Variable Intake Manifolds & Intake Tuning

[@MrBillShope]

I'm in my eighties and I was an engineer at Chrysler when the "ram manifolding" was being developed in the fifties. The most significant fact is that all the "magic" occurs while the intake valve is CLOSED! As I pointed out to Herb Bees (below), an understanding of water hammer is essential when it comes to the tuning of Otto Cycle engine manifolding. And, of course, it must be realized that water hammer principles can be applied to both liquids and gasses. There is a helpful KZbin video called "Ramming The Rat." It was written by Steve Magnante and originally appeared in Hot Rod, but I'm having trouble finding it. I'm the old guy in the pictures.

[@masonwaldner8923]

Man I’d love to talk about some of what you guys learned before it’s all lost to time!! I’m a engineering student at UNOH for Motorsport engineering

[@itsalgud1459]

As a retired engineer but still a gearhead (Don’t think its possible to retire from that), I really appreciate these videos. Obviously, you know your engineering and prepare very well. And on the very rare occasions you make a mistake, you quickly and publicly admit it and fix it. Excellent work!

[@der_pinguin44]

I had a 1991 Isuzu Impulse RS, it was turbocharged and had a variable intake manifold. It made all the difference in low end power.

[@dennisrobinson8008]

What was the difference in runner length long to short?

[@der_pinguin44]

@@dennisrobinson8008 butterfly valves, 4 to 8 runners.

[@Racer_8]

The car that turned me into a car-geek was my 2000 Ford Contour SVT. I loved learning about it's intake manifold - it had short runners and long runners. I always thought the reasoning was intake velocity, never thought about the pressure waves. Great explanation, as always.

[@theRealcbus]

Sick, love those. I was a gen before you with my first car being a 95 Taurus SHO. Pop the hood and the big intake would make people's jaw drop. Yamaha masterpiece.

[@kolideoskope]

I love the variable intake on my '94 Taurus SHO, it's a work of art. The transition at 4k is addicting.

[@kolideoskope]

Each runner is lined up with a valve, but the two intake ports have a crossover window between the valves and manifold. The single fuel injector per cylinder sprays into this window. Both valves receive air from the long runner below 4k. I might not have even noticed it when I shimmed the valves on mine if I hadn't read about it here: www.shoclub.com/news.php?extend.71.3

[@kolideoskope]

You're welcome. It's a fascinating engine, I miss it every time I have to drive a different car.

[@kolideoskope]

It sure was, and they did an amazing job of it.

[@baaablacksheep4003]

pops had a 93 Taurus SHO those secondary open and bust one 😆 🤣 😂 one of the best sounding and beautiful looking engine back in early and late 90s hands down none of plastic covers that bad boy

[@baaablacksheep4003]

@cisa93 it was

[@slep5039]

I love the creative ways engineers come up with new ideas that increase efficiency and power. Great video!

[@fernandohood5542]

This makes a big difference. I have used this on a turbocharged toyota(tvis) 1500cc engine and the short runners increased the horse power significantly at high rpm.

[@Xx1SailorScoutxX]

I was on the fence about this for a while when I was modding my R18 Civic. It was either leave the manifold stock or switch to the Weapon R unit. I'm glad I stuck with stock, and this video verifies it!

[@cogitateandabet]

I wish there was an option for giving multiple likes at a time. Your videos are strengthening my understanding as I can correlate pretty much everything with the Prof's lecture.

[@FixItAngel]

I love your videos. Always a pleasure watching and learning from them. Have a nice day.

[@schemeteam2954]

This guy does his research and uses visuals to prove his research, I love it!

[@Adam-sl3vp]

from what i have been taught, i dont believe that compression wave that hits the closed valves is the goal of pressure wave tuning. i think the added forced induction comes from the energy in combustion. when combustion takes place there is a compression wave which leaves the chamber and exits down the exhaust manifold. when the wave gets to a collector there is a change in cross sectional area. when this happens it sends an expansion wave back up the exhaust manifold. through intake and exhaust valve overlap this wave is able to make its way up the intake runner and into the plenum. the plenum is another change in cross section so when an expansion wave hits this change it sends a compression wave back down the runner toward the intake valves. with correct timing the compression wave makes itself into the cyclinder and then the intake valve closes. and hence i higher pressure is able to be achieved during combustion hence more power! #fsae #westernformularacing

[@cbremer83]

The intake on the RX8 has a lot of variability in it. It can have one, two, or three ports open for each rotor and also does the supercharging thing but from one rotor to the other. There are tubes that cross from one side to the other so when one rotor closes off the port the shockwave pushes air into the second rotor that is now open. Pretty cool little setup. It also has a variable intake before the throttle body. Two tubes with a flapper door that opens to allow more air in at higher RPM. It's all in the front bumper area.

