David Vizard's PowerTec 10 EP 27 Zero loss sound legal muffler systems

[@user-rp9pj6su8v]

Dale here. I am glad that you have mentioned that the engine does not need back pressure. I have talked with many people about this, and they always say that there needs to be some type of back pressure. As I mentioned in another video that you did "Grumpy Jenkins" once made a comment about using slightly larger exhaust manifolds (in this case headers) so he could block backpressure and therefore gain a few more horsepower and a slightly quicker time on the track. With what you are talking about here validates his comments and makes me want to agree with you about the person who demands that the engine needs that backpressure is either ignorant or parroting words that someone told them were gospel. Thank you for the information that shows the fallacy of that view.

[@marvingvx1]

TO ALL THOSE WHO HAVE MADE COMMENTS. i AM OVERWHELMED BY THE NUMBER AND THA GENERAL THOUFGHTFULLNESS OF THE CONTGENT OF THE COMMENTS IN GENERAL. THERE IS NO WAY I CAN GO THROUGH AND TYPE OUT RESPONSES. BECAUSE OF THAT I PLAN TO DO A SPECIAL VIDEO FOR YOU GUYS WHERE I PICK OUT THE BEST COMMENTS AND REPLY TO THEM. WILL LET YOPU GUYS KNOW WHEN I BGET TO THAT!!!! THANKS ALL! DV

[@marvingvx1]

FOLKS SCUSE MY SPELLING ERRORS BUT I AM DEAD BEAT HERE\!

[@brucesherrill4116]

Thank you!

[@jorgegomez4608]

I remember the sonic turbo muffler In that article they did beat all the others As usual not surprised that David had A hand in it.

[@zAvAvAz]

yeah and the walker version built they way he wanted initially but couldn't do to size constraint, the walker super turbo the bought out version that improved due to larger size on the original 'sonic turbo' muffler. changed the term 'turbo muffler' forever. However ,they are not the same.

[@johnw5242]

Only comments I have are, "Thank you" - "Please, don't let reading comments get in the way of making really great, informational content" - I am sorry to hear of the recent loss of someone else who has journeyed many a year and many a mile by your side. Grief is not something we endure alone, however, because every one of us knows the feelings that surround it themselves, too. You do your family AND your closest friends proud here, sir. What a journey you share with us! Tha k you for bringing us, "the pubilc at large," into your life.

[@alanhardman2447]

ALWAYS a good listen for anyone who wants to learn. David is one of the world's best teachers, easily! Thanks, David, and please keep up the great work!

[@jamesmumford774]

I still have a set of 2.5” Sonic Turbo mufflers on my 57 Chevy 150 series 2 door post. I have had them since 1986! I added a balance pipe to make them even quieter. These have always been outstanding mufflers, great performance and sound without all the unnecessary decibels. So glad I finally got the chance to say:” Thank you David, for designing such an excellent muffler!”

[@JohnDoe-pv2iu]

Man, I Loved the Sonic Turbo mufflers! As a Grown (but young) man, I kept telling my girlfriend that I didn't need anything for Christmas. She kept threatening me that if I didn't tell her something that I wanted, she was going to but me one of those stupid cordless screwdrivers! I wouldn't let her waste her money on that ridiculous novelty, so I told her that I wanted a pair of Sonic Turbos for my Firebird. Christmas of 1987 was my first set of Your mufflers, And they were Great! Thanks and I Loved learning about them!

[@martinharris5017]

Sonic Turbo mufflers, boy, that brings on some nostalgia. They were all the rage back when i was messing with A series engines! REALLY interesting about SuperTrapps. I nearly bought one of those things. Flowmaster? WOW indeed! Everyone raves about the laminar flow theory. I trust the Vizard oracle, however.

