Really interesting David. I built an exhaust for a single cylinder 640cc Husaberg in 2001, and after establishing the tuned lengths on an inertia dyno, I discovered longer open pipes favoured power at lower rpms, but maximum power at higher rpms needed shorter ones, so I created a bespoke large volume can that was a straight through. The total length to atmosphere was close to longer open pipes, but the larger volume can started at the shorter pipe lengths. I maintained the same horsepower at high rpms and gained the horsepower at low rpms I was missing just using the short pipe. Like you without your experience levels, my simplistic conclusion was the engine exhaust was seeing the shorter pipe at high speeds as the can was fooling the engine into thinking this was atmosphere, and at lower rpms the engine was seeing the longer length. Thank you for producing the video.
10 years ago I went to barns and noble and ordered every one of your books they had available. I came across your videos here on UA-cam the other day … my girl has been mad at me for the last few days. 😂 spending to much time listening to nerd stuff ! Thank you David for all that you have done for the entire auto industry!
Thank you David. I started reading your articles in magazines long before I was old enough to drive, I’m 44 now. I particularly remember one about this exhaust system. A few years ago, I loaned my brother my car to race, after his was destroyed in a bad crash. Around this time, Portland international raceway allowed a structure to be placed where noise was reflected towards the decibel meter and many veteran racers started getting disqualified for noise. My brother had run the car with the hooker aero chamber mufflers and the car was teetering on the noise limit. He built a resonator box and I bought some Walker super turbo high flow mufflers. The car ran high 10’s and only lost 0.03 sec. The car was also barely audible from the stands. In fact, standing behind the car in his shop, wicking the throttle produces more noise from the carb and ring of the noise in the resonator box, than out of the exhaust, where a distinct rush of air could be heard exiting. I have read everything of yours that I could find, once I figured out that you were the author of all of these articles that I had found to be so informative over the years. I am primarily a Ford and Dodge guy but bought your Chevy books in search for more good information. They didn’t disappoint. My brother and I have each built some engines that we’re pretty proud of, in excess of 1.4 lb-ft/ci, on very inexpensive builds. It’s always fun to impress the dyno operators and fellow racers.
I Wish I discovered David's books along time ago.. I just recently learned of David's work because of utg channel and I've been hooked ever since I've watched every video I found every lecture on UA-cam David has done.. he's my type of guy!
Thank you David for all you do, and the knowledge you share. It wasn't free when you acquired it. The fact you give it away now speaks volumes to what kind of guy you are.
We used the Applied Technologies & Research exhaust system cat back on our 87 Turbo Buicks and 98 Trans Am we ran through the system and Dump pipe seen no difference in gain dumping exhaust. The system is very quiet for street. This system is a 3 inch cross flow design. Name of the muffler was Pit Bull... Thank you for making these videos. I've bought several of your books growing up.
David I am a retired 75 year old automobile restoration technician, and Hot Rod , Mussel car restoration, fabrication , mechanic. I have been following your videos along with Uncle Tony’s videos because he had announced that you were going to work on a collaboration effort toward a 318 Mopar engine build! I have a 318 that was transplanted into a 1949 Plymouth which was I received as a bonus while I was working as a technician for So-Cal hot rods in Colorado Springs, some 20 + years ago. It’s a long term project hopefully the good lord will allow me to finish it !? As I have been battling a very aggressive Renal cancer which has taken my left kidney, tried to take my right kidney, and has attached my Pancreas! A product of Agent Orange from the Vietnam war! Regardless I am a die hard car guy! I love the way that you go into detail on why and what works in our automotive world! Doing what you are doing , extends your extensive knowledge to not only the younger generation that is tuning into your Chanel but to fellow automotive wrenches as ourselves ! I am looking forward to all the great information on the 318 Mopar project! Naturally since both my wife and I are retired and on a very minimal budget every month! Hence sticking to the 318 Mopar for the cars engine! And it’s a challenge! But doable! Just watched your zero power loss video on an exhaust system we can build! Loved it! Keep up the good work ! 👍….
Most popular exhaust systems are geared for sound not performance. Also aftermarket mufflers are usually smaller which can hinder performance. I have a generator that has 15 hp and has this little muffler and is loud as hell. My area has many power outages and some last for a couple of weeks. I don't have a dyno but I know the wattage limitations. I put an oem muffler from a car I scrapped that was huge. I welded muffler to pipe from the generator and turned on everything I knew generator could handle and was surprised it handled power with no problem, I might even say it performed better and was a whisper compared. 😁 Engine only being 15hp running house oil fired furnace 3 refrigerators and TV, computers lights etc. Oh yeah and in the summer add 15000 ac instead of heat. Wasn't much room for mistake !
Thank you for sharing! It is refreshing to see your testing and data based knowledge rather than the "feelings" based recommendations that are floating around the web.
I found those schemes a two decades ago black and white photocopied from somwhere and have been searching original. Now I know. I used your principle on one of my customers Corvette. It had 3" pipes and awful noise. He was so worried about losing power. I offered that I make hem a exhaustsystem and if he loses power, I swap back the one that he had with no charge. Now almost 17 years later I saw that same car at parkinglot. It still has exhaust that I made with your advices and guidelines! Thank you! Greetings from Finland!
I am soo soosoo sorry x 1milliion. Near to tears, i can't imagine. & Thank you David for sharing your knowledge. I used to read everything Smokey Unick put out. Your knowledge is greatly treasured by me, and Jesus is invaluable, remember that. God Bless you. Jim.
when i first began watching davids video's, it wasnt until i saw the graphics that i recognized them from books i used to get at the library back in the 80s.then it all made perfect sence.