[@Marzelmusik]

I do have such a system in my Engine (KF, in Mazda 323F 2.0 V6) :) Mazda used it in all K-Engines(V6 engines produced in 90's) and called it VRIS - Variable Resonance Induction System. it uses the pressure of sound to supercharge the engine. Mazda uses it today in all SkyActive models.

[@vt2704]

I have to admit I never commented on your video's before and I have been a subscriber as soon as watched the first video. You are a HUGE asset to the car,motorcycle or any type of engine driven vehicle depending on the viewers passion of motorsport(s) they have. With saying that I appreciate your channel immensely and feel that you don't get the respect of KZbin viewers that hunt for video's on just what they are trying to accomplish at the time of the build or repair they have at the moment. You have a great way of bringing attention to detail on what makes more power and what dosent when you do white board tutorials. A bit technical for some I'm sure, yet you do keep it as simply defined as possible. I can't speak for other's but I appreciate your channel just off the one fact that I am so fully capacitated mentally with multiple builds I'm doing that you remind me of things I loose track of that would make my builds better performing than some shop's out there. You deserve more subscribers than you have and I hope that you build more, maybe just off my comment here or shop teacher's should push the pupils to subscribe. Anyway I posted enough and thanks again for sharing your time and energy in making video's and just keep them coming with cold hard facts and remaining humble about it. Great work my man I love it.

[@karljay7473]

Back in the day, Offy had a dual port 360 intake. I still have mine for a Toyota 2L, it works great, you can really feel the response. It's like having two intake manifolds, one for primary and one for secondary and you can feel when the secondaries kick in.

[@keetonbob]

I never knew this technology was already in use!! I had imagined something like this and wasn't sure if I was crazy or not!! :D You've made my day EE!!

[@Torchi0]

My 1.8 20V (AGN) non turbo from VW, has 4 small flaps that makes the intake more narrow and when the car reach 5K rpm it activates a solenoid that lets a vaccum (that is store in a chamber of the intake) open the 4 flaps. It's really cool to see the ways they go with things like this.

[@vinamraagnihotri8145]

u knw what ur channel is phenomenal for any automobile enthusiast like me....plz keep making more intrstng videos...

[@KaroMaker666]

I felt back at school watching your video... My CRX had a GSR engine witch comes with the dual manifold system, i used to love it 😊

[@blahblah4874]

Aztoreth Blemuz thats exactly what i was thinking the whole time gsr motor. thinking about it for my civic 15 si with the k20a manifold not expensive but i wonder if it would actualy help

[@muhammadfariq2916]

congrats on ur 900k subs.!!! keep em up.

[@EngineeringExplained]

Thank you!!

[@muhammadfariq2916]

Ur welcome!!

[@PESx4xEVER]

1.7M now

[@symubi7180]

@@PESx4xEVER 2.4M

[@a7myth]

@@symubi7180 2.9M

[@jameshaulenbeek5931]

That's very similar to how the third gen Honda accord intake manifold works. There's a valve assembly between the intake runners and plenum that stays closed at low RPMs, and opens at high RPMs. The valve assembly is vacuum controlled. It was a very effective system for the time.

[@pgtmr2713]

There are 4 different intakes for my engine each one has a different length with the variable system so the ecu has to open the valves at different times. You can choose the intake for peak or midrange power.

[@Dethred1]

My 1992 Acura Legend had VIS (Variable Intake System), and was the most complicated contraption I've ever had to work on. Turned a 10 hour headgasket job into a 30 hour one. Sounded like "VTAK YO" when the flaps opened at 4,000rpm or whatever.

[@turningpointauto]

this is how the Ford SHO power works I finally understand. love it

[@baaablacksheep4003]

First and second generation sho's definitely

[@Sagina1999]

My 89 Accord Lxi is a good example of a trick intake manifold. It's has two intake runners and one set is controlled by butterflies to a vacuum diaphragm. So this stuff has been around for many years.

