They do. It doesnt come out like a stream with all of the fuel strking the intake valve. It comes out in an atomized cloud, so I would think port design still has an effect on the air/fuel mixture.

 

Yeah, I hear what you’re saying. However, if the injector already atomizes the fuel, then why would we need anything else do to the job it’s already done? Bottom line is fuel atomization is taken care of by the injector. That’s a fact. The hot intake valve helps too I’m sure.

Per howthingswork.com, the injectors are mounted in the intake manifold so that they spray fuel directly at the intake valves. Granted, some of the spray hits the intake port walls but that’s why you don’t polish the intake runners. I think ridges from a CNC machine are overkill as far as the degree of roughness an intake port should be. I by no means polished any part of my intake ports so I'm betting I'll be just fine.

Most of the spray will hit the top of the intake valve and the spray that doesn’t is far enough through the head already that it’s hitting a point that’s pretty smooth to begin with.

 

Then good luck... My question is why ask a question if you know the answer?

 

Good question I didn't know much at all about the subject when I first posted the question so I asked. Since then I've been doing quite a bit of reading and calling around. Whether or not it was worth it is another question. I'll know this after the dyno and after I get them flowed again.

 

I've been following this thread for a few days now.
I have to agree with John regarding rough finish on the intake port walls to aid in fuel atomization. If you had a direct cylinder injection engine then things would be different in regard to keeping the fuel in suspension.

That however is not the only reason to leave the ports alone. You will find you lost airflow by taking those ridges out. They may look nicer to you but they won't flow as well. I learned this the hard way a few years ago after "cleaning up" a set of CNC heads then setting them up and flowing them again on my Superflow 1020 to see what I "gained".

Those ridges actually increase air flow due to boundary layer effects. If you look at some of the latest CNC head technology, (high end stuff) you will see great care taken in the overall pattern or design of those ridges. Some of the ridges are parallel to the airflow while others are at odd angles to it. Hours and hours of testing is done to perfect that ridge pattern to increase both air flow and engine performance.

Steve

 

Well damn. Where were you about a month ago? I'll see what I lost in a few days when I get them flowed. Thanks for the post Steve!

 

Ya gotta love the internet...thanks everyone for all the posts thusfar!

I was doing some more searching and found this site: http://en.wikipedia.org/wiki/Cylinder_head_porting
It says: "Flow bench testing shows that the difference between a mirror finished port and a rough textured port is typically less than 1%. The difference between a smooth to the touch port and an optically mirrored surface is not measurable by ordinary means." So rough textures in the intake are a good thing where fuel makes contact, but because of flow not atomization. I still argue that fuel atomization is taken care of by the fuel injector, but what I didn't realize was that the rough texture in the intake port plays a big role in the flow of fuel where it touches the intake port. Fuel atomization like Guitsboy says, is not an issue, but flow is what we need to be concerned with.

I think the most important sentence in that article is: A rough surface on selected areas of the port may also alter flow by energizing the boundary layer...

I'm hoping that the boundary layer created from a rough texture will do the same job as the cnc marks do. I'm betting they do.

I'm just gonna rough up the ports (near the throat and guide boss) a little bit more with some 50-60 grit sand paper and I'm sure I'll be fine.

Sometimes I wish I paid attention in science, maybe I would have remembered something about boundary layers...

 

Flow wont vary too much on a dry flow bench, unfortunately dry flow bench testing is the equivelant today of using a points distributor. Technology has evolved, and the use of wet flow bench testing has allowed professional race teams to learn and do things that you guys havent and wont see for years to come. We at Dart streamline this process, as we have that technology, and we use it for our professional race teams, but also for our products we make for you guys. I am sure that you injector doesnt have a direct line of site to the valve, as it doesnt in a NHRA Pro Stock head with a 10 degree head. The cnc lines improve fuel distribution, help with atomization, improve air speed when fuel is added to the port, you have to remember air flow testing doesnt show real world, when you add fuel the density of air totally changes.

