EQUAL LENGTH tubular vs. LOG manifolds (headers) - SCAVENGING and EXHAUST BACK PRESSURE EXPLAINED

2024 ж. 28 Нау.
753 216 Рет қаралды

www.weldspeed.com.au/
Billet intake: www.weldspeed.com.au/product-...
For fabricators: www.weldspeed.com.au/product-...
In today's video we will be talking about exhaust manifolds or headers. First we will explain what exhaust manifolds do and then we will compare OEM short cast manifolds and equal length tubular welded aftermarket ones, like my awesome turbo manifold from Weldspeed right here, to see how different designs and materials influence the performance of your engine.
So as the name very obviously suggests the exhaust manifold has the very simple task of providing a pathway for exhaust gasses. They connect your cylinder head to the rest of your vehicle's exhaust system. An exhaust manifold is always bolted directly to the cylinder head of your engine and when the exhaust gasses exist from the exhaust port the exhaust manifold is the first thing they see. So obviously the exhaust manifold doesn't actually DO anything, it's a passive part, or a collection of pathways through which exhaust gasses flow, but despite it's passive nature, the design of the exhaust manifold can play a very important part in the p
Now exhaust manifolds will be very different on naturally aspirated and turbocharged engines. This is obviously due to the fact that a turbocharged engine will have a turbo bolted to the exhaust manifold and then the rest of the exhaust system will be bolted to the turbine housing of the turbocharger. On a naturally aspirated engine the exhaust manifold will be connected directly to the rest of the exhaust system, without a turbocharger in between.
Now the design of the exhaust manifold mainly influences 2 things: Scavenging and exhaust back pressure and these two things then influence the power, torque, responsiveness and efficiency of the engine.
So what is exhaust Scavenging? In the simplest possible terms exhaust Scavenging is using the exiting of the exhaust gasses to ease the entry of the intake air into the engine to improve performance.
But scavenging can not occur the entire time the engine is running. It's heavily dependent on the camshaft specs of your engine but most of all it is determined by your exhaust manifold.
Now the scavenging effect is obviously very important for naturally aspirated engines because they depend on the pressure of the atmosphere to get air into the chambers. On a well tuned engine the negative pressure wave can decrease the chamber pressure by as much as 7 psi at a relatively narrow rpm band. On the other hand turbocharged engines don't really depend on the scavenging effect because they can add one or two atmospheres of additional pressure to the intake air over a broad rpm range which greatly improves cylinder filling as soon as the intake valve starts to open resulting in dramatic power increase. Another factor is valve overlap. Although valve overlap isn't necessarily all bad for turbocharged engines having too much of it is counter-productive because you're essentially wasting the work of the turbocharger. By having the intake and exhaust valve open at the same time for too long you're actually sending valuable pressurized intake air into the exhaust which means that you're wasting boost.
Now let's look at our cast and our tubular turbo manifold to see exactly how this play out in practice. Probably the first thing you will notice is the difference in length of the runners. The cast manifold has much shorter runners and in addition to this the runners are of unequal length which increases back pressure.
To understand how runner length influences back pressure we must understand that pressure inside the manifold spikes every time an exhaust valve opens. By making the runner longer we are enabling a more free flowing form of the runner and by making all the runners of equal length we ensure that each exhaust pulse takes an equal amount of time to reach the turbocharger.
The final difference between the two manifolds is the material itself. OEM cast manifolds are usually cast using nodular iron and most will have trouble resisting temperatures beyond 850 degrees Celsius for prolonged periods of time. Tubular aftermarket manifolds usually employ stainless steel. 304 stainless steel is a good and common choice while 321 stainless steel is an even better choice.
Stainless steel welded manifolds also have much smoother internal surface compared to the rough surface of cast iron. This of course helps increase gas speed and reduce back pressure.
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#d4a #boostschool #exhaustmanifold

Пікірлер
  • www.weldspeed.com.au/ Billet intake: www.weldspeed.com.au/product-page/4age-intake-manifold-big-small-port For fabricators: www.weldspeed.com.au/product-page/copy-of-321-stainless-straight-tube

    @d4a@d4a2 жыл бұрын
    • How about tri-y headers?

      @jimmywise4538@jimmywise45382 жыл бұрын
    • How about tri-y headers?

      @jimmywise4538@jimmywise45382 жыл бұрын
    • Damn They dont actually sell the header, just the materials. :/

      @justinlizamor1541@justinlizamor15412 жыл бұрын
    • That's a tad faster than the speed of sound, 870mph. Mach 1 is around 750mph, maybe a bit faster but remembered that Mach was in the mid to high 7 hundreds of miles per. Dang it, now I've gotta look it up or it'll drive me crazy. Good stuff you putting out though, lots of interesting topics, thanx.

      @mrt2this607@mrt2this6072 жыл бұрын
    • Why don’t you show pressure in the operating engine and show the pulses of each runner , with dyno tests

      @buddyrojek9417@buddyrojek941710 ай бұрын
  • Your vids don't require overclocking. I love that. The pace and info in a short amount of time are perfect. The animations go a long way in allowing viewers to keep up with the pace. I know it must be a lot of work to make them. Thanks for all the hard work.

    @greg7886@greg78862 жыл бұрын
    • I have to agree (and finally, a Comments section devoid of idiots that complain "finally got to the exhaust manifold" or even sillier comments). This Video is a Top Notch explanation.

