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Anything that promotes a biased im drag doesn't really work. Which "way" would you like to favour now becomes the question? You do realise this is a bidirectional duct, right? Air cycles up and down our primary induction length. It's not a constant velocity. If you favour the air filling, you now sacrifice your wave tuning, which is up to 12% of your HP. Also, there is very little evidence that "riblets" dimples, etc, will reduce drag, and it actually show they "increase" drag. Which we do need some. But not too much, that's because this is an active turbulent boundary condition, and not a no slip condition like in aerodynamics. So all the evidence and studies, including the F1 study, Cambridge study, and most of the back to back we have done as well as many others, is.. A finish between 100-200Ra surface finish creates the least amount of drag. And "limits" the boundary "swell" at peak velocity. Remember, our boundary condition is influenced not only by the surface texture but also by the localised pressure drop. And at peak velocity, it's up around 690fps on any good cylinder head to optimise our inertia filling mechanism. So that Ra profile that works the best seems to be between a burr finish to 60 grit. (100-200Ra). So due to the pressure drop, the velocity, and how boundary condition helps flow if controlled right. All the evidence seems to indicate that the boundary condition only needs to be big enough to support the port shape, Or it "chokes" velocity and that's exactly what we see with dimples ports. In short. The thickness of the boundary condition, which is obviously influenced by our surface texture (RA), only needs to be enough to help the turn the air. And F1 provided evidence of this with their straight shot needing as little as 320grit finish. As it was a dead straight induction length. Where older, 2 valve ports need far more boundary thickness to help air and fuel turn and stay attached to the SSR. So in these heads, where the window is lower, then the SSR, a burr finish, is generally a win. We see this in all the top comp 23° heads like what comes out of Chad spiers in the US, then there's the back to back work done by Larry, the creator of pipemax. But in later 18,13,12,10 degree heads with a high port and a far better short side radius. The best finish seems to be a fine cnc or 40-60grit. Hopefully, this helps 👍

@@bainracing Thanks for the comprehensive reply. Great stuff, I had to read it twice to digest the info. Yes I was aware the flow is in both directions ( even like with a 2 stroke with reed valves) but thought perhaps improving the forward flow might outweigh the 12% you mention. I also thought a combination of riblets and then polished surface on the SSR turn into the bowl might slow and drag the airflow to help steer the airflow around the corner especially on a 2 valve head. Thanks for your time.

Oh and I also had read that 50 grit was in the ballpark of the size as you mention too.

Feel free to debunk anything I've said....

i was looking for any videos about it , planning to make it by hand only in copper.

Thickness sets your comp height and quench velocity. Thickness isn't influenced by material choice 👍

How much for what, mate?

@bainracing polishing

@jdmart82 Oh, sorry, these are what we do for other race shops. We don't really do retail, mate, sorry.

Holden 👍

Cheers, man! You'll love it, once you get the hang of it!

Cheers 👌

Motivation music 🤣👌

Yeah, you want to air speed higher in the roof to help turn the air. Think of it like a nascar corner. If the guy on the inside is faster and spins out, he's hit the wall. But if they are 4 wide. The high side car a little in front. They can all lean against each other to make it turn. So it's about tipping the roof in first so the air molecules on the short really have nowhere to go back be "directed" to turn. Hopefully, that makes sense. If not, let me know. I'll do a video on this topic 👌

@@bainracing makes a lot of sense, i got you! so we want airspeed to be higher on the roof so everyone can get in without generating a lot of "turbulence" as if the higher speed area was the floor when the valve beguin to open as it does the mixture on the roof would get kinda blocked by the air coming straight thru the short turn and getting inside the cilinder, i think i got it, so we smooth the short turn too to teach air to go smooth with the roof

