High Velocity Porting - Does it work? 

Go on then, lets hear it?

The proof is in testing and experimentation. He needs to prove his theory. I know from experience too large a port hurts drive-ability and too small can limit power.. it’s all about balance and where you want the torque.

Experience in what, I.e what type of engine...

This is what David Vizard recommends.

...or flow separation, or pressure drop, or Bernoulli, or energy loss. He's got an awful lot of confidence, which would be great if he were correct.

@@brianhaygood183 we forgot Reynold's Number (!) LOL (Actually just a few weeks ago when thinking about a flow problem, it struck me that at lower speeds, viscosity dominated while at higher speeds, inertia. And then I reread the definition of RN and guess what? RN is used to determine what regime the flow is in! My fluid dynamics professor could have made that point crystal, especially since it is a monumental and very intuitive metric. But Noooooooo....

At the end of the day it all depends on valve size and port shape and port size, smaller ports will make more power AT a lower rpm but you will restrict power at higher rpm, I built a non cross flow, siamesed 292 Chevy 6 I did what we call a lump port which adds a chunk of aluminum right before the intake valve which was proven to gain power over a flat intake port

@@turkeyboyjh1 I have a friend that mastered carbon reading (heads off after every trip to the strip) - he became a voodoo engine builder whose engines got town down after every win and the tech guys would notice things he did and say, "if you fixed that, you'd go faster." Reading carbon is huge regarding combustion chamber. It's all about the wet flow. He never used a flow bench and saw no reason to use them. And yet he built the fastest engines. His all Chevy parts small and big blocks were amazing.

Goodfellas Inc. I’ve got a kdx220 can you give me some advice on porting pls 👍🏼

Obviously never heard of a choke point and mass flow rates - shame for you that you're an idiot.

Like i said,air is elastic. You can have more mass flow rate with a turbo while it's squizzed in the turbine...

Poor choice of words there - elastic is generally described as 1 of 2 things - Elastic deformation when a material 'springs' back to its former shape/profile. The region before yield an plastic deformation begins. or Linear elasticity - based on hooks law etc. These are all solid elastic transformations. Liquids and gases do neither, because liquids and gases do not form crystaline structures that are bound through the metallic or covelant bonding.

Yeah, Try to explain yourself in technical french without looking at google like you did to get two definitions,and then you will can open your mouth (in french of course) You understood me : air is a fluid,compressible, contrary to a liquid (wich is too ,but just a little) You can push or pull a compressible fluid through a reduced section without loss of flow mass ,simply because its speed (flow on time) is good enough. It's exactly what you do in an engine head when well designed. Formula 1 cars did use that during the naturally aspirated era and had a huge volumetric efficiency,they were even able to have positive pressure in the intake when the valve was closing. The fact that air speed is appropriate and compressible.

"In Motorsports Flow is great but Velocity is king!" @ one set rpm. Flow is volume over time which means that velocity plays a big part in this.

If you can maintain flow #'s and increase velocity you will fill the cylinder better. which is essentially what it's all about. More air more fuel bigger Boom More Power.

jb weld in racing engines?? haha okay that is the least professional thing ive ever heard

@@davidrose5613 That's because you can't read.

Raise the roof and the floor for more power. Cast a new intake or add good epoxy. Which would you choose?

AGREE, put ALL the air and fuel that you can even if you have to pushhh it inside!!! then make the mixture the most perfect possible and HELLO 200% POWAAAAH

how2powah. turbo. Will this fit in my Honda? (anyone who gets the reference, I'm proud!)

TRX VLOGGER absolutley correct...velocity makes a big difference on a high performance street driven engine as well...throttle response--which you get from good velocity--- is fun...soggy response due to high flow and low velocity not so much fun...it's like a car with turbo lag but no turbo...thanks for posting....

i see a lot of torque gain with velocity, but 3rd dyno test is with velocity and the port opened up too? thats change the curve of the intake

how does those torgue curve is acting, when you acclereate you will need wide torgue

Down low torque is no good if you're on a race track... a proper race track not one of those straight line things...

