Busting the exhaust backpressure myth | Banks Entry Level

Sdílet
Vložit
  • čas přidán 2. 05. 2024
  • "A little backpressure is good, right?" In this latest episode of Banks Entry Level, we explore why exhaust backpressure is always bad and where the "some backpressure is good" myth originated. This one is sure to cause barstool banter.
    Protected by ‪@AMSOILinc‬ the leader in synthetics
    Featured products:
    1991-1999 Jeep Wrangler Headers
    bnks.pw/3QyPzUk
    2019-2024 RAM 5" Monster Exhaust
    bnks.pw/4aewNbG
    ____________________________
    Check out all our full line of exhaust products | www.bankspower.com
  • Auta a dopravní prostředky

Komentáře • 823

  • @vinciere3594
    @vinciere3594 Před měsícem +176

    That scavenging demo with the header and sticky notes was simple and beautiful. Thanks for continuing to battle misinformation!

    • @99jeepxjguy97
      @99jeepxjguy97 Před měsícem +7

      That particular header is the Revolver. For 4.0L Jeeps.

    • @umakemerandy3669
      @umakemerandy3669 Před 23 dny +1

      Yeah that was really neat to see

  • @noxious89123
    @noxious89123 Před měsícem +286

    Backpressure is bad, but exhaust velocity is good for an N/A engine. An exhaust that is "too large" will reduce exhaust gas velocity AND back pressure. The loss of back pressure isn't the issue, but the loss in exhaust gas velocity IS a problem, because it reduces scavenging. This is only applicable to non-turbo engines.

    • @skliros9235
      @skliros9235 Před měsícem +34

      This is very true. So many times you hear of people who put a high flow exhaust on their car, then complain of loss of low rpm torque.

    • @thatonedude5237
      @thatonedude5237 Před měsícem +13

      It also very much applies to turbo engines. It's harder to target an appropriate runner length and diameter and the effect isn't as dramatic but you can definitely modify your VE at various RPMs both on and off boost with a properly designed turbo header. The improved VE off boost can actually help low rpm spool time as well as provide a bit more part throttle response without hindering higher flow performance (within reason).

    • @user-im2tc6pl9i
      @user-im2tc6pl9i Před měsícem +9

      Agreed 100 %. Just change your small cam 283 exhaust from 2 to 2-1/2, you will notice right away lost low rpm torque. Big pipe only benefits high rpm power.

    • @sigmaprojects
      @sigmaprojects Před měsícem +9

      I could be wrong, but if you reduce the exhaust gas velocity and there's no scavenging there should be technically more back pressure than an exhaust that has higher flow exhaust and scavenging. Since you need a pressure differential to cause the scavenging effect.

    • @electrothecat
      @electrothecat Před měsícem +4

      Yes and no, scavenging is caused by a negative pressure differential in the combustion chamber, backpressure goes against this as it creates a positive pressure differential. It's better to have absolutely no backpressure in any engine, even in N/A engines due to modern engines taking advantage of the benifit of scavenging, turbocharged/supercharged engines are already forced induction engines, so scavenging is a really, *really* bad idea, as the extra boost will leak out the exaust port if u tune it that way. All scavenging does is pull more air in near TDC between the exaust and intake stroke, by leaving both the exaust and intake valves open slightly at the same time. High cam profiles on drag cars take advantage of this affect all the time, but have shitty low-end rpm power due to the side-effect of the exaust gasses being pulled back in near TDC during the intake stroke. What manufacturers did to mitigate this side-effect is introduce tech like VVT (GM's variable valve timing solution) and VTEC (Honda's variable valve hight solution), which allow for smooth low-end torqe and punchier high-end power utilizing only all the benifits of scavenging. So backpressure is really only an limiting factor of your vehicle no matter if its N/A or not. And if u say "what about Nitrous Oxide emmissions, isnt that more dangerous to the environment than loose hydrocarbons?", ill just say there's already a device that mitigates that issue, it's called the EGR valve, get a bigger EGR valve if u dont want backpressure from it.

  • @RobertLowery
    @RobertLowery Před měsícem +146

    Erik is getting really good at this, almost like he as taken an acting class or two. It is awesome to see him teaching like this, and following in grandpa's footsteps.

  • @thebigmacd
    @thebigmacd Před měsícem +114

    Backpressure is one of those things where its presence is a negative factor but since improving other factors (exhaust velocity and pulse tuning) tend to increase it, people think its presence is what is making the improvements. The reality is backpressure needs to be minimized while maximizing the other factors. Everything is a compromise.
    I like to put it this way, "backpressure is a necessary evil that should be minimized".

    • @D.L.PDevelopments
      @D.L.PDevelopments Před měsícem +9

      This is correct

    • @sigmaprojects
      @sigmaprojects Před měsícem +9

      I was thinking about this, I don't think there's increased back pressure on an exhaust that has great velocity compared to one that has a larger diameter and no scavenging. I think it's just the idea that people got in their head was bigger exhaust automatically equals less back pressure and smaller means more. So in their head they think there's a happy medium because too big made less. But the reason why a properly designed exhaust with great scavenging and high exhaust velocity works better than an oversized exhaust is because it reduces back pressure. Higher velocity air exhibits reduced pressure, not more, that's how scavenging works it creates a greater pressure differential. It's part of Bernoulli's equation. It's the same issue when sizing irrigation pipe. You go too small you start increasing the speed of the fluid, if the fluid starts speeding up too quickly what will happen is that it'll start causing turbulence along the sides of the wall effectively making the diameter of the pipe too small. It's the same issue when old gear heads think a high flow water pump doesn't allow coolant to "cool off" in the radiator because it's moving too fast. In reality what is happening is the volume trying to be moved at a certain speed has to deal with the fluid friction on the walls at a certain speed it create eddies along the walls, which reduces overall flow because it's effectively decreasing the size of the interior diameter of the pipe. Same thing when tuning an exhaust.

