Hey guys i'm at the final piece of my project, I upgraded this year to a 383 and although i love the TQ that came with it i'm ready to up grade my heads for more power!!! after all the research i've came down to two choices the 195 profilers or the 195 afr's. I was thinking afr's, but after a little research i'm starting to lean towards the profilers ($470.00 cheaper). Please let me know what you think? as always thanks for the input.:beers:
If you keep your duration around 235-236 degrees @ .050 or less, you should have good street manners. Whatever cam you are considering, just make sure the DCR is less than 8.5 if you want to run on pump gas. I was originally considering a CompCams XE 274 for my 383, but the DCR was over 8.5. I changed to the Magnum 280 which is similar in size and it gave me a DCR of 8.46. It runs fine on 92 octane and have never had an issue with detonation. I like the Voodoo cams 60103 and 60104. The 60104 is as large as I would recommend.
I talked to the guys at Pro-Filer a they have to check to see if my headers will work with thier heads. The guys at AFR said if I keep my current combo that i should get the 180's because the 195's are set up for a roller cam Humm. I would like to get the profilers after all the good things i just heard about them ( Thanks everyone:beers but I don't want to run into anymore unexpected expences.
Uhhh. The AFR debate I have enough data out there to make a wise decision on which way a person should choose. I do know that results FAR outweigh flow bench data, flow numbers, velocity, etc..
I am strictly trying to say if you have high velocities and high flow then its clear you have a winner.
Uhhh. The AFR debate I have enough data out there to make a wise decision on which way a person should choose. I do know that results FAR outweigh flow bench data, flow numbers, velocity, etc..
This statement is wrong is so many ways I'm not sure I have the energy to explain it!
I have a question, so it's not possible to have to much velocity?
What happens if you try to flow more air through a choked situation?
And last, what effect does air have on velocity and how does heat effect it?
I will say this, your right in line with your thinking as AFR.
Good to see you here Chad, hope you can give us some wisdom on the topic. Because its all about high velocity, small cc, high flow #s, and tiny P-rod pinch with lots of choke around here... 'cause thats all that matters in a cylinder head.
Guys, I will be more than happy to answer any questions to the best of my ability. I have learned (trying anyway) that I can sometimes come off strong. I just know what I've seen and can only talk about my experiences. The cylinder head debate is a hard one. The market is hosed up. AFR has been the KING, but we have options for street guys, drag guys and those options have been yeilding beyond believe results. I think some of the die hard AFR guys either dont want to accept it because the theory of high velocity, even in a street car, has/is proven to take a back seat to a properly designed port.
Speier Racing Heads has devoted many hours on developing what I feel are some of the best SBC heads around. We have a CNC 227cc port Pro-Filer core, a CNC 245cc RHS core in both aluminum and iron. I also have a RR RHS iron core and will be available in aluminum later on. The AIR Wolf 245cc offset rocker head is available also.
I would be more than happy to visit, answer PM's, answer email, even if you choose another brand.
Do you have any a-b type dyno tests comparing your heads to another brand? I know it is expensive to do but I'd sure love to see some numbers like that testing your heads against AFR (or any brand really). I think it would help you sell a TON of heads too.
All that really matters is HP and TQ at the end of the day. As consumers, we'll leave it to the experts to figure out what the best pushrod pinch is, how important flow is at X lift, what velocity is best, runner size, etc...it doesn't matter to us. We are not mechanical engineers and can't make sense of that level of detail anyway. What we can make sense of is power.
I don't care HOW it's made, I just care how MUCH power is made. If your heads make way more power than other heads on the market you should really try to document that and put some marketing material together.
I've learned over the years never to argue/debate with an engineer because they will science you to death! Keep your books, I'm fine thanks!
This whole subject doesn't need a dyno, you just need to understand Bernoullis Principle and he figured all this out for us..