[@josephschaefer9163]

Exhaust pipe thickness is worth mentioning. Quality thick exhaust pipe makes a very big difference in noise level

[@richardprice5978]

and pich as i love 440BBM R/T oe exhaust system on cold idling its got a nice after gong/tink to it ( aluminiumnised thin wall steel piping )( love the sounds but sometimes i wish i could turn it down a little but keep the vibe going ) and adds to the general charisma of pre-1972 mopars. but yes i can be a little louder on the freeways/town aka sometimes it's to much noise for me or trying to listen 👂to others/music 🎶radio 📻

[@StephenGiovi]

David: first of all, I would like to send my condolences for your loss with a family member. Second, thanks for your presentation on sound and performance using mufflers. I have been dabbling in sound quality and horsepower gains myself on a very "backyard mechanic level" to discover some of the same flow bench testing you have presented. Motorcycle two stroke engines have the same design characteristics by using an expansion chamber before the resonator/baffle section on the system. Cud-dos to you for explaining this insightful information to your viewers. Furthermore, I will get busy with my own build, and try to report my experience in timely manor with track times as a guide....see ya later, and thank you!

[@mikedeal8659]

Thanks David. More good stuff. I have read some of this in your books but having you explain it makes it much more clear. I appreciate the time it takes to do these videos, and enjoy the storytelling that goes along with the technical stuff.

[@rotaxtwin]

It's true, the side stories are a fun excursion!

[@benhowe2087]

Best muffler explanation I have ever heard. I have suspected that this design of open chamber at the end of the collector would work and built a system using a large bore Magniflow at the end of the collector with a tapered outlet. Did not realize the need to have an eight to one ratio. Thank you. Also the 2.3 cfm per hp is extremely helpful. Back to the welding bench.

[@rickzon166]

8 times the size of one cylinder termination box? Is that ratio specific to a V8 motor?

[@andredesousa96]

My dearest and deepest condolences go out to you and all the family.

[@davidparker9676]

I am not a V8 guy, I love this type of universally beneficial information. I truly appreciate the time, effort and knowledge that David Vizard and his staff have given us with this series. Keep the excellent videos coming and I will watch & like them (I'm already subscribed)

[@frenchonion4595]

Yep all engine's basically work the same lots to learn from v8 guy's inline 4 guys etc

[@JeoffreyHowes-kk9ff]

David, I have had many a discussion with people who assert that an exhaust system "must have back pressure" In future I will refer these people to your video. Thank you

[@ferdinandcuevas8457]

The Sound is what some owners want like everyone has an opinion which is what makes this country so great! Great content . Thank You 🇺🇲🇵🇷👍

[@YRR_J]

I've always had a very high appreciation for fast things on wheels with low noise output. When the sound is so that you KNOW there is power but it's still a "stealthy" vehicle. Once in a drag race there was this beautiful black VW bug with really nice looks. Chrome trims, even original blinkers etc. But at closer inspection it was a tube chassis thing with probably a Porsche engine. That thing went crazy fast and the sound was like nothing compared to some way slower V8's and other obnoxiously loud cars there. It really left a mark. Back when I had a 2 stroke 50cc scooter (Gilera), I put an aftermarket exhaust on it (LeoVince S) and it was way more silent than the original fat steel system with a catalytic converter (which probably was the culprit of the loudness, as I think it started to brake down inside the chamber, making a ruckus). The LeoVince had a really pleasant sound compared to most tuned mopeds and scooters at that time.

[@pmd7771969]

david, the amount of us car people who have damaged our hearing sure justifies not having a loud car. its an over rated hobby at that. signed ringing ears davis

[@ronnieb7408]

The supertrapp guy at PRI reminds me of when somebody tried to tell Smokey Yunick about engines and racing .... his response was " Its not often I get to hear a genius talk.....". Very humbling knowing how many patents and advancements in engine technology that he had his expertise in. You Mr Vizard are as much a genius as Smokey was. The only way to learn things is testing on the dyno and flow benches to know for sure.

[@5am278]

I’ve been an exhaust system geek for over 30 years and the high science behind this vid is much appreciated. I watched it twice😂

[@kingtut8381]

WOW. WHAT A WEALTH OF KNOWLEDGE !!!!!!!!!!!!!

[@EricErnst]

I've been quoting your articles on exhaust flow for years. You're brilliant.

[@terryheimerl8674]

Mr. Vizard, it is a pleasure to watch you not only convey your vast knowledge but to do it in a way that all can understand. Thank you. Terry.

[@broncobill54]

Your generosity in sharing your knowledge is priceless. I, and I am positive many many more, am very grateful for this. No one that I am aware of is doing or has done what you are doing for the performance enthusiast. I am building a 355 Chevy and as it turns out I have done many things that you teach.. but not everything I’m sure. It has taken longer than normal to bring this build to a finished product due to me looking for every good deal I can find. However, I will have a very high quality engine at a fraction of the price of buying at retail. Keep on keeping on dear Sir. I love what you do. Thank you!