    • @jasonreynolds9097
      @jasonreynolds9097 Před měsícem +4

      YES! Thank you! And scavenging efficiency can be optimized to fit the demands put on the engine by using a tuned header. ANNND if you want your N/A 6.2 to pull a house up hill in overdrive &&& sound good doing it, you will have more back pressure than a racing header will create. THE END

    • @sigmaprojects
      @sigmaprojects Před měsícem +5

      @@jasonreynolds9097 You mean you'll have less back pressure at low RPMs. It's all a game of reducing back pressure at different loads. Since there's not perfect way to reduce back pressure completely at all RPMs builders have to tune for how they want it to best perform per it's intended purpose. If the goal is to improve TQ at at 1500rpms then you'd tune the exhaust so that it flows the best at that RPM, so tubing sizing, runner lengths, etc are best matched to the power output and load characteristics of the engine, resulting at that RPM lower back pressure. But since it's a give and take system at high RPM you might not get as much power because the back pressure will increase. Unless someone has a really ingenious way of controlling exhaust gas pulses in a way that isn't a give and take you'll choose where to reduce back pressure to provide the best power and efficiency anywhere else on the power band will encounter more back pressure and reduce efficiency.
      In the end it's all about how to reduce back pressure for your intended purpose, it's just we currently have no way of eliminating it from every part of the TQ curve. That's why it's silly to say "we need back pressure".

    • @wolfvash22
      @wolfvash22 Před 4 dny +1

      ​@@sigmaprojectsGreat explanation, I have studied fluid mechanics and this kind of topics can be hard to grasp from the theory cause they seem very counterintuitive.
      As an additional fact I would like to add that this sort of phenomena happens due to the influence of “inertial forces" versus “viscous forces" and by changing the diameter of a pipe you are kind of favoring one against the other, but every system has optimal points of work and if you move outside of them, things won't behave as expected.

  • @Wtrxprs007able
    @Wtrxprs007able Před měsícem +18

    That demonstration of scavenging with post it notes was the best thing way to show it ever. Love it

    • @astrawally8448
      @astrawally8448 Před 22 dny

      It was a great party trick but it wasn’t a demonstration of exhaust scavenging specifically.
      When one port is open and has positive pressure (the shop blower), the others are closed. That negative pressure at the other ports is lost.
      On the exhaust side of the engine, there is both flow (from the piston moving the gases out) and continued expansion of hot gases from the combustion process (the continued expansion of these gases is primarily what a turbo uses to spin its turbine).
      When the exhaust port shuts, that flow stops but the expansion continues. The flow created by the piston is only minor and hence why this demonstration is properly representative of how scavenging works. only good as a party trick.
      The bulk of the required exhaust flow comes from the continued expansion (positive pressure) of hot gases after they leave the engine, and which continues well after the port is shut (and for several more combustion cycles for each cylinder).
      That continued expansion presents a problem for other ports when they open and try to flow out their initial gases, they are stuck trying to push against those previously burnt but still expanding gases.
      Headers address this by separating the cylinders for longer, firstly avoiding the potential conflicts to other ports, and then by being “tuned” length, they can use the properties of the expanding gases (momentum etc) to help create a negative ‘pulse’, which if timed properly, can assist the piston extracting the next lot of gases.
      This tuning or matching to application is also a reason why people think a little backpressure is needed. Put too big headers or exhaust onto a standard engine, you will lose the effects of headers and will not make more power. People’s minds tend to equate that to “you need less flow (backpressure)”, rather than “you should use the right exhaust for your application”.
      Hi performance two stroke engines absolutely rely on a tuned exhaust to make power, they use specially designed exhaust systems, with different diameters and changes in diameters to make use of the expanding gases, and to create very strong negative ‘pulses’ back to the cylinder to not just evacuate exhaust but to also help draw in a fresh mixture (two stokes primarily draw in mixture when the piston is going up which is opposite to a conventional four stroke).
      Also, residual exhaust gases in the combustion chamber can be good - Mazda are successfully using exhaust gases to reduce the effective cylinder volume in their new (and recently patented) supercharged two stroke to allow a much leaner fuel mixture without detonation, effectively achieving reliable diesel type lean burning.

  • @devynf3917
    @devynf3917 Před měsícem +63

    I love how concise and accurate this video is about the back pressure argument when it comes to exhaust scavenging for an NA engine.
    Hands down the best video I’ve seen so far explaining this engineering concept.

    • @claycoates5056
      @claycoates5056 Před měsícem

      you are Close the word Scavenging is the problem here still missing the point of air to fuel intermixing to attain the most possible work to power from the fuel that is consumed
      there is a point where back presser is needed and at a point where it becomes too great

    • @mattmorrison6958
      @mattmorrison6958 Před měsícem +1

      Completely agree devyn! Was really well done
      Clay backpressure isn't needed. If you have freah fuel/air going out the exhaust then it's now about optimizing valve timing for the setup

    • @jeremypike9153
      @jeremypike9153 Před měsícem +1

      ​@mattmorrison6958 if you have fresh fuel and air coming out of the exhaust you have a major issue. The fuel should be converted to carbon. Nox indicates an improper burn.

    • @thelasthallow
      @thelasthallow Před měsícem +1

      @@claycoates5056 yeah what you said here completely contradicts everything they showed in this video. back pressure of any kind is bad. scavenging is different and good but only works with a proper set of headers as shown.

  • @willk1828
    @willk1828 Před měsícem +61

    Please do a video on the science of exhaust headers!

