No More Exhaust Myths - /ENGINEERED

Do you need back pressure? How big should your headers be? Today, we interview Richard Waitas, Senior Manager at Magnaflow, to learn how an exhaust system actually works. Learn on Monday, wrench smarter on Sunday.
Introducing a NEW series on /DRIVE, aimed at educating you to build a faster, better, more reliable car: /ENGINEERED. We want to empower our fellow enthusiasts to know more, and do more, by learning from some of the best engineers in the game.

[@OldBuford]

"where does design begin?" well first youll want to make sure that the manifold is right next to the oil filter, being sure to block the filter as much as possible in order to make oil changes as difficult as possible

[@nitetrane98]

Number 1 and 3 tubes will need to be beaten nearly closed to clear steering box.

[@brianwenzel8791]

Exactly.!! the engineers that design vehicles have absolutely know idea what it takes to fix / work on them.. Cars should be designed by Real mechanics. which would help make repairs easier / cheaper.. the newer the vehicle is, the more over engineered it is.. which makes costs go up with repairs.. way more people need to know about this.

[@715101]

Don't forget close enough to the plug wires to burn them out frequently

[@thechosenoneilluminati4380]

Don't forget to wrap the headers around the starter

[@Piunti_302]

Yessss! I'm a tire and oil tech and I hate this, it mostly seems to be GMC that jus loves putting the oil filter next to or behind the fucking manifold!

[@NN-wd2vi]

0:07 The wife seems to disagree...

[@jebwatson]

I think the warranty is usually voided after you start blowing...

[@savagegod2106]

Phil Jones

[@michaellee1216]

HAHAHAHAHAHAHA

[@youngsloth7164]

😂

[@megaprimegamer1184]

@pete smyth you do realize this is not really any engineering conference but a random video on the net, don't you?

[@guitarplaya47560]

These Engineering videos provided by Drive are incredible. Very informing. While they are long, they pack a lot of info at an easy to understand level. Keep up the great work!

[@snaaail]

Half an hour long? That was exhausting

[@davidsinclair-black7494]

That's p-unny

[@Prizz419]

Booooo

[@flyjum]

+AJHedges I thought it flowed pretty well actually

[@kent8blue2007]

+AJHedges i'm sorry but for me those 30min passed like 5 minutes if you are really interesed

[@snaaail]

It was a joke...

[@CurtHousen]

Very informative for someone like me who never really thought about intricate exhaust design was.

[@fvl548]

This video was well worth the time! Normally I shy away from +15min video's but this one is very interesting if you're into exhaust systems and how they work. I learned that there are more dynamic aspects than static. Thank you very much to the guys at /Drive for making this and the guys at Magnaflow for explaining

[@Dgannt]

Always a pleasure to listen to professionals. It's obvious he knows his areas of work and could explain different parts very easily. Thanks for the lesson.

[@kellyokamoto1604]

Wow-after over 45 yrs wrenching on engines I was pleasantly surprised by the knowledge put forth in this vid. Now, my question is do ALL header mfgs put as much in-depth engineering into their header builds as MagnaFlow or are they just slapping pipe together and moving product???

[@sprintr6441]

One of the best presentations I've watched....Nicely done!

[@markiplierSINGSbadly]

what the heck kind of intro was that? XD

[@owanlazic9980]

ikr lol

[@117johnpar]

+markiplierSINGSb.a.d.l.y. A bare bones, Formal intro. I wish they would do a sexual innuendo intro to spice up the beginning. Missed opportunity.

[@Ktmzqw]

+markiplierSINGSb.a.d.l.y. Coloquial terms for the 4 stroke cycle: intake, compression, power, exhaust.

[@omfgwtfbbq90]

+markiplierSINGSb.a.d.l.y. Actually a very witty and intelligent intro ;)

[@duviday]

+markiplierSINGSb.a.d.l.y. a good one. why, what was wrong with it?

[@andrewpochettino8506]

Thank you for making this video. As the exhaust and intake designer for Iowa State’s Formula SAE team, I started with zero knowledge of the two systems and had to figure out how they worked with the engine on my own. Because we work with a single cylinder 4-stroke engine, I didn’t have to design a manifold, but I still had to learn a lot. One of the problems I had was figuring out where to start and you put the aspects of the exhaust in a logical order. After watching your video, I am able to connect these components together and have a better understanding of the exhaust system. For an introductory video, this is well done. Thank you!