I have had countless people debate with me about back pressure. I knew I was right, your video confirmed it. There are so many shade tree mechanics and even muffler specialists out there who think you have to have back pressure in order for an exhaust system to work correctly. Thank you for putting the knowledge out there.
Wow! I remember the Sonic Turbo muffler ads in Car Craft, PHR and Hot Rod In the early 80s? That muffler design was your baby, David? I had no idea. I have really been enjoying learning from your many videos. Thank you so much for educating me and others watching these fascinating videos!
Dear David ,.... another great tutorial with all the right info ! HOWEVER ,... from 16:00 mins. to about 20:30 , the BACKGROUND MUSIC IS SO LOUD I cant hear what you're saying ! So I had to re-play the video several times to hear your words ! It's very disturbing and totally unnecessary as we are here to LEARN as if we are sitting in the classroom and don't want any disruptive noises cutting into your lecture ! Your lectures are priceless and don't need any background sounds or music at all ! Thank you again for sharing your knowledge with the world of auto fans !
I've been a gear head all of my life. when I was in my early 20's, I had a Dodge Charger 440 six pack, that I built the engine up. I knew back pressure was for granny cars. i built a 4 glass pack exhaust, that was loud as 43LL but performed GREAT! I used 2) 2 1/4" exhaust tubes, flattened one side out, then welded them into the header flange that was meant for the reducer. i basically made a Y pipe out of them. and then ran just enough pipe to connect the glass packs. I lived next door to the local "cop shop" and I was always on the good side of them. so they never gave me any trouble. that car literally flew, well the front end anyway. it would go so fast that the front end of the car would get so much air under it that the front tires were not contacting the road anymore! I NEVER lost a top end race with it.
My favorite new channel!, I plan on watching them all at least once. My brother watched a few of your video's and harassed me until I watched a few video's. I didn't want to start watching because I knew if he was right about how awesome your information was that would become addicted to them! Too late now...
Hello David. Thanks for taking the time to make all these informative videos. I ordered your porting and horsepower books and am looking forward to reading them. It's been 20 years since I've built an engine and I'm going to get back into it as I picked up a nice 1978 f100 that I want to replace the anemic 400 with a nice 460. I did build a 460 when I was in my younger years but am looking forward to applying what I've learned from you and others along the way. I am lucky to be a machinist and have machine shop and tools at my disposal that I can use if needed. The goal is to see what I can get out of a 460 without breaking the bank and my marriage. ;-)...
Thanks for the great information. I now see why there is a resonator in the exhaust system on my minivan. It made no sense before but now it does. I may be thinking off it wrong but it reminds me of an expansion chamber on a 2 stroke exhaust system
Absolutely live your videos. Back in the day (mid-1980s) my brother's best friend had the best sounding mufflers I have ever heard........even to this day. They happened to be Walker Redline Z mufflers. Sounded great and also may be a reason the car ran like a scaled ape. It was a daily driven 1972 Pontiac Trans Am 455 HO 4-speed, basically stock w/ a Ram Air IV solid lifter cam and aluminum intake. The car was immaculately tuned and properly carbureted and ran 11.90s all day long.
I appreciate all the videos you're putting out. I wish I had half this info 25 years ago. Please continue with anything really. Even just general talk videos. Again, thank you.
Flowmasters are really good at flowing noise. Had to get rid of the ones I bought because they were too loud... Can't wait to build a system as you described DV
My Flowmaster Super 40s helped me achieve great numbers on my supercharged Foxbody. Might there have been some power on the table? Yes. Would it have sounded as good? No.
Thank You David. I had redesained and refrabicated stock exhaust from my yaris. Based on your calculation, without cat, I should decrease stock pipe. From 2" to 1.75", stock resonator, muffler deleted. Changed to termination box, and straight steel wool + glass packed. Strangely the power increase on dyno around 6-7 HP free power. With additional mpg. Thank you.
Always great to have facts. Whenever I've spent time reading up on exhausts, I've never come across this information despite the countless hours of reading I've done. I'm grateful to have found this perfect, simple recipe for a set of baseline design parameters. termination box volume = engine cylinder capacity * 8, then mufflers = 2.3 cfm / engine HP. All that's left is for a music company to help with the kind of noise that comes out... Yamaha comes to mind with their Lexus LFA exhaust.
By watching this I learned my reversion cone is backwards. I built mine based on the Denco tricone I used on my 1978 KZ1000 LTD. Learn something new everyday (I watch David Vizard daily). 😁
I'm going back to like every video of yours that I have watched bc you are sharing information that I have spent my entire life trying to learn. Thank you sir...... Also you are the only sub I have turned notifications on for.
Thankyou so much. "Another proud moment" .I really appreciate the effort and detail you put into explaining . When you take the time to consider the next word or phrase , it shows why un rushed, quality spoken language is so valuable. 👍
Hi Mr. VISARD many years ago while running in a modified street class we cut old 3 lb. Coffee cans it passed the tech inspectors I don't know how much hp it robbed but it was what we could afford this was in the 70s
David...Please lose the music, those of us with hearing loss can't hear because of the "back round noise." It's like being in a crowded room and everyone talking at once. PRD is about to build a "0" loss system on my 68 GTO with a 511 Kauffman 871 BDS twin PC 1200cfm on E85... Thanks for what you post, very helpful.