[@b.knutts2085]

That is the best video I've watched in a long time! It makes me want to cut my flowmasters off amd start bending some pipes. Thanks for the knowledge!!!

[@davidparker9676]

Cut them off. Flowmasters are terrible. Magnaflow is a much better design and value. Borla mufflers are nice but do cost significantly more than Magnaflow units.

[@frozenstang3868]

Yes but the 40 series sounds great , whats a few hp when you have lots these days.

[@cjbert6790]

Frozen Stang I agree, trying to engineer a complete exhaust system would make me exhausted!

[@luckyluciano4968]

@@davidparker9676 I am running a set is magnaflow. On my classic FastBack Stang. They sounds amazing. I thought flow masters were over kill

[@chrisperryman886]

@@frozenstang3868 Exactly!

[@jasonjaffray4025]

YOU SIR ARE A GRAND MASTER, NEVER HEARD SUCH STRAIGHT HONEST... GENIUS WOW WOW WOW I SALUTE YOU!!!

[@clivewilliams3661]

I keep backtracking through David's videos and it has been an enlightening journey. No BS, just good sound engineering. Thanks!👍

[@ChurchAutoTest]

Wow, I remember reading Mr. Vizard's work many decades ago, including the original piece on zero loss muffling. Great to see him still putting out content. Way back when I couldn't figure out how to effectively put a termination box on my 4 cyl race car with my limited fabrication skills, but we found that using a factory catalytic converter body (with the catalyst block removed) as a poor man's attempt at a termination worked pretty well. It was about twice the diameter of the header collector, smooth inlet and outlet, but only 4-5x the volume of one cylinder. Along with a large Dynomax Super Turbo suitcase silencer at the back, it made the sound levels quite tolerable and we never had an issue with getting flagged for noise - from the exhaust at least. Now that open element intake was a different story - had to build a box for that too.....

[@GB-zi6qr]

Just about 20 years ago, after reading David's exhaust tuning book, I designed a custom exhaust for a 1979 truck I had. My best friend at the time couldn't believe how well that truck ran and it had a stock 350 with just a Edlebrock Performer RPM intake and a 550 cfm Edlebrock performer carb. No, the truck wasn't truly fast but it did surprise a great many people. The absolute best part...All the "Noise" the truck made was induction growl. Many folks just couldn't figure out how that truck made "That Sound" when "getting on it" and have no noise otherwise. I'm working on a 302 based '67 Merc. Cougar now, can't wait to apply the same principals. Thanks David!!! P.S. Yes, I've read your cylinder head porting book. I already have a set for the 302, just have to get the car safe and legal to drive.

[@cjbert6790]

A well designed X pipe system seems to help a lot. I think David’s termination box is a great idea. It reminds me of trying different sized expansion chambers on a 2 stroke motor cycle engine.

[@spud4ever290]

Dave is the HP Wizard !!! Noticed 3 thumbs down - don't know why (can't think of anyone being forced to watch Dave's video's)!

[@jmc6940]

Ive been looking for a way to quite down my father laws lq4 after a rv cam and magnaflow muffler was installed by a shop. I think i just found the solution no muffler shop in the world knows about👍

[@evotoadracekartscars.6738]

Thanks David. I have to build a new silencer for our Biland kart engine. My original worked well but you just upgraded my design again😊 Many Thanks from the Uk.

[@bransonbasher6534]

I'm using this knowledge to fabricate a system for my 230cc dual sport motorcycle. Why? I'm having fun. Thank you, Mr Vizard

[@shanekirkwood7234]

It’s great to get your words on these subjects. There’s a lot in your books and your explanations really help them make even more sense. I have several of your books including the book on exhaust systems and this helps a lot. I also really enjoy the backstories on how things came to be. Thank you for doing this on KZbin and sharing what you know.

[@randallblack9519]

I'm 75 and have learned sooo much in the short time I've been listening to your channel. UTG directed me to your site after I contacted him. Reminds me of my high school shop teacher or my grandfather. Don't believe anything your told until you verify.