[@Bobby-ic2zd]

/ENGINEERED was such an amazing series, I wish they kept it going.

[@elhadjiamadoujohnson4166]

This man knows his topic, unlike most of the big mouth here!!! I tip my hat to him!!!

[@johnbeer5242]

Elhadji Amadou Johnson u must have magnaflow exhaust😂

[@TargaWheels]

That '69 Camaro was very distracting. I only heard half of what he said.

[@johnbeer5242]

TargaWheels haaha😂 si si yes

[@alwaysopen7970]

I kept thinking of my old one I sold in the late 80s. I loved that car.

[@dapsapsrp]

I had a difficult time taking my eyes off of it.

[@toka100]

Yah that’s mine. 😝

[@TH3C001]

Bro! SAME!

[@tomslater5198]

Holy hell. This was a fantastic video. Presenter seriously knows his business and how to break it down barney style for a youtube video. Love it.

[@ForkTheSpoonWrecker]

This guy has been the best one yet, his explanations are very clear and precise. Thanks!

[@rm-photography3289]

"blowing is important too" tell that to my girl friend :,(

[@lilpoindexter]

You aint even married yet and already putting up with this BS?

[@rm-photography3289]

lilpoindexter ikr the horror of this generation lol

[@PoliticalThrowback]

Rusty Ranger bruh I can't get mine off of me.

[@bootyman234]

+ Speed of darkness. Some of us are more fortunate than others lol

[@rm-photography3289]

Speed of Darkness bro super glue is not a good lubricant!!!!

[@sp4nrs]

HOW COULD HE NOT MENTION BACK PRESSURE MYTHS??????????

[@geoffpeters4474]

everything you need to know about the back pressure myth is there you just have to not be an idiot and think a little bit, he explained all about tube diameter and exhaust velocity, airflow, and exhaust pulses helping extraction. He just didn't outright say it maybe to help weed out the retards who can fuck off.

[@nos1000100]

by what i got was. If the tube is too big at the header its bad but mainly if the tube size isnt consistent all the way down the system. its worse

[@2ShoesPhoto]

He mentioned the science about back pressure when he spoke about the restriction in the header causing an increase in peak torque vs average torque. That's where the back pressure comes in. Now, if you want overall torque, open that exhaust up and let it flow.

[@codyparker679]

Back pressure isnt that important but you need about a minimum of 1ft of pipe and good tuning to not warp valves. Dealing with race cars bassically all I've noticed. Friend ran open header on his 302 f15p for 4 years towing and daily use and never had an issue but was very well tuned and he had a 3in to 2in on the collector to retain alittle back pressure. Loud as hell though but loved it

[@Thedirtylittlesecret]

Cfm to tube size.

[@ItumelengS]

Now, thats an intro that has been orchestrated beautifully. Thank you sir

[@prayanjaltomar752]

Respect to this guy who shares with us his knowledge and experience in just half an hour video ❤️🙏.Great work Sir

[@JD-lh2ve]

Awesome video, except it missing one piece, and that's turbos and turbo manifold design. I am sure the exhaust side of a turbo would have an impact on all of this, as well as waste gate routing. Would love to see another spin off of this that covers that side of the engineering.

[@charlespaul6725]

+JD Perham Magnaflow doesnt make turbo manifold

[@JD-lh2ve]

iStanceDaily Hub right, that doesn't meant they can't talk about the science behind it

[@timruddell125]

+JD Perham If they don't make turbo manifolds, he'd be talking about an area in which they really don't have a right to talk about, so he could spread mis-information and degrade the reputation of the company. A wise choice by him not to talk about it, but it is a shame turbo's were left out of the video.