    • @skippy2987
      @skippy2987 Před měsícem +2

      Seconded. I have much to argue/teach/scoff at on the subject!

    • @jasonreynolds9097
      @jasonreynolds9097 Před měsícem

      The Eyes have it. Science them ex haust savaging skills them ther header jobers have. But please make a video showing us how to choose the proper exhaust tune to reach peak efficiency for both N/A and Turbo engines at different points of engine RPM. Then compare their size and backpressure so we can lay this to rest.

    • @CL9k24a3
      @CL9k24a3 Před měsícem

      ​@@jasonreynolds9097it is engine specific... Nothing to lay to rest there. What works on ls not gonna work on k... I have tested that my self

  • @curtisroberts9137
    @curtisroberts9137 Před měsícem +37

    Scavenging is the opposite of backpressure. It's sucking gases from the cylinder by creating a negative pressure wave. I hate when people say you "need" a bit of backpressure. Drives me crazy.

    • @sigmaprojects
      @sigmaprojects Před měsícem +1

      This^

    • @JohnSmith-xu7ev
      @JohnSmith-xu7ev Před měsícem +4

      Yes, we need an exhaust system, which is a bit of back pressure

    • @robertmason8341
      @robertmason8341 Před měsícem +4

      Me too, i actually gave up trying to explain it to people. It’s just to much work getting thru the bullshit sometimes. I’ve had guys get red in the face and all bent outta shape arguing you GOTTA have back pressure 🤬. That back pressure myth is a strong one. Every once in a while someone will have enough knowledge and get it that you dont want/need any back press but most I encounter swear by it!

    • @curtisroberts9137
      @curtisroberts9137 Před měsícem

      @@JohnSmith-xu7ev 🤦

    • @sigmaprojects
      @sigmaprojects Před měsícem +2

      @@JohnSmith-xu7ev any back pressure from an exhaust is due to some undesirable trait usually. Especially for modern cars.

  • @splaw120
    @splaw120 Před měsícem +40

    When a hairdryer outlet is blocked the load decreases because it is no longer moving air. That is why the rpm of the electric motor increases. By blocking the outlet you have moved all the way to the left of the pump curve 🤯
    A better analogy would be throttling the outlet 😁

    • @zebmccollum
      @zebmccollum Před měsícem +12

      I was about to make a long and technical post about how the hair dryer has no load. You beat me to it lol

    • @noxious89123
      @noxious89123 Před měsícem +8

      @levimayes8488 No. It applies even if you completely block the OUTLET side as well. This is because if no air can go out, then no air can go in. And if it isn't moving any air, then it isn't under any load. Which is why you can hear the motor speed up. It's important to remember that devices like hair dryers also use the air moving through them to cool the motor, so blocking the airflow, whilst reducing the load on the motor, will still cause it to overheat.

    • @ajherman1
      @ajherman1 Před měsícem +1

      Came here to say this as well.

    • @BennettEberle
      @BennettEberle Před měsícem +2

      That's true of centrifugal blowers and pumps. The opposite is true of positive displacement blowers and pumps. Purposely throttling the exhaust on a diesel engine is one method of increasing engine braking on a diesel engine.

    • @thehilltopworkshop
      @thehilltopworkshop Před měsícem +3

      There was another comment spelling this out earlier but it seems to have disappeared... 🤔🙄

  • @jasonreynolds9097
    @jasonreynolds9097 Před měsícem +33

    I'm no expert, though I am a mechanic and an enthusiast, and I've been toying with exhaust for 20 years. The first time I put headers and pipes on a small V8 truck was 20 years ago and afterwards it could no longer do a burnout. I was young, confused, and devastated. Even put a smaller tire on it just to see what would happen, still no burnout. However, the truck did have a noticeable increase in acceleration after 3k RPM. A few years later I swapped the 2.5' pipes for 2' pipes and like night and day the truck could burnout forever, not even needing the break peddle. This was the beginning of my interest and research into exhaust. I promise this much, a stock non-turbo daily driver needs a smaller pipe to increase the velocity at the exhaust valve while in low RPMs to maintain cruising power and off idle torque. Also, my fuel milage increased with the smaller pipe. Scavenging and velocity is kind of my thing. lol I'd love to prove it.

    • @19Borneo67
      @19Borneo67 Před měsícem +9

      These guys are talking about wide open throttle readings on a dyno. Has very little to do with real world driving.

    • @jasonreynolds9097
      @jasonreynolds9097 Před měsícem +5

      @@19Borneo67 Mmhmm and if the dyno were reading idle to 3500 RPM, back pressure and velocity would win against open headers on any N/A engine any day. The "some people" he is referring to that say "you need a little back pressure to make power" are referring to both wide open throttle and part throttle on the street, where people push the skinny pedal.😂😂😂

    • @jasonreynolds9097
      @jasonreynolds9097 Před měsícem +2

      @@19Borneo67 I really wish I had read your comment, cause I would have just liked it. I mean, the dyno in the video is built to recreate real driving. 🙉🙊

    • @jasonreynolds9097
      @jasonreynolds9097 Před měsícem +4

      @@19Borneo67 Did you see the dyno in the video? No? Weird, must be because their real-world Dyno that they use for developing these parts isn't in this video. lol

    • @darrenotis5672
      @darrenotis5672 Před měsícem +3

      break peddle? Ahhh... brake pedal.

  • @tepidtuna7450
    @tepidtuna7450 Před měsícem +5

    I learned this 40 years ago while studying engineering. I've had so many 'discussions" about back pressure it is NOT funny. A great video that fully describes the matter in ways that would make any engineer proud. Cheers.