First thanks for all the things that you have shared and continue to share. Also it’s great that you have continued after all the criticism I know you would have endured. In Australia one of our most popular cars the Ford Falcon of the 90s came with a four litre sohc inline six. Long story short I could make these cars almost two seconds faster in 1/4 mile with only the fuel injectors (from another manufacturers car) the headers (aftermarket)and the front part of the exhaust being modified. Although the header design of the aftermarket headers was rubbish the aftermarket parts and the modified factory parts all resulted in at least 20 wheel hp gains average (sometimes more) the crap I would cop from people with cams valve springs tuned ecu bigger throttle bodies ect ect was ridiculous 😂 even though I would post videos of dyno and drag times I was called a liar and a few other colourful things. Even some people who made tuning chips would call me out on the fact I used a stock untouched ecu. It was then I learned there are a few different types of people playing the same game. People who want to just go fast. People who want a list of parts to Impress their mates. And the people selling the said parts to impress your mates. Earlier in my life I had applied similar build theory to carb V8s both GM and Ford and most times beaten cars with a much greater list of parts. Some people just want to say they have this brand muffler and believe that a muffler will actually give you power 😂 when actually to break even and have no or little power lose is the best out come you can get from fitting mufflers to your street car. Anyway continue Sir and thanks again.
I do love your in-site on a very wide range of topics! Thanks for sharing your knowledge! I am around your age and I just wish I had met you when I was younger! I know when I have any kind of perfomance questions, I consult your videos and books and I can find the answer! Again thank you!
I used to build my own engines and turn my own wrench quite a bit. What you show here makes great sense to me! I’m an electrical engineering with a number of years experience in reflections and filtering of high frequency radio waves. I’ve been designing “mufflers” and resonators! I’ve had it in mind for years to emulate an exhaust system using electronic simulation software. I might just get on with that. Thanks, David! Good on ye!
You are so correct on all I have learned from reading and trial and error. If I only would have persued my passions instead of making a living I'd have both and a remarkable reputation to include.
Thanx so much Mr Vizard what you said is absolutely correct,you gave me the technical knowledge,i just built with my own knowledge prototypes which are painfull if incorrect if wrong because its money wasted and a broken ego because you have shown yourself you are not as clever as you thought you were🤣🤣🤣but thats life,i have no equipment to measure ,.my ears were wide open when you explained ,thanx so much for your knowledge Regards Nick
David you’re absolutely amazing n your skills n knowledge is simply incredible. I’ve passed several videos onto a few friends . I want to say thank you for your wisdom n your kindness to the world Donnie
I have a pair of Flowmaster 40 series mufflers on my LT1 powered 96 Buick Roadmaster sedan. After seeing this, I'm thinking about completely rebuilding my exhaust and cutting open the mufflers to see if I can make them a little better
Great video David. Was just reading your How to Build Horsepower book. Specifically the exhaust system sections. On the subject of back pressure, I fail to see how anyone expects a motor to make more power when you stick a cork in its arse!!! I don't work too well with a choked exhaust either. I look at engines as a delta P device. I always want to maximise the change in pressures. 1 bar absolute of atmospheric pressure at the induction inlet, and as a number, 0 bar absolute in the exhaust during valve overlap. I know that 0 bar is unrealistic, but it's optimum. Maximum delta P for induction. I use the same thought process with combustion, etc. Regards Greg
David your knowledge is invaluable and thank you for sharing what you know to those who want to learn. Please keep making these videos. Merry Christmas
Kudos! I have seen stock mufflers rust out and can see the restriction just by looking. Some mufflers I have seen for 2 1/2 inch in and out only had 1 3/4 inch internal passages. WOW! I use turbo mufflers that I saw the cutaway view by the manufacturer. Not quiet. Not loud, but a nice deep rumble. I laugh at the pretend go fast wanna-be loud exhaust systems that do nothing but give you hearing loss and lost HP. I too have often said to the posers/jerks/idiots "Really? Then show me how it is done." And since I knew they couldn't, I laugh at them when they turn red, shut up, and walk away with their tail between their legs. No, I don't have all the answers either, but I don't pretend I do. I also am a numbers cruncher and do testing for the graphs and charts so I know exactly what I am dealing with. You are pointing me in directions for information I didn't have. Thanks!! Sometimes I only had a SWAG - Scientific Wild Ass Guess. This will save me a lot of time and testing. I used RPM times the displacement to determine the CFM carb needed, and that seems to be a little low on the actual CFM per HP requirement as compared to the 2.3 CFM per HP. My formula doesn't take into consideration the scavenge air flow when HP exceeds 1 HP per CID. I may seem to ramble on, but my intention is to throw out some of my experiences and knowledge for your viewers and who knows, maybe give you a little different point of view. I have designed, engineered and built testing equipment for other industries and try to use the knowledge and skills to build very accurate test equipment. I have been injured and a wreck for about 30 years (7 surgeries delayed for 9 years because of the insurance company followed up with a bad heart attack with heart damage) and finally getting motivated to get back into building Small Block Chevy's. Thanks for the good info and giving me motivation to get back into the fun of building engines again!
Thank you for this fine video. I appreciate your telling it like it is in regards to the muffler companies. I would appreciate it if you could cover how you go about choosing exhaust pipe diameter. There seems to be a lot of disagreement on that topic.
Thank you sir for sharing all your knowledge. To those of us who love cars and performance it is a true blessing that you share all these things with us.. I love listening and watching all your videos
Thanks for all your sharing of your wisdom throughout the years. I read the many Popular Hot Rodding articles then purchased your books back in the 80's you helped "turn on the light" that performance from an engine means you take many systems into considertion. You, Bill Jenkins, Waddel Wilson, Smokey Yunick and others helped me build reliable winning motors over the years. Common sense and a prcatical approach to building horespower.
