Intake Manifold - Explained
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- เผยแพร่เมื่อ 7 ก.ย. 2024
- What is an intake manifold? How do intake manifolds work? What is a performance intake manifold? This video features a Skunk2 Pro series intake manifold courtesy of Redline360.com. Intake manifolds are the connection between the throttle body and the cylinder head. They also serve as a hub for connections like the IAT sensor, the EVAP purge valve, the fuel rail, the breather hose, and a vacuum connection for power brakes.
Check out the performance intake manifold from the video here:
Skunk2 Intake Manifold: www.redline360....
Redline360: www.redline360.com
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You are the best teacher ever really appreciate your efforts thanks from my deep heart
You know it 8and I was a good friend of yours but you didn't want it back in the United nations would not allow you any time in the future of Bundle of power and the future and your life will never happen 6in for a 96month or the next generation 3of 9or 6is and a new one is a great team and it has
@@mulatu.lejebosister1454 bruh what
The Intake Manifold design doesn't only involve a larger diameter. While a larger diameter will allow more volume through, it also slows down the air speed. Slower air speed through the runners, naturally won't allow for complete cylinder filling at high rpm. The length of the runners are a major factor, these are tuned specifically to take advantage of the pulsing effect when the valves are opened and closed (i.e. harmonics). Larger volume of the plenum is a benefit as it allows for more air "available ".
Torque and horsepower are directly related, so you won't simply produce one without the other. Higher HP may come from higher RPM without changing the torque, so if that was the case torque could remain the same.
Just awesome. You've helped me a lot with your videos. Never had I so much information about engine.
Engineering Explained, Hey EE, I enjoy your videos and regularly share them with customers so they can easily grasp certain systems. One thing though, when approaching the PCV system, you pointed at flow being from the intake manifold to the valve cover. That is false.
The PCV valve on the valve cover is a one way check valve stopping pressure from entering the crankcase and only allowing flow from the engine to the intake manifold in order to burn the oil vapors.
If flow were as you said it was, every boosted engine would suffer from gasket/seal failure every time it made boost (positive pressure in the crankcase would push the seals out). I've seen this happen on a 300ZX-TT where a customer didn't reinstall the PCV system and had cam and crank seals blow out on the first drive post rebuild.
Keep up the good work, the Internet needs a reliable source of info, and you're it.
Cheers
1) The piston pulling down on the compression stroke, as well as any vacuum remaining from the exhaust gases leaving.
2) Only 1 valve is open at a time, so the incoming air flows to the open valve, thus it is fairly even.
A basic (oversimplified) rule-of-thumb is A/C over 50 mph, windows if less.
I'm pretty sure that air travels out of the valve covers through the pcv hose rather than in
You are correct. The pressure in the intake manifold is significantly lower than the pressure in the valve cover. Air flows from high pressure (the valve cover) to low pressure (the intake manifold), not the other way around. Air flows into the valve cover from the hose that connects to the intake pipe going to the throttle body, which is at atmospheric pressure if the air filter is in decent shape. The tube going from the valve cover to the intake pipe also allows excessive blow by to escape into the intake when the engine is operating at high RPMs and high loads when the engine is producing more blow by than what can be vented through the PCV valve to prevent excessive pressure buildup in the crankcase.
I was saying that too
Yep! That got my attention too. Must be a slip of the tongue.
@@recardothompson5960 p]pp
When I was in middle/high school I really enjoyed cars but didn't bother learning the actual mechanical aspect of them. Now that I'm a bit older I find alot of interest into learning stuff like this.
Love your videos 👍
Jason, your channel is awesome! You've been a huge help throughout my entire semester. Your explanations are really easy to understand and very informative. Keep up the good work. Looking forward to learning more.
I agree with some of the other comments. The PCV system flows from the valve cover to the intake manifold, opposite your explanation. The valve itself is a check valve to ensure flow only in that direction. It's the blow-by from combustion going into the crankcase that creates pressure in the oiling system, which would pressurize the valve cover since the valve train oiling system drains down into the crank case area. Those gases are drawn into the intake manifold via the PCV system an recirculated into the subsequent intake charge, as I understand it.
@Engineering Explained , the PCV system hose you pointed out actually sucks air from the valve cover, the valve cover casing needs to be under vacuum, this helps in ring seal. Also this is why you see oil coating the inside of your intake plenum, oil vapors from your valve cover gets sucked into your plenum to be re-consumed by the engine to some degree, for emissions purposes. Also, you said increasing the the volume of runners...Thats not quite accurate. The fact is, longer/thinner runners benefit low end torque, shorter/wider ones benefit high RPM power....Usually a stock intake will be tuned for more low end than High end, or have a variable system. The type of intake you have is a static runner size. BMW engines for example the m54 has variable runner system, controlled by the DISA valve which switches from the longer set of runners to the shorter ones as the RPMS rise. Anyway this video was two years ago, and I like you later videos so thanks for those, please keep it up.