  • @Levibetz
    @Levibetz Před měsícem +41

    I think the main reasons people used to think backpressure was needed was because headers do have a power drop if they're run open with no collector extension, and also because if you merely unrestricted a severely restricted exhaust (as was more common then) on an old carbureted engine, it could actually effect the fueling enough that it runs worse. On the topic of manifolds, as a gas guy I'm always shocked how even modern diesel engines are designed as if gases don't need to flow at all in a heavily turbocharged engine. All the same flow and reflected wave dynamics exist when a gas is under pressure. I'm curious how much free horsepower could be had on something like a duramax with a header style manifold over that horrific log.

    • @D.L.PDevelopments
      @D.L.PDevelopments Před měsícem +2

      Is that why drag cars that are chasing every last HP run like that? Makes no sense

    • @crisnmaryfam7344
      @crisnmaryfam7344 Před měsícem +4

      Headers dont "drop power", they "move" it. The same as any other exhaust setup. This is why Honda uses a Single outlet "header" on their J series v6's that make 250 hp from the factory... They use it to put the power down low for take off and drivability rather than your "wide open free flowing" headers that make all their power at the high end (where you want it for drag racing).

    • @crisnmaryfam7344
      @crisnmaryfam7344 Před měsícem

      @@D.L.PDevelopments see my comment about honda J series single port "headers". You can also look up actual dyno results with back to back testing to prove this claim. Banks power is WAY late... Decades.

    • @Levibetz
      @Levibetz Před měsícem

      @@D.L.PDevelopments Like what? Open headers? I think you'll find most NA drag cars now have either collector extensions or a full exhaust.

    • @Levibetz
      @Levibetz Před měsícem +1

      @@crisnmaryfam7344 They use it because it's cheap and easy, period end of story. Long tube headers pickup torque hugely over an otherwise well flowing manifold with no scavenging

  • @robertmason8341
    @robertmason8341 Před měsícem +7

    Gale, you are one slick ol’ dude I swear.
    While making everyone think “wow cool I just got a killer education on back pressure” you smoothly slid those advertisement in for your products, 😂😂….small, quick, but they were there, …nicely done sir 👏
    And btw, well done on the exhaust and header, they look top notch! I try to tell my buddies if you ain’t buying Banks your getting second best.

  • @MrPdiggity
    @MrPdiggity Před měsícem +16

    Common misconception about hair dryers and vacuums when you hear the motor spin up faster it is because the load on the fan (impeller) is actually decreased allowing the motor to spin more freely. You can feel the pressure build but opposite of a piston pump which gains resistance as pressure is built.

    • @dylanporras2655
      @dylanporras2655 Před měsícem

      Came here to say this.

    • @alexkram
      @alexkram Před měsícem

      Yep. I used to design pumps for liquids and it's the same thing where if you close a downstream valve the torque required goes down. Counterintuitive but it's true.

    • @MrPdiggity
      @MrPdiggity Před měsícem

      Interesting i wouldnt have thought about that with a liquid pump.

    • @19Borneo67
      @19Borneo67 Před měsícem +1

      @@MrPdiggity Centrifugal pump yes, piston pump no.

    • @Bob_Adkins
      @Bob_Adkins Před 24 dny

      When a vacuum cleaner gets clogged and spins faster and someone remarks that "it's straining" my head nearly explodes.

  • @99jeepxjguy97
    @99jeepxjguy97 Před měsícem +1

    This is why I appreciate you folks. Actual research and testing. Perfect example being the 4.0L Jeep "Revolver" header. It WORKS! I love mine. Definitely worth the money. Thank you for great products that actually improve efficiency.

  • @ChurchAutoTest
    @ChurchAutoTest Před měsícem +2

    One of the better videos you guys have done. Animation and production values getting even better. I always tell people you don't want backpressure, but on non-turbo engines it is important to maintain exhaust velocity for scavenging with a proper header.

  • @enoz.j3506
    @enoz.j3506 Před měsícem +2

    My wife said this morning, "i need back pressure,for my gas control",as i waffed the duvet, i'm writing this from the comfort of the sofa.

  • @baukanakuab
    @baukanakuab Před měsícem +3

    Backpressure is essential for two-stroke engines though.
    Maybe that is where the 'myth' comes from.

  • @doogie525
    @doogie525 Před měsícem +3

    Great video and I'm glad you touched on even, though very briefly, that belt driven boost is the only parasitic loss boost. The shop air in the 4.0 header was amazing. Best demonstration of exhaust scavenging I've ever seen.

  • @pearlbluesoul
    @pearlbluesoul Před měsícem +1

    Can’t love this enough, thank you for putting this together!! ❤❤

  • @MELOMEOUT
    @MELOMEOUT Před měsícem +2

    I had open pipes exhaust with my 2002 Harley 88tc, I put the original pipe tips back on that greatly reduces noise, and I added 10 hp easily by using restrictive factory pipe tips.

  • @TheMrgoodtool
    @TheMrgoodtool Před měsícem +3

    As a retired Master Plumber, I can say with confidence, that any bend in a pipe of any kind reduces flow. Any time gasses or liquids have to merge into itself will create cavitation to some degree. How much does a 90 degree bend reduce air flow?
    A long radius 90-degree bend (a bend radius of 4.5 inches, or 11.4cm) has a flow restriction equal to about 5 feet (about 1.5 metres) of straight pipe.

    • @CL9k24a3
      @CL9k24a3 Před měsícem

      Doesn't happen that way on exhaus gasses.