Bernoulli is a principle of energy change in the system or better put, an example of the conservation of energy. If you put X amount of air in the pipe and run it through a venturi the pressure changes, the area changes and the air speed changes but the same amount of air exits the system with no energy loss. THAT is Bernoulli. Pressure, Temperature,velocity and area are all proportional or inversely proportional to one another BUT energy always stays the same. None is lost or wasted it just changes from one form to another. Like this,,
The working fluid "air" is of high pressure before entering the venturi. Once its at the apex of the venturi the pressure drops and the temp drops with it. A perfect example of the conservation of energy. The total energy stayed the same it just transformed into other forms. The heat energy was used to accelerate the air! Once the air slows down and the pressure rises the heat is absorbed giving back the working fluid its pressure. The cause of all this change is,,, wait for it,,, AREA
If the port is turbulent at the mid point, backs up, stops flowing or goes into air speed choke the engine will "see" that situation far earlier and far more pronounced in the running engine because the air speeds are much higher. You may see the port stop flowing at .700 lift on the flow bench but in the running engine where peak air speeds can be as high as 150" the choke hits much sooner and cylinder fill is decreased substantially. Its called the MEAN INLET MACH NUMBER. When the MIMN reaches .55 the engine VE stops increasing or decreases at a faster rate. You spike the velocity with turbulence or an air speed choke and the engine stops increase air flow relative to engine speed. People always talk about air speed chokes but a turbulence choke will do the same thing just not as bad. If your turbulent and try to flow more air through turbulent area guess what happens to the air flow, it gets even more turbulent! The more air the engine demands, the more turbulent the flow becomes and the worst the choking situation gets. When a head is growing in flow, it assures us the port is happy, therefore the cylinder fill is sufficient. When it's sufficient, at any lift, it will make more power.
The more you turn the engine the more CSA you need. You enlarge the CSA to keep the same air speed.. Put a smaller engine on the same size heads and you must twist it higher in order to achieve the same air flow through the heads in order to get them back in the range where they are efficient ( air speed range). If the head is flowing well, your CSA would be larger. If it's flowing poorly, your CSA would be smaller. Everything is based off of valve size and how much it is flowing.
A venturi is designed to accelerate the air to a given velocity over a very short span and recover the energy at a given rate so as to not waste or use as little of the energy at hand to accomplish the task. Pressure recovery dynamics in the divergent region of the venturi are critical to the amount of air that can pass through it. That's why the bowl, throat, seat and chamber are so critical in a cylinder head. The bowl is the high pressure ( convergent ) region of the venturi and the throat is the venturi itself while the chamber acts like the ( divergent ) region to recover the energy.
I've learned over the years never to argue/debate with an engineer because they will science you to death! Keep your books, I'm fine thanks!
This whole subject doesn't need a dyno, you just need to understand Bernoullis Principle and he figured all this out for us..
Bernoulli is a principle of energy change in the system or better put, an example of the conservation of energy. If you put X amount of air in the pipe and run it through a venturi the pressure changes, the area changes and the air speed changes but the same amount of air exits the system with no energy loss. THAT is Bernoulli. Pressure, Temperature,velocity and area are all proportional or inversely proportional to one another BUT energy always stays the same. None is lost or wasted it just changes from one form to another. Like this,,
The working fluid "air" is of high pressure before entering the venturi. Once its at the apex of the venturi the pressure drops and the temp drops with it. A perfect example of the conservation of energy. The total energy stayed the same it just transformed into other forms. The heat energy was used to accelerate the air! Once the air slows down and the pressure rises the heat is absorbed giving back the working fluid its pressure. The cause of all this change is,,, wait for it,,, AREA
If the port is turbulent at the mid point, backs up, stops flowing or goes into air speed choke the engine will "see" that situation far earlier and far more pronounced in the running engine because the air speeds are much higher. You may see the port stop flowing at .700 lift on the flow bench but in the running engine where peak air speeds can be as high as 150" the choke hits much sooner and cylinder fill is decreased substantially. Its called the MEAN INLET MACH NUMBER. When the MIMN reaches .55 the engine VE stops increasing or decreases at a faster rate. You spike the velocity with turbulence or an air speed choke and the engine stops increase air flow relative to engine speed. People always talk about air speed chokes but a turbulence choke will do the same thing just not as bad. If your turbulent and try to flow more air through turbulent area guess what happens to the air flow, it gets even more turbulent! The more air the engine demands, the more turbulent the flow becomes and the worst the choking situation gets. When a head is growing in flow, it assures us the port is happy, therefore the cylinder fill is sufficient. When it's sufficient, at any lift, it will make more power.