Used sonic turbos ever since the you wrote about them. On my 69 camaro 327. And my 94 Cadillac STS .They were awesome noticeable improvement over the factory. Guiet at cruising speeds and reminded of an indy car when you really get in to it. Also needed a K&N air filter the factory setup was somewhat restricted. It would spin the tires shifting in to 2nd. This was on the STS.
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.
I think for 90% of people, noise is more important than power. People want what sounds "good", not what makes power. I won't say that peak power is the most important thing to me, but I do understand that keeping noise reasonable will help keep the cops from caring about me. Maybe it hurts performance a tiny bit, but not as much as getting impounded on a daily. Race car? Maybe it's a different story.
Nice! Now the whole termination/resonator chamber thing makes sense. Now to ponder the differences between what is the best exhaust system, and what will actually fit under my 66 Plymouth!
Thank you for a very informative muffler video. Far too much smoke and mirrors in the muffler business. I am trying to design a muffler for an airboat (100 hp, 1.5 liter 4 cyl Suzuki automobile conversion) so this was very helpful and might go a long way in keeping it quiet. Regards.
First and Foremost R.I.P. Jacque Vizard David Vizard I Read A Lot of Your Books, back in the old days, I'm talking '80's . I remember Reading about that "Muffler Shootout" in the Magazine at the time, and I do not remember what that "Sonic Turbo muffler" Price was back then, but it was much more than say glasspacks. Then Years later, Because of all the Fastest Street Car Shootouts, most being sponsored by, "Flowmaster" I bought them. They Worked well for me, but I ran better with Dyno Max Mufflers. You brought up Supertrap, as soon as you started, I knew were it was going. there are either loud, and produce power, or they are quite, and don't! I have a supertrap header, and muffler on one of our Quads, yes it goes Faster, but it is loud! Almost to Loud to be Riding it on the Trails for 4 hrs. at A Time. I Subscribed by the way!
I would love to meet you we think about the same way I agree especially with a lot of today's aftermarket parts they say more power or turbo this and that and you're right only in name most often they rob people aren't thinking right I like the way you think through I really wish I could meet you your freaking awesome
Great info, I've always questioned the "you need backpressure" theory. You really debunked it, thank you. By the way, your video ends at 30:03, but continues with mostly black screen to 1:20:58. As a fellow youtuber I can understand editor fumbling, just use the youtube trim tool to pull the time back to 30:03.
I worked to develop a system for a company. A 2014 KTM muffler seems to have passive cancellation where it seems able to convert sound straight to high heat while letting flow exit the muffler through a tube which sampled from the volume of a chamber at a harmonically quiescent location. This all happened inside a triple armored and insulated jacket. Put another way, they tricked the sound waves into combating one another at the very core while letting the flow slip out quietly. The guts of the muffler were the product of profound genius. I had a sound analyzer which was so sensitive it could hear a mouse fart in a room with a wide open jet engine running. Great video. I learned lots. Everyone, tell your bench racing chums about Dave’s new chan; “David Vizard”. We need to build his numbers back up.
This is one of my favorite video's David!! It really solidifies and ties everything together I've thought over the years about the way exhausts work! I'm also sorry you had to create a new channel.. It's actually a good thing for me because I get to rewatch alot of the video's! Thank you so much for sharing this information! I won't call this my favorite video because I love hearing your racing stories! I race 4 wheelers and 3 wheelers!
Awesome information! So much to learn! Also I have a Super Trap on my motorcycle and love it. I put flat washers between the discs to create a larger gap thru about 25 discs. It is still no where near as loud as the vast majority of Harley’s out there.
Really interesting David. I built an exhaust for a single cylinder 640cc Husaberg in 2001, and after establishing the tuned lengths on an inertia dyno, I discovered longer open pipes favoured power at lower rpms, but maximum power at higher rpms needed shorter ones, so I created a bespoke large volume can that was a straight through. The total length to atmosphere was close to longer open pipes, but the larger volume can started at the shorter pipe lengths. I maintained the same horsepower at high rpms and gained the horsepower at low rpms I was missing just using the short pipe. Like you without your experience levels, my simplistic conclusion was the engine exhaust was seeing the shorter pipe at high speeds as the can was fooling the engine into thinking this was atmosphere, and at lower rpms the engine was seeing the longer length. Thank you for producing the video.
10 years ago I went to barns and noble and ordered every one of your books they had available. I came across your videos here on UA-cam the other day … my girl has been mad at me for the last few days. 😂 spending to much time listening to nerd stuff !
Thank you David for all that you have done for the entire auto industry!
Thank you David. I started reading your articles in magazines long before I was old enough to drive, I’m 44 now. I particularly remember one about this exhaust system.
A few years ago, I loaned my brother my car to race, after his was destroyed in a bad crash. Around this time, Portland international raceway allowed a structure to be placed where noise was reflected towards the decibel meter and many veteran racers started getting disqualified for noise.
My brother had run the car with the hooker aero chamber mufflers and the car was teetering on the noise limit. He built a resonator box and I bought some Walker super turbo high flow mufflers. The car ran high 10’s and only lost 0.03 sec. The car was also barely audible from the stands. In fact, standing behind the car in his shop, wicking the throttle produces more noise from the carb and ring of the noise in the resonator box, than out of the exhaust, where a distinct rush of air could be heard exiting.
I have read everything of yours that I could find, once I figured out that you were the author of all of these articles that I had found to be so informative over the years. I am primarily a Ford and Dodge guy but bought your Chevy books in search for more good information. They didn’t disappoint.