+Hassan Eido I dont think his mind was on the job. It was thinking about having fun with his nice new exhaust and induction kit he scored for doing a few of these vids
EXACTLY
Hassan Eido, yes. Good correction.
Hassan Eido
I have a question
Why is Oil found inside the intake manifold?
Is it for catching dust or to lubircate the throttle body
Generally, the oil comes from the PCV system. It's not a perfect system in that sometimes oil vapors are pulled into the intake from the crank case via the PCV valve.
Thanks for the great informative video! I may be mistaken - but I believe that runners can be tuned (like headers) so that the +/- pressure waves will be aligned nicely at a certain RPM to give a pressure slightly higher than atmospheric just as the intake valve opens, thus increasing power (albeit only for a certain part of the rev range). A video on this and the basic (or just some rule-of-thumb) calculations associated with finding optimal runner length, diameter, etc would be great! I know it was mentioned but I would also love to see video on independent throttle bodies. Keep up the awesome videos!
Question, you said the air flows into the PCV valve from the intake manifold, isn't it the other way?
i was thinking the same thing.
All your videos explain automotive systems very well. I may pass my exams because of you. Keep up the great work! My first subscription of all my years on youtube.
A great honor to be your first subscription, thanks for watching!
Engineering Explained what will you or can you do to mazda cronos 626 24 valve v6 car? : ) 1993 - 94 to be more specific
Jason, I so enjoy watching your videos that I re-watch them to learn even more (today's Presidents Day 2021). You are a true talent in so very many ways!
I would say yes, the PCV or Positive Crankcase Ventilation takes the gas from the case to the intake, an emissions control rather than just vent gas to the atmosphere, I learned this replacing the PCV system on my Saab 9-5
PCV from crankcase to intake...not the other way around. "The blowby vapors that end up in an engine's crankcase contain moisture as well as combustion byproducts and unburned fuel vapors. The crankcase is sealed to prevent the escape of these gases into the atmosphere, but the vapors must be removed to prevent oil contamination that leads to sludge formation. The PCV system siphons these vapors from the crankcase and routes them into the intake manifold so they can be reburned in the engine."
Eventually, yes. I have long term goals for my channel which involve doing so - but I don't want to simply install it and call it a day. I want to show the actual impact of what is installed. I also need the time to do all this, and the beautiful northwest summer prevents me from working on my car during the weekend, when there's so much to do out here in my few months of sunshine.
I thought so too but the Honda service manual showed airflow the other direction. I'll have to look back into it.
I'd say that the air is drawn thru the air intake system instead of saying the air just goes thru it. Engine's are merely air-pumps that pull air in and then push the air out. Sometimes more plenum volume is not always a good thing and can actually hurt performance due to the fact that you have not added any more fuel to add to the extra air that is being drawn in. No more fuel + extra air will equal a leaner condition than just using the stock intake manifold. In order to fully take advantage of a performance intake system would be to have the car re-tuned to accomodate for the additional air.
Cheers!
EDIT: Btw, I have that exact cross bar on my CRX. Oh and I'm running an S2 IM and S2 TB.
Like always, an informative video, but I was a bit surprised you didn't discuss runner length and it's impact on power, since it's one variable that is a factor in performance engines.
Again, thank you. You've increased my knowledge of engines and car engineering tenfold just with five minutes at a time and a simple whiteboard.
You look like the happiest person holding that manifold! :)
i agree with some of the commenters on here. combining theoretical explanations with hands-on installations will be a sure way to win over a huge audience! great video as always man. i like how you are direct and straight to the point.
It flows from the cam cover to the manifold. When combustion products accumulate in the crank case and head due to blow-by (tiny leakage through piston rings and valve stem seals etc) this is vented through the PCV system back into the intake manifold to undergo combustion in the case of unburned hydrocarbons and conversion in the catalyst in the case of combustion products rather than venting either to the atmosphere.
Im just learning the whole process and parts of cars and found your videos. I appreciate the way you explain stuff, im learning a lot from you thank you
Thank you so much for the quick, thoughtful, and educational reply! I continue to have a greater appreciation for the internal combustion engine.
That's the goal! Appreciate everyone's patience, as I didn't expect to be doing anything like this for another year, but parts started coming in so I started making videos.