The more you turn the engine the more CSA you need. You enlarge the CSA to keep the same air speed.. Put a smaller engine on the same size heads and you must twist it higher in order to achieve the same air flow through the heads in order to get them back in the range where they are efficient ( air speed range). If the head is flowing well, your CSA would be larger. If it's flowing poorly, your CSA would be smaller. Everything is based off of valve size and how much it is flowing.
A venturi is designed to accelerate the air to a given velocity over a very short span and recover the energy at a given rate so as to not waste or use as little of the energy at hand to accomplish the task. Pressure recovery dynamics in the divergent region of the venturi are critical to the amount of air that can pass through it. That's why the bowl, throat, seat and chamber are so critical in a cylinder head. The bowl is the high pressure ( convergent ) region of the venturi and the throat is the venturi itself while the chamber acts like the ( divergent ) region to recover the energy.
For the record, I dont have a fricken thing in the World to prove to you! I've been down this road on other forums and I now have all this on my web site, easier to cut and paste!
Didn't say you did man... Bernoullis principle doesn't apply to head flow though because his principle is only valid for Incompressible, steady flow, streamline and invisicid flows without any work done to them. Head flow is unsteady meaning it changes according to time so your acceleration isn't merely a function of the coordinate system but time also. Which also makes calculating along a streamline invalid for this type of flow too. Bernoulli was a genius but his eq's are very limited.
Also temperature is a function of internal energy which in this case we know as pressure.There are many modes of internal energy such as molecule twisting, bending, vibrating in many different axises. Ideal gas p=(rho)RT. The heat energy was not used to accelerate the air through the venturi the internal energy was. But you hit my point right on the head, if the venturi isn't choking you can sustain flow through mass conservation and you increase your velocity which will increase swirl inside the cylinder on a 2 valve motor and tumble on a 4 valve. Thus if you have high velocity and flow then your head is excellent at its job. As long as you are not pushing the port capabilities to flow beyond their design.
Was an interesting read though not sure what 150" air speed means. Also turbulence can create a choking situation because it can create eddies that will hurt flow. Although we do need turbulence to a degree in order to have good mixture motion occur in the cylinder. The flow in the head is turbulent meaning unsteady because of what it is going through, its just a matter of how turbulent. I think we can both agree if we polish or intake ports we will increase flow (decreasing boundary layer) but we will also decrease turbulence and losses associated with it but we loose the ability to spark.
Are you saying the flow rate is not the same from the plenum to the chamber?
Can you have too much velocity in a head?
At the .55 mach the pumping losses reach a point where the energy used is more than the energy gained from the inertia ram effect. In other words, the engines converting pressure drop into velocity and keeps doing so in an increasing manner until 690ft/sec. At that point the conversion of energy into air speed and inertia is more than the return one gets from the inertia. This does not mean the flow stops. It mean the power increases stop and both TQ and HP drop like a rock. All your doing past 690ft/sec is stretching air molecules out and getting nothing in return (inertia ram effect) as far as cylinder fill.
Hey radcannon you might want to do a little check in the NHRA world before you get in a pissing match with Chad Speier . His past looks better than your 600 hp 383 that lost 150 hp on the way to dyno :noway:
I am an AFR owner and you cannot really argue with the results that are being obtained with Pro-Filer heads. It's also nice that there is finally a more budget minded MADE IN THE USA head out there that is able to give these results. I personally went with the AFR's because a year ago my builder (who runs a world champion race team but I wasn't building a race engine) said that for what I was wanting, the CNC'ed AFR's were about the best out there as far as bolt-on ready and they came with a lifetime warranty. I'm happy with my street engine but don't pledge my allegiance to any one brand. If I ever have another one built, I'll gladly research what is available just like I did then. After it's all said and done, you will always....always.....have those thoughts of "well, what if I had used this or what if I had tuned for that or what if what if what if" unless you're just dead inside.
This is not related to this increasingly heated head debate but all I will say is that for a street car, if all you are looking for is the highest peak power numbers then you are a fool. THAT IS NOT DIRECTED AT ANYONE and is just my opinion so please don't get offended anyone. Build your car around where it's going to live 95% of the time and you'll be a lot happier with it. You can still just lie to everyone about how much peak power it makes if you think you left some on the table. It's fun.