They main issue is mistuned camshaft timing - intake manifold length, exhaust etc. pp. -> less pressure drop is always a good thing - but you need to get you intake/exhaust timings tuned to this. At carb engines a massive reduced pressure drop is an issue like on old V8 engines, the vacuum is too low to keep the carbs proper working. So you run into different issues (slider doesn't open maximum for example or slider spring is too weak and bouncy), you have to understand the impacts. And yes big does not mean ideal .

Wouldn't the fix be to send more air/exhaust through the port, to gain velocity?

"When you suggest putting the carb butterfly" - just a butterfly - nothing to do with carbs. "Energy isn't really lost" What energy? What is this energy and where does it come from? "with its extra inertia to supercharge the cylinder by drawing in extra air behind it," - Dude, I'm sorry but you don't understand how air works or what inertia is. "The new shape also guides the slug of air to hit the back of the open valve more evenly rather than have the air flow mostly hit the far side of the valve seat." - This is something you have just made up... "Higher swirl speeds allows faster and more thorough combustion and less chance of detonation." - and now you've made it clear you don't know what detonation is.

AHAHAHA! Some chart grabbed from the internet with NO context or validation.. and... the HP doesn't even cross torque at 5250. HMMM. If hp = torque x RPM / 5250... then... every chart in the world must cross at exactly that point and no other. FAKE dyno sheet.

@@dirtygarageguy Ouch. People need to stop arguing on the internet and destroy some heads and post a video. PSST Engine masters has does this test and getting as much air in as possible with the least struggle is the best because the moving parts aren't trying to pull things in.

@@@aaronchadwick2682 … you mean because the moving parts ARE trying to pull things in; things in this case being air and fuel. If the pistons didn't create a vacuum how do you suppose those things would get in there?

@@chestrockwell8328 I mean't struggling to pull air and fuel in. r/corrections Good lord if you have a brain about engines you shouldn't need to use technical terms. If there a vacuum is present then don't create areas for there to be friction (velocity idiots) which causes loss of power

@J well golly gee... I wonder how it is possible to achieve 120+% volumetric efficiency in a normally aspirated engine ? I"m going to give you a hint: it has something to do with charge velocity and that old saying "an object in motion tends to stay in motion."

Always great when your piston plays 'smash the expoxy' game lol

The Workshop you make great videos :). thanks a lot man.... could you pleace make a video where you explain how the 2 stroke direktinjektion engine like brp gets a ignitable mixture during the upstroke? i mean it works, but how it works in this short amount of time and the shit air flow of a 2 stroke. please keep up your good work. best regards from germany ^^

Already done the video, just need to edit it and post - matt

We owe it to gas gas for dirt bike injection. anyone who says ktm did efi on 2 strokes is full of shit. Gas Gas brought efi to the 4 stroke dirt bike world, and then, they brought it to the 2 stroke world. some of their current 2 stroke trials bikes have efi

"raise the VE beyond 100%" Heh funny guy

@@robingrantgast2065 It's known as "inertial supercharging", see here: en.wikipedia.org/wiki/Volumetric_efficiency en.wikipedia.org/wiki/Inertial_supercharging_effect

@@robingrantgast2065 I found one more for you: www.autospeed.com/cms/article.html?&A=1127

@@robingrantgast2065 top race engines achieve 120% volumetric efficiency (a better term is Delivery Ratio).

@J You need to review the basics if that's what they are telling you. Please educate yourself and stop relying on whatever you are calling common sense. If you are interested i'd recommend books Harold Bettes , David Vizard and John Baechtel. You are full of crap and this is coming from a person who actually owns a flowbench and does dyno testing every tuesday (engine) and wednesday (chassis)

What? Do you know what this is? PV = nrT

@@dirtygarageguy I know putting up the ideal gas law makes you seem smart, you have however missed the point.

Temp of what?