[@FrozenHaxor]

BMW uses that on older engines including mine, the valve in the manifold is called DISA. The best engines...

[@djwonderbrad]

m50?

[@FrozenHaxor]

M52B25TU :)

[@maciejsashimi6054]

M43 4cyl. with DISA about 118hp and without 105hp.same shaped intake,both versions where available

[@yoshi1u2]

MPOWER!!!!

[@jonathandicamillo1051]

This is pretty neat. What would cause the butterfly valve to move in the intake manifold? Would the air velocity at the higher rpm have to pass a certain threshold in order physically move the butterfly valve or would it be electronically controlled?

[@R0yL33]

I always thought the "supercharging" effect had to do with the inertia of air that caused it to continue filling the cylinder even after the piston is past BDC and on the start of the power stroke. Longer duration cams raise the rpm level at which this supercharging effect is optimal since more inertia is required to overcome reversion back into the intake. There is more inertia with long narrow intake runners, so more supercharging effect; at high rpm though it becomes restrictive.

[@JustAlanIsCool]

Similar to the old ka24de in my Nissan, with the individual butterfly valves in the runners. Removing those was a big mistake, wish I could remember where I put them. Removing them dramatically killed the low-end of the engine, but (may be placebo) higher rpms seem to be improved.

[@justinsu7241]

had to watch about 5 times to fully understand it, all worth it though. love how informative this channel is.

[@trizkial7592]

My 1988 Celica gts with the first gen 3sge has the TVIS system where it opens and closes changing the diameter of the intake runners. Pretty cool for how old of an engine it is

[@baileystrupat2113]

Was a bit confused on why they did this but this explains it very well. Awesome video!

[@UltimatePwnageNL]

Thanks, now I'm going to fit an arduino controlled trombone slider to my intake. If it doesn't make more power at least it'll sound really... unique.

[@uncreativename9936]

Don't forget to post a video of the install

[@DrewLSsix]

Check out Mazdas design for the Lemans cars of 80s early 90s.

[@UltimatePwnageNL]

SheepTrees You could take most physical complications out of the equation entirely by doing an electric conversion.

[@donperegrine922]

Better yet; don't program the arduino for efficiency....Program it for "flight of the bumblebee"

[@UltimatePwnageNL]

@Jonathan Anderson nope, i dont have a workshop and the project is too involved to do it on the street without neighbors complaining :(

[@karlmoltzan6196]

I like your videos. Here is some info on intake tuning you may not know about. Check out the long ram intakes that Chrysler used in the early 1960s on the 413 c.i. V8 in the 300 letter cars. This was way before Porshe even thought about tuning intakes. Chrysler also used short ram intakes on thier race engines in the 1960s. Max wedge and hemi big blocks.

[@3-E]

This was a great video. Can you do one that goes into a little more depth on how to size intake and exhaust diameter? What happens when you go too big or too small and how to determine the correct size.

[@Jjnoriega900]

dude your awesome. I try to explain some heel and toe techniques and people don't seem to get except me. But your great at explaining this

[@levigamesparody1228]

Thank you very much!! I didn't undrstand what was this valve seating on my intake manifuld. first time I get across this fitcher. Now its all clear to me.

[@samuelleblanc8589]

Very interesting once again ! Me and my team from Polytechnique Montreal university are actually starting a project on the modification of a formula SAE engine. One part of this project will probably be on the intake, this video is a good way to start !

[@nimmen]

Toyota's ACIS in the 3S-GE works even differently. Above 5k rpm it opens up a second plenum halfway the runners where the waves can reflect off of.

[@benjv85]

Peugeot 206 180 gti has that setup . also has air pump . 2nd valve opens at 5k rpm.

[@daviddepriest1849]

SVT did this with the early 2000s Focus to keep making power above 5500 rpm, made 10 more hp than the hondas of the same time.

[@turtle30304]

no disrespect meant, you kind of sound like super dave, and that's awesome. also, you didn't even flinch with that hit, you carried on. Good for you.

[@FransjeFranchise]

Some systems actually even linearly extend the intake runners

[@KhushalBadhan]

Please make a video on use of only front and only rear brakes considering stability and vehicle control.

[@jannadrielcervo7753]

Thanks Jason. I'm finding an explanation about this. Yours is the best and clearest explanation.