I once had my 1800cc cruiser dynoed so I could get a torque plot before and after an exhaust change. The place that did it took about thirty minutes to figure out how to get torque to show up on the plot. They mainly used the dyno for tuning bikes for their race team and were only concerned with getting peak hp. One application does not suit all.
I am an AFR owner and you cannot really argue with the results that are being obtained with Pro-Filer heads. It's also nice that there is finally a more budget minded MADE IN THE USA head out there that is able to give these results. I personally went with the AFR's because a year ago my builder (who runs a world champion race team but I wasn't building a race engine) said that for what I was wanting, the CNC'ed AFR's were about the best out there as far as bolt-on ready and they came with a lifetime warranty. I'm happy with my street engine but don't pledge my allegiance to any one brand. If I ever have another one built, I'll gladly research what is available just like I did then. After it's all said and done, you will always....always.....have those thoughts of "well, what if I had used this or what if I had tuned for that or what if what if what if" unless you're just dead inside.
This is not related to this increasingly heated head debate but all I will say is that for a street car, if all you are looking for is the highest peak power numbers then you are a fool. THAT IS NOT DIRECTED AT ANYONE and is just my opinion so please don't get offended anyone. Build your car around where it's going to live 95% of the time and you'll be a lot happier with it. You can still just lie to everyone about how much peak power it makes if you think you left some on the table. It's fun.
I once had my 1800cc cruiser dynoed so I could get a torque plot before and after an exhaust change. The place that did it took about thirty minutes to figure out how to get torque to show up on the plot. They mainly used the dyno for tuning bikes for their race team and were only concerned with getting peak hp. One application does not suit all.
I hate to argue about this stuff and in the beginning I was adamant about my point. However, the market is big enough for everyone. My whole thing on AFR is their marketing. They say, "The most Powerful Standard Racing Head Available", and "The baddest 23º Standard Port Head". That is BS! Why is it I can take that head, spend 2 hours on it, and find 50hp or .20 in ET? Oh yea, this comes from fixing the velocity issues. Let's get real, if your going to claim it, it should be the truth!
However, they are and will always be a killer street head. Just another player on the block and it's time to catch up.
Chevy High Performance did a two part series with several designers. An excerpt:
"Our daring cast of experts includes Tony Mamo of Air Flow Research; Kevin Feeney of Racing Head Service (RHS); Al Noe of Trick Flow; Tony McAfee of Dart Machinery; and Darin Morgan of Pro-Filer Performance, who's the former head R&D man of Reher-Morrison's Pro Stock engine program. As you gawk over that impressive list of all-stars, we'll take a moment to introduce you to CHP's newest department. The goal of our "How it Works" section is simple: tackle the intricacies of complex technical topics in a scope never before seen in a magazine article. Our two-pronged approach for accomplishing this is dedicating lots of space to accommodate meaty tech info and letting the real experts of our industry explain things in their own words."
For those of you interested, Darin Morgan, my friend and mentor, is going back to Reher-Morrison. He is going back to his first love, engine building and reuniting with his brother Brad.
Chad
Can you explain how piston speed effects the port,
its sized, shape... and all. How does one use piston speed in designing a port.
Like on my 420sbc, 3.875" stroke at 7000, with a 2.6"csa, just wanna see how bad a screwed it up.
piston speed = 4,520.83 ft/min.
Thanks
MOST feel that an engine is most efficent with a certain piston speed. Achievable VE potential should follow piston speed, in other words, the faster the piston speed, the greater the VE potential. Now what I was saying is that if a cylinder head has a choke issue, the higher the piston speeds, the sooner the choke. Because the engine is a pump and the more RPM the more air it's trying to pump. The design of the head will determine where it needs to be run to be most efficent. Remember, you turn a cylinder head with a larger CSA more to keep the same air speed on the same sized engine. And yes, rpm bore stroke, etc will determine CSA, but average velocity is as important. You want a well balanced port. You can't have one that has the proper min CSA and large everywhere else. All your doing past 690ft/sec is stretching air molecules out and getting nothing in return (inertia ram effect) as far as cylinder fill.