[@JD-lh2ve]

This is true and a good point, but they do make cat backs for turbo based cars so hopefully they do have some engineering experience with them, which would have been nice to be shared here. Oh well maybe another video from another company some time then

[@kleetus92]

+Rich Smit Except that locomotive engines are 2 stroke, and diesel... that completely blows (no pun intended) this discussion out of the water. The EMD/GM 2 stroke needs that blower to force the exhaust gas out of the cylinder, without it, it won't run. The 567/645/710 engines have ports like a chainsaw or weedeater motor on the low end of the cylinder bore. When the piston is far enough down, it uncovers those ports and fresh air from the blower or hybrid turbo charger forces the air into the cylinder, also at the same time the 4 exhaust valves open up and let the combusted fuel air mix out, while the fresh air from the blower fills in from the bottom. Once the piston moves up and closes the port off, the power cycle starts again, and fuel is injected when the appropriate timing dictates. I said hybrid turbo because the turbos on the EMD locomotives are actually gear driven at low speeds, and once the engine output is high enough, the exhaust turbine will pick up the compressor load, and the overrunning clutch allows the turbo to spin faster than the gear drive could spin it. That's why most of the 645/710 engines have that yang yang yang yang sound at an idle... that's the turbo gear drive you're hearing.

[@yadidimeanmaine]

Anyone notice he drew a Flowmaster delta for his reflection example? He knows his competition.

[@superwout]

it's a Friday afternoon, the sun is coming out ... and one second in you gave me the best laugh in days, I salute you

[@andreaandchris3868]

Very well spoken. I could listen to you speak for hours. It's quick and precise.

[@omfgwtfbbq90]

Very good video. But he didn't cover catalytic converters. How those affect the flow and the sound, and the different kinds of catalytic converters. 2 into 1 or 2 into 2 or metallic or ceramic and how many cells... and how all these things affect the sound and the flow...

[@JonnyD3ath]

Decat all the way😄

[@omfgwtfbbq90]

JonnyD3ath not possible due to emissions

[@JonnyD3ath]

+omfgwtfbbq90 "not possible" 😏😜

[@danneu8]

+omfgwtfbbq90 If you can dream it, you can do it.

[@FrostyCoug]

+omfgwtfbbq90 pff, cuz he knows we don't run that shit on our cars...

[@2stroketurbo]

that was very informative

[@M13asan]

as a car young car lover and mechanical engineer, these ENGINEERED videos have been great. keep them up Ill still keep revving my 04 wrx sti

[@deankay4434]

Yes, indeed! You ask 1,000 techs, fabricators and race car engine builders, you will get 1,000 different answers with some commonalities. With covering all the possibilities of various power adders from turbos, centrifugal belt driven blowers, etc., this video will last four hours and still generate thousands of more comments. This topic, as many when it comes to complex fuel driven engines can make your eyes bleed. As a self trained mechanic in the late 60’s, then time in a two man shop behind the guys house, I was technically an apprentice. No shop in high school. They didn’t have one and it was new but rural. I fell into jobs I never saw coming, but by the grace of god, they found me at the right time. All I have to comment on, is the very nice straight forward job that Richard Waitas did in this video for Magaflow! It was well thought out, produced properly, since attention spans are short he didn’t go to long each segment. You have to admit, he covered a bucket load of information, right? Did he cover everything under the sun, no! I don’t blame him nor hold it against him. He did an excellent job. As a guy who traveled to 7 states and held 4hr technical service seminars, 4 nights a week, he was great. I never taught the subject the same way each time as I forgot something or answered questions from techs, shop owners and tech school instructors, made each cession different while trying to rely upon the PPT to remind me what to cover! Many times afterwards, I ask myself, why did I forget this or that! Give me a break! Maybe the next video goes into a little. We had cross-training for a manufacturer and had engineers talk for 1.5hrs and not make any sense or do a very good job on their “Subject Matter Expertise.” When a good one talked, it was great as they allowed a Q&A section. I give Richard an A+! Thanks guys. Great job! DK, Omaha. ASE Master Tech since 1978, retired.

[@JackTruitt]

dang mike. that intro

[@Doggepp]

Im loving these videos. I love having stuff explained to me by very knowledgeable people. Too bad he didnt touch on turbo exhaust systems. Because the downpipe/header part is not the same there. I understand the basics, but would like to have further knowledge about it. And everywhere you go on the internet it says different.