My brother and I have each built some engines that we’re pretty proud of, in excess of 1.4 lb-ft/ci, on very inexpensive builds.
It’s always fun to impress the dyno operators and fellow racers.
I Wish I discovered David's books along time ago.. I just recently learned of David's work because of utg channel and I've been hooked ever since I've watched every video I found every lecture on UA-cam David has done.. he's my type of guy!
Thank you David. I can sit and listen to your wisdom for hours.
So much wisdom to be learned here ..but he can't spell legal correctly 😁
I completely agree.
Thank you David for all you do, and the knowledge you share. It wasn't free when you acquired it. The fact you give it away now speaks volumes to what kind of guy you are.
We used the Applied Technologies & Research exhaust system cat back on our 87 Turbo Buicks and 98 Trans Am we ran through the system and Dump pipe seen no difference in gain dumping exhaust. The system is very quiet for street. This system is a 3 inch cross flow design. Name of the muffler was Pit Bull... Thank you for making these videos. I've bought several of your books growing up.
David I am a retired 75 year old automobile restoration technician, and Hot Rod , Mussel car restoration, fabrication , mechanic. I have been following your videos along with Uncle Tony’s videos because he had announced that you were going to work on a collaboration effort toward a 318 Mopar engine build! I have a 318 that was transplanted into a 1949 Plymouth which was I received as a bonus while I was working as a technician for So-Cal hot rods in Colorado Springs, some 20 + years ago. It’s a long term project hopefully the good lord will allow me to finish it !? As I have been battling a very aggressive Renal cancer which has taken my left kidney, tried to take my right kidney, and has attached my Pancreas! A product of Agent Orange from the Vietnam war! Regardless I am a die hard car guy! I love the way that you go into detail on why and what works in our automotive world! Doing what you are doing , extends your extensive knowledge to not only the younger generation that is tuning into your Chanel but to fellow automotive wrenches as ourselves ! I am looking forward to all the great information on the 318 Mopar project! Naturally since both my wife and I are retired and on a very minimal budget every month! Hence sticking to the 318 Mopar for the cars engine! And it’s a challenge! But doable! Just watched your zero power loss video on an exhaust system we can build! Loved it! Keep up the good work ! 👍….
Most popular exhaust systems are geared for sound not performance. Also aftermarket mufflers are usually smaller which can hinder performance. I have a generator that has 15 hp and has this little muffler and is loud as hell. My area has many power outages and some last for a couple of weeks. I don't have a dyno but I know the wattage limitations. I put an oem muffler from a car I scrapped that was huge. I welded muffler to pipe from the generator and turned on everything I knew generator could handle and was surprised it handled power with no problem, I might even say it performed better and was a whisper compared. 😁 Engine only being 15hp running house oil fired furnace 3 refrigerators and TV, computers lights etc. Oh yeah and in the summer add 15000 ac instead of heat. Wasn't much room for mistake !
amazing! somebody that actually knows what they're talking about! a breath of fresh air!
This gentleman tells it like it is from experience and education, not from a cash register. I greatly admire his wisdom.
How lucky we are to get lessons from a master like you. Thank you!
As a gearhead I just love watching your videos and gaining auto knowledge.
Thank you for sharing! It is refreshing to see your testing and data based knowledge rather than the "feelings" based recommendations that are floating around the web.
I found those schemes a two decades ago black and white photocopied from somwhere and have been searching original. Now I know. I used your principle on one of my customers Corvette. It had 3" pipes and awful noise. He was so worried about losing power. I offered that I make hem a exhaustsystem and if he loses power, I swap back the one that he had with no charge. Now almost 17 years later I saw that same car at parkinglot. It still has exhaust that I made with your advices and guidelines! Thank you! Greetings from Finland!
This is a great no nonsense video. Love the knowledge and stories. Subscribed. Rest in peace your daughter. Taken too soon.
What a beautiful video and excellent information. Very grateful to have seen this.
I am soo soosoo sorry x 1milliion. Near to tears, i can't imagine. & Thank you David for sharing your knowledge.
I used to read everything Smokey Unick put out. Your knowledge is greatly treasured by me, and Jesus is invaluable, remember that. God Bless you. Jim.
when i first began watching davids video's, it wasnt until i saw the graphics that i recognized them from books i used to get at the library back in the 80s.then it all made perfect sence.
I have had countless people debate with me about back pressure. I knew I was right, your video confirmed it. There are so many shade tree mechanics and even muffler specialists out there who think you have to have back pressure in order for an exhaust system to work correctly. Thank you for putting the knowledge out there.
Wow! I remember the Sonic Turbo muffler ads in Car Craft, PHR and Hot Rod In the early 80s? That muffler design was your baby, David? I had no idea. I have really been enjoying learning from your many videos. Thank you so much for educating me and others watching these fascinating videos!
Have several of your books, and just found this video series. Outstanding. Thank You for your lifetime of contributions to the performance world.
Dear David ,.... another great tutorial with all the right info ! HOWEVER ,... from 16:00 mins. to about 20:30 , the BACKGROUND MUSIC IS SO LOUD I cant hear what you're saying ! So I had to re-play the video several times to hear your words ! It's very disturbing and totally unnecessary as we are here to LEARN as if we are sitting in the classroom and don't want any disruptive noises cutting into your lecture ! Your lectures are priceless and don't need any background sounds or music at all ! Thank you again for sharing your knowledge with the world of auto fans !