      @arcanondrum6543@arcanondrum65432 жыл бұрын
    • if it can overclock it should be overclocked - PCMR gods

      @bigcazza5260@bigcazza5260 Жыл бұрын
    • yea it really is nice not havin to speed up a video n miss half the other shit that Does move at normal speed, vs some ppl talking speed, its like they got into the dope before recordin :p i get it tho theyre tryin to stretch the video every once in a while 2x isnt even quite enough

      @4dirt2racer0@4dirt2racer0 Жыл бұрын
    • Lmao... overclocking.. I love it

      @chewchewtrain1841@chewchewtrain184111 ай бұрын
  • This is, by far, the best education channel for petrolheads. I really appreciate the work and research you made in the making of this video, keep it up.

    @madjidben8240@madjidben82402 жыл бұрын
  • True story: Back in the 90s, I dyno'd the very first X-pipe originally made by Dr. Gas. This led to every Nascar team ordering them. 1994 Daytona 500 was won by Sterling Marlin in the 4 car. This was a huge story and had everyone curious as to why his car sounded like an Indy car. Thanks for sharing.

    @jhuntosgarage@jhuntosgarage2 жыл бұрын
    • If you want to get an inside glimpse into the world of NASCAR strategy watch this. It's rare. kzhead.info/sun/latrf8ePlnqtnp8/bejne.html

      @kozatas@kozatas2 жыл бұрын
    • Cool 👍

      @Twobarpsi@Twobarpsi2 жыл бұрын
    • ... I know for a fact my father was building x pipes back in the late 70s on street cars, he still has the first one he built on his nova. He never sold them professionally but I know for a fact yours wasn't the first

      @Prestiged_peck@Prestiged_peck2 жыл бұрын
    • @@Prestiged_peck I know for a fact that your dad's x-pipe wasn't not the x-pipe that didn't get dyno'd when they weren't dynoing x-pipes back when Indy cars were not dyno'd on the dyno with an x-pipe not being dyno'd.

      @crxtodd16@crxtodd162 жыл бұрын
    • X pipes were being used commercially since like 1980

      @buildingracingvideos4714@buildingracingvideos47142 жыл бұрын
  • I thought I knew quite a lot about engines but this is partly new to me! The Scavenging part. Thanks!

    @NLBassist@NLBassist2 жыл бұрын
    • Me Too! I knew 2 strokes used scavenging but I never really thought of 4 strokes using it.

      @robwhite3241@robwhite32412 жыл бұрын
    • Some ones not been the Harry hole of rabbits have they....Weslake or Ricardo not bad place to start ....

      @tonypate9174@tonypate91742 жыл бұрын
    • Longtubes always win.. ;)

      @P71ScrewHead@P71ScrewHead2 жыл бұрын
  • This was a good and interresting video. Nothing make a sunday better than learn more about our cars. Thank you for the video.

    @terjejohnsen3651@terjejohnsen36512 жыл бұрын
  • Somewhat simplified, for obvious reasons, but this was a really good overview not overlooking the 'horses for courses' aspects. Well done!

    @alanmumford8806@alanmumford88062 жыл бұрын
  • Such a simple explanation with exceptional illustrations. This also makes it abundantly clear why 2-stroke engines require such precise tuning of their exhaust systems to function.

    @ssvis2@ssvis2 Жыл бұрын
  • Back in the 80's Yamaha introduced the EXUP system on their 4-cylinder high-performance bikes. It used a butterfly valve at the collector to change the timing of the negative pulse in response to changes in rpm. Later they also introduced variable length intake runners. To improve low-rpm intake velocity on single cylinder bikes they fitted two carburetors, one with a small bore, one large. The larger bore carb would only open at larger throttle openings.

    @jiyushugi1085@jiyushugi10852 жыл бұрын
    • All very very relevant examples!

      @d4a@d4a2 жыл бұрын
    • is that used in any other bikes of other manufacturers?

      @vasilisgreen@vasilisgreen2 жыл бұрын
    • @@vasilisgreen yeahh but yamaha the true genius who create the brilliant system later then copied by other manufacturer

      @JAVTROOPER@JAVTROOPER2 жыл бұрын
    • @@d4a can you make video on this Yamaha exup system?

      @lordjaashin@lordjaashin2 жыл бұрын
    • @@JAVTROOPER the "genius" who copied Walter Kaadens work at MZ disc valves

      @chrisdeli7547@chrisdeli75472 жыл бұрын
  • Every time I watch your videos I'm blown away by your knowledge, and the clear and simple ways in which you describe these fundamentals. THANK YOU 🙂 An inspiration for young and old engineers alike and a great tool for all. I wish you every success

    @toliver.99@toliver.99 Жыл бұрын
  • dude, your the best at explaining the most technical things so we can all understand complicated concepts well done !!!

    @youtube-is-trash-2277@youtube-is-trash-22779 ай бұрын
  • On a naturally aspirated engine, the exhaust header and intake should both be tuned to the same rpm range for max gains. Today some intakes have variable length runners for a wider peak curve and variable cam timing helps capitalize on that. When the intake cam and exhaust work together you get a sweet spot to upshift into.