  • @bkims
    @bkims Před měsícem +5

    There is so much I cant stand about this subject. Especially when people try to "debunk" backpressure. The term was an oversimplified misconception that was likely made up by a sales person. In my opinion the common understanding of "backpressure" in an exhaust system can really only start after the last meaningful point of harmonic tuning in the system its self. These points generally being dictated by the changes in pipe diameter and the distances between them. Examples being, exhaust runner to header/manifold primary, primary to collector, collector to emissions or turbo, and so on. Everything after that "can" only create back pressure if that part of the exhaust is able to present a meaningful impedance to the engine's exhaust flow at or beyond some point in its operating exhaust cfm range. In this circumstance I do agree backpressure can only be a bad thing, but it also generally only becomes significant in max engine mass flow situations that most trucks rarely experience. I'm attempting to speak as accurately as I can, so apologies for the wordiness.

  • @1337Hans
    @1337Hans Před měsícem +8

    Amazing video! Please do that header explanation one too!!

  • @johnjones928
    @johnjones928 Před 27 dny +1

    I think the whole back pressure argument came from the race cam in a street car crowd believing they fond a way to regain some of the cylinder pressure they were losing through their wide open cam timing. The fact is thinking you can gain power by leaving unburnable gas in the combustion chamber is ridiculous.

  • @MrChevelle83
    @MrChevelle83 Před měsícem

    the scavenge demo with the sticky notes and air was excellent! awesome video!

  • @thespartanproject001
    @thespartanproject001 Před měsícem

    You guys are awesome!!!! Thank you so much for informing us on this matter!

  • @benjaminbuffin9812
    @benjaminbuffin9812 Před měsícem +1

    Nice work Eric. Thank you. 😊

  • @kjohns236
    @kjohns236 Před měsícem +3

    Thank you for sharing this, I learned a lot! I have a 2000 jeep xj and will for sure be looking into a bank full exhaust system for it after watching this video!

    • @JohnSmith-xu7ev
      @JohnSmith-xu7ev Před měsícem

      Back pressure is bad according to banks, run no exhaust

  • @ianr02
    @ianr02 Před měsícem +2

    Strange - I missed the part where he explained the principles of valve overlap... Good ad for exhaust systems that use turbos.

  • @tg9388
    @tg9388 Před měsícem

    Outstanding job Erik!!!

  • @swicked86
    @swicked86 Před měsícem

    Thank God you're doing this video, I've been arguing with people forever about this. At best your reducing overlap any way your doing it your reducing the atmospheres ability to move air into the motor. If you need to shrink primary tubes to the collector then do that but after the collector there should be zero pressure as fast as possible.

  • @detonationpyrotechnics4156
    @detonationpyrotechnics4156 Před měsícem +3

    Me simple man. Me hate back pressure.

  • @ericcsuf
    @ericcsuf Před měsícem +1

    Outstanding presentation in every respect. I developed technician training courses and instructional materials for most of the Asian car and motorcycle companies based in So Cal for 20 years. This was top level stuff.

  • @matthewrandazzo9240
    @matthewrandazzo9240 Před měsícem

    Been more of a fan each video I see but now I like it so much I'm going to ask for motorcycle products. Ya boy wants a top tier exhaust from the geniuses you are. Unbelievably brilliant and extremely easy to understand content. Never stop. But also please start motorcycles. Thank you for the education time and time again.

  • @E1337Jerk
    @E1337Jerk Před měsícem +1

    Its funny for me to hear Erik referring to his grandfather as Gale. Love your products and the vids keep it up!

  • @budwiser2323
    @budwiser2323 Před měsícem

    Yes, please. An exhaust header video would be great! I eagerly await it's release.

  • @dalemcmartin9201
    @dalemcmartin9201 Před měsícem +2

    Hi Erik, I happened across your channel and found it to be extremely informative and interesting. I found myself binge watching a lot of them. It is extremely apparent that Gale is a genius to say the least. However, I have one small problem, and that is I have absolutely no idea what language you and Gale speak (that’s code for a lot of the technicalities go over my head). Hello from Australia. Keep the informative information coming.

  • @fivestar2227
    @fivestar2227 Před 6 dny +1

    Run these open headers on a dyno then add a complete exhaust system after the headers and you will see an increase in power and torque below 3500rpm (cruising speed). The exhaust contains unburned energy that is utilized at cruising speeds when kept in the combustion chamber with a slight amount of back pressure.

  • @xaviergonzalez5828
    @xaviergonzalez5828 Před měsícem

    Beautiful video! Marvelous! Thanks for sharing!

  • @libertycosworth8675
    @libertycosworth8675 Před měsícem

    Well done Eric! So true.

  • @GJBricks
    @GJBricks Před měsícem

    You explained that so well breaking down each step. It seems so obvious but you can see how people got sucked into believing it.

  • @BrodeyDoverosx
    @BrodeyDoverosx Před měsícem +6

    I’ve been arguing against this bogus claim for so god damn long, it’s ridiculous.

    • @JohnSmith-xu7ev
      @JohnSmith-xu7ev Před měsícem

      So you dont run exhaust headers?

    • @lasskinn474
      @lasskinn474 Před měsícem +4

      @@JohnSmith-xu7ev having scavenging from proper headers and mass flow is different to having back pressure

  • @mikefarrow5271
    @mikefarrow5271 Před měsícem

    My favorite type of Banks videos

  • @roBLINDhood
    @roBLINDhood Před měsícem

    Great stuff guys!!

  • @cmdr_scotty
    @cmdr_scotty Před měsícem +2

    i would absolutely love watching Gale do a video explaining how tube size/length/style effects backpressure and how that translates out to power band

  • @KarlGreaves
    @KarlGreaves Před měsícem

    Love this series! Teach me everything!

  • @sean199142
    @sean199142 Před měsícem

    Please do the headers video. These tech and explanation videos you guys do are the best 👌 keep em coming !

  • @jeremyway6571
    @jeremyway6571 Před měsícem +1

    This is some good info, a video on exhaust manifold/Header design and applications would be useful too!