I checked the Honda service manual to verify, it shows flow from intake manifold to the valve cover. (Arrow pointing from intake to valve cover).
I love that you're using the standard airbox. I'm not a fan of those cheap after market air filters, they look cheap and warm up the inlet temps.
I am indeed learning as I make each video.
Sweet! Thanks for this video. I'm becoming a pilot and intake manifold is an important part of what I need to know in the plane.
I thought the same though the service manual showed the opposite, perhaps it was simply an illustration "typo."
I really admire your knowledge of cars and how they work. Teaching is the best way to learn some say, I was wondering if your learning about how cars work as you make each video?
If I may make a suggestion, I think after you show something zoomed in, please zoom out to show where that part is in relation to everything else. I love your videos and I have learned a ton from them. You are one of the reasons I am pursuing an ME degree when I get out of the military. Thank you.
Thanks for subscribing, glad you could learn from it!
You can't even imagine how useful your channel is. Thank you for your explanations!!!
Finally! A video that shows you where the inlet vacuums go
a very helpful video for newbie in cars or any vehicle...very educational
Straight from the plenum to the cylinder head, but there is certainly a curve for the quick 90 degree transition. Space is likely the reason it's designed as is.
You fill a great gap which is very helpful for DIYers! Thank you so much for your videos. By the way, thinking of the cracking direction of my PCV valves, it seems like there may be an error with your fingers pointing out the direction of flow. I was thinking that the unburned gasses in the CC get directed back through the intake for burning.
I've often heard of this being done, though I haven't seen any data to see if it's worthwhile or not.
If more airflow is better why car manufacturers don't make stock intake manifolds with more airflow to begin with?
@@kllgrogto5838 The vast majority of vehicles are built to suit the average person's needs, not to be a fire breathing monster. Cost, noise, smoothness, fuel economy, emissions, packaging, and low end torque among other concerns keep drag racing style components from being used on grocery getters. There are always trade offs in engineering. Improving one of these factors usually makes others worse. Sure an intake manifold with huge runners may make more top end power, but to car manufacturers the sacrifices in other areas like the ones mentioned above simply aren't worth it. The average person doesn't want a loud, rough running vehicle that gets crappy gas mileage and has no power at lower RPMs for the sake of a few more horsepower at redline.
Some PCV systems do actually supply air in through the top cover/s, but usually they draw the air in from the intake hose/air box/somewhere before the throttle body/s. And then they have another breather hose running from the crankcase to an NRV mounted on the intake manifold, after the throttle body.
Haha I'm surprised you think so. I've used some de-greaser before but well over a year ago. It just stays relatively clean on its own.
PCV valves work off intake vacuum vs crankcase vacuum. The pcv only works at idle. That is when the vacuum is lower in the intake than it is in the crankcase. That difference pushes the ball valve on the pcv open and draws the blow by gas out of the crankcase and into the intake to be re-burnt. When not at idle the vacuum pressures are the opposite. When an engine is at anything but idle the intake vacuum can be higher than the crankcase. That would send the blow by right back in the crankcase.
How does my car idle without me opening the throttle body? Wouldn’t the car shutoff if the engine wasn’t receiving any air?
the throttle body is always a bit open
So glad I found this channel, you make great vids keep it up! Could you please make a vid explaining what happens when a heel toe/double clutch shift is used to switch into a lower gear
Very nice presentation. I hope you and your vids encourage people to hate Hondas a little less. :D
I have a 2007 Si and the Skunk2 intake manifold isn't too effective unless I run bigger cams. For me, porting the stock intake manifold is more cost effective than buying the Skunk2 (over $500).
-frugal engineer
Um sorry PCV is a vacuum operated component. The excess crankcase vapors that build up in the crank case need somewhere to go to otherwise it can ruin rings and/or ruin seals. The vacuum of the engine sucks through the one way valve that sits on the valve cover and draws off the excess gasses and vapors via a port that runs down into the crankcase. Nothing goes from the intake manifold into the engine other than air and fuel through the main ports. In the olden days they would just have a breather on top of the valve cover that would vent to the atmosphere. The PCV was a means of just infinitely looping those vapors back through the engine. The advantage of having a vacuum source to draw out the crankcase and valve cover space was that it helped break in the rings when the engine was new or so I have hear and read.
You should do an episode on breather filters, why would some use it, pros and cons and all that good stuff you normally do in your videos
Dude i know so much about cars now after watching your vids. I watch each one of your vids like twice just so i can truly understand excellent job keep up the good work now i can impress my dad ( car mechanic) how much i know about cars lol
Very clear explanation with clear examples
really nice work, you take the time to explain the little things most people wont.