    @3dw3dw@3dw3dw2 жыл бұрын
    • @Snowman88 damn straight! Reading your reply feels kinda like looking into a mirror.

      @3dw3dw@3dw3dw2 жыл бұрын
    • @Snowman88 I've seen opposed piston engines where 2 pistons share the same bore. It was not something anyone would consider fast but it was unique. I like the cosworth that was made for Gordon Murray's T.50 and I love the Aston Martin Valkyrie engine. All I have now is a Yamaha R6, a supercharged 2zz-ge and whatever Tesla put in my wife's model y. They all move out pretty good. I'm not gonna lie, I could gap a countach with either of them. I've worked on motors that were so big they have their own 5 story buildings to live in. I came to work one one engine that had a plug wire arcing and it developed a gas leak (it was a natural gas engine out by st. Joseph's bayou in a place called east bay) well it blew the roof off the building and melted all the window frames. It was frightening to see the carnage. So glad no one was in there when it lit off. I worked on some cooper b250s. A man can fit in the cylinder sleeve. Max rpm maybe 500 if one were being foolish. It's a LOT of power at 350 rpm though. You want it to turn slow because it is also a gas compressor. A really big gas compressor.

      @3dw3dw@3dw3dw2 жыл бұрын
    • @Snowman88 alright, hear me out, variable length headers, like telescoping tubes. Alongside telescoping ITBs, Ti-VCT, and a VTEC system. (Or even better, just go freevalve with the adjustable intake/exhaust manifolds

      @Prestiged_peck@Prestiged_peck2 жыл бұрын
    • You guys are looking in the wrong place for gains until you have experienced your own variable-nozzle turbo

      @fastinradfordable@fastinradfordable2 жыл бұрын
    • Today people just use turbo

      @ArneChristianRosenfeldt@ArneChristianRosenfeldt2 жыл бұрын
  • The knowledge on this channel never cease to amaze me.

    @TheRealTomLauda@TheRealTomLauda2 жыл бұрын
  • Greetings from oregon brother i am a gearhead! There ive said it you are by far well educated gearhead i really enjoy the way you explain the mechanical world we live in thanks great channel

    @davidbones8947@davidbones894710 ай бұрын
  • Another part of the Scavenging is helping Evacuate the exhaust from an adjacent cylinder with pressure and back pressure. More so in a multiple y collector header situation. That typically pertains to NA engines. You did a great job considering you could make an entire movie just about headers and exhaust. Keep up the good work and keeping the masses educated.

    @wilbur9416@wilbur94162 жыл бұрын
    • I had a kid claim that I messed up my exhaust scavenging by switching from a dual exit exhaust to a single exit 🤣 its a turbo v6 and split to a y section at the back of the car, but I switched to a single exit.

      @codydillenbeck4443@codydillenbeck44432 жыл бұрын
    • Well said WILburr. "Scavenging Sucks".... thank goodness. Cheers!

      @ovalwingnut@ovalwingnut2 жыл бұрын
  • Well video came out 15 seconds ago so you could say this is the most on time I've ever been. 😌 D4A video means good day.

    @802Garage@802Garage2 жыл бұрын
  • One of [if not] the best descriptions of "the process" (and in under 18 mins) I've ever heard, bar none. It was like having my GF talk dirty to me again but before she gained the weight. So, Yes, I APPROVED THIS VIDEO :O) The rumors are true. You "are" the Gear-Head Whisperer. Cheers!

    @ovalwingnut@ovalwingnut2 жыл бұрын
    • This comment has me straight f***ing rolling 🤣😂🤣 Let’s go Brandon!

      @patmygroin@patmygroin2 жыл бұрын
    • What does talking dirty have to do with weight? You can successfully talk dirty to someone, without ever seeing them in person, so their weigh should have very little bearing.

      @the_hate_inside1085@the_hate_inside10852 жыл бұрын
    • @@the_hate_inside1085 I hear you T.H.I. But once you've seen Ms. Muffy trodding down the hall in a towel (that will always be to small).. well, you just can't un-see that. This has a direct impact on future Remote Oral Stimulation (ROS), for me at least. Just saying. Anyway, that's the skinny on the subject. You RoCk! Cheers.

      @ovalwingnut@ovalwingnut2 жыл бұрын
  • Good topic, headers are so important on natural aspirated engines , i switched from a stock 41 narrow tube to a wider 421 and the gain is noticeable on a K24

    @vladdutz20@vladdutz202 жыл бұрын
    • especially with reflash :)

      @Denonavr1907@Denonavr19072 жыл бұрын
    • Waiting for your video on this subject ;)

      @stefan.2833@stefan.28332 жыл бұрын
    • Same with my Panther, made it faster n seems lighter..lol

      @P71ScrewHead@P71ScrewHead2 жыл бұрын
    • I can agree with this 100 percent. I put in carless headers on my tsx with the ktuner reflash and it is very noticable.

      @vhssociety@vhssociety2 жыл бұрын
    • @@vhssociety just got a clutch overhaul and it shifts smoother, 20s 100 200kmh

      @vladdutz20@vladdutz202 жыл бұрын
  • Awesome as usual! Less than 20 minutes, covered and explained cam overlap, exhaust gas flow theory, effects on NA and boosted intake and a few other "incidentals"- all in one very large single breath! And it was intelligible! And you are sure you are not a home brewed motorhead from Philly? Awesome ! FR

    @fredericrike5974@fredericrike59742 жыл бұрын
  • I am amazed at the quality of his videos. Such deep knowledge of engines and he is an excellent educator. The illustrations are very helpful. I feel like I owe him something for everything he has taught me.