  • @MoparMissileDivision
    @MoparMissileDivision Před měsícem

    Best video I have ever seen explaining the difference between backpressure and scavenging!

  • @relmdrifter
    @relmdrifter Před měsícem

    I love it, right out the gate!
    Negative back pressure, that's what's up!
    Please make the header video!

  • @fvl548
    @fvl548 Před měsícem

    Got into this video with questionmarks. But as you stated. Backpressure is often mistaken for exhaust scavaging. And yes.
    Good video, nicely made, good sequence. And hella informative

  • @wademiyataki9221
    @wademiyataki9221 Před měsícem +24

    Some people are wrong.🤣🤣🤣

  • @dougc190
    @dougc190 Před měsícem

    Yes please do a header video. I also learned that glass packs have back pressure? I never would have thought that.

  • @MXWJ01
    @MXWJ01 Před měsícem

    As a kid I was told headers were always better. Didn’t know exactly why but as grew older I found out. Great video! 👍🏼👍🏼

  • @dylsk8r
    @dylsk8r Před 14 dny

    thank you for putting good stuff out.

  • @Dreska_
    @Dreska_ Před měsícem +1

    My understanding: You can't get scavenging without having an exhaust system, which could be thought of as a restriction, but really you're benefitting from the continuous positive controlled motion of air away from the engine, and any actual backpressure is a side-effect not a thing you specifically target.
    People that say an oversized exhaust has 'not enough backpressure' should actually be saying it has 'not enough velocity'.
    Correct me if i'm wrong!

    • @73Datsun180B
      @73Datsun180B Před 23 dny

      This is exactly why chopping off factory exhausts especially ones with cast manifolds makes engines run like shit and not rev out anymore. My daily drive is a 92 Nissan Bluebird with stock spec rebuilt CA20e, headers running into standard 2" or 2.25'' tube, cat delete, original resonator halfway and rear muffler replaced with 3.5" resonator. The velocity is so good it makes big flames out the back like a race car when shifting over 3000 rpm!

  • @jdmjesus6103
    @jdmjesus6103 Před měsícem

    I remember trying to teach Honda owners this back in the early 2000's. Man that was hard work.

  • @tfaubus
    @tfaubus Před měsícem

    Awesome, thanks for sharing!

  • @SuperRamcharger
    @SuperRamcharger Před měsícem

    Absolutely 100% spot on. I've been building older carbureted V8's, carbureted Inline 4's (motorcycles) and of course the almost indestructible Jeep fuel injected 4.0 HO's for decades. This whole "back pressure is good" myth started in my experience back in the 70's and 80's when guys would bolt on a respectable brand of headers, decent mufflers and loose power on a stock machine... WEll, YEAH! They never jetted the carb up to take advantage of scavenging and the Helmholtz effect of resonant tuning on, of course, carb'd vehicles/bikes. Once tuned in, a genuine (oh damn man!) response was typical. On FI vehicles, the stock computer fuel trim can easily compensate for reduced back pressure especially if you live at high altitude. Case in point.... On my 4.0 I had a Magnaflow cat, generic SS header (AFM which I believe is out of business and had to weld up the the cracks twice) and generic cat back system that always passed emissions until my state changed to California emissions standards. I band clamped in a Cali spec cat, passed with flying colors but lost 2+ mpg and it lost a huge amount of power while merging into traffic (above 3k rpm), it was sad. Just for grins, I got a Banks after cat system and popped my old cat back in and gained 3+ mpg and my 3000+ rpm power was back! On top of that, the Banks sounds so much better at idle and no more drone than the summit cat back turbo muffler. I'd love to try your headers but is there any guarantee in regards to cracking?

  • @Juanito548
    @Juanito548 Před měsícem

    This is really awesome. I would love to see a more technical video with fluid flow principles.

  • @destruxandexploze2552
    @destruxandexploze2552 Před měsícem

    I’ve told people time and time again, an engine is a big air pump, getting air in and out as fast as possible is what makes power. (Including fuel)
    And people still argue with me!

  • @numinous4789
    @numinous4789 Před měsícem +7

    Great vid in lots of ways. It’s worthy to note, however, that the physics at play in boosted apps are differently influential than those in N/A apps. Apples and oranges.
    To be strictly technical, the best exhaust system in boosted apps is basically as close as possible to no exhaust at all, which is obviously illegal on the road.
    In N/A, the fluid dynamics in the exhaust influence torque curve and effective rpm range, among other factors.

  • @1dave301
    @1dave301 Před měsícem +4

    I bet the "engine needs back pressure" tale is a result of removing the exhaust restrictions causes the engine to be less powerful, but the less back pressure caused the intake side to become lean.

    • @budgie98
      @budgie98 Před měsícem +1

      In my experience, when you remove the exhaust system, there is a small power increase: BUT, there is a 2 or 3 times more increase in exhaust noise. This makes you think that the engine is much more powerful, but when you drive the car you don't get the performance that the increase in noise suggests. (I spent 23 years in Ford R&E Engine Lab testing engines)

    • @Bob_Adkins
      @Bob_Adkins Před 24 dny

      Yep. If top fuel dragster builders could get 5 more HP by using longer headers, they would certainly use them. They use just enough length to deflect the flames away from the car.

    • @73Datsun180B
      @73Datsun180B Před 23 dny

      @@budgie98 my experience removing exhausts off standard engines is they run like a bag of shit and won't rev out!

    • @73Datsun180B
      @73Datsun180B Před 23 dny

      @@Bob_Adkinstop fuel dragsters run at high rpm with a blower so there is no need for exhaust scavenging!

  • @thmanx
    @thmanx Před měsícem +1

    Solid video friends, well done.