The big bore short stroke engine needs more air flow because it has to turn more RPM to get the same piston speed. More cylinder cycles at same VE needs more cfm though the port. MAJOR DIFFERENCE BETWEEN PISTON SPEED AND PISTON VELOCITY! A slow decending piston cannot cause the needed velocity in a port large enough to supply the needed volume. A small port will raise velocity with a slow decending piston but will not handle the needed volume for a high VE.
Chad personally I just want to thank you for being willing to share a fraction of what you know with a bunch of guys that haven't spent a dime with you. I'm not in the market for heads right now, but I'm sure I will be again (I'm a junkie), I will look you up for sure. I wish I would have known about you 9 months ago before I bought the heads I did. I don't know how they are going to perform yet, if it's not what I am after I'll be in the market sooner than planned.
For the most part the guys on this board are good people and want to learn. I hope one yahoo doesn't run you off. Just do a search on his screename and you will see this is the norm. Many people have had long drawn out discussions with this individual (me included). Too much time in the books and not enough time in the tool box.
a customer was looking for more power and you pull a set of heads you massaged with your mad skills to replace with another set. This new set was approx in size but out of the box but yet you went through all this work sure that you would gain enough power to satisfy the customers needs? You said yourself that the SBC hasnt changed in decades so I dont understand why you were sure the new heads were the answer?
Im far from an expert but most people know it doesnt take much material removed/added in the wrong spot to seriously alter the flow characteristics of a port. In saying that the head you compared to the Pro-filer head was no longer an AFR design. You yourself dont seem to have much faith in your own port work so why should everyone assume the AFR was so much better than before it was modified? And how does this make your comparison between the two an even one?
After all, its not like we are re inventing the wheel here?
50 Hp after it has been touched by the hand of god is a huge claim! I guess you could say at least 75Hp over the unmodifid AFR's... Thats a little hard hard to swallow.
a customer was looking for more power and you pull a set of heads you massaged with your mad skills to replace with another set. This new set was approx in size but out of the box but yet you went through all this work sure that you would gain enough power to satisfy the customers needs? You said yourself that the SBC hasnt changed in decades so I dont understand why you were sure the new heads were the answer?
Im far from an expert but most people know it doesnt take much material removed/added in the wrong spot to seriously alter the flow characteristics of a port. In saying that the head you compared to the Pro-filer head was no longer an AFR design. You yourself dont seem to have much faith in your own port work so why should everyone assume the AFR was so much better than before it was modified? And how does this make your comparison between the two an even one?
After all, its not like we are re inventing the wheel here?
50 Hp after it has been touched by the hand of god is a huge claim! I guess you could say at least 75Hp over the unmodifid AFR's... Thats a little hard hard to swallow.
What in the HELL are you talking about. What gives you this impression. But how about A-B testing. Ever thought of that? Or dyno work? Like dyno the engine, take off the heads, FIX THEM, re-dyno the engine. Or how about chassis dynos, or simply driving the fricken thing!
50 hp isn't a claim, again I just proved it and I can prove it again and again and.... It's hard for you to swallow because your a typical brainwashed magazine reading customer. You fit exactly the mold that has had the wool pulled over their eyes forever. Typical.. Sad, but you would rather question my skills..
Again, the size doesn't matter. Do you get that. No faith in my skills, bring it on, I'll prove anything your heart desires. You said yourself your not an expert but your on here trying o disprove me, that make you a fool. However, I have 100's of happy customers that know the truth. Every once in a while I run into a guy like you and it makes me realize just how much my MAD SKILLS is proving my point. Go on with your bad self, keep talking, your looking stupid.
Believe what you want, if you were smart you's listen and then disprove me rather than bash me or call me out by saying something about my faith in my mad skills.
I call it having a cement mind. It's already set. I also say for some its easier to believe what they want because its to hard for them to accept something else. I call that old.
this is like arguing with a liberal about global warming... you can bring all the facts, dyno figures, track testing, port profiles, and theres always gonna be someone who doesnt wanna look at the proof.
I just dont see how someone can argue track performace, thats all the proof I need, the track dont lie.
50hp isnt huge when you see all the issues that a stock, improperly sized casting has, but 1st you'd have to know a bit about porting to have an idea where the power in the port is. And there are people like Chad who do it for a living, port heads for more power, I think hes done enough R & D to know how to sqeeze more out of a set... of any heads, especially 23*sbc heads as they have some design issues to begin with.
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