    @livingon2wheels@livingon2wheels Жыл бұрын
  • I keep watching your videos, not a car enthusiast but you make a great learning experience with the way you explain the mechanical intricacies and details.

    @wouldyoudomeakindnes@wouldyoudomeakindnes2 жыл бұрын
  • thank's for this video ....!!!! im not a car driver, but a motorbike driver ... and all this of the "back pressure" has helped me to understand many things about "changing the exhaust line to improve the bike's performance" (sacrificing other things, obviously...)

    @lucasmari8643@lucasmari86432 жыл бұрын
  • Such a good content! I am honoured to be able to watch something like this for free🙏

    @ILKOSTFU@ILKOSTFU2 жыл бұрын
  • You are amazing bud, simple, very detailed, well drawn diagrams! Great stuff!

    @qzammit89@qzammit892 жыл бұрын
  • Nice video! Cast manifolds aren't always bad. I have dynoed volvo 5cylinder engines with oem s60r cast manifold. It is quite short and equal leng. Sturdy af, hot exhaust gasses makes fast spooling turbos.

    @Minitonnar1@Minitonnar12 жыл бұрын
    • Long manifolds gives higher peak power but sacrifice a lot of spooling time. Probably slightly oversized turbo with realatively short manifold should be optimal for track use

      @el_kuks@el_kuks2 жыл бұрын
  • After watching your videos i feel like I can build my own engine. Great job

    @tomaszrazik2991@tomaszrazik299110 ай бұрын
  • I thoroughly enjoy the depth you go into topics. You are an excellent presenter!

    @etype-dad@etype-dad Жыл бұрын
  • Thanks for being accurate and well informed. I haven't found a single instance of inaccuracy or misinformation in any of your videos. That can't be said for many channels, even some of the so called experts.

    @Dane33781@Dane337812 жыл бұрын
    • The only thing I can fault him on is the use of "bars" for pressure. It's just "bar", regardless of how many there are. Just like you don't say PSIs.

      @TonyRule@TonyRule2 жыл бұрын
  • Learned more about turbo manifolds than ever 10 min. into this vid. Good stuff 👏 👍

    @PC-iv5so@PC-iv5so Жыл бұрын
  • your video is very good, all the important things you explain in easy to understand terms. it makes it very easy for people or lay mechanics to digest the concept you want to explain. I just saw the first few parts of this video, I was immediately interested & automatically subscribed. I really appreciate your work

    @faddiehakim531@faddiehakim5319 ай бұрын
  • About 20 years ago I had a truck and installed 3” dual exhaust, a programmer and an intake system. It made a small difference but once I installed headers, it made such a big difference. Now I’m old with a kid so my fun days are over.

    @Tim.1113@Tim.11132 жыл бұрын
  • Excellent ! That has to be the best explanation of manifolds that I've ever seen. (Another one of my automotive heroes is David 'the wizard' Vizard who goes into great detail, based on a very scientific approach.) The only thing I would add is exhaust gas momentum - at higher rpm the exhaust gases have a fast moving mass which pulls out the following charges from each cylinder. Again, as you mentioned, the manifold design and optimum pipe diameter are important, all depending on the engine and the spec you want. 👍 (PS: I can only comment on normally aspirated engines.)

    @theondebray@theondebray2 жыл бұрын
  • There are so many variables on a N/A that the easiest way to determine the optimum configuration and dimension is to mount the engine on a test bench and make a modular telescopic manifolds with at least 8in of adjustability. Starting from a ball park dimension in the first place. Turbo manifolds seem more subceptible to pipe diameter, not pipe length, unless you are compeating and have cam shafts that allow the engine to rev. as high as a competition NA motor, as in the video. Well explained theory on a subject that has sent many a good man mad

    @gothicpagan.666@gothicpagan.6662 жыл бұрын
  • Long time ago hear about exhaust scavenging, then today you make it clear. Great Job

    @yr6sport418@yr6sport4182 жыл бұрын
  • I usually listen to your videos twice...so the first time is like "basic Math" and I get the ideas and concepts... and the 2nd time aroind, I pick up more of the details, and also get a better understanding of some of the things mentioned earlier in the video.

    @BucketWheat@BucketWheat Жыл бұрын
  • Thank you sooo much for this great video. The best video I've watched in three weeks. So amazing, so educational, my subscription is very much deserved. Please keep the good content coming.

    @cjpowers2637@cjpowers2637 Жыл бұрын
  • bro. wow. just wow. you literally make this stuff so easy to understand. help it up brother

    @KeepinItReal890@KeepinItReal890 Жыл бұрын
  • You spent a lot of time and effort on the video, graphics and mathematics, thank you !!!

    @ronsmith7739@ronsmith77392 жыл бұрын
  • Very fascinating topic. One can get a sense how designing the exhaust system effects how an engine can run and feel and cost to operate. It really is an art.