[@ev0sx1]

Another great informative video from EE! love your channel!

[@scottshepherd1365]

there are drawbacks. sometimes referred to as shutter valves in the intake. they have been known to stick and rattle and cause air flow issues. I've had to remove some before.

[@tomprudhomme1032]

you should do a video on CV carbs and pod filters...why they affect air flow (turbulence)

[@monteiro5306]

JUST WATCHED YOUR OTHER VIDEO ABOUT LA FERRARI CLEVER VARIABLE ADMISSION SYSTEM. FUNNY, IN MOTORCYCLES BOTH SYSTEMS WERE USED, IN DIFFERENT BRANDS. THANKS FOR THE VIDEOS.

[@2AMech]

my 04 focus SVT had this. you could hear it close off the long runners and switch to the short runners at about 5k rpm before it redlines at i think it was 6.5k. it felt like a softer version of honda's VTEC, but obviously not the same thing at all.

[@gsxellence]

work fine in my specV (I use a window to control my secondaries) but u can see the difference on the dunk and in most Honda Acuras exam 6/6 has secondaries and vtech u really notice and the 3 Intake time changes. however this is def, old technology which now days has gone away due to shorter resin premiums and direct injection.

[@davidmcclelland8090]

I'm confused because when I was growing up in the 70s/80s the aftermarket intakes were designed opposite of how you're describing these effects. The more mild cammed, daily driver cars with lower end torque got the little intakes with the short runners and the dragsters with their high revving high hp engines got what we called "ram intakes" with runners that ran straight up sometimes looking almost a foot high. These were horrible for low rpms but awesome for high. My experience does agree with what you said about runner width though. Ford never had a problem with its Windsor version engines, but when they put those huge wide oval runners on their Cleveland engines they got high horsepower but lost low end torque. When they went to the extreme with the original Boss 302 engine and mated Cleveland 4V heads to a little 302 (5.0L) engine, it was like driving a turbo powered car. NO low end, incredible high rpm horsepower. heh

[@menger88p]

Great video. You should say couple of examples at the end of a lesson.

[@Pifferfish]

So, this (3:22 example) would be an example of how a 1994 Taurus SHO intake works? Great video!

[@stevenfarrington2361]

The other thing to think about is that the same scenario happens between the air filter and the throttle body when the throttle snaps shut which is why manufacturers like Honda would put extra plumbing in the carefully-sized intake tubes upstream of the throttle body to control the pressure waves, all of which boy racers would throw away when they would fit an after market intake which consists of a not-at-all-researched over-sized random-length metal tube and a randomly chosen K&N air filter resulting in reduced air flow speed (and therefore torque) and messed up the pressure wave synchronisation.

[@jrobpat0154]

Its interesting to note that modern intake manifolds are less complex now than they were in say the 1990's. I could never understand why you needed a complicated manifold to improve airflow into the cylinders when you have a throttle at the front of the manifold which is choking off the airflow in the first place ! Most engines spend all their time with the inlet manifold at different levels of vacuum so theories regarding throttle size, plenum volume, runner length/volume etc are only relevant at wide open throttle ie zero manifold vacuum, the rest of the time it doesn't matter. If you want more air in your cylinders just open the throttle (reduce the vacuum) a bit more.

[@The3rdCoat]

Yeah my understanding is that these systems are not about getting more air into the cylinder, but getting faster moving air (but the same volume). This ensures a better mixture of fuel and air in the combustion chamber. I could be wrong though.

[@benoitdequick2562]

Hey, thanks for the explanation. However at 0:48 you say that the pressure wave 'hits' the plenum, what do you mean by that? Are you referring to the physical boundary? Since a high pressure wave will reflect against Atm conditions as a low pressure wave. In contrast, when the intake valve opens, it creates a low pressure wave which will reflect against Atm conditions as a high pressure wave, which we want to arrive at the right moment back into cylinder. Somebody please correct me if this is wrong.

[@gokulm1755]

Can you make a video on different types of injection systems?

[@2450logan]

You know too much about cars I admire you 😀

[@Utahraptor110]

Great Video! Would this effectively be similar to the Mazda 787B's Variable Length Telescopic Intake System?

[@BabyxBandit]

Your videos are always awesome

[@FlaviaPitariu]

My current car has two solenoids for the vris and I absolutely love the effects it has on the engine. Is it possible to use a supercharger ahead of the vris to increase power or do I risk blowing the vris valves up?