"When he passed the noise changed... there was a distinct difference between the intake and exhaust notes." - That is called doppler shift, and nothing to do with intake or exhaust.... "I'm not saying your wrong, I'm just asking if you have put your ego aside enough to actually try it?" - Yes, and in the next 6 months I'll be proving it out. Also it's physics, not an opinion. Nothing to do with ego or anything related. There's something alreadyin your engine that does the same thing, it's called a throttle.... 3/4 throttle doesn't produce more power than WOT. "Volocity has always been more important than CFM." - 1) I'm sure you meant velocity 2) The speed of a flow isn't more important than CFM. That is crazy. Fuel volume per unit time is directly proportional to fuel and fuel per olume is directly related to power. "Big CFM doesn't count until you get at the top 25-30 percent of your rpm range." - That is utter bollocks.

Thank you for your reply and I look forward to you doing actual tests, comparisons and showing track numbers for evidence. "That is called doppler shift, and nothing to do with intake or exhaust...." -Anyone who drives on the highway much has has dozens and dozens of bikes wiz by and knows what doppler effect sounds like. Normally you don't even hear the bike until it passes you. His bike had a distinct intake noise to it. I had never heard a bike sound like that until that point. "Yes, and in the next 6 months I'll be proving it out. Also it's physics, not an opinion. Nothing to do with ego or anything related. There's something alreadyin your engine that does the same thing, it's called a throttle.... 3/4 throttle doesn't produce more power than WOT." -Great! I look forward to seeing the results! Yes, physics. The funny thing about physics is that there are so many theories and not many laws. Plus there is a huge difference in theoretical physics and actual physics. And if you really expect anyone with any knowledge of physics to buy that a butterfly valve is anything like the shape of the intake runner then you need to talk to a physicist to tell you just how wrong your thinking is. Again, I'm not saying that your wrong that high velocity porting in the way Motoman shows is not conducive to making more power, I'm just saying that if your holding a butterfly throttle up in comparison to any kind of intake runner alteration then it just shows me that your lack of understanding is far worse than I originally thought. -"1) I'm sure you meant velocity -Yes. I meant "vElocity". Like I correcly spelled before and after that. It's called a typo. You see, when you are typing on a small touch screen device sometimes another finger will tap the screen and cause a letter to be typed that you didn't mean to type. But thank you for taking the time to point that out. Your so smart. "2) The speed of a flow isn't more important than CFM. That is crazy. Fuel volume per unit time is directly proportional to fuel and fuel per olume is directly related to power." I agree and disagree. If you have a port that can provide 300cfm just do to the total area it doesn't mean that it is effective enough to fill a combustion chamber efficiently. In addition to that the fuel is much more likely to fall out of suspension creating poor atomization. Maybe saying proper velocity is more critical to an efficient engine than most CFM you can flow. If you still disagree then we will just agree to disagree. "Big CFM doesn't count until you get at the top 25-30 percent of your rpm range." - That is utter bollocks." -In the vast majority of engine build WITH ACTUAL PROOF AND DATA, if you take a well designed and efficient engine and bore the intake out to flow the biggest numbers it shows both in practical on track racing and on the dyno that you loose torque and horsepower in the low to mid range and only start to be more efficient in the upper 30% of the rpm range. If you are building an engine that produces peak efficiency at only the top of the rpm range then the compromise of sacrificing velocity for biggest CFM will be of benefit in some cases. However, keeping velocity is still important. So I stand by my statement.

Don't think you can hide... pressure is N/mm^2 or Pascals if you wanna be posh. So we know what mm^2 is, that's an area, so what is the N? What two properties define N?

In other words.. Choosing to place a restriction before another restriction (that you had no choice in.). can make sense. If the restriction you placed is less restrictive than the valve seat area there should be no issue. A port can easily be too big for the valve seat area (restriction).

You are forgetting mass flow rates, the speed of sound and pressure differentials

I don't pretend to know all that stuff... you should learn the basics before loosing yourself in all the other stuff that way you would get less negative comments.Learn to take your mistakes on the chin or understand the stuff you are talking about first.

