This gentelman is 100% right on ALL points. In the early 90's I was a Fabricator in Aussy building V8 Super Cars. We spent hundreds If not thousands of hours on the dyno and track testing all sorts of header combinations. We had a 5 litre V8 limited to 7500rpm limit because of CAMS Rules. So to get every ounce of H.P out of such a small engine took a huge amount of development, even on the intake side also. We ended up having the engines so finely tuned an 1/8 inch change on just the intake length could cost us 45hp. All our headers ended up being 4-2-1 with an expansion chamber of the collector to an X pipe, all lengths where based on the heat (Sound pulse) signature of each tube all the way to the X pipe. If you listen to the engines (Before we had to really muffle the cars) of the higher funded teams (Holden, D.J.R etc) they ALL sound like high reving two stroke V8's, and we where making North of 600h.p reliably all day long. Awesome to see this dear man share his wisdom 👍🏻

@skippy2987

Жыл бұрын

@Jay Riley From what I've seen in my simulations it makes cylinder to cylinder balance a lot better. Exhaust blowdown pulses going the wrong way through other cylinders creates more problems with the inlet stroke (because it messes up scavenging) than having intake runners that interfere. It also lets you run a choke a lot smaller without restriction, protecting the low-mid range without top end cost. End result: Crossplane cranks with crossover headers make sexy Ferrari noises, make more mid-range torque, and can run with timing closer to ideal (because you don't get as much tendency for one cylinder to detonate from contamination). But it's difficult to get the length short enough for top end power, so on high RPM V8 racecars it's not always worth it overall

@NicoKyunKyun

Жыл бұрын

5 L V8 "small engine"

@LawrenceTheKiwiBryant

Жыл бұрын

@@NicoKyunKyun They are in my world Lol.

@bmmarshall79

Жыл бұрын

Kiwi, we’re those Perkins engineering cars?

@LawrenceTheKiwiBryant

Жыл бұрын

@@bmmarshall79 DJR cars. I was on the floor in the early 90's for the development of the E.A V8 Falcon and we where working along side Roush and his NASCAR boys! I know Perkins was doing the same if not more!!

Thank goodness for 2X playback speed.

@LuckyCharms777

8 ай бұрын

Great idea! 😂

@aldostefanini1392

7 ай бұрын

It is a must to make this video from a soul searching yoga video to a informative one

@bigseksi5514

7 ай бұрын

Lol. Ditto

@notsponsored103

7 ай бұрын

2x was a bit much for my pea brain to process but 1.5x was a good compromise 😂

@Billydevito

7 ай бұрын

Talk slow, race fast !

My dad was a race engine builder and machinist (Pacific Northwest USA). His career spanned the 1960's through the 1990's. He did a lot of development and dyno testing (mostly V8's of every make). I know he would have been fascinated by your work. We had a customer that went to the trouble of building a 180 degree header system for a C3 Corvette running in the American SCCA Trans Am series in the 80's. The primaries came up and over the valve covers and back to vertical collectors that went down over the passenger side of the bell housing. They made the engine sound like a formula 1 engine. The pounding roar was completely gone! The power improvement was on par with what your work shows (2-4 percent). That's a lot when talking about the tiny margins we fight for in racing.

@barrycuda3769

Жыл бұрын

Yes' I only recently became aware of 180degree headers 'and how the sound of the engine is changed ' and I finally understood why a 289 in a mustang or fairlane etc ' doesn't sound like a 289 in a GT40.

@vonzipper24

Жыл бұрын

@mark Hatch, that car was built by Jim McCrocklin, mike Halloran and myself, we did a ton of testing with Dennis Fisher, lots of fun

@blackfrost273industries4

Жыл бұрын

Holy cow for heat batman. I wonder if that was a concern at all.

@markhatch1267

Жыл бұрын

@@blackfrost273industries4 We worked with the customer to design a quite elaborate insulated stainless steel enclosure with a lot of ventilation in the firewall and floor.

@bradgriffith4231

10 ай бұрын

180* headers usually only work with a flat plane crankshaft. Latest tests prove that the bigger the diameter of the primary tube, the more torque the engine makes at ALL RPM & that an 18" collector is the ideal length. They also proved that running both sides into a Y pipe with a single outlet makes more power than duals or any other configuration.

180 degree headers are the true equal headers. they put the pulses all 180 from the last cyl. sounds more like f1 also, a hum rather than a classic v8 rumble. dude made a set on youtube great video & informative

I learned a lot from David’s books. Very knowledgeable guy with tons of experience.