[@WhiteDieselShed]

How have you never popped up on my feeds before? A legend of the A series Mini days. I have several of the Vizard A series books. Taught me a lot.

[@flathead1930]

This man would make an army of friends in the motorcycle world. Harley Davidson riders would love a quiet bike and all the torque and horsepower

[@jamesgeorge4874]

Quiet Harley ? I have never heard, or seen one in 50 years. 99% of them have open drag pipes, and are obnoxious as hell.

[@theoldbigmoose]

David a lifetime of research, insight and hard work you are giving to us. You are an amazing man! You deserve more followers and likes!

[@gordowg1wg145]

I remember that muffler test. 👍 With the back-pressure, I keep pointing out the piston has to push against that pressure in the exhaust port - which is partially a result of that system back-pressure. Down here, NZ, back in the seventies I was rather disappointed by one of the local exhaust (muffler) "professionals" who wouldn't help my with parts for a dual 2 1/2" to replace the OEM single 2" - it was originally a lo-po 283 that had a mild 350 replacing it - because exhausts don't make any difference to power... There was another shop in town that wasn't much better - I ended up getting the stuff from out of town.

[@terrygrover6440]

Your right david i used these mufflers and to this day in my opinion they are the best mufflers

[@Dr_Reason]

I saw a Chevy Gas truck with headers and a 5 inch exhaust meant for a diesel. It was terrible sounding and droned on the highway. WE went near the axle and put a 5 in to 3 inch adapter, a short length of 3 inch pipe and then a 3 to 5 inch adapter. It mad it sound a lot better, quieter, and no more drone. He also got to keep his 'cool looking' sewer pipe exhaust tip.

[@thomasroth4695]

Would really like to see an episode of equal vs unequal length headers. Youve made several comments about it on your channel but cant find much info. Anything be much helpful always looking for an edge. N/A dirt track Be GREAT😊. Thanks Mr Vizard

[@mattbirt114]

I had the pleasure of working for Bill Hill at Tenneco, who I believe was the inventor of the "bicycle fender" flow directors in the ends of the triflow mufflers.

[@philzellmer6073]

David, thanks for another great tutorial. You went through this in great detail in your book, but it's great to see it explained again live. I've been using these mufflers for years thanks to your instruction. I'm sure this video will be an eye opener for others who may not be familiar with your written work. Thanks again for the excellent information!

[@lawrencekashak]

I think I remember reading 30 pages of this exhaust knowledge that you wrote. I kept the magazine for years. I’ve been trying to find it. It’s cool to see someone I’ve only read about. I remember this! Those numbers, and the ‘secret’ to the pressure waves stuck with me from reading this back then. At that time I was in college for an AA in Automotive Technology. I still do this for a living and a weekend hobby. Thank you!

[@rayhall7906]

I contacted many USA performance muffler companies to see if they could design a exhaust system for a 500hp turbocharged engine that was quiet. I could not get anyone who knew how to design the exhaust system. In fact they thought I was a idiot for not wanting noise. I found they only know how to design something big that make more noise.. So I decided to do what I though would work. I was very happy with the result, while not dead quiet it was quiet enough to not attract the police attention and the car made 500hp at the wheels. I wish I had known about your experience. I am a self taught engineer using common sense and experience to learn. Ray.

[@arnekarlsen528]

The famous www.turbofast.com.au/ ?

[@bobgyetvai9444]

Most inteligent designed muffler out there was the Hooker Aerochamber .

[@loicdore39]

Flowmasters makes high pitch sound that changes the tone and makes the engine sound mean and desirable, to me the flow perfs comes after . On my lmp race car I use a walker because the goal is to be under 95db and no power loss

[@back2bizz69]

WoW 1987 I was 17 years old in H.S. and had a 70 Cuda with a 318 and big hydro cam Torker intake 750 vac secondary carb Blackjack Headers AND Sonic Turbo’s slapped right on the collectors. Sounded beastly Ahhh those were the days.

[@GabrielKish]

Truly, one of the masters of horsepower.

[@michaelgpreuss8695]

I learn something with every episode.....just amazing.....

[@Oyou812-b1x]

Excellent work David! It really works!

[@KevinRHill1]

Thank you Mr. Vizard. I found your video fascinating.