[@omerkhan9286]

please do a video on what is torque steer and what is behind it?

[@discocyclinapath]

could not have been explained that simple. thx a tone

[@johnd5805]

Can you do a video showing modern engine timing and how that works. Not the old distributor stuff. Thnaks

[@claudioDWIW]

Can you do a video on the pros and cons of air-cooled engines and water-cooled engine?

[@MylesHSG]

Do a video on Toyota TVIS system

[@lgliam]

The TVIS in my AW11 makes my wanger jangle

[@vincentbaelde-millar670]

And how many other engines have such pretty cast aluminium intake manifolds

[@MylesHSG]

+Vincent Baelde-Millar Metal Intakes! (Mr Regular, Regular Car Reviews)

[@dfw_motorrad1329]

I'm so happy to finally be in the MR2 club. Just bought an '89 that had been sitting for 15 years. Got it running but it idles at 1,500 RPM warm and has a weird whistle/whine near the intake manifold. I'm going to set base timing and see if that calms it down a little but I suspect either an air pocket in the IACV or a bad IACV. I will eventually port the head and tune the intake and maybe throw a custom map into it. IDK I'll see how far I go with it. I just have to get it running right in stock form first.

[@MylesHSG]

+RyanRants Check the Waxstat is working. that's a common fault that causes high idle.

[@hugoperry1452]

The Mazda rx8 intake manifold is a good example of what was explained at the later half of this video.

[@adlorin]

Reminds me of VRIS in the Ford Probe, and the dual runners in the SVT Contour.

[@grahamthomas8178]

Great video, love learning about the science and engineering behind engine technology, and the rest of car technology.

[@xspitefire101x]

you should do a video on the difference between mivec vtec vvt and all the other ones

[@lakesidebc]

What a great video, thanks for clearly explaining this concept. I'm looking at designing a new intake for my 2L Alfa spider and was thinking, "what's the deal with variable length intakes?". I think I could program a valve to position from closed to fully open based on rpm, and adjust that curve to maximise and flatten the torque curve. Cool stuff. Any pointers on diameters and lengths from a design guidelines perspective, i don't mind pulling out the old slide rule. Liking the new e-car content also!

[@souravzzz]

How much pressure difference does the wave actually make? Any numbers?

[@theboss-agario8599]

69

[@An.Individual]

32

[@Mudux]

Are you accepting negative numbers?

[@ecsolha]

Since you don't "force feed" the engine, this is a way to shift the peak torque to a higher rpm. Just imagine if you had a fully adjustable intake. that would be an interesting torque- rpm curve to see. but 2 tuned intakes are better than one. Perhaps you only need 2?

[@shi01]

Basically you can look at the volumetric efficency. It's stated that it is possible to achieve 130% volumetric efficiency with a natural aspirated engine, so basically 30% pressure increase. But that's really if you hit the sweet spot with a perfectly tuned intake manifold.

[@tturi2]

yeah my falcon has this (4.0l dohc inline 6), its a very good plenum, they kept it for nearly 20 years, tb in the middle and a ribbed circular barbell on top with a butterfly in each runner, the only problem with it is that its either opened or closed so there is a dead spot in the middle of the rev range

[@tturi2]

*barrel

[@smokefast90606]

good morning would you please make a video on the difference between individual throttle body's vs single thank you for the great videos

[@EreksonJ]

this reminds me of expansion chamber exhaust tuning for 2 strokes.

[@MikevanLieshout]

Strangely the same idea at the two stroke exhaust makes more sense in my mind, but the principle is the same!

[@jon111685]

Surprised you didn't discuss Helmholtz resonance tuning. Ford seems to have all sorts of "growths" on their intake tubes to quiet down the intake, but also as a by-product have that "supercharging effect" by resonating that pressure wave back. Have enough of those resonators at different sizes and shapes, and you can tune for all sorts of RPM's.