Guy's - I am so busy doing new videos that getting to answer your questions is getting to be really difficult. Hopefully you will get most of the answers you are looking for in future videos. DV

@duygukayhanisaskank4915

8 ай бұрын

Hi David, The information you provide in this video is phenomenal. THANKS for creating & posting it. I'm interested to know if headers on engines with flat-plane crankshafts need to be configured//built differently than headers for typical cross-plane crankshaft engines. Please do a follow-up video addressing headers for "flat plane" crankshaft engines. I believe the information would be very interesting & beneficial. Your consideration & attention are sincerely appreciated. Best regards, Ben

@erikredIV

7 ай бұрын

Yes great job clarifying what everyone tries to keep a dark art. You covered the typical v8 well. I know you can't do every request but it would be great to have a follow up video that fills in the gaps for other types of engines and for building a 4-2-1. For example primary length/diameter (4), how to choose the secondary (2) length & diameter, and how does this effect the collector/tailpipe (1) length/diameter for other engines as well as the typical v8, as well as any info on step tubes, merge and venturi design, and if they produce any benefits. Would also be cool l to here more on the 9' primary header and any other stories about design successes. Thanks for all the hard work you and others put in!

@iloveaviation-burgerclub-a8145

5 ай бұрын

No matter if you make it or not I am damn pleased being able to get all these real knowledge and partcipate your experience. Many of you guys should do this. So much knowledge is lost forever because young beople show weather interrest for knowledge nor respect for the wise guys. I learned in aviatikn from the old guys. The tricks and bits. We need to learn listening again.

This is very interesting; the thing I’m finding is, the more I learn, the more I realize that I don’t know. Thanks for all you do David to give us your help and years of experience; greatly appreciated,.

i used to swap headers around on my small block nova quite frequently, shorties, long tubes, tri y's, manifolds etc. always liked tri y's the best. never had access to a dyno but the butt dyno always said they were the ticket on my street cars. glad to see some science back up what i experienced. thanks for sharing i grew up reading your books and am still learning to this day!

Thanks David for your time to explain all that we should know about.

Back in the '50s, Motor Trend or Hot Rod Mag had an article on exhaust pipe tuning with a crayon. Draw a line port to end of pipe, eight individual pipes on V8, with a crayon. This is with the engine warm and the exhaust pipes cooled to ambient temperature. Fire up the engine and run it at the rpm you want peak HP, where the crayon melts is where the pipe needs cutting. I suppose several people would be needed to get this info on one run, or it could take several runs. It might be worth a try to find each cylinder's favorite length. Have not tried it, being a two stroke motorcycle racer, I went with other information. If you or others try it, let me know if it works. Good luck on your endeavors!

@matthewfredrickmfkrz1934

8 ай бұрын

I thought that was for where to put the x or h pipe for a v engine

@AB-80X

7 ай бұрын

That has been debunked several times. Same with x pipe placement, same with header extensions.

@DieselRamcharger

5 ай бұрын

thats for 2 strokes.

Can't wait for part II. Great job as usual. Much thanks.

The wisdom of senior mechanic and engineer. Very interesting stuff. I just subscribed.

These kind of topics are great, brilliant as always. Just re assures me I'm going in the right direction as i converted a set of 4 into 1 headers made for my (4 cylinder, sub 7k rpm) engine into 421s. Interested to hear about anti reversion chambers as i dabbled with that too.

This is the real practical knowledge that comes from experience, not bench-racing or marketing speil .. Thank you sir for sharing your experience. I'd really like more details on the 2v vs 4v heads. Looking forward to more of your content.

Thanks DV! Just finished this chapter in the big block book last night so I did the homework! Starting your small block book tonight

Fascinating video. Thank you for sharing your knowledge David.

Really connected with your teachings. Understanding building my winning 2 stroke motors with proper pipe/pulse calculated really brought me to you. I feel like I now have a PhD after reviewing all of your videos. God bless you sir!

VERY interesting. From the beginning of time I was always told that a 90 degree engine is the optimum and equal length headers are a MUST. Thank you for clarifying.

I have followed your career all my life before the web, I sucked up everything you have shared via print and have several of your books next to me right now, Everybody thought Earnhardt could see air move, You were the Pioneer of Air Movement and traction Your my Hero and a Legend. Thanks, David for not keeping your wisdom to yourself and sharing your infinite knowledge, I have always appreciated it.

On my 2 stroke racing kart the distance from the piston to the end of the header tube is measured and you can put longer ones on for a different torque curve. Or shorter ones. But it deffinetly makes a difference. This is on my Yamaha KT 100 race kart. I change the h.p from 12 to 16 h.p with different length pipe. On race boats the make tunable headers that move with a lever. Cool stuff. Thank you for sharing your wisdom.