@@dougharvey9766 actually he's pretty much spot on... it's something motorcycle race engine builders focus on... a restrictor plate on the intake is used to keep HP figures down... same with race car engines if the car goes above HP limits they install a restrictor plate to reduce the amount of air getting into the engine... all this does is amplifies this practice... if you blank off 10% of each port on a 4 cylinder engine you are losing 40% of usable airflow... however, if you look at the ports on a factory turbo application they are shaped in such a way because the air has no way of returning back to the intake because it is being "forced" into the cylinder...

geogineer Thats what a old engine tuner told me. Get the inlet and outlet ports as smooth as possible. From the factory they ate a bit rough to say the least.

They don't... Perhaps in F1, they put som effort to it, and look at those ports... their smallest cross section is actually quite small compared to valve size vs. a normal production engine, and the venturi-style port has a good diffuser section before the valve and seat insert area. As there is none to little pressure recovery to be had in the very flat combustion chamber... Typically the port mCSA of a F1 engine is roughly 75% of actual usable valve curtain area. Your typical OEM car cylinder head often has it the other way round... Port mCSA is often larger ( often 125%) of valve curtain area... Production engines (other than bikes) as a whole seldom moves above 100hp/liter without the aid of forced induction... their ports flow just "good enough" to get the job done and is mostly configured towards meeting emmisions, and quick/easy casting and manufacturing. And with regards to "polishing" a intake port... if your engine got anything else than direct injection you loose power with "shiny" ports... If you want a port injected engine that has poor start and idle, and low to mid-range power, whithout having any added benefit at high rpm WOT, In addition to be more prown to end-gas detonation... by all means... go ahead and polish the living shit out of it... It's not my loss :)

Slick ports don't allow for efficient fuel vaporization. Better to have roughness and small surface turbulence.

WELL PUT!

Njål Nilssen you are completely right: the port in production engines is bigger then what the curtain area flows. In doing this the valve seat controls the amount of air entering the cylinder. Not the incosistent cast port. Therefore a smaller port works !!!!!!!!

At some point you have to test your theory that it doesn’t work, you’ll learn something . do you think the engineers in formula one test their theories?

@@bsharpe Absolutely, I do this for a living. LOL

"Well explained again Matt. Doesn't matter. Some people will never understand." - aw well, if I can deter 1 young lad then its worth it lol

69waveydavey or Graham Bell. his 4 stroke tuning book and his 2 stroke tuning books are updated as new vehicles and theories happen along.

Motoman was talking about peak HP and torque

"They've already extensively tested and proven the concept of port velocity relative to torque." - where? A link would be awesome.

It does when your ramming air in there from the velocity! Once in motion an object tends to stay in motion! Cylinder is still filling at bottom dead center from the ramming effect cause by the velocity of the in coming air. Piston is already bottomed out but you still having incoming air. I.E volumetric efficiency.

No they don't. I have a friend (Andy Firth) in BSB. Stop talking shite.

There are many points in this video I disagree with, but literally that's a very basic law of physics. As speed of a fluid increases, it's pressure decreases. It's how venturies, chimneys, and aircraft wings work. Coming from an aircraft mechanic specializing in environmental systems, but really this is high school science 101.

@@dsan94 You may be confused as to the which side of the restriction you are thinking of. Post restriction the pressure will be lower. In front of the restriction the pressure will rise (or in the case of vacuum decrease).

This video is all opinion and no science.

You have an anime profile picture

"Toyota and GM used swirl ports on some of thier engines back in the 70s and 80s to keep good atomization and emissions down." - because of the use of either carbs or single point injection - with multipoing injection they stopped doing this. The reason is due to flow seperation around a radius.

Imagine the top of the port as you have drawn it but the bottom floor is lower than where the curve down to the valve is. So, the transition to the valve opening is by far and away the restriction at WOT and with the valve at max lift. All they are doing is raising the floor to attempt to minimize the transition. That transition is key because flow at that area needs to be streamlined as much as possible because air particle momentum can influence boundry layers and further minimize flow potential. That said, everything I have seen is on 2 valve per cylinder heads.