[@waneirvine355]

Hands down best info covering a subject mostly ignored thank you for sharing your genius

[@joshuaburlison30]

I wish I had listen to Andy before and come over to listen. I'll have you in my ear until you stop producing content. Thanks DV

[@kellyhinkelman8591]

Your cool David. More than anything else you are outstanding in the breakthroughs in the mystery of what's really happening. Very smart. Carrol Shelby knew tri y headers were the cats ass,you verified why.pretty cool!

[@thatguy83ful]

Beautiful mechanical music.. amen brotha!!

[@johnmarkgatti3324]

getting to grips with a rotary way out on the boondocks of NZ , I found it best to build my own straight though with lots of stainless polypads , the brass ones got flattened in days , any normal glass pack large mufflers fell apart . I made a few attempts at internal reflection cones too , were ok but stainless is to noisy . And with turbos have found a big expansion tube after the turbo is good . now it seems there are ways to design noise reflecting grooves at about the size of the sound waves , Gismag/new atlass had an article a few years ago ,would like to know more ,could greatly simplify the muffling , even make effective aero mufflers , next project I hope . Thanks David ,great info, and attitude , we say you attitude determines your altitude ,and fame without good character will destroy you .

[@charlesperkins8654]

David I've built a stepped exhaust system, starting with 2" to 2 1/4 to 2 1/2 to x pipe to tapered 3" to dual through flow mufflers with excellent results of torque. And fuel efficient. I followed your technique's of porting throttle body, intake,and heads, with a 4.3 V6 . Somewhere in the nayborhood of 300 hp and torque. 0-60 in 5 sec. And 21 mpg. O yeah 300,000 miles.

[@lonnieayers4365]

have most of your books and learned so much, so glad you have this channel

[@craiganderson3170]

Switching due to DRONING from 14 in Dynomax glass packs to 20 inch Dynomax Super Turbo based on this video.

[@GMan-ym9xl]

Thanks David for sharing your many years of expert engine building knowledge. You are nothing short of brilliant.

[@martinfalls1023]

Hi David, again, you have given me another key part of information to produce the best horsepower with manual mechanical concepts. I like with your attitude that questions all the common ideas that hold currency in our world and then chase down ways to achieve what you believe is possible. It has frustrated me most of my working life that so many supposedly educated people have no imagination are cannot use basic logic structures to see what is possible. Thanks again, Martin

[@pauljconroysr4080]

I Remember those Sonic Turbos :) they were sweet .

[@audiophil4946]

Great video that gives me some ideas on how to build a street legal exhaust for my Westfield 7 that matches the twin 48mm Dellortos on the intake! Thanks David, Cheers from the right coast of Canada!

[@paulzellner9447]

I learn something every time I listen to your vast knowledge . Thank you , God bless

[@kennethperian4370]

Thanks for showing telling me, I learned about the noses now I can do it to my motor.less noses , well David thanks again and well see ya next time see ya bye bye.

[@fric8489]

Appreciate your video. Love the craftsman socket set in the background. I am on my 3rd set unfortunetly due to theft everytime popular with the theives to steal must be an easy item to pawn. I have to say my red trays are filthy and black.

[@SuperTambo69]

Great segment David. I also read that section in your "how to build hp" book, which I understand Jacqui had some input.

[@rickrack78]

Thanks for the support that I can build an exhaust system that is quiet and flows!

[@scottsenter7649]

David. I got my first inspiration to work on my 68 Camaro engine from the Book How to rebuild Your small-Block Chevy and I still do all my own engine work...Respect!

[@carbf1942]

Definitely going to try this on my 71 Chevelle.

[@derranged28]

Have a look for a book called "the scientific design of exhaust and intake systems". There is a good deal of information regarding silencer designs. I'd be surprised if David hasn't read it.

[@richardprice5978]

is there any active trixs that works? like valves/moving parts or speakers ect. to change the residence tuning ? aka HZ hemholtis ? like the intake that mopar has use ?