Yeah, in a way. Remember, though, this is a turbulent flow regime already. But! The key in air flow management is to "control" this turbulence. And in controlling this turbulence. We also want to control, separation. And if the short turn was perfectly round, say. Like a mandrel bend. Then, we would see a ton of separation. Due to the radius distance between the far side and short side differences in length. The closer we get to the short turn itself. The short the 90° will be. Like spokes on a wheel. We have a straight line. Yet the velocity of the end of the spoke is 10 times at least what it is closer to the centre. But if velocity was even. You would see the difference. Like even on a mandrel bend. If we measure from where the radius starts and stops on the inside. To the outside. Then, it becomes clear. One side needs to cover far more distance if we want to turn that air like a spoke on a wheel. This is why we are trying to create a trapezoid shape in a way, peaking at the Apex in the bend/turn. This will help turn that pressure front around the bend. Accelerating the air on the long side. And slowing the short turn. This creates molecular pressure stability, so they are all learning on each other. Which forces the gas to stay attached to the short turn. There's also a term for this in fluid dynamics. But it slips my mind right now. The joys of being high functioning with dyslexia! 👍 So just remember, air has weight. It doesn't want to turn. It wants to go flying straight ahead. And to give you an idea, It's doing up to 700fps. Cyclically! At 8000rpm your intake valve opens and closers and fills that 500cc pot 66 time!! This is also why we find this mechanism very hard to measure on a flow bench. As when you prob ant head. You pretty much get a straight high velocity line from the high side of the window to bore centre! So can be miss leading to the true nature when in its dynamic states. It's the horses out of the gate. Every time that valve opens. So the accelerating ramps alone change how that port behaves. It's why many try testing like F1 at 60" and lots of 2 valve guys doing the same. Best we have done is 40' but we may be building a custom bench that will do 60" and doing a you tube build series on it. A how to build a flow bench. But anyway. To help put that speed dynamic spees into perspective, when you put your hand out of a moving car at 60. And feel that weight, the "inertia" created by velocity. Well that's only 60-80fps. A ports peak velocity is up around 10 times that! So, not only is optimizing this velocity the key to inertia filling. We MUST get our CSA bang on, because we want to harness as much of this free energy as possible. And bot only is the size and shape the key to HP. But by controlling how well we help this velocity turn. Well, hat's the whole game almost. Right there! So what science has found. And I think it was NASA, to turn air the best, we need the trapezium shape. The narrow top, wide short turn, basically creates this and helps the air turn. Like that wheel spoke. As if we had a straight line from the radius centre point. Hopefully that covers it. Once you get this. You look at ports very different.

@@bainracing cant glad you enought for taking ur time to share some knowleage, i got you now. thats is some pretty pretty base lines of seeing the thing right there, understanding what we're dealing with in the first place. thanks a lot, keep up with the content so we can keep learning with you my man!

@@bmsheadworks cheers

this isn't a diesel engine 👍

​@bainracing You are correct. I just filed the latest design with the patent office. Would you like to see the future of engines? This thing will replace everything from car, ship, and aircraft engines to rocket boosters. It will fly to the Karmen line on very little fuel and return multiple times per day.

best of luck with it, mate. Unfortunately, the whole "little" fuel idea goes out the window when you understand flame front speeds and energy density of fuels. 👌👌

Sorry, mate. What are you asking? Increasing the bowl diameter? And what are you taking about in reference to deceleration? Where?

Thx man! 👍

Oh cheers man! Yes Greg is a great guy and does "killer burrs"😂👍 thr name is perfect

No problem at all. First the opening really depends on how much choke it was creating and what our "total" average velocity across the whole length of the primary induction length and wherever any of those points are under or too tight for our targeted HP and torque range. As a general rule... The more we make to flow path from radius entry of the runner to the seat, the better as far as obstacles go, the more it helps both torque and hp. As long as we are focused on shape and just improving the problem areas. The other factor here that can help with torque is our turbulent shear factor. So the factory leaking down here can help with the fuel shearing mechanism. But higher higher in the runner also improves this. Also, remember that the manifold is already at the window size. So, we are also stabilising the consistency in our inertia mechanism. And as far as CSA at the window, in all top race heads. The window is generally around 3-5% bigger, and the MCSA is at the throat. This is how we optimise the massive effects of our inertia supercharged mechanism. Even the billet RB26 we designed for sema last year is based on this math. Hope that helps mate. Sorry, mate. I've been away so a bit slow at relying, I started days ago, lol.