And this is why modern engines have straight runners - more on this in a future video

I know...starting with shit

We are talking motorcycles here and they have secondary throttle valves.

Secondary butterflies in a motorbike engine have fuck all to do with port flow. The secondary butterfly is ecu controlled so a hamfisted twat doesn't bog the motor when accelerating. Works in a way like cv type carbs. As for adding epoxy to reshape the port (raise the floor) of it didn't work Hrc wouldn't have done it to their works bikes.rvf750 comes to mind.They use epoxy as the rules state they can't weld material to reshape them. Ever heard of v&m racing they made tuned the rvf for Honda UK. And guess what they used epoxy to help reshape the ports. One huge error in your theory is not thinking of the pressure wave of the valve closing . In a big port can slow or even stall the in coming charged air. Where as high velocity ports (epoxied) will effectivly negate this issue. Go do some proper research into this . Ask fw developments they do it all the time .

"They want to keep the air flow from hugging the walls." - this is called boundary layer effect - and you can't stop air from hugging anything LOL

Like hell you can't... It's why they run water injection. It cools the air charge to stop fuel from hugging the intake ports and pooling up. No to mention other benefits.. So trust me son. I had access to a flow bench on engines making 700+ HP.. You can see the difference is huge! Good Luck

Next time try some real evidence instead of a lot of blah blah and a squeaky dry erase marker.

Real evidence would be an actual experiment that included ways to measure the different approaches to porting. Are you afraid of a little old flow bench or a big bad dyno? I challenge you to bring an entry to the Engine Masters Challenge since you know so much about port design Mr. dry erase master.

I wont be watching any more of your videos unless I need a good laugh. Only a moron would claim that theory trumps experimentation. Fools like you dread having your theories tested because you know they wont hold up. I saw a well known engine builder use epoxy to fill in intake ports on a set of high dollar race heads that flowed over 420 CFM right out of the box. Guess what happened? They flowed way more when he was finished. Bigger isn't always better. Port shape is very important. Some places need to get bigger and some may need to get smaller.

Just weight. Priceless!

My next video is going to be on how to install your new power band. That should be right up the alley of your target audience. V Tech kicked in Yo!

Dipples work for golf balls - if it did work then aircraft would be covered in them

If you're doing that, that's because the ports are shite. Also cfm is called flow and speed isn't a seperate entity from flow.

You do need speed, as cylinder filling is time dependant. And the higher the rpm the less time you have...

Yeah, It is true, but you want speed without airmass restriction

So decreasing exhaust port with D shape is worst?

Great question and I think I get what you mean. So tumble is called turbulance - which ever way you wanna cut it it's like this... Turbulance is great for fuel mixing Turbulance is shit for mass air flow. This is what injectors are for. The Z900 I have now has 12 pintle holes in each injector. This increases atomization, which reduces the size of fuel droplets. Why would you want that? The smaller a sphere the greater the surface area to volume ratio. In other words - the surface area increases for the same volume. Why does surface area matter? Because this is where vaporisation happens.

@@dirtygarageguy thanks mate 👍

Not even gonna start with this one. Wait for the fucking videos, like I said IN this video - jesus

*lol* Study on little wannabe. (but i must confess, you talked so much mumbo jumbo i got tired and didn´t watch the last minute)

well.. As i have seen a lot of your clips and many of them are some kind of just mumbo jumbo. put on a cool shirt and draw some stuff on a whiteboard doesnt make you mr knowitall. it might feel like it. question though: did you ever read my first sentence in my first message? a advice for the future: be careful what you are preaching people might belive you. advice two: take a couple of hours study on shaping ports on speedtalk forum. then get back to me. study on!

Yes for low speed - to increase the port velocity at low flow rates - this increases low end torque - but it increases in port cross-section when the revs increase. On motorcycles who wants to sit at low revs? Just drop to a lower gear.