Best of the best. Your accomplishments are mind numbing. I majored in auto mechanics in school... Thank God. Just love engines and working on mechanical things of all kinds. I can do my own repairs small or large. Garages are so expensive, I have saved thousands of dollars in my life. Always learning and blessed to find men like you. David you are amazing and inspire me to get even more horse power out of my lawn mower. Engine science is amazing. Thank you for sharing your hard work. Cheers to and your health

The key to getting it correct it must include the most important fact dual plane puts the pulses not even time period for each side. To get the max flow 4 into 2 then collector and the rest all counts. A flat plane v8 is different. The information he is sharing is spot on.

I got a friend with an h22 engine honda. No turbo. Did a naphin drawing of a tuning tube to install at the collector flange. He installed it while bolted to a mustang chasis dyno. Picked up 10 hp at 6500rpm 265 to 275hp . Changed the sound from a raspy honda with a lot of reversion slap. After it sounded like a healthy big block chevy. The tuning tube used the inertia of the exhaust pulses to stop the reversion. I think it also increased scavenging in the primary.

@hayden6056

Жыл бұрын

A twin cam vtec inline 4 sounded like a healthy V8 with triple the cubes and a pushrod cam? That's an amazing piece of tube.

@waynep343

Жыл бұрын

@@hayden6056 figure out what size your collector flange is. Buy an adapter that takes it from like 3" to 2 1/4. Weld a foot of 2 1/4 tube to it. Slip it in. At the collector. Be sure to have an air fuel ratio gauge to verify which way you need to go with idle transition feed restrictions at 1700 rpm. After that. Primary main jets at 3800 rpm. Then you can see what happens just below wide open throttle under load for the secondary mains. Why not wide open throttle as a third step keep the manifold vacuum above the power valve opening manifold vacuum. With the jetting all done. Then go wot with the manifold vacuum below the power valve rating. So you can see what you need to do with the power valve restrictions.

@lilorbielilorbie2496

Жыл бұрын

@@hayden6056 Exactly .I'm calling B.S. on a 4 cyl. anything sounding like a BBC. Ain't gonna happen unless you are on the Really good drugs.

@hayden6056

Жыл бұрын

@@lilorbielilorbie2496 I've got four v8's here and 3 different kinds. My poncho sounds sort of similar to my Holden as they basically nicked the design off them but still different. Then nothing sounds like my LS motors due to the change in firing order and the aluminium heads. Also my two LS motors sound nothing alike because of exhaust and head and cam differences. I'm unsure where a 4 cylinder sounding like a big block Chevy went to talking to me about my jetting so maybe is cooked. Especially seeing as the only one that runs a carb isn't running anyway and probably won't be a carb next time around.

@ulisesavila2879

Жыл бұрын

How do you fuck so much the sound signature of a "flat plane" 4 cyl to make it sound like a crossplane

As usual another excellent education my DV.

Mr. Vizard, absolutely the best explanation of the flow into & out of and why of the internal combustion engine. Using pressure is genius as I would bet someone made such sensors to withstand the rigors of this environment. But using them in this fashion makes perfect sense. Thank you! This is a keeper for my KZread save file. In your name sir. DK, ASE Master Tech since 78.

Fantastic video. Worth its weight in gold. Well Done.

I am going to have to rewatch this a couple of times.... great work

Great comments on Total Seal. Keith Jones, and Kevin Studeker have been critical assets in all of my racing engine builds. They are hands on experts.

Wow!.....your video just popped up. ...I’ve subscribed instantly! I bought & read multiple times your 1st & 2nd (tuning the mini ‘A’ series books) ...40+ years ago! Your knowledge & expertise was awesome back then, so without hesitation I will watch & support everything you do... Regards Tony 👍

Thanks DV! I have always thought equal length’s were BS! You have really put it into perspective for me with which one’s should be different lengths! I have always figured a big torque increase, but didn’t realize the amount of HP increase at high rpm!

@kart70

Жыл бұрын

It's not exactly BS. It depends on the type of header we are talking about. The top fuel type of header, where each tube is self scavenging, equal length is important. All cylinders are running at the same rpm and have the same resonance. The reason equal lengths are BS in the rest of the world of headers, is that scavenging due to other cylinders is more important than the self scavenging of each cylinder.

@dons1932

Жыл бұрын

@@kart70 Correct there are many more things to take into consideration including merge collector design (which ARE equal length anyway) and overall length etc.

I speculate a factor that is very important to equal exhaust flow is not just the length but also the degrees of turn the exhaust header passage , if we add up all the degrees of turn that occurs in the bends ! you can have anywhere from 180 to over 360 degrees of turning the exhaust will transition through. obviously a near straight shot out of the heads exhaust port is ideal ! every bend creates restriction and turbulence,So in my theory when calculating the length we must take into account degrees of bend , a stream of exhaust gas goes through as it gets more delay through the bends than in a straight path , thus there needs to be a formula that converts bend to equivalent straight path , so we need sum of straight lengths plus our turn coefficient which is greater than 1 multiplied by the center tube lengths in the bends ! reverse thinking to take advantage of this theory , would be to use length and bends to time pulses into the collectors. I wonder if any tuners have performed experiments to study this concept to find the formula for the coefficient table for various header diameters .