  • @fredyellowsnow7492
    @fredyellowsnow7492 Před měsícem +1

    The continued use of 'backpressure' had me gritting my teeth for the first half.
    It's a reaction to the over-use of it over the years by those who couldn't tell chit from biscuits.
    Motoring journalists, I'm looking at you.

  • @petermcneill80
    @petermcneill80 Před měsícem

    Interesting video, nice demo on the scavenging affect and lack off.
    Ties in with stuff I’d been taught in the 00s about turbo exhaust system
    “ the best post turbo exhaust is no exhaust “
    Not always practical lol 👍🏻

  • @ifyoucantjointhem
    @ifyoucantjointhem Před měsícem +1

    Looking forward to the science behind the design and considerations for a tuned header 👌

  • @kingrhun
    @kingrhun Před měsícem

    The very first time I heard of back pressure and the explanation it came with, I said to myself, "That doesn't make sense at all." Now, scavenging, that made sense. Backpressure always translated to resistance in my mind. Thanks to the Banks team and this video, it turns out I was right. I just couldn't put it into words. Thanks for proving I wasn't tripping about it all these years. 😅

  • @paullongley1221
    @paullongley1221 Před měsícem

    This comes up so often, people absolutely adamant that ‘you always need back pressure, it gives you more torque’ then they get really upset when they can’t explain it 😅
    Being a truck mechanic, I remember Gardner diesels having issues meeting minimum horsepower requirements as truck weights increased. Their quick fix was a tuned exhaust, Gardner called it ‘negative pressure’ for a loaded 32 ton truck , it used about a five inch diameter pipe that with matching stack.
    It used a flapper to stop rain getting in, but the pressure pulses were so strong that at three quarters throttle it still sucked shut, made a proper din 😂 drove the driver mad

  • @masongiles8443
    @masongiles8443 Před měsícem

    Love this keep it coming

  • @michaelevans2975
    @michaelevans2975 Před měsícem

    Brilliant video thanks. I assume variable geometry turbos further increase back pressure compared to fixed geometry?

  • @coreyfro
    @coreyfro Před měsícem

    THIS IS GREAT!!! Make more of these! My kid is in the automotive program in highschool, when they take one semester, they become eligible to work on the diesel SFMTA busses. A sires of these videos would be perfect for them.
    Just a LIIIIIITTLE less selling banks... just a little ;-)

  • @robertoschols3599
    @robertoschols3599 Před měsícem

    Hi there, first of all thx for the very interesting video about back pressure. I enjoyed watching it and also learned a bit at the same time. But, my understanding of back pressure is that it is needed as to not burn up your exhaust valves or in other words to reduce the exhaust gases flow a little but not too much! But it seems I was wrong!

  • @newtranslationdevicestevec301
    @newtranslationdevicestevec301 Před měsícem +1

    Q. Why do ALL forms of racing run as straight as pipe and open headers?
    A. Just follow the best race teams.
    You know do as I do !!!

  • @ShawnDunca-bc2ru
    @ShawnDunca-bc2ru Před měsícem

    Awesome video thank you

  • @matiasdamian8106
    @matiasdamian8106 Před měsícem

    I would be a bless to have gale make the video about how exhaust scavnging ties back to exhaust back pressure man, hope you guys at banks can make it one of these days. All the engineering about exhaust has it complexity y precision and it's so useful to learn it for any aplication! Hope to see that video soon💪

  • @ccbproductsmulti-bendaustr3200

    Well done Erik 👏👏👌nice presentation

  • @negan454ss
    @negan454ss Před měsícem +4

    Now make some tuned manifolds for a ecoboost. Great video . Thank you

    • @JNorth87
      @JNorth87 Před měsícem +1

      Want

    • @208Concepts
      @208Concepts Před měsícem

      They would cost as much or more than the FullRace manifolds I bet.

    • @arielmateojesusdelacruz5186
      @arielmateojesusdelacruz5186 Před měsícem

      Lmao believe it or not the 2.0 after market headers is literally just a 90° elbow pipe because the head design although the 2.0 suffers from a small turbo

  • @davidortiz173
    @davidortiz173 Před měsícem

    Love this video!

  • @teamsafa
    @teamsafa Před měsícem +1

    Where i come from the issue of backpressure was with 2-stroke engines. It should be tuned to the motor, if too low you waste fuel by letting the the air-fuel mixture going unburnt into the exaust or if too high you loose power.

  • @TheMissingxtension
    @TheMissingxtension Před 20 dny

    Very important information to clarify is that pressure does affect the power curve. The more free flowing the exhaust, the lower the rpm range for peak power, the more restricted pressure makes your torque curb higher in the range. Awesome video, especially the scavenging part, but I believe a turbo diesel is the wrong example. Diesel already has a very low and narrow RPM range, practically non existent. Then you pair that with a turbo for diesel engines that has to produce peak flow at very low and narrow rpm ranges. Its like a quarter or less of most gasoline engines.

  • @Blackinterceptor999
    @Blackinterceptor999 Před měsícem

    For those of us that are using non turbo engines There is calculators available online to find the proper size, however you gonna have to find the best design for your situation to minimize the losses from bends.

  • @arthurwagar88
    @arthurwagar88 Před 22 dny

    Very interesting. Thanks.

  • @jsa310
    @jsa310 Před 21 dnem

    Very timely as I was just considering which cat (green versus high output) for my 2024 Mustang 5.0
    Thanks!

  • @GoldenGrenadier
    @GoldenGrenadier Před měsícem +4

    Volvo had an interesting Log style exhaust manifold for their 5 cylinder. It had 3 seperate holes for exhaust to exit at the turbo flange and it was set up in such a way that no 2 consecutive firings would use the same hole. That way, none of the pulses colided, although they did have an unequal distance to travel. I'm looking at a 90s t5 manifold right now and cylinder 1 has its own outlet, cylinder 2 and 5 share an outlet, and 3 and 4 share an outlet. With a firing order of 1-2-4-5-3, the manifold almost behaves like headers.