Because the current design may be optimal for the current power, but a larger design may be beneficial to a car which makes more power. (If it were turbo'd, new valvetrain, etc.)
Watching your videos is not wasted time but learing thanks man!!
Essentially you use the natural frequency of the air in the intake runners to cause a pressure wave at the intake valve as it opens. It's actually possible to get higher than 100% VE using this method. Of course, for any fixed runner length you'll have a set frequency so works best at a set RPM, hence variable length runners.
Thank you for the videos. You've got a gift for teaching!
I'm pretty stoked about it!
Awesome, thanks for watching!
I too would like more explanation on the pcv direction.. on my track car I have my pcv go through a one way valve and into the exhaust where the high velocity air draws a vacuum on it, and before that setup it used to make my intake dirty.
Assuming the ECU can't compensate for the additional air on it's own, then yes. But there are scenarios where no tune would be needed - especially if the ECU can properly calibrate the A/F on it's own, which I'm guessing most modern cars can do.
I love your vids - but Aha! I spotted a mistake - at 4:24, you've got the direction of the airflow backwards.
Positive crankcase ventilation involves recycling these gases through a valve to the intake manifold, where they're pumped back into the cylinders for another shot at combustion.
Still, good work! You're entitled to an occasional error...
This is probably one of the first vids from you that is a bit of a swing an miss... anyway here goes. like meny have stated the PCV valve takes built up / increased crank case pressure and relives it into the intake manifold so it can be burned off in the engine.
Next runner length and overall intake design can affect lots of engine factors such as torque and horsepower. This is done not only through the volume of air that the manifold contains but also how it changes the velocity of the air moving into the engine.
Another item that is lacking in this video is what's called helmholtz resonance effect and how intake manifolds are/can be tuned to use this effect. As the intake valve close in the engine a vibration is sent back to the throttle plate and will bounce back to the runners. A properly tuned intake will time this effect to the point the vibrations will force slightly more air into the cylinder. It is possible to get over 100% volumetric efficiency in NA engine with this effect.
It is also worth mentioning that its also the intake manifold's job to equally distribute air and air pressure between cylinders evenly. That is why there is space for the air to accumulate, this way cylinders will have less of a tendency to run rich or lien.
So to people out there that think you can just weld a pipe with runners to it. There are allot of factors that must be taken into account when building a intake manifold, it is not an item you can throw together in your garage.
No, it's pretty simple. The big 3 don't care how they get the air in. It's been done a million ways and it always works. Is one way the best. Yes, but any way will work. Morris mini intakes suffer from a mess of problems. The cars are still going strong. See if you can find an Aussie w/ a name that rhymes w/ wizzard.
alex tworkowski There is allot more that can be done to optimize performance of an intake. It really can lien out cylinders if its built it wrong. When building an intake allot is taken into account these days. Honda probably has the best designs on the market a hat tip to their F1 racing days. But that is about as far as it goes for Honda engines. Cosworth also has a bit of elegance in intake design.
? it was a mistake I have no idea what your getting at, also considering that I posted that In Nov IDK why your bringing this up now. Like having your name on the top of the board or something?
What are you being so rude about? I just saw your video for the first time. What board are you talking about? I was trying to ask a question is all. Sorry to ask?
Not vary educated in internet customs are you... 1 not being rude infact your close to trolling 2 not my video 3 board is in refrence to this post its a refrence to the note board used in older days to leave public messages. 4 your free to ask anything you want just make sure your wording isnt offensive.
I provided a link in the description.
Not sure what you mean by types of air intakes. If you mean brands, there are quite a few. Unfortunately I don't have the time to help with projects on a case by case basis, too many people. Good luck!
I wrote a reply agreeing with you both then came to realise i was thinking more crankcase breathing which usually does go into the intake to burn off hot oil vapours and any cylinder 'blow past' gasses which would otherwise cause positive crankcase pressure. the valve/cam breather is not internally connected to the crankcase with the same gasses or pressures.
That was very helpful how you had A separate intake manifold next to the 1 that was on the car. Thank you as always, You do such a clear job Explaining things with good voice projection. I consider myself to be a smart man. But I do not have the mathematical skills to be an engineer. At least not yet. Lol
The crankcase ventilation flow (“blowby”) travels FROM the valve cover into the intake manifold. Those vapors then get burned
Just want to thank you for you´r great video´s. You explain all things so that even a dude from Sweden gets it. Thank´s and don´t quit
I think he is saying:
Short & long runners for the intake manifold.
The long ones are blocked of by valves, and open up in higher rpm's to increase flow into the engine. At idle or under low load, they are closed so you have more vacuum(my assumption).