I found out about your videos when my ex was in a class taught by Marvin & I must say you make very detailed informative videos

Your How to Build Horsepower book is very good, and I am a Mopar guy, but concepts hold. Fantastic analysis and presentation.

When I started watching and getting the jist of where you were going with this video I immediately thought about pressure transducer sensor as a means to graph the pulse. It was neat to see you went the same direction. This is my first exposure to your KZread channel. Looking forward to watching more.

Thank you for sharing your great knowledge.

My reading has led me to believe that the same people selling headers have a second job of selling camshafts. Header design often locks you into a compromise because it forces you to design for a narrow range. Most people pick too short a tube and too large a diameter thinking they will magically drive above 5K rpm everywhere they go. Engines are dynamic and change constantly.

@briandetrick2688

Жыл бұрын

that's old school thinking. with his headers you can run anything

Awesome, awesome, awesome!! I just watched Engine Masters S1 E12, where they tested dyno-tested for the right sized header primary on a street-mannered Blueprint Engines 400ci SBC, with a cylinder head that flows ~220CFM at .650" lift on the exhaust valve. Guess what they found? The 1-3/4" headers made the best power, looking at the entire graph. Yes, the 1-7/8" headers won the HP war by 3hp or so but they produced a funky torque graph down low, compared to the 1-3/4" headers. This matches up perfectly to the chart presented in your video here, David. Well done!!

Mr Vizard you are an engine builders hero and a saint for casting the precious pearls of your wisdom and experience before us oblivious swine. I shall endeavor to stand in the light of your experience so that I may always go faster than the other guy. My hat's off to you, sir.

Absolutely love your videos, I'm addicted to learning more. My project old peace of family history is going kinda in the opposite direction in performance, but laws of physics still apply. I''m a diesel guy, drive truck (boss gets the money, I put in the hours, I'm on poor mans budget) My little Cummins pulls 16,500lb EMPTY camper and horse trailer --- 19,000+ lb loaded camper and horses most weekends up extremely steep off road, logging roads, hard climbs. High country of WA. Love the sound on my over worked straight pipe Cummins, whistling 32lb of boost, at a beautiful throaty sound 1,800 RPM, blowing out some quite hot EGTs. To say there ain't much carbon build up in my lil 5.9 Cummins. BUT!!!! I also dearly miss driving my 71' F250, 360. Open up the 4bbls on my Edelbrock 600. I know the first answer will be, go put a 428 or 460 in it and be done. I'm weird about keeping as close to factory original as possible. Just want to tune the most efficiency, torque in what I got, 360 FE. Factory original (I put on the manifold and carb, single glass pack, Edelbrock cam timing chain with +/- 4 degrees / stock timing keys). Everything else stock. I'll never pull 20,000lb, but it DESPERATELY needs bottom end torque help, to help pull 10,000lb horse trailer up a grueling 6-9% grade, slow / low RPM - 25mph pull up, off road mountain. Any short quick advice is greatly appreciated. My thoughts, please correct me where I'm wrong... Advanced cam timing "power curve down, raise compression 🤷", small tube long headers, long collector. I'm still learning... I'm on a poor mans budget. Can't have something that doesn't do a job, yet I miss the sound of a 4bbl V8 working. Any pointers are greatly appreciated.

Regarding the power gain with unequal length: I think it's stunning to see the effect in the 3000 to 3500 range. Over 5%, almost 7% at best! Imagine a "boost" of that magnitude on your daily driver 😲 My main worry is though: this arrangement will surely ruin the sweet rumble of the V8, as it evens out the pulses...

@Hashiriya985

5 ай бұрын

makes a crossplane sound like a flatplane. so to me is a win win situation

@White.Elemant

5 ай бұрын

@@Hashiriya985 infidel!

Priceless information and guidance.

Thanks, David. The great thing about the Ford 2 liter is, it's a non-inerferance engine. Timing belt breaks, easy fix. Reliable, decent power, good on gas.

Thank you, DV; When you do your next video on this could you touch on pairing cylinders for scavenging in conjunction with optimizing unequal length primaries in addition to anti reversion, collector types, and secondary lengths? If that sounds more like two more videos, perhaps you could include the secondary length discussion with the scavenging pairing strategy with the appropriate un equal primary lengths. v/r wh

I love the idea of setting track records through sheer "drivability"!!!! Theres a lot to be said for having the torque right when you need it. : )

So glad this video Exists, thank you again David.