On the internet you can find all kinds of theories, ideas, hypothesis, etc. about how this and that work, some are good, and some are not. Ask yourself, what have those companies or individuals done to prove that what they say makes sense?! There are very few guys in the position that Richard Maskin is in as the owner of Dart and the owner of his own NHRA pro stock car. This allows him to do and see things you guys wont see for years yet, and he isnt afraid to pass on the knowledge we get from the testing we do here daily. Sure we could just make a port flow alot of air to sell more heads to the general public, after all more flow more power right? Couldnt be further from the truth!!

There are reasons that Nextel Cup teams leave the ports rough, NHRA teams the same, etc..... WE know it works, we have done the testing, on the bench, on the dyno, and most importantly where it matters on the race track! Last time I checked there are not too many race tracks have a race your flow bench day, or race your dyno day!!!

John

 

sorry dude, but since noone else will say it, your an idiot. You have people that do this for a living telling you not to do it, yet you take the advice of howstuffworks.com and wikipedea, two sites that although good, have known inaccuracies in the REGULAR stuff they post much less something as specific as head port design for fuel injected LSx engines.

I love how people think the companies that put out $1000+ heads don't actually finish the heads, they just do it halfway and any average joe can make it better.

 

This was just a friendly discussion and then you came along...

The fuel injector atomizes the fuel. Nobody can argue against that. The only part I was wrong about, and this was JUST brought to my attention by Steve at Race Eng, was that a rough surface helps FLOW by creating a boundary layer. The rough surface does nothing for atomization. Atomization is taken care of by the injector. That's what it was designed to do. Do I have enough horse power to have a difference between cnc ridges and a rough texture, I seriously doubt it. I'm guessing the difference would be marginal. In something like a top fuel car, that's probably a good difference at the 2000+ hp level.

By the time I had started working on the intake, the only reason I was hearing about why not to was that "you could screw them up". Yeah, that sounds convincing. If you knew anything about hand porting you'd know that there is flow left on the table from a lot of CNC programs. You're the idiot for thinking otherwise. I took the advice of how howstuffworks.com? Yeah, they told me to take out the ridges in the intake runner! If you're going to question the general information I was using from that site or the encyclopedia, then you're definitely the idiot here.

 

believe whatever makes you happy.

 

Not for nothing, but I home ported my own heads and I have an engine that out-dynoed some similar setups on my club's dyno day. Granted, some may have been in the tune, but im happy with the way my heads stacked up against the pros. If I recall, all but two people online told me I was going to turn my heads into boat anchors.

Also, CNC cut heads usually leave a little extra meat around the valve guide since they have to allow for head casting tolerances and clamping inaccuracies. Even a new hand at porting can take a little more off and clean heads up with a careful eye.

Also, Take that "Idiot" comment and shove it up your ***. Nobody needs to hear that ****.

 

I just wanted to say thanks for posting up in this thread. It's nice to get info from somebody who's got experience in this area.

The biggest thing I think people miss when it comes to head porting and other things that I like to call a science like I feel head porting is considered is that they look at just certain aspects of it (like the idea that smoother will make more flow etc...) but miss to see that it all works as a system and all factors need to be looked into. Just like anything else, you change one factor and it may change everything else!

Take Nascar as an example. They don't just flow the heads, they put an engine together (without any pistons or crank in it) and flow the carb., intake, heads, and block as a whole so they can see how everything works as a system. I'm also guessing this is how the bigger teams with more money for research are able to get more power out of the restrictor plates but that's only a guess on my part.