    • @djnone8137
      @djnone8137 Před měsícem +1

      Did you know banks made the first Volvo turbo for production cars?

    • @mlc7boosted
      @mlc7boosted Před měsícem

      Having driven a '95 Volvo 850 turbo and later a '97 Volvo 850R for around 9 years I do remember the tri-divided exhaust ports on the exhaust manifold. I do think those disappear on the Volvo S60R manifold though and that manifold is more of a shared design...though it's considered and performance "upgrade" on the 850 turbo, R, and GLT. I miss the 850R, but I am liking the '04 Corvette I traded for. Both are fun cars for daily driving enjoyment.

    • @GoldenGrenadier
      @GoldenGrenadier Před měsícem

      @@mlc7boosted popup headlights FTW! Won't find a volvo with those unless you import a 480. The R manifold is still somewhat tri-divided but cylinders 3, 4, and 5 all share an outlet. It still flows better than the 850 T5 manifold because of its larger diameter but at higher RPMs, a "Japanifold" will flow slightly more than the R.

  • @gordowg1wg145
    @gordowg1wg145 Před měsícem +1

    Excellent presentation!
    Depends - in theory it's bad because the piston has to push against the pressure to expel it and in a perfect world there would always be a vacuum in the exhaust.
    In practice it can't be achieved, although Detroit diesels, and some other large 2-stroke diesel engines, used exhaust scavenging pumps - that were re-purposed by "hot rodders" to became the foundations of the x-71 series superchargers!
    Best one can do is try and control the pressures to best achieve exhaust scavenging and initial intake flow - this is done with tailoring the pipe diameters for velocity, and lengths so place the low(er) pressure waves in the exhaust pipe to be low at the best time for cylinder filling and net torque.
    I do wonder if some work on the turbine housings, to improve the transition from the turbine outlet's inlet through the housing to the outlet's outlet, and the pipe's transition from that flange to the full diameter, wouldn't show some significant improvements?

  • @02116Ryan
    @02116Ryan Před měsícem +1

    Please make a video on manifolds or tubular headers in a turbo application and how or when if one or the other is advantageous

  • @damham5689
    @damham5689 Před měsícem +1

    Nice trick. On the headers you have the air gun down inside the header manifold. On the log manifold you had the tip outside the manifold.

  • @BSA210
    @BSA210 Před měsícem

    Excellent video.

  • @7.12_am
    @7.12_am Před měsícem +1

    I think this misconception comes from info about 2 stroke exhausts, where they don't burn all of their gases so they have to design the exhaust in a way to shoot the gas back into the cylinder. I think this video describes super well the effect this has on many vehicles and i love it!

    • @Lorddxt
      @Lorddxt Před měsícem

      You are right, two strokes are a completely different design, and need the correct back pressure (pressure waves) to get the full potential of that engine
      Which is why you see expansion chambers on two stroke dirt bikes.
      It's a real science to make a two stroke exhaust, because it needs to resonate at the correct frequency to aid cylinder filling at a specific rpm range

    • @73Datsun180B
      @73Datsun180B Před 23 dny

      @@Lorddxt back in the day when I had a scooter, I googled making exhausts for 2-strokes and I made one out of car exhaust, block of wood and hammer, grinder and a mig and I instantly got another 20km/h!

  • @welndmn
    @welndmn Před měsícem

    Love these!

  • @rayowens4355
    @rayowens4355 Před měsícem

    Good video. Accurate info!

  • @alanhilder1883
    @alanhilder1883 Před měsícem

    A "Tuned pipe" exhaust works, at the correct revs, by the having the high pressure pulses hit the exhaust port before the valve opens, bouncing away, creating a low pressure pulse as the valve opens, helping to "suck out the exhaust gasses", outside of that rev area, super high back pressure, which makes it hard to get to the correct revs.

  • @trackpackgt877
    @trackpackgt877 Před měsícem +1

    This was a great video I used to believe the back pressure myth I know other people that still do! This is a great video to show why its always bad because they may not believe me when i tell them but they cannot argue with Banks!

  • @joecool509
    @joecool509 Před měsícem +3

    that is incorrect using the hair dryer as an analogue ... when you block the air flow the fan/pump stops moving air which is the definition of work. moving fluid requires work. the fan is spinning but not moving anything... it is doing no work and current on the hair dryer would decrease...thus power goes down. put it on a watt meter... the blades have no differential pressure across them to resist flow. Part of the reason is a hair dryer is not a positive displacement pump it's a centrifugal pump.

  • @TonyTheTruckGuy
    @TonyTheTruckGuy Před měsícem

    Great video!

  • @john1703
    @john1703 Před 28 dny

    Exactly. Race car exhausts are short and without mufflers, and the headers are blended not logs.

  • @j.helvie6563
    @j.helvie6563 Před měsícem +1

    Unfortunately, the thing he doesn't state is that most common operating conditions fall outside the range where either exhaust back pressure or scavenging have any real effect on engine performance..... Most big diesels & hot rod engines spend most of their time chuckling around town unloaded & at low load conditions, not working hard. Furthermore, you (& your neighbors) have to listen to your hot rod exhaust.... Loud pipes do not save lives, loud pipes annoy the neighbors. Save your money, Guys.

  • @timobatana6705
    @timobatana6705 Před měsícem

    I was watching a video where a dude was designing a custom exhaust pipe for a street bike and he said that there had to be a certain bell-shaped curve coming off of it so that the shock waves coming from the motor were absorbed into the air flow. It sounded like magic. I don't know