[@SlikLizrd]

Turbo Exhaust is for a whole nother program/video. The most important takeaway from this video is that a Flowmaster chambered muffler will not flow as much air as a straight pipe --- but a perforated glasspack can and WILL flow as much (or more) air than a straight piece of pipe.

[@mr59301]

Impressive. This guy has single-handedly sold me on Magnaflow for my next exhaust system. Imagine loving your work as much as he does his.

[@ROHITSIMHAREDDY]

I knew exhaust systems are complicated, man I had no idea that a lot of engineering is required to design one, after watching this video I'll think twice before getting a random after market exhaust !

[@edog6900]

This guy clearly knows what he's doing, but several times he indicated that there was both a pressure AND velocity drop at certain points. Bro, do you even Bernoulli?? I.e. 20:15

[@DrewLSsix]

Do you? Pressure and velocity will both drop at some point.

[@edog6900]

+DrewLSsix Educate yourself. www.princeton.edu/~asmits/Bicycle_web/Bernoulli.html

[@pauloptionalsiegfried8618]

+eric kemp The Bernoulli equation applies at constant mass flow. An engine varying its angular velocity does not have constant mass flow, so both pressure and velocity can drop simultaneously.

[@edog6900]

+Paul Optional Siegfried That's a good point, but not entirely relevant to the situation in question. Richard states, "...as long as the drop in pressure does not impede upon the CFM airflow..." What I'm saying is that a drop in pressure would increase airflow. What he meant to say was, "...as long as the drop in VELOCITY does not impede upon the CFM airflow..."

[@rcduck2010]

+eric kemp I think what he is trying to get at is that in a full system a drop in one of the two would result in an increased resistance to flow through the system hence dropping the other. I may be wrong as Im only just getting an understanding of this side of things but that was how I understood it

[@mojothejester9889]

Very informative :-)

[@annelizevanzyl117]

Thanks for a well covert topic! Once again confirms that most of the "off the shelf items" is just rubbish instead of a work of art. Love you work.

[@tripeee58]

You had me at Hello! This guy is AWESOME! I was only at 8:57 in and was already enthralled. I can't remember the last time I've been so excited about Science, Physics, Thermodynamics and Gas flow! This is geek heaven!

[@FIVEOHBAIT]

So... straight pipe it is.

[@MrLoony1212]

Agreed!

[@theroadahead415]

Jarrod Swick you saved me 30 minutes

[@andrewbartleman9169]

Apparently straight pipe has less flow than a MagnaFlow muffler because of friction lol

[@esh92]

nope. 21:02

[@Tuffenough4u]

Actually it's still true, only dictated by length. If the pipe was long, this would be an issue. The length of the pipe needs to be more or less tuned to the CFM flow volume and speed. Temperature drop is a factor to.

[@tjeremiah9747]

fuck automotive engineering college. Just watch /Engineered

[@tjeremiah9747]

I know very well, don't take it so seriously it is just the internet. I am a engineering student myself actually. So I know the information here is kinda superficial....

[@bigballstouchem1560]

+Mari Onette sssssshhhhhh, dont tell them that.. Before he thought the exhaust was just to keep it quite. now he tells his mates his exhaust is fully modified super customized electronic pressurized badass

[@zachfrickel4925]

Watching this on lunch at work. Love it!

[@luckyrocks1]

Thank you Richard! Very informative information and helped me a great deal as I have been trying to decide between the different muffler systems on the market (Chambered vs Straight through). I do not have an automotive background but do understand a little about airflow, duct sizing and cfm, along with how they may or may not affect sound issues, from my HVAC background. I do also enjoy modifying my truck with accessories and am more concerned with performance than sound in the exhaust system...

[@davidstuck2866]

you FORGOT to come back to that marvelous horsepower eater, the catalytic converter.

[@LazyRASHO]

YES!! That's what I wanted to hear the MOST!

[@cecet5534]

David Stuck don’t use

[@BensCoffeeRants]

They're pretty efficient these days. I mean sports cars come with them and they're making more power than ever out of smaller displacement engines.

[@pinkfiffty3094]

Exactly! Picture of the video showed catyletic converters and didnt even talk about them...dumb. maybe they had to remove that part so they dont get sued??