[@richardprice5978]

ps. i have a turbo TT ( EFR-76-70 mm ) setup ( and is a max wege ram-style exhaust manifolds ( intake is cross ram active 36"to9" tuned runer length by ford SHO valve style systems ) / block huger / cramped/👠 shoehorned in a b-body ) that stared out with a 383 BBM+727 but modifying my car for a 4.5 stroker hemi+SS oil pan 10"+TR6070. planning on twin 3"main exhaust piping 2"~primarilys and 🤔 if theres any trixs that i can use but keep the turbocharger housings still aka had bolted inplace and or not taking of a lots of space under the floor boards as i have a BEV battery pack under the back seats for electricity A/C and other use's and not a lot of ground clearance 3"-4"@bottom of the rocker's

[@johnhennery8820]

Another great video David thanks again great info and love the story behind it makes sence all the way around

[@niceguy37058]

Good stuff. Makes your book make more since. Thank you

[@michaelhargarten5118]

This was a great video to debunk the myth of back pressure. The Dyno and graphs prove it.

[@ricvis44]

It seems you and I go back many years ago! My first car was a 1980 Chevrolet Monza Spyder with the 3.8 L V6. I took the factory muffler off and put a sonic turbo muffler on it when they came out. I truly loved the sound of the exhaust note. My father actually did too. The car was only six months old when I put it on. If my memory is correct. The next change was to the carburetor. It had a Rochester Dual-Jet 2 carb. (Sealed). My father and I took the carburetor off and drilled a hole in the caps and took a small screw and screw the screw in to the little hole and pulled out the seal caps. That was the very first thing that my father and I did together on a car. Memories!!! The idle improved greatly. Next we put a catalytic converter test pipe on it. I followed that with a distributor recurve kit. Dad and I followed that with a brass tapered reamer to the gas fill inlet. Then we were able to run regular gas instead of unleaded.

[@sethbarnes7608]

This will be very helpful to use on the 460 I want to build for my 74 Lincoln. 😁

[@shawnbins203]

Although cylinder heads and port work ARE the most important part of performance in general…. It’s really good to see other aspects such as this video.

[@hankclingingsmith8707]

YOUR THE MAN ALWAYS SHARING, AND STILL HUMBLE ENEOGH TO KEEP LEARNING.

[@smashedfootlefty4726]

I remember those upgraded turbo suffers called "sonic Turbos". used to tell buddies to run them but they were all about Blow masters... Thank you for sharing your knowledge!

[@BruceLee-xn3nn]

On foxbodies?

[@smashedfootlefty4726]

I would never associate with those types... foxes were the enemy back in the day, perhaps because they all had blow masters. :)

[@dannydennis318]

Holy crap I learned a lot from this genius. I've had my muscle car in storage almost 30 years. We just pulled it out and restoring the body. It's got 500 hp and still has Sonic turbos and nobody's muffler sound as good as those. They say the Super Turbo similar but it don't sound anything like the Sonic. This Sonic is smooth Bassy and quiet. I'm going to try to go with the 3" straight through Borla XS. They're supposed to be the quietest straight through ones but I'm probably going to have to put a race bullet in front of it to try to keep it smooth and quiet.

[@andrewsanders6270]

Glad to see your channel growing ! Stay with it you'll have 100k before you know it 👍

[@finnroen2334]

I have your book were you write about this. A local BMW owner had put a M5 engine in his car and when dynoing it, horsepower was not impressive. I informed him and the exhaust system was then modified like you tell us here. The car was dynoed again and he was surprized and very happy about the horsepower gain he got. On an other note, many years ago, a friend of mine had a Yamaha RD350 motorcycle and wanted more horsepower. We cut the silencers off an welded on a stinger in correct diameter and length. There was no notable gain anywhere and the sound level was insane. The original RD350 muffler / silencer has to be one of the most impressive sound silencers ever.

[@gregtreble9086]

Hi David, thank you so much for sharing and so impressed with all your technologies which I have embraced on my Triumph Bonneville 2011 in which I followed your information and undertook you David Vizard Polyquad head porting design with many other performance modifications and ohhhhhh so so impressed with its performance ……….. In regards to your exhaust design I am now very interested in looking into undertaking your advice and implementing a under engine behind frame open muffler design before the reverse cone muffler to reduce the sound while still allowing a free flow exhaust. Thank you again so much your sharing all your performance experience ! Regards Greg

[@gothicpagan.666]