This man was great friends with my old tech school teachers. Glad I got to meet him

These men know their stuff, keep it coming , gentle men, and thank you both, Andy, and David, proformence is their profession, a labor of love, of going, Fast, and First, the first time,,,,,and the last,

I literally just punched the air after hearing the intro. This is what I'm talking about. Thank you for sharing!

Great info and love the presentation

Brings back memories of Phillip Smiths old book . Priceless to me.

I've been building exhaust systems starting with lawn mower engine go-karts I'm racing things that others weren't just because since I was about five or six years old. I definitely see where you're coming from and you're the first person I can say thinks pretty much like I do. Working with 2-stroke knowledge keeps me from being put in the box building 4 stroke exhaust systems. People have always hated my designs but have never been able to surpass them. Most of my street cars were straight pipes , very quiet because of properly phased pulses until you got bad. The funniest I ever built was an autocross full-size 69 station wagon with a 390 engine side pipe. That was so two of us and our lady friends could do comfortably the all night rally with special stages. The horrified look of the Fiat Audi VW Datsun drivers was great. I can only imagine your life was every bit the thrill living in the European continent. Chevy small-block tri-y headers 1973 in high school was when I seriously started developing my shut up and listen ability. Have a crippled math teacher with a slant 6 Dodge start I think it was that would eat anything the kids thought they had that was hot. Young ones you need to learn from the Masters 😉

Sure, after watching the videos on this 99% headers are wrong, I have to agree with you whole heartedly, I have over 12 years of research and development technology from chemical plants. Understanding what you're talking about is so easy to digest. It is all based on what we used to call a batch process with multiple reactors. And measuring what comes in what's going on through the reaction phase and what is being exitive needs to be measured understood. And then if you're tying all these reactors together, you have to have the ingress. And egress shut up in an opportune manner to where they work in unison to the best yield that you can get, keep the videos up, and I love your work, and I think everybody needs to listen to you and understand your formulas and your pathway to this. But you're right on the money, buddy. Navigator

I have never seen more adept adept header discussion. Best on KZread

Thanks David I've had this same argument with a many of other engineers for years and years, I've also proven that there is no difference between or sometimes a gain in the use of a crush bend radius over a mandrel bend. My own testing i used water flow instead of air as the mass flow. Didn't have alot of funds in those days and a water flow tester was easier and cheaper to make. Great video.

Great insights DV.

I went and searched for some more material and saw the child. It makes sense. My condolences, I can only imagine. May things be as well as possible.

Very impressive information David. Currently looking at applying this to an Australian Ford Windsor 5.0 and a Cleveland 351 small port. Same firing order on both. Same objective on both. One is a work vehicle, hauling a load all of the time, the other a 4x4 and tow vehicle. Maximising torque at low rpm for drivability, and fuel efficiency is the objective. It would appear that Ford Australia took your advice to the extreme on the Windsor. The factory 4 into 1 system pipes, range from about 22" down to 4" LOL. The information that you have provided, along with your low noise exhaust video, plus the information in your How to Build Horsepower book, means I have some design directions to follow. Thank you very much. Regards Greg from Perth, Western Australia

@jamesmedina2062

9 ай бұрын

Hello Greg from Perth! I have a 351C in a 3500 lbs Ford Mustang 71 and I drove it around with a built engine using Australian 2V heads but did not get very good fuel econ. I tried smaller carb but it ran hot that way which is no good. It had 10:1 compression dished Ross pistons and mild cam. At least it was fun. How is your economy so far on your vehicles? Have you thought of Injection? That and overdrive tranny would probably increase my fuel econ from 8 mpg to perhaps double that but I don't feel like switching fuel delivery. I'm more open to a T5 trans with overdrive. Got C6 now.

I have tri-ys on my 64 C10. They fit, were cheap used, they're silver coated and they look cool.

Spent 2 years modeling NASCAR motors for Hendricks Motorsports, and designing and fabricating headers. We went from 740 to 815 hp in that time, cica 2000. Cup cars were running 9700 rpm, we learned the primary lengths were way long by instrumenting engines on a dynamic and timing the negative pressure waves.

@scramlll529

9 ай бұрын

I would trust your info more than his. Actually out there winning races.

BTW, I love Big Block Chevies. I currently own a 1997 GMC Suburban with a 454 that I just built and upgraded last year. About 400 HP now. Not too crazy and plenty of power to get out of its own way.

As always thank you Mr. DAVE

Intake runner layout and A/f ratios also play into the exhaust system. Equal length headers won't flow the same when each cylinder has different amounts of pressure in them.

I don't know this guys channel, just wandered here by accident and watched the whole 30 min. SO I will summarise his answer. YOU ARE GOOD WITH EQUAL LENGTH IF YOUR ENGINE FIRES AT EQUAL TIMING. Thats it, his title is a bit misleading. Most of the time some cylinder are not firing equall timing so you have to adapt those accordignly. Thanks for coming to my ted talk.