[@Maverick09171]

Cats don’t give up shit. It’s like 2% on 1000hp engine. On stuff less than that, its negligible

[@proto35]

Im surprised back pressure nonsense wasn't discussed here. Considering tons of people live by that shit for some reason.

[@psychotogen1]

Just briefly he said if the diameter was too large it creates a restriction.

[@nos1000100]

at the header

[@GirthQuake47]

proto35 it was discussed the whole time hahaha

[@andrewbartleman9169]

proto35 people think of restrictions when in fact it is velocity you want.

[@Jakalwarrior]

Maybe they think back pressure adds torque because it reduces losses from cam overlap. Course the same back pressure cancels out the top end power the over lap was put in to achieve in the first place.

[@heraldotello1639]

I took fluid mechanics last semester and what this guy says makes perfect sense it's nice to see the engineering side of automotive though this does also apply to other industry as well. Just nice to see it for automotive. My teacher told me above anything else make sure you remember about Reynolds number when it comes to fluid mechanics.

[@kevlar_87]

Nice introduction to exhaust design. It's more complex than many people realize. Thanks for sharing your knowledge.

[@bartvanriel6767]

I'm exhausted

[@FGKaye]

You forgot to discuss catalytic converters...

[@cecet5534]

F.G. Kaye Don’t use cat.

[@Meatwad.Baggins]

Cut them off. Sell it

[@jimmbbo]

EXCELLENT presentation of just about everything you need to know about exhaust systems

[@rcduck2010]

More, Please More!! Really answered some thoughts for me. Particularly interesting as im just starting to get into fluid dynamics so some of these principles really made sense and I could see how they related. Thank You Sir

[@SexyMistaMustard]

Dat Panarai Luminor

[@towers3135]

+1 !!!

[@arlindjax]

that was the first thing I noticed too

[@Eric-ue5mm]

+SexyMistaMustard Guy makes some money, eh? Also bonus points to us for noticing. :p

[@SexyMistaMustard]

I love that watch maker, I always notice when someone has one on.

[@Krnnerdboy]

Doesn't match his t shirt though....but you can tell he put that shirt on for the interview

[@yungfatazz]

I love the Casey Neistat esque filming with the camera being overhead with the paper an marker

[@DLSHARPSHOT]

Amazing video series by drive!Extremely informative and helpful to understanding the complexities of the modern car and or racecar.Keep up the great work!

[@idleprechaun]

I've been looking for something like this forever. Thank you so much

[@leibel1498]

That compressed air is hot, so speed of sound is way faster.

[@user-qw8um5mb6m]

Leibel 500 to 600 m/s depends the temperature

[@MrS22222]

It all depends on the temperature, the speed of sound is slower than exhaust gas in Siberian gulag, comrade. 306 m/s at -40C, 411m/s at 300F lol

[@BrandonKent136]

So how much performance is compromised with the catalytic converters?

[@brussell639]

They're getting much better, and smaller (not internal diameter).

[@SlikLizrd]

That depends on the type of Catalytic converter. Early General Motors and Toyota cats were the pan-type, which had the active ingredients in a semi-pellet form, and they were very restrictive, compared to the modern "Honeycomb" design, which will flow enough air to accomodate about 350 HP PER BANK without loss of exhaust flow . Today, we have 700 HP cars with full cats in place -- on the street, and LEGAL in ALL 50 states. Novices and morons get in line to eliminate their cats -- while they scorn the folks that want to keep our air and water clean. I've run a lot of illegal shit over the years, but nothing that could compromise our air quality.

[@BrandonKent136]

Chuck Hallowell because racecar

[@SlikLizrd]

@@BrandonKent136 WTF is wrong with you!?? Did you miss your nap !??

[@enriquezambrano1]

Hello, I own a 2001 Kia spectra, I went to the junkyard to purchase one single resonator, instead I took two home, I wanted to change the sound inside my car, and it did, made the car sound much better inside, plus increased the horse power and the tork tremendously. I love it. Now I am planning to do the same with my BMW. Thank you for the video, I really enjoyed...EZ.

[@melsilva9158]

I have watched a couple of videos hosted by Richard Waitas and I've enjoyed listening to his analysis and design points.

