Not all sources which agree with me have a monitary interest in this argument. Though I don't claim these two sources to be authoritative, they do not have a vested interest in this argument and are, as much as can be, unbiased:

http://auto.indiatimes.com/articlesh...,prtpage-1.cms
http://en.wikipedia.org/wiki/Cylinder_head_porting

As I said, I don't claim them to be authoritative, only neutral. The first one mentions the analogy of the golf ball in relation to "swirl polishing" the intake valves. The second one mentions that analogy in relation to "selected areas of the intake port".

They both also mention the idea of wet flow. You'll get no argument from me that rough surface helps keep fuel droplets from sticking to the walls as well.

I never said anything of the sort. I said that a slightly rough port texture might, in some cases be beneficial and I explained why. Nothing more. Nothing less.

I do happen to know the basics of port gas speed, thank you very much. I also know that just because you don't see benefit in flow on the flowbench does NOT mean you won't see some in the running engine for reasons other than just wet flow. The pressure on the flow bench is different. The gas speeds on the flow bench are different. There's no on/off flow pulsing on the flow bench. And the temperature of the surface of the head is different on the flow bench, as well as the air after passing through it. There is very little dynamic similitude between a flow bench and the actual running engine.

In any case, there are plenty of people "in the industry" who agree with both sides. Many of those people are probably much more authoritative than either of us.

Do you just think the people on your side, whom you used to work for, are automotive "gods" and incapable of error? Have you ever considered that they might have their own motives for what they tell you?

You know I like technical discussions. I like them a lot. But it seems like every time I argue with you, you usually end up making ad hominem arguments and attacking my character, as well as the character of my sources, without actually making an argument against the science behind any of it. I can only think of two exceptions to this, in the several times we've butted heads, and both times you still attacked my character before making a scientific rebuttal.

Perhaps we can still salvage this debate in a mature fashion. How about this as a starting point: you said I was missing 9/10 factors regarding flow into the intake, why don't you tell me what you think those factors are so we can discuss whether they are relevant or not?

-Adrian

 

only if I had the funds

 

dont we all

 

Is links all you have?

India times link is sad. Swirl polishing back of valve is marketing hype. Find me a Del West, Zanzi, Xceldyne shelf valve that is swirl polished.

Second one, again you miss the point about what is rough and what is smooth. Quantification. Rough cartridge rolling is normal.

The links you provide speak nothing of a pure businessman's warping of technical truth.


Both of us have agreed on this from the start. I've never argued against this. You make it sound like I have?

No, you did argue more. "Looks like they were aiming for the critical Reynold's Number" you said. You said that after seeing the grooves in the photo. You decided they were important and a result of some high tech process.

No, you don't. "Bearing in mind that drag cars, endurance racers and sprint cars all have high port velocities during the majority of their use, perhaps that is why they have smooth ports." you said. When in fact a performance engine running 10 laps and a race engine running 10 laps can both have the exact same peak and mean gas velocities.

I am aware of the differences.

Problem for you is that earlier you said "If you were to polish the ports, the transition would happen at a higher RPM." When in fact on the lower speed bench tests this is still not seen! What more at higher speeds, warmer surfaces?

Where are these magic CFD groovians? All you have provided so far are links that skim the surface.

These people are my friends, old classmates, roommates, objective people I've met. They don't have reason to lie to me. Everything I test myself, hear about, read, is referenced against everything I already know and will learn in the future. Somehow it all matches? These people have more than links.

Above I have put down your two links. You consistently deny what you have said earlier on in this thread, and keep harping on the already obvious and covered, repeat the same mistakes, then make unsurported statements. When there is no logic how can I discus the points? I have to point out the circularity that doesn't allow logic. Maybe I shouldn't spend my time explaining this since the people who bother to read the thread carefully and think about it will figure things out themselves. I tell you what... I really don't have time for all this. Until I see something credible I'm not going to comment on it. In the future no matter how ridiculous something you say is, I will not post a rebuttal. I will email my direct friends. As I said before the reason I do this is mainly for them, so they don't get all tangled up in rubbish. Helping anonymous people is a side benefit and I don't anything to lose there if it saves me all this time.

I don't need, I can't, I don't want, (take your pick) to get into this micro theory when I have more tests to conduct, much more immediately pressing and significant things to worry about in getting my engine running. I'm not about to worry something that world championship winning GT heads and many other great heads listed in my earlier post, do not.