    @torque350hp@torque350hp Жыл бұрын
  • Another thing to mention with turbocharged engines, short circuiting (excessive valve overlap) of charge air into the exhaust usually results in melted turbine wheels and exhaust valves, as the raw fuel and fresh air usually ignites as it blows past the red hot exhaust valves

    @jeffhurckes190@jeffhurckes1902 жыл бұрын
    • Antilag. Yuck

      @ifixeuros@ifixeuros10 ай бұрын
  • one of the very best youtube channel I enjoy to watch!!! thanks alot

    @onurakatlar3126@onurakatlar3126 Жыл бұрын
  • You did miss one trick where cast manifolds are superior. Yes, stainless steel can handle higher temps, but the wall thinness makes it very likely to expand when heated, which often leads to cracking at the welded points where each tube tries to expand but is locked in place. In addition, each weld acts as a stress riser, meaning the force of holding the turbo and absorbing driveline vibration is concentrated in a small area unlike in a uniform cast material where load is distributed quite evenly. This uniformity and thicker overall wall thickness of a cast manifold makes it much more durable under repeated heat cycles, despite having a lower rating. I am also curious how the plenum effect, where exhaust gases collect before entering the turbo, might lead to improved balance of backpressure vs keeping each cylinder so separate. ITB's are much harder to balance for individual cylinders than an enclosed airbox for pressure and flow reasons

    @timocallaghan4408@timocallaghan44082 жыл бұрын
    • i would not agree with you , i saw many cast iron manifold cracked , and cast iron manifold has ticker walls that is not good because difference in temperature that causes stress in material. i had long tube header and because i floored it is burnt and melted but not cracked on welds

      @makantahi3731@makantahi37312 жыл бұрын
    • I get what you're trying to say but it's a bit misleading. Assuming good welding technique, proper purging procedures and materials a weld's role as a stress riser is negligible. The same goes for each tube expanding separately, this really doesn't happen and the manifold expands and retracts as a whole under normal operation. The final point is the uniform structure of casting. I'm afraid castings most often have the worst and most irregular grain structure and exhibit porosity due to the nature of the manufacturing process. When it comes to wall thickness this definitely makes sense and with enough thickness a cast manifold can indeed be extremely durable but you need so much thickness that weight and bracing really becomes an issue. But this is why you see very thick manifolds on trucks where they are expected to last for a very long time. As to ITBs and balancing I'm afraid we're taking apples and oranges. ITBs will always yield superior power and responsiveness compared to a plenum due to somewhat obvious reasons (more air faster and more directly - all other factors being equal). Their balance is only really relevant at engine idle and has next to zero effect at WOT. An equal length manifold will always be superior to a log in terms of power due to reasons explained in the video. There really is no need to complicate the analysis by trying to include things that really aren't a factor in this.

      @d4a@d4a2 жыл бұрын
    • @@d4a that is right except one thing wall ticknes is problem , more tick, makes stress when heats up, because inner part is warmer , outside is colder, can not be heated up simultaneously, but if is thin , it heats up imediately

      @makantahi3731@makantahi37312 жыл бұрын
    • I don't see the logic. Blocks are very thick and they never crack because of their thickness? I don't see how heating up of a thick material increases stress vs a thin one. I think that this debate is overall a moot point honestly. Neither casting nor welding guarantees durability and longevity. Both types are used by OEMs and there are extremely durable as well as very poor examples of both cast and welded manifolds. I believe what's far more important for durability is design, quality and vibration minimization.

      @d4a@d4a2 жыл бұрын
    • @@d4a mostly, people with stock car does not races, but i saw many cast iron collectors cracked, maybe because there are plenty, if you try to weld cast iron you have to preheat it slowly, to avoid big differences in temperatures in material, and big collector on truck is not loaded by temperature as on petrol engine, because it has lower ex temperature because diesels work with plenty of air, more than 20:1

      @makantahi3731@makantahi37312 жыл бұрын
  • i fucking love watching your videos, i am a mechanical eng on last year and although your explaining style is similar to lectures at uni but the only difference is that i understand wtf you are saying :) keep it up

    @Ali-uf1sq@Ali-uf1sq2 жыл бұрын
  • Your explanations are very clear and understandable. Great work.

    @dominichayes9808@dominichayes980810 ай бұрын
  • Very well explained, I've always thought of an exhaust system as simply a "drain pipe" that is or isn't restricted by mufflers etc.

    @gazzafloss@gazzafloss2 жыл бұрын
  • I’ve always been a little under the bar when it comes to this topic, excellent explanation

    @1cnfour349@1cnfour349 Жыл бұрын
  • Great explanation of the two manifold Vs. Headers! This is why I've subscribed! Thanks

    @scubbarookie@scubbarookie Жыл бұрын
  • Favorite part of Sundays.

    @deciplesteve@deciplesteve2 жыл бұрын
  • No way!!! Posted right when im in the market for headers for my subie😮‍💨

    @natanaelonate5193@natanaelonate51932 жыл бұрын
    • its because "they're" listening to you on your phone, and voila....you get "header information" in your feed.

      @iBackshift@iBackshift2 жыл бұрын
  • I'm learning so much from this channel. Thanks for the education.

    @dennisal1481@dennisal14812 жыл бұрын
  • I enjoy watching your videos, your explanation on everything is very well thought out and I learned a lot in this video as I am busy looking to upgrade my car's exhaust 😁

    @360-Speed@360-Speed2 жыл бұрын
  • No better KZhead channel !