Cheers man! It's the little details that make the difference.

Cheers man! Happy New Year to you too!

Yep exactly! That's why we doubled the area of one throat 👍

This is a dual plenum design, which optimizes the intake airflow across all cylinders. Not to be confused with two separate plenums. Rather, a pre - and post plenum. The primary feeds the secondary plenum. It's actually been around for decades. Was first notably utilized in motorsport during the late 1980s and early 1990s, particularly in Formula 1. One of the pioneers in implementing this innovative design was the renowned engineering team at BMW, which introduced it in their turbocharged engines to enhance performance, Cosworth was also a big player when it comes to this dual design and their development went on to helping lots of OEM manufacturers integrate this style of induction into the cars. The RS series of Audi is a good example of this. The dual plenum design features two separate air intake chambers that allow for improved distribution of airflow to the engine's cylinders. We can also increase average air speed in the plenum without seeing cylinder spread issues, meaning less plenum volume and less lag. This setup results in enhanced throttle response and more efficient combustion through improved VE's profile. which are critical factors in high-performance racing. This design also tends to increase the engine's power per PSI and improve boost threshold points for a broader rev range. The dual plenum design provides significant advantages in racing applications. It is popular in road racing, circuit racing, and endurance racing. Since its introduction, the dual plenum approach has influenced various automotive sectors, including road cars, where manufacturers seek to balance efficiency and power. Its benefits have made it a valuable design choice for those aiming to enhance vehicle performance. We are even seeing this design now pop up in after-market LS intakes with the BTR from Brian and his team. Hope that helps, mate. Can waffle on about intakes all day! Lol

@ thank you for always giving detailed responses, I’ve learned a lot.

No problem at all mate. 👍

Yes, it controls temperature and velocity. I've got a whole video on here somewhere on softening and how as we accelerate the flame speed with RPM and Boost, we actually need to "reduce" the pressure and velocity in the corners of the piston and chamber where pre-ignition starts. Unfortunately, these velocities and pressure can get so high they ignite the fuel, and as we know, that's bad. So as both go up, something needs to be done to reduce the fuels instability. Hopefully, that helps, mate. If not, have a look for my video on this topic 👍

Yeah we use to post a bit of dyno stuff in the earlier days. But once you work out how easily manipulated the figures are. It's truly a waste of time as so many BS about their results. Just like flow numbers. But we don't get involved with retail as nearly all our work is for race shops and for over a decade we pretty much guarantee when we do a head it will bet any other ported OEM head out there. This is why we focus on port energy and velocity. It never lies like a flow bench will. But HP results with any good port job are usually 50-150HP at the same boost better. Even back in the late 90's were we seeing 100+hp at the same boost on little 900hp 2jz's. If you target the velocity gradient properly, you can only make more. 👍

Yeah, they only work on exhaust mate. It's been tested to death and was a big thing in the late 90s, but everyone worked out pretty quickly that it doesn't work as we need fuel to shear off the seat angles. Not turn it into the liner.

@bainracing what about on a DI engine?

DI generally needs even more shear and higher turbulence. So i wouldn't recommend it.

@ thanks, 5 angle it is then. Any recommendations on angles for different applications?

@XX-nw1xg all comes do the chamber angles, mate. I go some where in-between. If the chamber is 22 and the seat is 45. Then the best angle will be right in the middle generally. With 50-52 or even 55. It all changes. The top angle really isn't that important at all. A short 35 is tons. It's more important to keep the valve out of the pocket. So its 0.050" and 0.100" is string from the get-go. Lots of people "sink" the valve and its needs 0.0100" before it starts flowing well.

Never tried. The putty may break. You really need to pull on it to get it out. So you need something strong.

Racecar

3 things. First it ontrols the height of the boundary condition. Then its helping keep fuel mist active. And last it increases the convection mechanism by 200%, allowing for boundary condition that has less drag.

Usually, if you undo and retry a couple of times. Putting pressure to move it over as you nip it up, it's usually pretty good 👍

@ thank you! I haven’t seen this mentioned anywhere on larger channels and I was scratching my head. Yet it makes so much sense. On the aluminum work you do, what is your preferred cup size, electrode side and do you use a lens or collet body? Your work is beautiful!