I realized I forgot something in my comment and I apologize. My name is Jeff Thompson. I'm 63 and live in Montana. Thank you for sharing your valuable wisdom. Jeff

@ZEPRATGERNODT

Жыл бұрын

Man, I just left out of Helena a few day ago.

Some race engine header designs took that issue into account. They had tubes from the opposite bank collected to give 180 deg separation of pulses and equal length tubes to provide maximum scavenging of exhaust gasses.

Great info on this channel, but I am so thankful for 1.5-2x playback speeds..

Way back in the day, one of the US "hot Rod" type magazines tried 5 different design fenderwell "headers" for a 57 Chev with a street-strip 327- there was around 50hp difference between the best and worst. IIRC, these were 4>1 designs, so there was even more potential for a 'better'. Making it even more significant, that was only a 400-450 hp engine and if you project to some of the strongest modern NA engines, that could easily be pushing 100hp!

its amazing how small differences to how the air coming out of your engine can affect performance so much

i think i bought 3 of his books about 20 years ago, fantastic reading

The GT40 with the crossover exhaust eliminated the 2 cylinders being close to each other. I believe it alternated the firing order from bank to bank and it spaced all the pulses equally. It also ran the firing order in a circle in each collector to create a vortex.

As a twostroke guy I like that content very much!

I remember when Walker and Banks did those tests! Wow David, thats a great story! thanks for sharing, never knew that was you behind those awsome walker mufflers! Flowmasters are junk, not mufflers!!!! Always learning from your vids! I learn something everytime i watch any of your videos and I've been around for awhile as well...LOL

Finally someone confirmed to me what I have been thinking for a long time Equal length is only for even firing engines LS and cross plane american engines requires unequal length as you are saying here depending on the fact that cylinders of 1 bank do not fire 90 degrees exactly after each other Some more which require longer and some less which require shorter With the exception of the 8 to 1 exhaust LS with rotary fire pattern where the collector recieves pulses sequentially in order In this case equal length is the way to go

For performance street use, my favorite headers have been tri-Y design. I wish that was a more common offering. Street motors don't live at the top of their RPM all the time. And tri-Y is a not-terrible answer to the cross plane crank. My favorite thing about this channel is how well the info agrees with things I know from: being a general physics nerd, building speakers, sailing boats, and aviation. Also, it's always a "science based" approach here. The dyno is the arbiter of truth.

@bradgriffith4231

10 ай бұрын

Dynos are not the arbiter of truth because they don't apply real world loads. I know numerous people with good running Super Comp cars that had them dyno tuned & they slowed down considerably. Went back to their old tuneup & the car picked right back up. Nobody other than some "exotic" spaghetti cars run cross plane cranks in street cars. Ford tried it for about 1 year in the Coyote & went back to a 90* crank. GM is using it in their race only Corvettes. The harmonic vibrations cancel any gain one might get in performance & the Ford cranks were destroying the engines. The longer the stroke, the worse the vibrations. It's the same as 4 cylinders without counter balance shafts, only twice as bad! As far as Tri-Y headers, they're ok for trucks pulling a heavy load but they don't make nearly the peak HP as a correctly designed 4 into 1 with merge collectors & step tubes with merge collectors are even better

All the Subaru engines from early 2000s (and probably back to the 80s) up to 2014 had unequal length headers, really bad but sounded great. 2 of the pulses were running into each other with another right behind and then the 4th dragging behind. They sounded cammed with open headers. Then the turbo models sounded even hotter, until they put "equal length manifolds" on them and now they just sound like a mild engine. Still has a unique sound being a boxer 4 cylinder but just sounds like its neutered now.

I’m way out of my league. Glad it’s a video. I can watch to overload, stop, and go again later. Learning LOADS. I always just accepted that four equal length into one was best. Hm. It leaves power on the table.

Thank you for your knowledge 😊

I always figured that extractors are for the purpose of tuning the length of each pipe so that as the timing of the gases reach and enter the collector individually as to not create a que.

Thank you for sharing this David. It's a pleasant review for me, with some extras, as I own and have studied judiciously, many of your books. If you would, Is primary length critical for an inertia pulsed exhaust header? I'm referring to the tri-y 4 cylinder example you showed. If you'd be so kind, as to take it a step further, have you tried a tri-y header on a V8 and do they scavenge at all?