You are the most informative all out gearhead ive ever listened too, appreciate every bit of this shared knowledge. Thank you
I really enjoyed the music to go with the dialogue. Made this feel like a motivational speech haha, love the video I'm watching it all
I've been a gear head all of my life. when I was in my early 20's, I had a Dodge Charger 440 six pack, that I built the engine up. I knew back pressure was for granny cars. i built a 4 glass pack exhaust, that was loud as 43LL but performed GREAT! I used 2) 2 1/4" exhaust tubes, flattened one side out, then welded them into the header flange that was meant for the reducer. i basically made a Y pipe out of them. and then ran just enough pipe to connect the glass packs. I lived next door to the local "cop shop" and I was always on the good side of them. so they never gave me any trouble. that car literally flew, well the front end anyway. it would go so fast that the front end of the car would get so much air under it that the front tires were not contacting the road anymore! I NEVER lost a top end race with it.
My favorite new channel!, I plan on watching them all at least once. My brother watched a few of your video's and harassed me until I watched a few video's. I didn't want to start watching because I knew if he was right about how awesome your information was that would become addicted to them! Too late now...
Hello David. Thanks for taking the time to make all these informative videos. I ordered your porting and horsepower books and am looking forward to reading them. It's been 20 years since I've built an engine and I'm going to get back into it as I picked up a nice 1978 f100 that I want to replace the anemic 400 with a nice 460. I did build a 460 when I was in my younger years but am looking forward to applying what I've learned from you and others along the way. I am lucky to be a machinist and have machine shop and tools at my disposal that I can use if needed. The goal is to see what I can get out of a 460 without breaking the bank and my marriage. ;-)...
Looking into building a car from the engine up and your advice is priceless… have ordered several of your books… Ty! Cheers
I've been working on cars all my life never really thought about mufflers that way very impressive
I really like the exhaust info. All things exhaust flow interest me.
Thanks for the great information. I now see why there is a resonator in the exhaust system on my minivan. It made no sense before but now it does. I may be thinking off it wrong but it reminds me of an expansion chamber on a 2 stroke exhaust system
Absolutely live your videos. Back in the day (mid-1980s) my brother's best friend had the best sounding mufflers I have ever heard........even to this day. They happened to be Walker Redline Z mufflers. Sounded great and also may be a reason the car ran like a scaled ape. It was a daily driven 1972 Pontiac Trans Am 455 HO 4-speed, basically stock w/ a Ram Air IV solid lifter cam and aluminum intake. The car was immaculately tuned and properly carbureted and ran 11.90s all day long.
Mr Vizard, you are a brilliant man. Thank you so much for sharing!
I appreciate all the videos you're putting out. I wish I had half this info 25 years ago. Please continue with anything really. Even just general talk videos. Again, thank you.
Flowmasters are really good at flowing noise. Had to get rid of the ones I bought because they were too loud... Can't wait to build a system as you described DV
"Flowmasters are really good at flowing noise." That is funny. :D
That’s why people buy them, to make their stock POS sound “mean”
My Flowmaster Super 40s helped me achieve great numbers on my supercharged Foxbody. Might there have been some power on the table? Yes. Would it have sounded as good? No.
Thank You David. I had redesained and refrabicated stock exhaust from my yaris. Based on your calculation, without cat, I should decrease stock pipe. From 2" to 1.75", stock resonator, muffler deleted. Changed to termination box, and straight steel wool + glass packed.
Strangely the power increase on dyno around 6-7 HP free power. With additional mpg. Thank you.
Thanks again for an amazing video. Best tech available anywhere! Well done.
You have the most interesting thoughts on engine performance with hard proof.
You've got me hooked. Thank you.
Always great to have facts. Whenever I've spent time reading up on exhausts, I've never come across this information despite the countless hours of reading I've done. I'm grateful to have found this perfect, simple recipe for a set of baseline design parameters. termination box volume = engine cylinder capacity * 8, then mufflers = 2.3 cfm / engine HP. All that's left is for a music company to help with the kind of noise that comes out... Yamaha comes to mind with their Lexus LFA exhaust.
I didn't know Marvin but he sounds like a great friend. Another great video DV.
By watching this I learned my reversion cone is backwards. I built mine based on the Denco tricone I used on my 1978 KZ1000 LTD. Learn something new everyday (I watch David Vizard daily). 😁
I too watch Mr Vizard daily.
I'm going back to like every video of yours that I have watched bc you are sharing information that I have spent my entire life trying to learn. Thank you sir...... Also you are the only sub I have turned notifications on for.
Thankyou so much. "Another proud moment" .I really appreciate the effort and detail you put into explaining . When you take the time to consider the next word or phrase , it shows why un rushed, quality spoken language is so valuable. 👍
I agree wholeheartedly!
Hi Mr. VISARD many years ago while running in a modified street class we cut old 3 lb. Coffee cans it passed the tech inspectors I don't know how much hp it robbed but it was what we could afford this was in the 70s
David...Please lose the music, those of us with hearing loss can't hear because of the "back round noise." It's like being in a crowded room and everyone talking at once. PRD is about to build a "0" loss system on my 68 GTO with a 511 Kauffman 871 BDS twin PC 1200cfm on E85... Thanks for what you post, very helpful.
I had one of your Sonic Turbo mufflers on a 2.3L 1976 Ford Pinto. It worked wonderfully!! Wish they were still made.