 

Are unsubstantiated evidence from friends whom you do not even cite all you have?

Nah, I just wanted to be clear that I do not argue against you on that point. That's all.

No, I didn't. I was saying that the Cosworth head was one of those "some cases" in which this was beneficial, especially in light of their claim for increase in torque and spool up, rather than top end power. (The lower RPM bands generally have lower port velocities, as you know.)

Yes I do. "Street cars" do not spend as much time at high RPM as pure race cars. They spend most of their time on the road, or during spool-up/torque RPM. Those RPM ranges are less than those typical of a race car on the track. Thus, typical port velocities are different than those of a typical race car on a track.

If we are talking about an engine, whether sport or race, which is designed for only high RPM use ... then I agree, the port velocities will be similar, if not identical. (But that is not what we were talking about.)

What makes you think the "normal" flow bench tests represent high RPM? If anything, the 28" pressure drop on a flow bench is LOW for an actual engine, especially at high RPM.

The same places as yours. I have friends who have been building engines for high-end racing teams for decades (like Sig). Others, such as my best friend's family, work with racing teams and drivers such as TRD and Ivan Stewart. They pit for them, as well as several other teams/drivers, in the Baja 1000 race regularly and supple many of the parts for the team. They even have their own shop with several race cars. Another friend I've known even longer races SCCA Formula Ford. So does his dad. Both have won many races. I helped build my friend's Crossley 55 Formula Ford car with him, literally from bare block and frame.

So do all of mine. One of my close relatives even used to work for the engineering division of Skunk Works. Another did CFD modelling as part of his PhD thesis. I suppose he wouldn't know anything about it, right?

Lack of logic? I can think of at least three seperate logical fallacies you've used in EVERY argument against me since we've met. (ad hominem, ad verecundiam and appeal to ridicule.) All three of those are in the above quoted paragraph. Although it bears no effect on the argument itself, when I told you I was taking university science courses at 12 years old, I wasn't kidding and I do have the transcripts and permanent records to prove it. Trying to poke holes in my knowledge is fine, but debating my logic, reasoning and internal consistency is not wise.

Unfortunately, I think this will be your undoing. If you refuse to understand the basis for all these concepts, you will never understand when exceptions apply. Althoug, in your defense, this is the exact undoing of almost all gearheads who know only what they think they need to know based on word of mouth, I had hoped you were better than this.

In any case, everyone in this thread has exactly two options:

1) Take Cosworth's word in that the roughness may be beneficial and intentional.

2) Take Shaun's word in that the majority of the readily available information is purely the result of corporate greed and the need to fool the sheep for the sake of saving money.

I will leave that choice to everyone reading, who may each read the information presented for themselves.

-Adrian

 

I don't need the support of my friends because you have again proven on this thread that you have the very basics wrong, yet you are trying to get into heavy detail.

Before this thread, you did not understand

1) What rough is on the intake.
2) How good ports whether for street or race engines are designed about gas velocity and how they can be similar, despite engine speed operating ranges.
3) That swirl polishing is hype.

English language is clear. In any case for better low end the cross section would be smaller and velocity higher.

Here you underline your ignorance. You do in fact have absolutely no idea what you are talking about. I will NOT spend the time explaining this to you. You are leaving out the cross section variable and forgetting that it is velocity is a major factor (perhaps the largest) that designers design to.

Read my previous post again. "High speed" as in high gas speeds in the port. You must stop jumping to conclusions.

Who said anything about 28" pressure drop? Haven't you heard about 40"? 60" ? 100"? 140"?

I think not, seeing as you do not have a clue as to the very basics.

This is very different from engine development on a world class level. You don't know what you don't know. Neither do your crew friends.

Sorry but Formula Ford is one of the lower Formulae and is not a big deal.
Owning a shop with several cars is not a big deal either. Building cars from ground up doesn't mean you know a thing about engine dynamics.

Did he get an F on that thesis? Did they not tell you about port speed relation to cross section and engine speed? Were they the ones who recommended swirl polishing valves ? Did they hint to you that because a head has machining marks left in it that it must be result of CFD surface texture?


Again with the chest thumping. It is getting old, Adrian. It means nothing if you cannot apply it objectively. Get yourself out there and get a little perspective on the industry and a little professional experience and then your wonderful mensa brain will do the rest and you will dominate F1.

Yes you jump to conclusions, yes your logic is desperate and often circuitous.