That why I love the old 255 Indy Ford snake exhaust engine of @1965... Buick used a 15deg upward angle on their exhaust manifold, this worked like a reversion dam top side of the exhaust outflow - that 15 degs helped make a vacuum helping the exhaust flow turn on the down flow of those factory cast manifold. Back in the 80' s there was Aftermarket custom exhaust headers known as AR --- Anti Reversion

I love Total Seal rings. in my last three sbc and current 383 sbc

The 30% of sound reminded me of the one of the reasons why MP3 files are relatively small. When the audio is compressed it drops the quieter sound waves that most ppl can’t hear under the loud ones. I kinda got hopeful when you mentioned 4cyl. That you might touch on 6cyl. I’m interested in slant 6’s those things need all the help they can get. 😂

@ericvoge6678

Жыл бұрын

The leaning tower of power needs nothing but gas and time. They will outlive humanity.

@chevy6794

Жыл бұрын

When it’s all over the only things left will be roaches slant 6s and 90s jeep cherokees.

@gorkzop

Жыл бұрын

Exactly, I'm going to make my own headers for my slantie!

@richardprice5978

Жыл бұрын

but people like me MP3/compression sounds and all-8 firing i can hear 👂clearly it's the really high pitching wines i can't anymore or at least not as much as im around industrial equipment that changed my ears and or brain tune's it out so lower human-male voice is easier for me to understand ect

@lasskinn474

Жыл бұрын

there's a bit more wizardry going into mp3 than dropping 'quieter' sounds, it's dropping data that doesn't "matter" as much based on tests on people and stuff like that.

Hello David, Marc on the Isle of Man here. Thank you so much for your incredible knowledge on this subject and the time you take to put out these videos. I am extremely glad to have found your series and grateful for everything I can learn from it. I wondered if being in the USA you primarily work with V8's or if at any time you intended to talk about the straight 6? I have an m54b30 BMW engine that I am trying to optimise for open class rally cross and any advice from a time served master engineer like yourself would be greatly appreciated.

I (now) choose pipe off the head based on projected horsepower thanks to some insight by an ex-NASCAR exhaust builder. Assuming long radius bends and a good port-header transition, 1.5" off the head can handle up to around 500hp on a V8. But it needs to step up fairly smartly to not be a restriction. Works well in try-y designs as the primary-secondary join is often where you'd need to put a second step (third diameter) on a 4-1 so the headers just look like the only big difference is a stepped primary. There's a ton more to it than that though...

@bradgriffith4231

9 ай бұрын

Step tube headers improve power over the entire RPM range. Tri-Y headers improve torque BUT NASCAR teams ran them(& still does on trucks & Xfinity cars for ground clearance. Nothing new. Mickey Thompson manufactured & sold Try-Ys 60 years ago & Thorley headers STILL sells Try-Ys for trucks, Thorleys don't make as much peak power as 4 into 1s, but they do improve low end torque for trucks pulling trailers. Engine Masters dynoed several different primary tube sizes & proved that bigger primaries make more power throughut the entire RPM range. My buddy runs what's considered huge primaries on his all motor 440ci small block Olds in his 86 Cutlas Super Comp car & it runs low 5s in the 1/8 & low 8s in the 1/4, 60ft times are 1.10. Car ran 7.97/168 with his 555BBC with 4,000ft air

@skippy2987

9 ай бұрын

@@bradgriffith4231 It's not just the pipe size where the low-mid gains come from. A lot of it is the collector size. You can't fix the low end of a 250hp v8 (late C3 Corvette for example) with a 1.75 primary by running a 2" choke without restricting it a little in the top end. The expansion of a single pipe into a 4-1 collector then back down to a small choke is too much turbulence. But if you build a new set of headers that start at 1.375 then steps to a 1.5, you can run the small choke without the same turbulence. The effect is even more pronounced with a 4-2-1, you could go 1.375 primary into 1.5 for the secondary, then use a 1.75 final choke. You can get away with that because the expansion of a single pipe into a 2-1 collector is a lot smaller than a 4-1 and there's less turbulence. Are those videos here on KZread? I'd like to watch, see if they tested collector changes as well

David listening to you is like listening to my Physics instructor Dr Carlton. Car headers are a far cry from the Denco, Carpenter, and Vance & Hines headers I used on my motorcycles years ago. theyre just now using a pyramid in the collector where the 4 pipes merge, we were using them on our sidewinders going back to 1978. So you sir are 100% correct on this which is why I built the headers on my Superstock Chevy II and Monte Carlo SS. I couldnt "buy" what I wanted so I built them. And yes theyre a stepped header design and my collector uses a tricone for the sonic pulse.

I tried 2" Tri Y and Equal length extractors on the mild big block chev in my Holden Monaro. The Tri Ys always felt as though they made more power.

It has everything to do with flow! I’v been in the HVAC industry for 33 years and it’s the same in my industry. Everyone is focused on the efficiency of the equipment I focus on the duct work and air flow.