Dynomax super turbo, same
First thanks for all the things that you have shared and continue to share. Also it’s great that you have continued after all the criticism I know you would have endured. In Australia one of our most popular cars the Ford Falcon of the 90s came with a four litre sohc inline six. Long story short I could make these cars almost two seconds faster in 1/4 mile with only the fuel injectors (from another manufacturers car) the headers (aftermarket)and the front part of the exhaust being modified. Although the header design of the aftermarket headers was rubbish the aftermarket parts and the modified factory parts all resulted in at least 20 wheel hp gains average (sometimes more) the crap I would cop from people with cams valve springs tuned ecu bigger throttle bodies ect ect was ridiculous 😂 even though I would post videos of dyno and drag times I was called a liar and a few other colourful things. Even some people who made tuning chips would call me out on the fact I used a stock untouched ecu. It was then I learned there are a few different types of people playing the same game. People who want to just go fast. People who want a list of parts to
Impress their mates. And the people selling the said parts to impress your mates. Earlier in my life I had applied similar build theory to carb V8s both GM and Ford and most times beaten cars with a much greater list of parts. Some people just want to say they have this brand muffler and believe that a muffler will actually give you power 😂 when actually to break even and have no or little power lose is the best out come you can get from fitting mufflers to your street car. Anyway continue Sir and thanks again.
Wizard of hp, would love to know the 5c change on a flowmaster to cut the noise
"I'm just a plain old ordinary ENGINEER " nope good try, its nice that your humble. love the content! keep it up!
As always very interesting and informative info! Thanks DV!! 🏁
Ive built your system , And it Works !!! Thank you !!!
I do love your in-site on a very wide range of topics! Thanks for sharing your knowledge! I am around your age and I just wish I had met you when I was younger! I know when I have any kind of perfomance questions, I consult your videos and books and I can find the answer! Again thank you!
Great videos, lots of information
I used to build my own engines and turn my own wrench quite a bit.
What you show here makes great sense to me! I’m an electrical engineering with a number of years experience in reflections and filtering of high frequency radio waves. I’ve been designing “mufflers” and resonators!
I’ve had it in mind for years to emulate an exhaust system using electronic simulation software. I might just get on with that.
Thanks, David! Good on ye!
You are so correct on all I have learned from reading and trial and error. If I only would have persued my passions instead of making a living I'd have both and a remarkable reputation to include.
Thanx so much Mr Vizard what you said is absolutely correct,you gave me the technical knowledge,i just built with my own knowledge prototypes which are painfull if incorrect if wrong because its money wasted and a broken ego because you have shown yourself you are not as clever as you thought you were🤣🤣🤣but thats life,i have no equipment to measure ,.my ears were wide open when you explained ,thanx so much for your knowledge
Regards
Nick
David you’re absolutely amazing n your skills n knowledge is simply incredible.
I’ve passed several videos onto a few friends .
I want to say thank you for your wisdom n your kindness to the world
Donnie
Basically…..it’s a piece of garbage!
Best quote of the day !
Love all these fascinating stories! Keep them coming, please.
I have a pair of Flowmaster 40 series mufflers on my LT1 powered 96 Buick Roadmaster sedan. After seeing this, I'm thinking about completely rebuilding my exhaust and cutting open the mufflers to see if I can make them a little better
Thankyou David For Sharing Your Knowledge With Us I Actually Learned Alot From You That I Didn't Know,
I love your videos, you have a great ability to get the point across without to much useless rambling in-between the good stuff.
Thank you so much for all the information that you're giving us I have learned so much from the last 2 months thank you again and God bless you
Great video David. Was just reading your How to Build Horsepower book. Specifically the exhaust system sections. On the subject of back pressure, I fail to see how anyone expects a motor to make more power when you stick a cork in its arse!!! I don't work too well with a choked exhaust either. I look at engines as a delta P device. I always want to maximise the change in pressures. 1 bar absolute of atmospheric pressure at the induction inlet, and as a number, 0 bar absolute in the exhaust during valve overlap. I know that 0 bar is unrealistic, but it's optimum. Maximum delta P for induction. I use the same thought process with combustion, etc. Regards Greg
David your knowledge is invaluable and thank you for sharing what you know to those who want to learn. Please keep making these videos. Merry Christmas
Your information is Awesome
Kudos! I have seen stock mufflers rust out and can see the restriction just by looking. Some mufflers I have seen for 2 1/2 inch in and out only had 1 3/4 inch internal passages. WOW! I use turbo mufflers that I saw the cutaway view by the manufacturer. Not quiet. Not loud, but a nice deep rumble. I laugh at the pretend go fast wanna-be loud exhaust systems that do nothing but give you hearing loss and lost HP.
I too have often said to the posers/jerks/idiots "Really? Then show me how it is done." And since I knew they couldn't, I laugh at them when they turn red, shut up, and walk away with their tail between their legs. No, I don't have all the answers either, but I don't pretend I do. I also am a numbers cruncher and do testing for the graphs and charts so I know exactly what I am dealing with. You are pointing me in directions for information I didn't have. Thanks!! Sometimes I only had a SWAG - Scientific Wild Ass Guess. This will save me a lot of time and testing. I used RPM times the displacement to determine the CFM carb needed, and that seems to be a little low on the actual CFM per HP requirement as compared to the 2.3 CFM per HP. My formula doesn't take into consideration the scavenge air flow when HP exceeds 1 HP per CID. I may seem to ramble on, but my intention is to throw out some of my experiences and knowledge for your viewers and who knows, maybe give you a little different point of view. I have designed, engineered and built testing equipment for other industries and try to use the knowledge and skills to build very accurate test equipment. I have been injured and a wreck for about 30 years (7 surgeries delayed for 9 years because of the insurance company followed up with a bad heart attack with heart damage) and finally getting motivated to get back into building Small Block Chevy's. Thanks for the good info and giving me motivation to get back into the fun of building engines again!
Your amazing for sharing this information.
