
2. Send me a scanned copy the parts. I will simulate it and provide an explanation of what happens.
3. Then the readers can decide which observations are more useful.
Sound reasonable?

Honestly, I have no desire to spend anymore time on this with you.

Maybe someone else has the desire but I find your approach cumbersome.

You just posted images of the scanned data you have, what is so cumbersome about that?

[John Wallace]

Here's my take on what I think some of these guys are saying/wondering.

I have a Pontiac head with a narrow pushrod pinch point before the valve seat.
I send it to a head porter like Chris S.
He sends me back the heads capable of making 100 HP more than what I had before.
He uses his experience along with his flow bench.

I send the heads to you (before he does his magic) would you send them back to me making the same amount of HP?

[Bucky]

Here's my take on what I think some of these guys are saying/wondering.

I have a Pontiac head with a narrow pushrod pinch point before the valve seat.
I send it to a head porter like Chris S.
He sends me back the heads capable of making 100 HP more than what I had before.
He uses his experience along with his flow bench.

I send the heads to you (before he does his magic) would you send them back to me making the same amount of HP?

And how long will it be before you get the two sets back? I can tell you from experience that Chad pretty much gets after it when he gets a project in. I don't think projects collect dust there.

[SchmidtMotorWorks]

Post the scanned data from a casting, and we can compare.

[Bucky]

Post the scanned data from a casting, and we can compare.

I don't think anybody wants to engage this with you because the conversation is theoretical, endless, and generally unfruitful. This is not a bash on you, but simply what I found countless times on these types of threads.

[user-9274568]

I had a situation just recently that I actually had the pinch too big in a 23º. Engine on the dyno, wouldn't respond to change. Head moved 340cfm with a 45º seat. The port had the minimum at the seat ring. It had 3.00in² at the PR. It was 265fps through that area and the floor was 350/350/340 straight across. I get the heads back. Put a steep top 50º seat on it. Picked up 5 cfm. BUT, the pinch averaged 280 fps and 380/380/340 on the floor. The valve job was pulling harder on the port.

It made 25 more hp. It averaged more power.

REAL WORLD THAT NO CFD WOULD HAVE CONSIDERED!

[SchmidtMotorWorks]

Post the scanned data from a casting, and we can compare.

I don't think anybody wants to engage this with you because the conversation is theoretical, endless, and generally unfruitful. This is not a bash on you, but simply what I found countless times on these types of threads.

To the extent that what you are saying is true, I think it is because people are denying something they don't understand.

It is ironic that someone is calling BS on me but when I offer a fair challenge to compare two different approaches and an opportunity to learn about somethng they may not have exposue to the one callling BS is the one to walk, not me.

[SchmidtMotorWorks]

REAL WORLD THAT NO CFD WOULD HAVE CONSIDERED!

Please explain how you know this.
As far as I can tell, you have no idea what CFD does or does not do.

[user-9274568]

Post the scanned data from a casting, and we can compare.

I don't think anybody wants to engage this with you because the conversation is theoretical, endless, and generally unfruitful. This is not a bash on you, but simply what I found countless times on these types of threads.

To the extent that what you are saying is true, I think it is because people are denying something they don't understand.

It is ironic that someone is calling BS on me but when I offer a fair challenge to compare two different approaches and an opportunity to learn about somethng they may not have exposue to the one callling BS is the one to walk, not me.

Sometime it's logical to withdraw from something that is endless.

Like I tell my kids, it's not what you do, it's how you approach it. You come from a non-teaching angle. Your coming more from the, your a dumb ass and irrelevant..

[user-9274568]

REAL WORLD THAT NO CFD WOULD HAVE CONSIDERED!

Please explain how you know this.
As far as I can tell, you have no idea what CFD does or does not do.

now your assuming....

Jon, you have all answers, that is why debating with you is like going to a DUI class...

[Bucky]

Post the scanned data from a casting, and we can compare.

I don't think anybody wants to engage this with you because the conversation is theoretical, endless, and generally unfruitful. This is not a bash on you, but simply what I found countless times on these types of threads.

To the extent that what you are saying is true, I think it is because people are denying something they don't understand.

It is ironic that someone is calling BS on me but when I offer a fair challenge to compare two different approaches and an opportunity to learn about somethng they may not have exposue to the one callling BS is the one to walk, not me.

You ask like you will be open minded and able to have an open discussion about the pros and cons. But that isn't how conversations go with the threads you take over. Everything you say, you say with absolution. It isn't fruitful to discuss anything with anyone who deals in absolutes....particularly when it comes to them being absolutely right all the time.

[SchmidtMotorWorks]

Sometime it's logical to withdraw from something that is endless.

Like I tell my kids, it's not what you do, it's how you approach it. You come from a non-teaching angle. Your coming more from the, your a dumb ass and irrelevant..

Nothing endless about it, just post the scanned data.

I think it is clear that you know CFD in the hands of a clueless person like me will produce a more comprehensive explanation of the consequences of pinch than you can provide from experience.

If you review the posts I think you will find that it is you that have said i couldn't find my ass.

[Lakki]

Cant you people discuss without getting mad to each other? I have seen too many interesting topics getting locked becouse people somehow turn all this interesting technical discussion to personal fights.

To the topic, how big the differences might be in a head designed with talented head porter vs. as talented guy designing head with CFD? I mean differences real performance. Can the difference be very big? Since there is a lot of fast cars with heads ported without cfd, using just flowbench, and IRL testing.

Mr. Schmidt, in the first topic you said that there are plenty of examples of flow bench improvements hurting performance. Can you tell an example?

Also, you were going to explain to rookie about how wave action simulation programs work. He didn't seem to be interested but I am

One more thing,

In CFD you can set it up to flow the way a flow bench does or like the way a piston draws air, the difference is huge.

If not too much work, I would be interested to see that (if it isnt already shown on some another thread?)

[Lockwire]

Jon, you really are sounding like the Dyno Ball Buster guy, are you related to him by chance or birth. ?