    @flyonbyya@flyonbyya2 жыл бұрын
  • 3:38 The intake air coming into the intake valve is almost always below atmospheric pressure. The air cleaner and throttle plate cause reductions below ambient atmospheric pressure. This is an important distinction when considering part-throttle operation.

    @ronaldjensen2948@ronaldjensen29482 жыл бұрын
    • without computers, the thought would not exist.

      @HighAway@HighAway Жыл бұрын
  • I just put long tube ISR headers on my 370z, this video helps explain alot!

    @quinn7174@quinn71742 жыл бұрын
  • I love watching these. Hard to find a “Turbos for Dummies” cliff notes!

    @BoostedNDMiata@BoostedNDMiata Жыл бұрын
  • Very clear, very well stated. I understood most of this, but you clarified some questions that I have had. Thanks!

    @TestingPyros@TestingPyros Жыл бұрын
  • This is a great informative video. Best one I've seen

    @MadelnOahu@MadelnOahu2 жыл бұрын
  • Awesome vid well explained, i love it when i can understand what techs are talkin about. Well done , Cheers

    @clutchkicker392ison5@clutchkicker392ison5 Жыл бұрын
  • This is such an amazing explanation. Thanks man. I’m going to apply this new knowledge to my project car

    @dooby1445@dooby14452 жыл бұрын
  • Also something to note, as you widen a runner it is possible to reduce the overall flow due to the resulting bends. Larger diameter pipes end up having sharper bends in a direction change over the same distance. Just something to keep in mind. Also going too big can have negative effects in other ways, like reducing exhaust speed.

    @Oblithian@Oblithian2 жыл бұрын
  • With turbo motors, it's all about the temperature of the exhaust gases. That heat energy goes to power the turbo so cast iron log manifolds are good in that application. My BMW M2 has a simple exhaust log manifold and I'm happy with the overall performance.

    @billymania11@billymania112 жыл бұрын
  • Those headers are just a work of art. I wouldn't care if they worked or not. I did have Genie extractors on my six cylinder holden so I'm a fan anyway.

    @SteveMuir@SteveMuir2 жыл бұрын
  • Here in the UK there was a car called the Vauxhall Corsa B which had a 1.6 16v engine and made approx 108Bhp. There were two common mods people would do. One was a 4 branch free flow manifold, de-cat, and free flow resonator and backbox and the other was a "power box" where they removed the stock intake manifold and put in a "less restrictive" version The problem was, this upset how accelerated the air was in the cylinders at low / mid rpm and messed up the scavenging effect. On the dyno the mods took the power to approx 130bhp, but unless you were revving it's nuts off daily it didn't make a good daily driver.

    @hardcoretam@hardcoretam2 жыл бұрын
  • That was an excellent and well put together article. I learned a lot, thank you!

    @OldManRoo@OldManRoo2 жыл бұрын
  • The next well put together lecture on how to consider different design choises making an internal combustion engine. Thanks for the effort and I hope you cover the intake side and valve timing and duration too.

    @andik.4235@andik.42352 жыл бұрын
  • You truly are a living legend!

    @philippepanayotov9632@philippepanayotov9632 Жыл бұрын
  • Brilliantly explained as per usual ! 😀

    @olspanner@olspanner2 жыл бұрын
  • Very informative video as usual; thanks for that and for demonstrating that gorgeous aftermarket exhaust header.

    @LooseNut099@LooseNut0992 жыл бұрын
  • Once again, interesting stuff and very well explained! Thank you.

    @SerbanCMusca-ut8ny@SerbanCMusca-ut8ny2 жыл бұрын
  • Very interesting and high-quality video as always! I was thinking about how the pipes of an exhaust system join together. Like on a 4 cylinder you merge pipes together 2 by 2, sometimes all 4 merge together at the same time. I know it affects scavenging and back pressure as well. Would do a nice video subject to follow this one in my opinion.

    @OdamaKamayuka@OdamaKamayuka Жыл бұрын
  • Your point of the narrow range of the scavenging effect reminded me of an article in Cycle World back in the late 1960s. The author was racing at Daytona in the 250 cc class and he rode a Harley Davidson that was an Aermachi rebadged as an HD and it was a single cylinder engine with the piston horizontal to the ground. Due to the tuning they'd done on the intake and exhaust tracts and the cam timing and their attempt to get maximum horsepower it had an unusual torque curve. Running alone on the high speed sections of the track he could only pull 9200 RPM in top gear. But if one of the slightly faster bikes was in front of him or pulled in front of him he could draft behind the faster bike till he got up to about 9800 rpm then his torque curve had gone up enough that he could go ahead and accelerate up to 10,500 RPM and pass the formerly faster bike he'd drafted behind and it could maintain that speed until he had to brake for the turns. If I remember right, that Aermachi was a pushrod 2 valve per cylinder engine. That it would run reliably at nearly 11,000 rpm over a 500 mile race was amazing to me, for any engine really, in the late 60s. My 1970 Honda 750 K0 originally had the redline set at 9,000 rpm. it was later lowered to 8,500 rpm. I seem to remember Dick Mann winning once on a Honda 750 and his engine was pretty much destroyed at the end of the 500 miles. I guess he got everything out of it that it could give. Back on Point! Scavenging apparently is only important on turbocharged engines for extremely high performance. The intake and exhaust tracts on my Cummins are pants on head retarded if you think about them. Even the aftermarket exhaust manifold on my truck is barely more than the original and puts the Turbo in exactly the same position. The intake manifold is a square cross section box bolted to the side of the head, and the pressurized air is dumped in from the top after going through an intercooler, and "airhorn". the airhorn receives the air from the intercooler and makes 2 fairly abrupt changes of direction before dumping into top of the intake manifold well off to one side of the cylinder head between cylinders 2 and 3. I guess it has the advantage of being cheap to produce. I would imagine that any sort of tubular spread of pipes coming from the intercooler into the side of the intake manifold in even just 2 places would be a huge improvement in efficiency of the system.