Not trying to knock anybody here but it seems sometimes that people will discount the time, desiging, modeling, and testing engineerings put into things. I personally am a geek where I like hearing about the technical aspects of things. Here's another example, in Will Handzel's book they speak of how before the Gen III LS1 head was created, on physcial models the fast-burn intake port design where shooting the air/fuel mixture vertically into the combustion chamer with as much force as possible would net power. After they got some advanced computer modeling when desiging the Gen III head they saw that gain in power from doing the fast-burn design was negated by the air/fuel charge actually pushing against the piston coming up in the bore and was actually eating power. They instead used 'swirl' port and combustion chamber design in the Gen III head to produce more power. (taken from page 18 and 19 of "How to Build High-Performance Chevy LS1/LS6 V-8's")

Ted

 

Get off ur high horse man. I'm not talking about 50,000 dollar heads; we're talking about cnc programs that ARE NOT being used for NASCAR and top fuel. We're talking about cnc programs that DO NOT have that kind of budget. I said that there is flow left on the table after a cnc machine is done w/ a head. I wasn't specifically talking about the intake. Go back and read again. If that were the case you'd be saying that cnc lines on the combustion chamber and exhaust are optimal? Umm..NO! Although, the valve guides are probably an area where there is something to gain from hand porting ON MY HEADS, NOT 50,000 dollar ones. Like we all agree, it just needs to have a rough finish.

Not that any of you will care what my source but a here's a nice quote from Joe Mondello who is by the way the only Professor of a Porting School in the country and he's been associated with almost every aspect of racing. Chevrolet performance cylinder heads still utilize the identical combustion chamber, which Joe designed in the early 1960's known as the "Posi-Flow" chamber. HE SAID: "There are a lot of CNC profiles being sold today, but I think most have some room for improvement. Additional hand grinding can usually pick up another 10 to 12 or more cfm." Sound familiar? Why don't you get back to work and stop pretending you're a porting expert. I might just be “another regular joe”, but who are you? You’re just a sales manager. I appreciated you’re input up until this point, now all you’re doing is mocking me and being completely wrong in the process. Good job

http://www.babcox.com/editorial/us/us110128.htm

I could find countless other porting how to's that will say that there is flow left on the table after cnc'ing. Rough is good on the intake port, but Steve was the first person to present anything factual about why. It’s for air and fuel flow. If I had that information when I first posted, I wouldn’t have touched the intake. Well, I probably would have smoothed out the valve guides with a rough finish but kept it to that. Regardless, what's done is done.

 

See ignorant response like yours is why we as companies dont bother posting on boards, waste of time. I happen to be a Sales Manager, tech manager, and work on new product developement so maybe you should go back to school and learn something. Joe Mondello and Lloyd Creek have been here, and built our wet flow bench that showed what the cnc lines do, you are arguing with no facts you yourself have found just information you have hunted down on the internet, and read in a book.. Being a professor in a school that you own and operate doesnt make you the man, and the one and only man... If I open a **** school and become the professor, does that mean I am the only one who know about ****??? Doubt it. And no the chambers are not the same design since the 60's, you are clueless, 60's chamber designs were horrible, new plug locations, and new chamber shapes have been reasons why performance in heads has improved not just airflow.

The relationship in regards to porting and cost, lets think, would I rather buy heads from someone with the technology I mention and who has succeeded at the highest level of racing, or someone who on the internet spews a bunch of bull$hit about flow numbers, you go with your choice!! I will go with mine.. Trust me an hour of work around the guides after our cnc machine gets done wont give you 3 cfm, and we know it wont make any more power.

Look I am trying to help you but apparently you know it all, so you sit on your high horse, qoute all the people you want, we know all those guys, we have worked with all them... Joe Mondello like I said built our equipment, ask him if we know what we are doing....

You know no matter how much experience I have some jack a$$ always wants to argue because of my job title, come on down, I will show you what I do, why we are who we are, and why you are here, show you why you dont polish intake runners, of heads. I didnt say manifolds, we were talking about heads. I also said you can do the chambers and exhaust, maybe you should read the post again... Intake ports, hmmmm must not have any of those in the heads????

LS guys it was fun but now I have realized once again why I stopped posting on here, unless I blow smoke up your as$ and give you what you want to here as advice, you wont beleive me...