[@MrMarkjax]

idk if im right but i always consider air like water and this to be something like fluid dynamics... for more torque you want longer runners because of the air being more organized but at higher speeds the runners become more of a restriction and you lose top end power... shorter runners means air has less restriction and thus more top end and less torque from less organized air.... but with TC motors i see after market intakes using larger intake plenum's im guessing at higher boost high hp applications youll want as much air on tap as possible. i would say its like trying to drain water effectively in most fuel efficient applications vs something that wants to suck up as much water as possible in high hp scenarios.... i dont know if there would be too much wave benefit in either.. just seems like ther would be so much going on and if it bounces out it would probably be diverted to another cyclinder

[@GrimReaper528777]

@engineeringexplained wouldn't you want to time the intake resonance for when the valve is open rather than closed? For example, the exhaust headers resonance tuning is done with the exhaust valve open to get all of the exhaust out so the intake side should be done in theory to get all of the air in imo. The ambient air already is at a higher pressure than inside the cylinder of the engine because the piston going down creates a low pressure area well below ambient pressure. That is with a naturally aspirated engine as a forced inducted engine would only have the same effect multiplied with positive/boost pressure. To give an example that would mean that the intake resonance tuning of an advertised 260 degree intake cam duration would be timed for 260° of 720° instead of 460° of 720°.

[@Hachiae]

you should do a video on turbo vs individual throttle bodys. or just ITB's

[@ktm640lc4BGD]

Nice video but you could mention Continuous variable length intake manifold which BMW uses. It is most efficient among these and a bit different. (BMW N62 has it)

[@AndrewMillhouse]

Hey Jason. You should consider installing a megasquirt (or any standalone ecu) in your car. I'm adding one to my race car at the moment and am learning a ton. You could probably get some good videos from it!

[@heyitsdrew]

+Engineering Explained do a video about spark plug gap and index. why it matters for performance. do more videos like this please.

[@kirtanpatel5137]

make video on rollcage and chassis

[@TheMatrixcube]

i was wondering about this for a while thx for explaning

[@billyluangkhen]

the old 91 Mitsubishi Galant vr4 japspec 4g63t has this intake your talking about ... pretty sure they called it the cyclone intake.. been awhile since I've owned a gvr4

[@derikbreon7685]

Great video! You should do one on Individual Throttle Bodies sometime.

[@randomname9283]

Ironically enough the QR25 first gen had variable intake runners then switched to non-variable in the second gen which made more power. Would be cool to see some numbers/equations for the where/why one setup becomes better/worse than the other.

[@trackcarobsession]

+Engineering Explained Can you do a video on the effects of forced induction with different intake manifold length and width?

[@Cruton2025]

Question: you talk about the valve closing on the intake to produce the pressure wave that bounces around, but where is the piston while the pressure wave is headed out and back?

[@EngineeringExplained]

Doing it's combustion thing inside the cylinder (closed off from the valve).

[@oraculox]

I had a thought about drive by wire throttle bodies, and if it would be beneficial to use them in sync with the maniflod compression waves. Let see if I can express it, as the buterfly opens and revs go higher, you harmonize the opening by stepping it with the frecuency of the compresion wave to help minimize the back pressure of idle air due to the valve timing...(I don´t know if I´m making sense to you, hahah). In simple terms, make the throttle vibrate to that frecuency as it opens, sort of pulsating the air comming in to take advantage of pressure oscilations. And with itb's it could be simplyfied by dislocating the opening on each cylinder by a drive belt conected to the throttle bodies using a type of actuator like v-tec to regulate the opening, hahaha. But I guess that would be v-tec on another position, ha.

[@don0karnage]

I know you did a video on intake before but could you get more into induction wave pulses vs restriction because of length Is it better to have the full length to get it to hit one of the 3 first waves or is it "better" to have a straight runner as long as the surrounding allows you ? (For HP That is )>5252rpm

[@edgarcorrea7866]

do a video on the ecomode on the newer corvettes

[@Thuglos]

Can you do a video on individual throttle bodies?

[@junevillemen]

I aways think that the velocity of the air in the runners makes the "supercharching effect", when the valve is closet the air get compressed, and in the right time, the valve opens again and get the compressed air. I am right? because if I'm not, how the waves resonate in engines without plenum? like many competition cars. Thanks.

[@Stratt94]

Hi, I'm a mechanical engineering student from Argentina. Really enjoy watching your vídeos. I was wondering if you could reccomend me a book or anything to study this kind of stuff as I'd love to design performance parts for my car. thanks !

[@hondmilodoggo]

Could you use the same technology for the exhaust manifold in order to improve scavenging across a wider rpm range?

[@n9athan]

Can you do a video explaining Nissan's VVEL system?