    @chrisbaker2903@chrisbaker29032 жыл бұрын
  • Appreciate your mounting the turbo backwards at ~ the 1:00 mark to make it easier to show how the rest of the exhaust line mounts up to it... 😁

    @nunyabidniz2868@nunyabidniz28682 жыл бұрын
  • Great video. I fabricated plenty of short tube and long tube turbo headers for various race cars. Your point about 5-15% more power is an interesting one.

    @cujet@cujet Жыл бұрын
  • Great explanation man. Also classic argument about how everything on a car and generally any other product, has tradeoffs. You want more power? Well you get less longevity etc and it goes on and on. Guys throwing out just hp and torque numbers think its the be all and end all... And forget about hp to weight, driveability, efficiency, etc. Awesome as always

    @samcoote9653@samcoote96532 жыл бұрын
    • Very true. Numbers are sexy and allow easy comparison but as you pointed out, it can be very misleading and draw attention away from the bigger picture.

      @d4a@d4a2 жыл бұрын
  • Great video as always. That manifold looks great. On my current budget it's cast log life for me. :D

    @802Garage@802Garage2 жыл бұрын
    • Nothing wrong with last logs honestly. Plenty of real world benefits which explains why they're so widespread

      @d4a@d4a2 жыл бұрын
  • One of your best videos, thank you :-)

    @Slaktrax@Slaktrax2 жыл бұрын
  • that manifold is gorgeous

    @aergaetrhethaergertha2099@aergaetrhethaergertha20992 жыл бұрын
  • Just started viewing your content very informative and I appreciate your in-depth discussion or explanation of material you present I have been a gear head all my life grew up around the ice of all shapes and sizes and your content has taught me things I’ve learned wrong all my life or I thought was one way and you proved it to be different My question is if I decide to go ev and build it myself will a 5 spd trans be beneficial I’d like to try it if nothing else but I watch your video on ice vs ev and it got my brain turning instead of running the electric motor at max rpm mount it to a stick tranny and use gears just like a ice reduce rpm while maintaining speed what are your thoughts

    @ericjernagin7902@ericjernagin7902 Жыл бұрын
  • Brilliant & informative vid conveying many points concisely, clearly. Thanks.

    @villiamo3861@villiamo3861 Жыл бұрын
  • Great video mate! Well explained 👏🏼

    @Adok24@Adok242 жыл бұрын
  • I've found this enjoyable, useful and informative. 🎯💯

    @aaronwalcott513@aaronwalcott5132 жыл бұрын
  • Great video, I run long long tube headers on my Mustang to improve the mid range power. Keep up the great content 👍

    @robertb3409@robertb34092 жыл бұрын
  • I made 445rwhp on a 3.0L 7MGTE with a log type manifold. That's 520 crank! 18psi on a 64mm

    @Twobarpsi@Twobarpsi2 жыл бұрын
    • Plus you didn't have to build a mount to prevent the weight of your turbo destroying your manifold.

      @3dw3dw@3dw3dw2 жыл бұрын
    • Fun fact: turbos work better with cast manifolds, NA engines work better with tubular setups.

      @Prestiged_peck@Prestiged_peck2 жыл бұрын
    • Turbos are not that picky what feeds them, all you need is velocity and heat energy…..not surprised at your numbers. Is that motor in a MK 3?

      @miketess4272@miketess42722 жыл бұрын
    • @@miketess4272 yeah 87 mark 3 back in the day, on a fresh all new stock parts engine rebuild.

      @Twobarpsi@Twobarpsi2 жыл бұрын
  • Excellent explanation and presentation!