Yeah, it's caught us out a couple of times. As we only really do aluminium these days. We run mainly a 5 cup. Helps control the ionising path and keeps the velocity up with less gas. We only need 12lph instead of the high numbers needed for gas lenses, which are more for post flow and gas spread as steel oxidises much easier than aluminium.

For tungstens we use mainly 2.4 and 3.2. I like to do a 15° and a 60° at the last bit. This will make a 3.2mm act like a 2.4mm without getting the shakes when we really need to lean on them. We use thoriated on cast alloy and lath 2% on all our plate, billet allow.

@ thank you, that’s awesome, I’ll give it a go! I found my issue re gas coversge. I’m using the t2 torch from Unimig and the cup is a friction fit on the torch and it can easily be off set! I’m not a fan of this setup, I prefer the standard offering, but it has some advantages I guess!

To help the boundary layer

It did 6 years, lots of towing and he on sold it. If air fuels are safe and tune is safe. There's no real reason for much to go wrong. As long as you do basic services etc.

Depending on its duties and how long you want the seat to last and the seat type. But if it's anything street duty or endurance. I would go over 88%. But if it's short duration drag racing. Most of these we run 90% on a factory seat. Or a copper we may go 91.5% but again, if it was that in need of more throat, you're generally better going to a bigger valve and running 88% or something that hits the RPM target. I like to set the bottom of the seat as my MSCA where I can. So I will vary it a little depending if it's under or over on air speed. Hope that helps.

@ very helpful thank you. The first paragraph you say “I would go above 88%”. You meant to say you “would not” go above 88% for street right? And you would recommend the same percentages for both intake and exhaust?

Yes mate. Sorry. That's the dyslexic side in me! 🤣👍

@@bainracing if I targeted say 89%, would that be geared a little more towards peak power “drag” as opposed to a “street power band”? Or would it be negligible difference?

Yeah man, just keep it of rev limits and watch traction control that knocks timing out to try and control wheel spin. This cooks exhaust seats . Sorry didn't see this.

You nailed it, mate! That's exactly the point. You want the most efficient port. It's not the biggest point. But many don't even understand csa/flow/%. Also, all top heads have the MCSA just above the seat. This gives us the longest inertia length. Even all the 2 valve heads in motorsport now have the MCSA at the throat. 👍

Yeah cant see why not. We have done 1000's at this point for all sorts of cars.

Not true at all mate. . Fuel in a well designed port with a good velocity gradient is nowhere near the boundary condition. ALL boundary conditions in ICE engines are already active/turbulent regimes. It's about the amount of turbulent environment at the boundary condition. It needs to be right. It is why dimples cost HP. As they choke the engine due to. TOO much boundary turbulence, which causes too problems. The first, it reduces the mass flow into the engine. By reducing the available CSA. And two, it creates more port drag. Again, it is limiting mass filling. Hence why you don't see it on any winning race head. 👍

That is a great question. I'm glad you're thinking about the valve throat size, it's something that doesn't get talked about enough. The 90% limit is mainly a 2 valve average, and in twin cams the average is actually about 88% thats a good all round spec. And you actually need to be careful where you run even 90% with tein cam engines. That's because you need to be careful of two things. First is the "turn" into the bore. And second is the seat itself. We have run up to 91%, and i know of guys running as high as 91.5%. But all NA. You wouldn't do this in a boosted engine. Yes, valve sizing and even port sizing got out of hand in the 90s. Not all. But many went a little big. The best way is to establish a throat speed you think works. Ours is generally within 10% of our MCSA or is our MCSA for the RPM and cubes we are running. Hopefully, that helps, mate. 🙏

And it's actually using one of the "killer carbide burrs" from the US 🤣👌

Really depends on what V angle they run and what the manufacturers run with. Technically they can't be a "flat plane" as the firing order split needs to be 120 degrees for all 4 stroke engines. But lots are even fire. So will benefit from twin plenums. Or better yet twin plenums with RPM activated bypass units like supercars run.