I loved that sonic turbo muffler and would be using it today if I could get them. I should have known it was your baby
Thank you for this fine video. I appreciate your telling it like it is in regards to the muffler companies. I would appreciate it if you could cover how you go about choosing exhaust pipe diameter. There seems to be a lot of disagreement on that topic.
Greg! Lol, here trying to make his euro hotrod street quite. (Same as me)
Thank you sir for sharing all your knowledge. To those of us who love cars and performance it is a true blessing that you share all these things with us.. I love listening and watching all your videos
That resonator box is like a very large x-pipe 🥰
Thanks for all your sharing of your wisdom throughout the years. I read the many Popular Hot Rodding articles then purchased your books back in the 80's you helped "turn on the light" that performance from an engine means you take many systems into considertion. You, Bill Jenkins, Waddel Wilson, Smokey Yunick and others helped me build reliable winning motors over the years. Common sense and a prcatical approach to building horespower.
Thank you for sharing looking forward to your next video
Thanks David always good to learn a different point of view, and technical proof
Helped to clarify what was written in your book(s). Another Gold Nugget. Much thanks, Greg
I've recently found you on UTG's channel. I find your channel very interesting also I'll admit im no pro but i really enjoy watching your videos
The Guru himself!!!!!!
Used sonic turbos ever since the you wrote about them. On my 69 camaro 327. And my 94 Cadillac STS .They were awesome noticeable improvement over the factory. Guiet at cruising speeds and reminded of an indy car when you really get in to it. Also needed a K&N air filter the factory setup was somewhat restricted. It would spin the tires shifting in to 2nd. This was on the STS.
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.
I think for 90% of people, noise is more important than power. People want what sounds "good", not what makes power.
I won't say that peak power is the most important thing to me, but I do understand that keeping noise reasonable will help keep the cops from caring about me. Maybe it hurts performance a tiny bit, but not as much as getting impounded on a daily. Race car? Maybe it's a different story.
Finally someone says flowmasters are terrible for making power.
Nice! Now the whole termination/resonator chamber thing makes sense. Now to ponder the differences between what is the best exhaust system, and what will actually fit under my 66 Plymouth!
Thank you for a very informative muffler video. Far too much smoke and mirrors in the muffler business.
I am trying to design a muffler for an airboat (100 hp, 1.5 liter 4 cyl Suzuki automobile conversion) so this was very helpful and might go a long way in keeping it quiet. Regards.
I've always loved borla, and every vehicle ive owned has had either their off the shelf mufflers or complete catback. Good to hear they flow as well!
thanks david
First and Foremost R.I.P. Jacque Vizard
David Vizard I Read A Lot of Your Books, back in the old days, I'm talking '80's .
I remember Reading about that "Muffler Shootout" in the Magazine at the time, and I do not remember what that "Sonic Turbo muffler" Price was back then, but it was much more than say glasspacks.
Then Years later, Because of all the Fastest Street Car Shootouts, most being sponsored by, "Flowmaster" I bought them.
They Worked well for me, but I ran better with Dyno Max Mufflers.
You brought up Supertrap, as soon as you started, I knew were it was going.
there are either loud, and produce power, or they are quite, and don't!
I have a supertrap header, and muffler on one of our Quads, yes it goes Faster, but it is loud!
Almost to Loud to be Riding it on the Trails for 4 hrs. at A Time.
I Subscribed by the way!
Great Information Thanks
I would love to meet you we think about the same way I agree especially with a lot of today's aftermarket parts they say more power or turbo this and that and you're right only in name most often they rob people aren't thinking right I like the way you think through I really wish I could meet you your freaking awesome
Great info, I've always questioned the "you need backpressure" theory. You really debunked it, thank you. By the way, your video ends at 30:03, but continues with mostly black screen to 1:20:58. As a fellow youtuber I can understand editor fumbling, just use the youtube trim tool to pull the time back to 30:03.
I thoroughly enjoyed that! Cheers mate.
Cherry bomb makes mufflers that are designed this way, good to know that this design has some advantages, great content!
also owned by walker.
I worked to develop a system for a company. A 2014 KTM muffler seems to have passive cancellation where it seems able to convert sound straight to high heat while letting flow exit the muffler through a tube which sampled from the volume of a chamber at a harmonically quiescent location. This all happened inside a triple armored and insulated jacket.
Put another way, they tricked the sound waves into combating one another at the very core while letting the flow slip out quietly. The guts of the muffler were the product of profound genius.
I had a sound analyzer which was so sensitive it could hear a mouse fart in a room with a wide open jet engine running.
Great video. I learned lots.
Everyone, tell your bench racing chums about Dave’s new chan; “David Vizard”.
We need to build his numbers back up.
I actually need to track rodents using sound and am interested in knowing what specifications your audio system meets please .
It sounds like KTM integrated a Helmholtz resonator into the exhaust system. Very cool!!!
The door in my wallet.
Never heard that phrase before.
Love it.
Im going to unscrew the handle and keep it safe.
Awsome work your a blessing🙏
Good video
This is one of my favorite video's David!! It really solidifies and ties everything together I've thought over the years about the way exhausts work! I'm also sorry you had to create a new channel.. It's actually a good thing for me because I get to rewatch alot of the video's! Thank you so much for sharing this information! I won't call this my favorite video because I love hearing your racing stories! I race 4 wheelers and 3 wheelers!
Thanks David
Awesome information! So much to learn! Also I have a Super Trap on my motorcycle and love it. I put flat washers between the discs to create a larger gap thru about 25 discs. It is still no where near as loud as the vast majority of Harley’s out there.
Thank you brother for your wealth of knowledge you are willing to share with us.