    @tomciancitto7328@tomciancitto7328 Жыл бұрын
  • I used to build race exhausts and i found the best way to create negative pressure is to have the primary tube expand in increments 3 times over its length by the thickness of the wall of the tube in each step up. This creates vacuum because the negative pressure wave, as it moves at the speed of sound travelling through the increase in size of the tube it increases the volume creating extra negative pressure at the chamber which scavenges spent gasses and sucks in fresh air/fuel even before the exhaust valve closes. We had to make our own pipes for racing as you cannot buy these systems. The primary tube lengths should always be exactly the same length so the when the positive pressure wave hits the secondary pipe it creates a second negative pressure point on all chambers that the secondary pipe is connected to and thus working in harmony time wise. I found this information out by observing some formula 1 exhausts which are designed this way and needless to say cars that ran my designed exhausts were always front running cars. Primary tube length requirements are governed by your requirements for where you want your maximum power output to be in the rpm range. Longer means max power at lower rpm and shorter at higher rpm. Also larger diameter pipes are for higher rpm power and smaller for lower rpm. Use the correct sizes and you will go faster, bigger is not better, the right size is better. Secondary pipes should be shorter than the primary's and the secondary's should be connected to ONE final exhausting pipe which should be as short as possible and which ties all the harmonics of the pressure waves together in perfect sequence for maximum effect. This design creates max power at a certain rpm and does not spread the power around over the rpm range which in most cases you dont need because spreading the power around while giving you more power across the rpm range you will have less power as a peak, better to have all your power in one spot in your rpm range and get that power point exactly where you need it most in the rpm range. This is also the best way to create torque. As for what length and diameter pipes you need, that's a guess, or least an educated guess. We built 6 exhaust systems before we knew what worked best for us. All engines and applications are different and will require different sizes. i was running a six cylinder in circuit racing with an engine that didnt rev over 6k. max concentrated power came on at about 4000 rpm. Strangely it held most of that power to the rpm limit even though power was not spread about the rpm range, (hard to explain) We ran 900mm primary's, 500mm secondarys and a 3 inch final that exited as soon as was possible out beside the drivers door. Primary's started at 1.5 inch and stepped up two more times over its length by the wall thickness of the pipe each time and the secondary's were 2 and quarter inch.

    @matton36@matton362 жыл бұрын
  • Thank you for your content 🙏🏼

    @StephanSchmali@StephanSchmali2 жыл бұрын
  • Wow i never knew exhaust gases hit the speed of sound in the manifold, that's super cool

    @dominicrichardson5546@dominicrichardson55462 жыл бұрын
    • The gases don't, pressure waves do. Presure waves always travel at the speed of sound.

      @igornoga5362@igornoga53622 жыл бұрын
    • @@igornoga5362 do not turn sew upside down, , speed of sound is equal to 20.1 times second root of termodinamical temperature of gas, , so if gas flows faster than 2582km/h with temperature of 1000c deg, i flows faster than sound

      @makantahi3731@makantahi37312 жыл бұрын
    • @@makantahi3731 Gas can travel faster than the speed of sound, for example in rocket nozzles. Here we are talking about internal combustion engine exhaust, which is never even close to Mach 1 to avoid backpressure.

      @igornoga5362@igornoga53622 жыл бұрын
    • @@igornoga5362 one lesson from aerodynamic, if you have ad tunel with smaller diametre,in middle and after expands,(venturi tube) and forces some gas(air) to flows , as raises pressure , speed raises , until pressure reachs 1 bar , in smaller diametre, speed reaches 1Ma, if pressure raises more, speed in smaller diametre is still 1 Ma, but in part of tunel where diametre expands, speed starts to raise over 1 Ma, so you have supersonic speed, same is in exh primar tubes, gasses from cylindre are under pressure and when exh valve opens it expands into primar tube or collector with supersonic speed, with no muffler you will hear bangs-what is supersonic expansion

      @makantahi3731@makantahi37312 жыл бұрын
    • @Snowman88 not density, speed of sound of air/gas is in direct relation with termodinamic temperature

      @makantahi3731@makantahi37312 жыл бұрын
  • You are a treasure to humanity

    @mstrshkbrnnn1999@mstrshkbrnnn19992 жыл бұрын
  • So much to learn here, excellent video!

    @kieranstephenson3187@kieranstephenson318710 ай бұрын
  • As usual, great video!

    @memra777@memra777 Жыл бұрын
  • Man you are making me seriously consider keeping my 2GR-FE naturally aspirated when I go to increase its power output.

    @johnrickard8512@johnrickard85122 жыл бұрын
  • Very informative, great vid!

    @joopterwijn@joopterwijn2 жыл бұрын
  • thanks for the knowledge ^^ awesome video man!

    @Rogerdin13@Rogerdin132 жыл бұрын
  • As always very informative video

    @ramadhanisme7@ramadhanisme7 Жыл бұрын
  • I suppose it's all about what you want from the engine. Touring hill country is vastly different to racing or cross country across the desert regions. Nicely explained.

    @alexjames1146@alexjames11462 жыл бұрын
  • Thanks a lot. This is professional-level knowledge that the professor does not teach you at school. If there is a video of natural intake back pressure in your video, I really want to see it.

    @user-ub3ph3zz6w@user-ub3ph3zz6w2 жыл бұрын
  • With NA engines you can use early exhaust valve opening with a properly tuned header with a reverse cone megaphone. It will bring the cylinder pressure below atmospheric pressure when the intake opens the signal sent back thru the intake and produces increased flow into the cylinder. Professor Blair’s book on four stroke tuning is a good book for the mathematical inclined.

    @copisetic1104@copisetic11042 жыл бұрын
  • From memory, the exhuast manifold can also affect the peak power rpm of your engine as well as how broad or narrow that peak is. This is determined by length and diameter respectively.

    @Nyxteros@Nyxteros2 жыл бұрын
  • Thanks man. I was thinking about this topic. Kind regards from the Netherlands

    @pacolicious@pacolicious2 жыл бұрын
  • Mainly watched to just dust off the rust but I do have 1 question... Doesn't the angle of each pipe on your manifold want to be close, if not all the same degrees of angles?

    @tankeater@tankeater Жыл бұрын
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