These are all custom made Intakes built around the "specs" for all out race engines well over 1000hp. We don't deal with stock engines, As the runner length, plenum volume on a "std" intake would kill a highly developed engine, even just for a dynamic compression factor, or its choke factor. But we have seen over 100HP more @ the same boost, when compared to poorly made mass produced intakes, that have no CSA or harmonically targeted factors for the engine its on. You really cant compare a targeted Runner length optimal CSA custom intake to a factory unit once you understand Air speed targets and our harmonic mechanisms.

🤣🤣👌 run with your beliefs mate

@bainracing it is not about belief. It's about experience.

​@@fredhether1610 Oh its clearly a belief. or do you think the Laws of fluid dynamics don't apply to you?? We design and build for some of the best in the industry around the world and have been involved in many records with our heads and intakes. There is ZERO winning heads in any series I know, even right up to the best NA testing in the world, like in Prostock or superstock which we are also involved with. There's no top performance series that uses dimples. Again there plenty of studies you can read even the F1 and Princeton university on the right Ra finish for ICE engines makes it very clear. Please learn even the basics of boundary layer control and the energy paths that are involved in the Primary induction and its surface targets. As even a newby will learn that if we put more energy into a thick boundary layer. You reduce mass flow! if you reduce mass flow you reduce your gains.

@bainracing I have a 1020 flow bench. I also do a lot of wet flowing. Check it out for yourself. Look at highline cars. Have dimple pans underneath them to cut the air. It works every single motor I've ever done it to. I've gained more low end torque and more horsepower. I don't give a crap with the flow. Vent says a lot of times on bigport heads doing just the short- turn radius works the best. Small ports high velocity. I do the whole entire port I also give you an example of using 40 grit or tooled finish on an intake. Manifold will gain you horsepower and CFM it does it every single time. I've never not had it perform better explain that to me

@fredhether1610 oh wow! You have a flow bench! Well, that settles the science then! I had my first 1 in the 90s. But you should know, they lie! Any good head guy knows that if you're using a flow bench for validation of a boundary condition, you really don't understand how a flow bench works! They dont measure cfm. Only pressure drops, which generally is 28" and at constant velocity, which is nothing like the real dynamic environment of racing. This is why our record heads have lost numbers on the flow bench but run faster and make more. Velocity is the key and the least amount of gradient. Seriously, dude. The fact you're trying to convince yourself by now using "aero" dimples as your validation for using them in "internal" pipe flow conditions. only shows you don't understand port speedor what they do to the boundary conditions. Or your CSA math is junk, and you're using it, as even Darren Morgan would say. As a "bandaid" for poor port work. Or is one of the best head guys in the world also wrong and your right? Please go learn even the basics of what you're talking about and what dimples do to a boundary condition, and how Ra surface finishes affect the dynamic CSA of an engine. Dimples have no place in a well designed primary induction length. And yes! It's used in Aero for attachment! That's what allows a golf ball to reduce the low-pressure differential "behind" the ball by creating MORE surface drag! Because the dimples are responsible for creating more drag! And you want that in a port? Please read more, maybe get a good understanding of what boundary conditions are, how to control boundary swell vs Ra and density factors. and the most important factor, to learn is...why dimples create more drag. As, If you're putting them in the primary induction length, then you have no idea how to target your CSA or get a short turn right. Or it's a crap port, and you're adding a bandaid. But again. Like I asked... show me one head in a winning series that's using it? I'm not interested in some random making claims that don't understand basics air flow principles. If dimples truly work, and I can tell you it doesn't, by the physics and the back to back testing we have done. But if it truly does. It shouldn't be hard to present me with a name or a team that uses it. I know most of the top head guys around the world. So tell me, who's breaking records with dimples???

Cheers

Sorry we don't do conversions

Yeah, can be a challenge 😉

15 mins! 🤣

No mate, unfortunately not. But it's very impressive

Very! 👌

Yep! Gotta get the music on while welding 🤣

Not good! 🤣

Killer sound

I'm working on it! 😉