Just curious what exactly is your experience level??????????

Being you seem to know so much, and know more than I, after all I am just a Sales Manager according to you.....

 

If you want to not listen to me, fine, call up Darrin Morgan on the net and look for information about wet flow.. Jeff Smith was just here from Car Craft which i participated in the wet flow testing that we did for them, they video taped it, and will be doing and extensive article. They are trying to educate people that old methods of porting, old valve job designs, etc are all being changed due to this new equipment. If you choose to keep looking at old technology, which so far looking at your post has been all you are digging up, then again your choice.

You keep referencing dry flow information, its old school, I am trying to tell you and show you and give you the latest information, **** other companies wont give you, for free. But you want to argue it!! Instead of arguing maybe you should listen and then do what I said, find some post from Darrin on speed talk, and he will flat tell you our machine that we use for developement is the ****, and Darrin has been around a long time, and he is widely respected by some of the best head porters in this industry, he also teaches classes at Reher Morrison... He also thinks Tony at Dart is one of the smarted head porters and designers in the industry.... And I work with him daily...


Dont let a title get in the way of your thoughts, I do more than type, answer phones, etc.. if you dont know what I do and how we operate, maybe you should come by and see... Glad to buy you dinner and show you whats up!!

As for the 50,000.00 heads, we use the same equipment to port all of our head, and the same machines to valve job all of our heads, so your heads get the same care and concern and technology we use on our high end race motors, that was the point which you missed, you wanted to turn it into an arguement!!!

 

Thanks man!

Not a problem. I didn’t see anything else on this site about this topic so instead of mocking me and calling me an idiot, I’d much rather a thank you for finding this out for you rather than middle school name calling and mocking.

A sales manager doing new product development huh? What do you test, new clipboards that have state of the art timecards on them?

I love how you discredit the guy that’s “written the book” on porting. You are much more wise than him I’m sure!! Do you discredit everything that's on the internet? Nothing on here is of use huh? I was simply giving the credentials of a PROFESSIONAL head porter. Read about all you like here: http://speedtalk.com/shows/018_joe_mondello.html If Joe Mondello built your equipment, you obviously didn’t stick around and talk to the guy because you disagree with him.

I'm not a pro, we all know that. However, I'm learning from people who are and would take their advice over your's any day. All you're doing is hiding behind the company you work for. I don't discredit anything Dart does, I'm sure it's top notch. Stop implying that I am!

About me not believing you, how about you post some factual data and we’ll talk about it. That’s what this site is all about anyways. You have yet to post anything factual and data related. If you don’t believe “the man” of hand porting then why don’t you do some of you’re tests that only a sales manager can do and post your findings.

 

Dart331Stroker -
Youre attitude here on the boards does not reflect very well on your employer. You have made me seriously reconsider buying dart products in the future, or even suggesting them to others.

 

Since you have hand finished the heads, we would be glad to send a pick up for one of them and re flow one of them to see how the heads reacted to the finishing. Just thought you might be interested.

 

How trying to educate one, and defend causes someone to not want to buy Dart... Whatever, I wont be on this board anymore anyways... I didnt try to discredit Joe, I said he has been here and designed our wet flow machinery. We are talking about equipment that has showed us the rougher intake port worked better, this test is real world compared to a dry flow bench, believe great, dont great. Like I have said in the past, and you can believe what you want there is lots of smoke and mirrors out there.. I am officially retiring from LS1tech, so no worries. Other boards have appreciated my insight and my professionalism, this one does not. I have had several Private Messages regarding this post, and many thank me, and dont want me to leave, but I refuse to continue to have to explain myself, and argue with people because of a job title... Several agree with me even...

Clip Boards, and guitsboy you talk about my professionalism?? What about his mud slinging??? Not all companies have job titles and people that only perform one job task, and we happen to all work here because we all are involved in racing, not because its a job and we went to college.... No engineers, just racers, making parts that fly!!

Whatever...

I'm out...