You have been wrong too many times in a row to be at all credible. I do not go by word of mouth alone. I go by what I read test myself, what I see in the industry, from authoritative sources (not random links), referenced to physics, referenced to word of mouth from good people, good friends, all industry.

Now you can claim to be the same way, but I'm sorry, your lack of understanding of area-flow relation and your belief in all these little rubbish things like swirl polishing and CFD port texturing just proves you are a liar or just don't know what you don't know.

If your table is missing a leg, investigating what type of additional wood top to nail onto it in order to make it the stiffest, hence most stable in current form, is retarded.

1) Replace the missing leg.
2) Figure out what material is good and attach it.

If you do not understand basics, you are wasting your time with everything else.


Readily available information is made by the ready army of liars and/or fools, very willing to gain from greater fools.

 

1) I understand what rough means just fine, though you may have misinterpreted how I was using the word.
2) Of course they are designed around gas speed. Both street and race engines will reach similar port speeds at the upper-end of their operating range. The difference is that street engines are not generally driven at the top of their operating range.
3) You claim that swirl polishing is hype and have not offered so much as a shred of information to support this claim; instead, you attacked the people making it. (Circumstantial ad hominem)

Certainly, but you sacrifice high end when you do so. Similarly, you generally sacrifice low end when you use large ports. In many cases a race engine operates in such a narrow powerband that the entire engine is designed around that powerband alone. IE: massive intake ports which, though they bump up the VE 5% in the top 1/3rd of the powerband, sacrifice the VE by 20% in the bottom 2/3rds On a street engine, even a "sport" engine, that might not be a desirable compromise.

So why don't you share some of your flowbench data instead of getting all pissed off and calling everyone else ignorant, foolish and liars? If you have soooo much evidence against this, it should be incredibly easy for you to find some that you can share. Why not do it?

 

The trouble with a modification like a ported head is that the consumer places a great deal of trust upon whoever is doing the job.

The problem stems from many different factors, as in my opinion it is impossible to tell if a head is good or not by the way it looks. Also, flow charts can be manipulated and 3rd party testing adds additional cost and most enthusiasts don't bother with it. The porting from head to head can also be inconsistent (that head you see on a sponsored racecar could be different than what you're buying). When it comes to modifying cars, rarely do enthusiasts and club racers just change one part, as it is usually more cost and time effective to upgrade multiple components, so it is difficult to determine what the ported head did or didn't do exactly.

The one thing we all having going for us all here is that the EVO is turbocharged, and it is pretty damn hard to get a ported head wrong in this application. In my experience, getting a ported head correct for a naturally asparated engine is much more critical.

My general impression of head porting on engines that already have nice flowing heads for the most part is that a good set of cams and a spring/retainer combo will get you very far already, and head porting isn't necessary. And I've come to this conclusion after purchasing heads ported by who I thought was the best at the current time.

Having said that... it may seem kind of confusing as to why I'd choose to purchase a cosworth head to test out. I'm basically interested in seeing what a professional motorsports engine development company can produce vs. the club racer / amateur outfits I've been dealing with in the past. And the only way to see if it really works as advertised is to try it for myself, arguing about the theoretical designs on paper really can't answer that question.

I'm pretty confident that the head will make gains on the top end, but if the head can really manage to spool a bigger turbo sooner that would really be something!

 

Read the earlier posts you went on and on about plain rough... without ever trying to quantify it and quoting numerous links on "rough", in desperate search for support of your wonderful CFD CNC grooves.

If you claim that a paperclip needs to be made of at least material A in order to clip 5 sheets of paper together, I don't need to prove to you in calculation that everyday and common material B is all that is needed to do the job and do it great. I just need to ask you to show me an office supply company that makes material A paperclips or any major office that clips very common stacks of 5 - 20 sheets together. Once you are unable to show me that requirement exists for material A in 5 sheet application, I have just proven your claim false.

This analogy is not entirely similar, but it is close.

Now show me a Del West, Xceldyne, or Zanzi valve that is swirl polished. I will even leave it up to you whether it is a shelf valve or custom valve. And then show me the type of head it is put in.

I already have in earlier post on finish and picking up flow in single percentages. What more do you want? Port flow analyzer printouts? You want me to redo the tests, just for you, and print stuff out that is so easily falsified, just so you can shoot it down again after I put more time into it? No thanks, you are already demonstrating you don't know what you're talking about, so I won't give you any more time than necessary than to defend myself against having my words twisted or faulty logic applied against them.