Never stop learning ah. Some time ago I used some Paul Ivey valves with the anti reverse grooves made by GS valves in a imp engine with a George Bevan race cam (car was for hill climbing) The valves didn't help the bottom end rpm to any measurable amount. 20 years later i measured the reverse flow of both ports. With a particular max rpm in mind Ken Newman ground up a cam with .170thou ex .150thou in. Both at tdc On this particular head the reverse flow was about equal at those lift values It made 122bhp by about 8000rpm. Torque was up 9 ftlbs over any thing I'd tested at that point. Put an extra 2" straight through silancer on after the manifold to go with the Roy Lane supplied Super flow silancer, mounted across the back, it lost 20+ hp peak and a min of 5hp every where. Thats over 15% on a silencer + in the wrong place. Truly great that your making these videos. Guess your not going to bother with electric tunning😆

[@danielwoodard680]

I will revisit this video several times while building my small block Ford project

[@craighansen7594]

I am learning so much from David! Starting to put what I've learned into practice with all positive results.

[@autotek7930]

Man my jeep xj is not a race rig but I am putting a stroker engine in here soon, I wish I could work hand in hand with you to get it setup for max efficiency lol. It don't need it but I want it haha. I've built custom exhaust for many years and but never had any dyno stuff as it's been a repair shop like midas or meineke. I recently found your videos and am gonna take on the porting of the throttle body and intake manifold on my jeep and build my own exhaust. It's a working rig for offroad recovery so every little bit helps. It's got a stock cam and better head than factory plus more compression ratio and displacement

[@tonyjones9460]

My first engine building book I read was your Rover V8. Sparked my interest, so glad I happened on your channel. Thanks for expanding our knowledge and sharing with any that will listen. Cheers.

[@terrycarter8929]

Flowmaster muffler makes the cracking raspy noise that too many people think sounds cool. That noise is the sound of vortex that cause restriction.

[@twinsemi]

Circle Track magazine was onto the same line of thinking many years ago. I don’t remember the precise dimensions of the box, but it was pretty close. I haven’t tried it yet, but that might change.

[@terrywillis5784]

I set out to increase the gas mileage on a 2001 ram 1500 5.2 v8 . The exhaust size was reduced from 3 inch down to 2 inch before the Cat. Same diameter into the stock muffler then back up to 3”. I installed a 3 “ cat and a long 3” truck muffler to keep it throaty but quiet. No improvement in gas mileage. Muffler rusted out internally in 4 years. Replaced with an American made flow master style muffler. Sounds amazing on start up. Louder but at highway speed no more noise in the interior but I can hear the sound of the engine nicely. No change in gas mileage. The original window sticker says it should get 19. It never gets any better than 13 but it sounds great ,lol. I could probably change the cam and have more power but I don’t think the mileage would improve. I will probably just drive it as is. It’s in perfect condition and drives good but there are better trucks out there.

[@nathanrice1796]

Flowmaster mufflers aren't very good - interesting. I'm glad he told us that. His research on exhaust systems in his book is very good.

[@rotax636nut5]

Back in the day trying to quieten a race car exhaust I fitted one of your mufflers to a hot race tuned Ford CVH engine, the original on the car was a 2 1/4" straight through glass pack and yours too was 2 1/4" bore, the noise was reduced from 111 Db down to 96 on my own test equipment which later passed the track side test but the important point I'm making was that the engine power when the 2 silencers were dyno tested back to back, yours showed 165 rwhp compared to 150 rwhp of the straight through glass pack, I have to say I was shocked at that time to see such an improvement and had to repeat the test over and over to confirm that I hadn't got some kind of false reading, later like yourself I went on to develop my own silencer technology for race engine exhaust's which is nothing like your tech but that's another story. Nice to see you again since we last met years ago at the Motor Show in London. Roland Hayes, HT Racing Ltd.

[@marvingvx1]

Roland, I remember your name!!!

[@harrisonbrown672]

THANK YOU FOR ALOWING ME TO...

[@mikeleschber1316]

Flowmaster is the k&n air filter if the muffler world

[@dustinhillis5336]

Thanks for all of your videos.

[@MoparMan-ff8fb]

David check out the new mufflers by the company Pypes - turbo pros . their guaranteed max flow and some tamed down sound. so those are some short section of muffler pipe coming off the side of the main exhaust pipe then down to a hollow muffler box then through an actual muffler or mufflers for duals and then pipe out the back. 🍀

[@TheRobphobos]

Looks similar/same to the Superturbo design