[@bvsandman]

Sooo, straight pipe it is!

[@johnbeer5242]

ChrisHallett83 or u u can turn the headers upwards and have them come out through the hood and make some holes on it😀

[@bradnaylor]

Awww, he didn't say anything about resonators... But, pretty informative

[@cecet5534]

Brad Nay don’t use

[@EuroE55]

Really enjoying this /ENGINEERED series. Thanks.

[@eel1331]

First of all, I love this series and second of all, the intro was hilarious lol

[@Foxontherun2]

OMG just make a straight pipe that comes out of the hood , job done

[@jgizzy]

+Foxontherun2 You didn't watch the video, did you.

[@crashandburnbirner]

puts a dip in and cracks beer...

[@cdstruckandoutdoor7219]

Yeah I did,so.

[@puffy1238]

Jesus

[@peterjones6945]

Never had a v-8 ;o)

[@brwi1]

what if i want my exhaust to sound like the beginning of "hot for teacher"?

[@Gardner0871public]

brwi1 buy a drum kit and practice practice practice

[@BadDadio]

Excellent video. The exhaust system was broken down into smaller components and the design challenges were clearly and succinctly explained.

[@kengit2]

This was fantastic! Didn't expect to enjoy it this much. Thank you!

[@nd318865]

I'm under the impression 180 degree crank would be seen as "flat plane" while "180 degree headers" bring together exhaust events which occur every 360 degrees of "crankshaft" travel. That is: 8 firing cylinder events involve 720 degrees of crankshaft rotation... Where am I wrong?

[@IpodsNightmare]

+James Tennier That is correct. A four stroke engine takes 720 degrees of rotation per fire in a cylinder. Power stroke, then exhaust stroke.

[@davidmartin7099]

720’ / 8 cylinders = 90 / cylBut the banks are tilted, so the bank angle comes into play too. A V8 will usually be 90’ between banks, with pistons sharing 4 crank bearing points, so you have two 4-cyl banks with one lagging the other by 90 degrees. Now you can spac the four cranks by 90 degrees, pick your 180 degree pairings, assign a firing order, design your cams, and finally run your header tubes for optimal pairings.

[@gordowg1wg145]

Bit lateresponding, but close - exhaust pulses 180 degrees apart are grouped together - the other four are 90 degrees to the first. In practice, that usually means the outer two on one band and the inner two on the other, eg traditional SBC has a firing order of 18436572 with the left (?) bank being odd and the right even so one group will be 1, 7, 4 and 6 and the other group would be 3, 5, 2 and 8. You can check that and other engines on the interweb, as there are multiple sources.

[@ThePaulv12]

Well I don't believe scavenging works on the street as header manufacturers would lead you to believe. The reasons are complex but it's something like this, cross plane cranks benefit from scavenging but it occurs in such a narrow band as to be pointless chasing it on a motor that has such a broad spread of power as a street engine. There are too many variables for it to work properly. There is a way however that MAY (no promises) work and that is anti reversion cones in each of the primary tubes. There are some things that are known to work generally for specific motors. For example the 440 Mopar is known to benefit from 2" primary tube headers going into 3 1/2' collectors. Indeed it seems to be the case but that is from a factory sponsored drag racing data collection and the info gained is so narrow nothing is relevant outside that particular motor with iron heads and larger valves as specified by the factory manual for hot rodding the B/RB. I am sure there are other knowns for other motors, but for the home hot rodder unless you have a dyno, about 1000 hrs, $150k, 49 different combos of header primary tube length, intake type, head work valve size, port size, camshaft and on and on and on into infinity then you're just guessing. Headers are about reducing pumping losses and stopping reversion. Some do it better than others, but the main cylinder filling effect is the inertia of gas flow initiated by camshaft lead and lag (AKA overlap). How well that flow can be kept moving, post exhaust, may give an added boost but I doubt all cylinders are going to benefit equally due to intake manifolding! The whole header thing is designed to even it all out as much as possible by having the leaner cylinders running at the correct A/F ratio and the richer ones running too rich rather than the richer cylinders running the correct A/F ration and the leaner ones being a bit too lean but within specs for longevity. The whole thing is a balancing act and reducing exhaust pumping losses will yield a power increase since the the volumetric efficience of the engine has changed. Port fuel injection aids this since the intake runners are intentionally tuned. So that's my take on it. Header manufacturers say it's science, I disagree, so I guess they're right and I'm wrong because they have more money than me implying I have shit for brains. As I mentioned they're right.