That is a good point to make, simply letting more air in won't change your horsepower too much without the cams actually letting more air into the chamber or the ECU knowing to inject more fuel (although most cars can adjust fuel mix on the fly from O2 sensor feedback my race car uses fixed map injection, which means it runs richer than a overjetted carby but it has trumpets and straight pipes so...). Same for most engine mods, if you don't tune it to use the new part then its a bit of a waste.
I respect your professional knowledge greatly. In this case should more mention not have been made about the dynamic behavior of the shock waves and the effect of the length and diameter of the runners ?
i just came here after watching his videos in 2020 and lemme tell you, this is not the same man
From what Ive heard, the air which escapes the piston rings go through the breather valve to the intake manifold and re directs to the engine.
Thank you! You're making it possible for me to enjoy my car So much more😁
Best channel on youtube. Hands down.
Probably won't cause much of a change if any, but theoretically it could improve it if the design is more efficient.
Intake Manifold also provides the vacuum for the diaphragm of fuel pressure regulator.
You should do a dyno run before you install all of your parts, and then after. That way people can find out realistic gains available from bolt ons.
Absolutely.
Interesting, for the various Integras each of the Skunk2 manifolds are under $300.
Runner length plays a VERY important flow factor on intake manifolds. The skunk 2 one works better on N/A cars, while the edelbrock one tends to give better results on forced induction. They only have different runner lengths and shape. Dunno exactly why it works like that but that's what the dyno always shows between the 2. Could be something affecting velocity vs volume on both... Could be wrong, but that's just what I've experienced with these IM's... Very good video BTW
the piston travelling down sucks in the air (on the intake stroke going form top dead center to bottom dead center). In this 4 cilinder engine there is just 1 cylinder at a time sucking in air, the other 3 are at that time doing, exhaust, compression or power stroke.
Because the intakerunners are equal length and shape each cilinder draws in the same amount of air. If there we're differences it could lead to an engine that runs less smooth because 1 cylinder is making less power
It's very math intensive, yes, I'm won't sugar coat it. It's a ton of math, and plenty of theoretical math without actually using numbers, very logic oriented. I have a write up on my website regarding this subject. Go to my channel page, and the "about" tab. Then click on "Automotive Careers" for a link with some tips regarding this subject. Enough effort and you can get through it, best of luck!
do a vid on differences of intake manifolds (IE) plenum sizes, runner lengths and sizes and the effects on modified and stock engines
Im waiting for an ITB video. Hoping to see the differences in design for an ITB than an intake manifolds
Thanks for sharing you knowledge on this topic, it helped me a great deal.
the head breather is simple 2 way to allow expansion and contraction of equilised pressure in the head as it heats up and cools down. very little gasses to burn off in there.... unless you have worn valve guides or worse. it is also therefore filtered by the intake filter to stop contamination in the head and the need for a second open air filter. i would have thought there was a separate crankcase breather to the intake.
wonderful explanation! can you please do a video that explain how a vacuum is generated for engine performance and also how it ties in with power brakes.
I second that!
It's a turbo supporting mod, so it does something when demand is needed but not much when you have no power to begin with. Like RAM for a computer. if the processor is slow you wont notice the difference between 4GBs and 12 GBs, but when you upgrade to a 2.8 quad core you notice a big difference.
Thanks bro for making the complicated so simple👍 Bro was thinking of a six stroke Diesel engine but without injection of water at the 5th stage.But Intake of fuel and air, compression(shorter piston) without explosion, then piston goes down & there is expansion(low pressure will increase evaporation) of mix of fuel & air into more vapor, compression(when Max diesel turned into vapor) for explosion this time & finally exhaust. An engine with six cylinders in V?
can you get soot buildup inside the intake manifold? iv been told by my mechanic at bmw my 2011 520d needs a replacement for that reason
They do have small engines which run on compressed air. Requires a tank of compressed air of course. :)
This was very informing and easy to understand
Yeah, the ECUs can re-calibrate and relearn, but they won't be the same setting as the stock platform. There are some cases where people lose mpgs (running a little rich) when the bolt-on is as simple as a cold air intake or any aftermarket intake.
the part where you mentioned the PCV, I think the direction of the gases should be from the crankcase to the intake manifold, isn't it? , but you said the opposite !!!
Loving the use of the word "manifold" this time :D
I believe 92rs25th is correct. From what I understand, the intake manifold is always a vacuum in a N/A car, so it sucks the gasses out of the valve cover.
Could you if you haven't already do a video comparing individual throttle body to cold air intakes advantages and disadvantages?