​@@dirtygarageguy A port being larger does not automatically mean it's efficient. Often a smaller, but efficiently designed port will start flowing sooner than a big one, but keep flowing where the big one finally gets going. An example: This FSAE team used a novel additive manufacturing process to produce an idealized intake manifold that allowed a CBR600RR engine to reach it's red line despite breathing through a mandated 20mm restricter. 3dprint(dot)com/201534/3d-printed-intake-manifold-carbon/

Definately - its easy to mod ports in hind sight.

It was common to raise the port floor on early R6 s look at tony homes and other iom sidecar engine builders .. I would give 2-3 hp on the 99 600's just saying...?

Clean ports.

@@dirtygarageguy so the power of d shape porting is lower than porting polish

Power?

@@dirtygarageguy horsepower, sorry for my bad english

I get what you mean, but you're missing the point...... There is one major pinch point (restriction) in your engine - the valve skirt (around the valve and the seat. This is far smaller in cross-section that the cylinder bore. You're also limited in how big valves skirts can be 1) by lift 2) by port area in the combustion chamber. You said your lung capacity doesn't change - like a cylinder volume - but the rpm does. There's a big difference between 5000rpm and 10,000rpm - double infact. "The goal is to put as much air/fuel as much possible and as fast as possible." - there's 2 things that are important here 1) How much or mass flow. and 2) Velocity. For the same port size increase the velocity by restriction reduces the mass flow rate.

I just acquired a 02 Buell Blast. An improved roller cam in couple years might be sweet.

The maths is here - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-qnkJCEu8WNo.html

no it doesn't make sense..... what do you mean?

@@dirtygarageguy it's hard to explain English it's not my mother language, but I'll try again. When u have a curve without a belly (the way u like) the fuel do the turn with the tube and goes straight down, hitting the valves. With the belly option the fuel jump on the ramp and goes inside the cylinder not 90 degrees like the first option but like 45° Soo it "Dodge" to hit the valve. But I really don't know. Just saying because u didn't mention this theory

That's not his logic. That's your attempt to trash him.

If you're talking about American v8s (which i think you are) then stop right there. I'm taking about well designed engines, not shit ones

@@dirtygarageguy what I said applies to all porting basics, so your insult on amarican v8's isn't really necessary

@@dirtygarageguy I however have not personally put epoxy on that radius. It's not effective when you buy good cylinder heads to begin with

LOL I don't know how you know if I insulted American V8s, did you ask them? And it's not an insult, it's the truth. American V8 engines are cheap first and then everything else is secondary. I think that because you called it an insult that you took it personally. Are you a V8 engine?

@@dirtygarageguy I personally own American v8 engines. They get me to and from work every day with no problems. Does my motor get as great of gas mileage as your little 4banger? No. But I have what's called balls. This isn't driving Miss Daisy. Where is your manhood?

Which is better, a pipe that tapers smoothly from 2" down to 1/2" with a smooth 60 degree bend in it, or a pipe that starts at 2", narrows a bit, then widens, has an abrupt corner in it, has a void on the outside of the 60 degree curve, and then ends up at 1/2" diameter? The annular opening around the valve is the biggest restriction. You have that restriction in either case. How smoothly you restrict down to that size and how smoothly you make the corner are the controlling factor. There is nothing in that theory against using bigger valves or bigger throttles; just smoothing the trip between the two as much as possible.

There's something even more important. Mass flow rate...

@@dirtygarageguy Right, so which of my two examples delivers the best mass flow rate? I agree velocity isn't everything, but mass flow rate is a direct combination of volume and density; and density is moderated by temperature and pressure. Lousy air paths drop pressure and velocity as the air becomes more turbulent (turning useful movement into useless movement in the airflow) and slightly hotter (more shear and entropy); which are bad.

Mass flow rate is NOT a combination of volume and density. A closed cylinder has both but has no flow.

You have to remember that the driver in this is volume increase in the cylinder and that's all. You can exchange velocity for density and density for volume as much as you like, turbulence is the killer. So which is more turbulent, going from large to small to large or just large to small? Sticking shit in a port increases velocity, but reduces density/time. The problem here is time as the timing of valve openings is finite. At the end of the day atoms is what matters, not how fast they're moving.