[@accordaffair]

this is really hard to watch while baked

[@roberthinojosa1155]

Try watching it on Lucy. I feel like i just went to college.

[@johnbeer5242]

Alexander Garcia hahha baked 😂 square ass 😂 hahah

[@craigwall9536]

..and yet we persisted...

[@RBAERO]

That series ENGENDERED is one of the best on you tube about car performance!

[@exige3604]

wow...thank you, very well put video! In the early days getting into cars, guys use to say...back pressure this and bp that! Now as you have explained it, this makes a whole lot of sense. And about the Ford GT40, that is a very good point too, regarding 180* collectors. Thank you very much, appreciate the great information!

[@Bruceillest101]

@ 22:52 He's talking about the "No Slip boundary condition" When the fluid (or in this case air) is flowing over or in a boundary. A tiny layer of air will be created on the boundary its self, which will have a velocity of zero. But this guy exaggerates the size of the layer and the over all net affect it will have on the flow.The arrows he draws are very misleading. The exhaust Will NOT FLOW towards the walls of the pipe. They will continue to flow smoothly unless the walls of the pipe have a ton of carbon build up. As for the inside of the perforated muffler, the pipe will still experience the no slip boundary condition but with the added benefit of being at a lower sound level.

[@achillezx14r45]

Agreed

[@FourTwenny]

Does he know he's an ad?

[@ejaokay]

A THIRTY MINUTE ad! A little more like an infomercial.

[@s1mph0ny]

I wish more ads were like this. If there was ever a real case to convince someone of the value of your product it's using an experienced engineer like this to share information with a crowd of actually interested buyers.

[@swaraj7993]

That's not just another way to look at it but a bad way to look at it.

[@reallyhappenings5597]

Do you?

[@alwaysopen7970]

I wonder if he's a dad?

[@Neudezign]

Awesome video, incredibly informative. Thank you for posting this.

[@ryanklett5277]

Best explanation of exhaust systems that I have ever seen!

[@corvettez06ss]

so this is a long magnaflow commercial??? it would have been better if you guys interviewed someone who does not belong to a exhaust company. also actual data from a dyno, comparing mufflers/headers

[@stephencain3467]

your an idiot

[@stephencain3467]

corvette z06 guy probably doesnt evem have a corvetter

[@brad3378]

+Stephen Cain Learn the difference between "your" and "you're" before calling someone an idiot.

[@johnbeer5242]

corvettez06ss yeah exactly

[@Oblithian]

Only clicked on this because I thought it was Engineering Explained... it isn't.

[@saint6563]

The Industry is lucky to have you. Thanks!

[@user-gl3gc8hr8v]

Incredibly informative video. So much knowledge here. Thank you to all involved.

[@LZKS]

All that talk about the advantages of absorption muffler is garbage. They'll drone like the end of the world when cruising despite what garbage science the MF guy is trying to tell you. You really want a "reflection" muffler as he calls it if you want a decent sounding muffler. How good the muffler will sound will 100% depend on how well the chambers inside the muffler is designed specifically for the vehicle, and that requires a TON of R&D. Cheap-ass magnaflow will try to tell you absorption is fantastic because they're easy AF to make.

[@JerryTheHeretic]

+Woo Cheol Shin My Roush muffler (actually made by Borla) on my mustang has no highway drone and is loud as hell when you get on it and it's a straight through absorption design.

[@Daveinet]

+Woo Cheol Shin The exact opposite is true. If you have an absorption muffler that drones, then the absorption material has failed. An easy way to tell is to tap the outside of the muffler, if you here a dead thud, then the absorption material is OK. If the outside surface rings when you hit it, then the material has failed. For comparison, I had 70 series Flowmaster on my motorhome. Not only did they kill the mileage and power, but they droned like crazy because even through the sound bounced around in the chamber, the noise transferred through the case, because there is nothing to absorb it. The 70 series may have been quiet at the end of the pipe, but up by the muffler, it was very noisy. I removed the pair of 70 series Chokemasters, and installed two Magnaflow mufflers. I made no other changes to the system. The mufflers were much quieter in the coach, with no drone. My mileage went from 6 mpg to 8.5 mpg. My zero to 60 time went from 19 seconds to 16.5 seconds.