Ive just started watching your videos and have learned a lot. If i could make a recommendation, it would be to reduce the amount of animations and cuts in your videos. Specifically the random zooming of the camera. It is quite distracting to ME. Maybe not others but to me it is. Either way lots of good info and always appreciate spreading proper knowledge.

I noticed many years ago on ford Ranger 2.3L trucks they has a Cast exh manifold that was a 4 -2-1 design.

Mr Vizard, in my reading over the years, I have come to believe Sir Harry Westlake came up with the first flowbench. This is in the history of British practice of getting your gas to fuel your home was through the coin meter in your home . Young Harry seen this as a way to adapt to his cylinder head testing on his Norton racing motorcycles.

Absolute legend 🤙🍻

Thanks DV!!! 🏁

Thank you for the valuable info very informative. Note: Please see if you can enhance audio quality of your productions.

I'm trying to my best to follow this for my upcoming build, and I'm getting a little lost. Basically what we're trying to do here is ensure that each cylinder's pressure wave arrives at the collector in evenly spaced intervals. At 26:35 we see our big moment that gives us the exact measurements (although there is an error here, cylinder 1 is listed twice and cylinder 7 is not listed), and it was in trying to apply those logically that I realized that I was lost. With a classic firing order of 1,8,4,3,6,5,7,2, evenly spaced at 90* intervals of crankshaft rotation, this doesn't add up in my mind. Please see my diagram below of cylinders and the number of degrees of crankshaft rotation that have occurred since the previous fire of a cylinder on that same bank: 8 - 180 7 - 90 6 - 180 5 - 180 4 - 90 3 - 270 2 - 270 1 - 180 It seems to me that we should be making the cylinders that fire after only 90* should be the ones that are 4" longer, and that the ones that fire after 270* of rotation should be the ones that are 4" shorter, however this does not match up with the "big moment". I considered the fact that this test may have been done with a firing order swap of 4&7 and perhaps even 3&2, but still it's not making sense to me. Hopefully Mr. Vizard sees this, or someone else who can clear this up and help me understand.

@johnsnow1355

Жыл бұрын

Figuring out pulse widths is simple math really.

@lukeperry085

Жыл бұрын

@@johnsnow1355 please share

@johnsnow1355

Жыл бұрын

@@lukeperry085 exhaust pulses have a known velocity so it's a simple math calculation of time and speed to know where the pulse is at a given time

@rashidalbishri7181

Жыл бұрын

@@johnsnow1355 can you please elaborate more? I have an in-line six cylinder engine, and I am designing an unequal headers, the firing order 1 - 5 - 3 - 6- 2- 4 it’s a Nissan tb 48, it’s going to be a true duel exhaust , so therefore two manifolds will be available, first manifold will have its primary tubes on 1 5 3 and the second one will be 6 2 4, I am doing this to get the scavenging. I want to avoid the pulses from hitting each other. What’s the ideal situation to get the most of it

@LuckyCharms777

8 ай бұрын

⁠​⁠​⁠@@johnsnow1355 “exhaust pulses have a known velocity so it’s a simple math calculation” Apparently it’s a simple math calculation that you don’t know or are unwilling to share. 🤦‍♂️

DV, I think that a Tesla Valve (the scientist, not the car company) conduit design in a header could assist in solving some of the problems with back-flow due to pulse asymmetry issues that result in collector flow conflicts. Combining a high flow primary of the correct length to smooth exhaust pulse frequency alignment with a backflow prevention mechanism that doesn't significantly restrict flow would free up another HP boost like that achieved with primary pipe length tuning. That would be a fun experiment to try.

@gtoron

11 ай бұрын

I had the exact same thought about the Tesla valve principle.

I dont know why you hand out so much of your hard earned knowledge for free on KZread and next to nothing in your books. However unrecognized, it's greatly appreciated

That could explain the results Engine masters had when they did the header smash test video way back...even all smashed up the things still flowed and had no measurable difference in power till they got crazy with it and started really kinking them off with dents.

The best engine builder in Nascar history after Smokey, was Runt Pittman. He taught Robert Yates everything he knew. Runt was the engine guy for Morgan McClure Racing...the famous Kodak car, and no one was faster on the super speedways. There is a video of the Pontiac heads they used and its port and valve work is the same as what David has said. They also had an exhaust guy from Utah who pioneered unequal length headers , cross boxes and fan shaped secondaries to even out the pulses and it sounded like an F1 car going down the straights. Bill France tried to ban them but it was pure science, not cheating and those exhausts dominated for ten years. But they were so expensive and in the end they dumbed it down because the cars had too much power anyway.

you mentioned the pinto engine, this is where I first heard about you in the late 1080s. I would love to see you do a full feature on modifying the pinto engines as an update to your books. a modern take on an old classic :)

Ive always figured each exaust pulse should hit the collector at a different time so they're not "slamming" into one another and causing a disturbance in the flow.