[@muznick]

The Dynomax ultraflow sounds good and doesn't drone any more than a Flowmaster 40. I don't care for the Magnaflow sound though. It's too bland and quiet.

[@andrewbartleman9169]

Woo Cheol Shin this was not about sound...lol

[@Punjabimoney187]

MagnaFlow garbage af...

[@Buggabones]

Not really garbage. Just over priced.

[@Buggabones]

Not really garbage. Just over priced.

[@tibomoltini2851]

never thought about it , very well explained. espacially vacums, designs, active technology and sound tweeking. Tx!

[@vader540is]

IMHO this has been the best engineered video yet!

[@Master-di4di]

Awesome explanation of the exhaust system.Thanks for sharing.

[@WrecklessEnterainment]

I really like the engineered videos. I love seeing how companies make things work. Magna flow seems like their style runs in the same direction as borla with muffler. glad packing and perforated cores to let the mufflers flow good at high rpm with out drone at cruising, and of course they say flowmasters style of muffler won't flow as well which we all know by now.

[@trigun12121]

Omg, I'm taking a thermal class for the energy career field. And you have expanded my mind. Great job, you are amazing. Usually engineers make me angry but, your way of explaining was perfect for my brain waves. BROVO!

[@crsp76691]

I got the exhaust in a box from magna flow on my ls1 68 firebird. I love the sound, performance and fitnfinish! All my friends are starting to switch to magna flow mufflers because the hate the droning at freeway speed. Magnaflow has no drone it makes driving the car very comfortable, love it!!

[@MorganOliff]

Thank you so much. Very cool of you to avoid name-dropping your products along the video. Smart video for intelligent customers!

[@neoanderson7]

Loving these engineered episodes. Truly amazing how archaic ICE is. Imagine all these resources and know how eliminated when you deal with electric vehicles. Don't get me wrong, ICE is still king when you're racing around a track (for now that is), but things do get a lot easier when you go electric. Keep these episodes coming!

[@peterjones6945]

When battery technology gets better and energy recovery increases range electric vehicles will be more prevalent. In fact, all aspects of electric vehicles need to be improved.(cost, range, lifespan) At present, 25%~30% efficient IC engines 'rool'

[@dominiczanella7378]

Excellent explanation of what an exhaust does, and how it relates to performance.

[@craigpennington1251]

Very informative. And he made sense. Great video for learning.Thanks a bunch.

[@deere3321]

Very good presentation. It helped to understand how complex an exhaust system can be.

[@atraxr603]

This series is very cool. I really like it. Thanks for sharing.

[@2ShoesPhoto]

That intro was just perfect!

[@jaredgarner7380]

This was a really fantastic explanation of most of an exhaust system. Will definetley be reffering to it as I plan on designing my own system. Only details that i know of that are missing are cats, and the use of an exhaust box to essentially simulate the exhaust going to atmosphere at any point you desire without having to actually have an exit there, allowing for an ideal tuned length, and it makes anything done after said box less of a concern for tuning as long as optimal flow rate is still achieved

[@bigjmeister]

This guy is very knowledgable. Thanks

[@complexgrafix]

LOVE these videos.. Keep them coming!!!!!

[@arnomaas6452]

thank you for the very explanatory and interesting insight Mr Waitas !

[@ZenDude65]

Thank you for your time, that was a great informational talk

[@k1ng0fk1ngsromelo6]

Best explanation I’ve heard I’ve learned more from this video in the last 20

[@StopItRyan]

I love this series! Keep it up /DRIVE

[@mikeyri2tx]

Awesome informative video. Nice summary. I had MF on my Chevrolet 6.0 2500HD and putting the same 1 to 2 MF on my 6.2 Hummer H2.

[@forpointsix4.678]

These videos are great. I really want to see more like them!