Straight-through (high-flow) vs turbo (tri-flow) mufflers: what is the effect on exhaust tone?

This video describes the effect of common muffler and resonator designs on exhaust noise: both the tone and the loudness. From the header back, exhaust components take away portions of the engine noise. (The diameter of the exhaust tubing, be it small or large, also "voices" the character of the sound.) High-flow straight-through mufflers such as Borla, Magnaflow and Vibrant primarily filter out high frequency engine noise, while baffled triple-flow (tri-flow, turbo) OEM style mufflers (and similarly designed but louder aftermarket systems like Remus, Milltek and Larini) primarily filter out low frequency engine noise. The best (quieter than straight-piped!) exhaust tone is often achieved by using a blend of different styles of mufflers.

[@txreal2]

Thanks muffler Professor!

[@Dnasty1]

I've been looking at videos for months and this is actually the most informative thing i've watched about mufflers. Very good work well done.

[@martinharris5017]

Great explanation Tassie. Those triple-bypass mufflers can actually be used in a no power-loss system. they were designed by Diavd Vizard, and on the Corvette Turbo they were first applied to show no loss of power coupled with legal sound output. The secret was to place an expansion box just after the headers from the engine, then onto the mufflers. This was a well done presentation mate! Thanks.

[@kiantay9843]

Thank you for the detailed explanation. Very clear :) I’ve got an Alfa Romeo 159 2.2 with nice bassy Novitec backboxes.

[@gustavvang2482]

Really good video explaining the differences

[@davidmizak4642]

This is really interesting material. I appreciate the effort you put into providing it. Many thanks!

[@ralmslb]

Great explanation, thank you

[@carlosh9491]

Excellent explanation!

[@isaacnoor7255]

awesome video . thanks

[@donnyazoff980]

Nice video mate.

[@ianrufford3698]

Good job mate, thank you.

[@roadking01234]

Awesome clear explanation.......Great video.....

[@KK-qx5ys]

Awesome video.

[@durbancraig]

Thanks so much for this informative video. Trying to tune my 5 cylinder turbo motor to my liking and this certainly helps!

[@wilschnella1202]

@durbancraig I know it's been a year or so therefore not sure if you'll see this query but curious what you ended up with on your 5 cylinder turbo? By the way is it an Audi or Volvo or something alphabetically in between?

[@durbancraig]

@@wilschnella1202 thank you for the response. The vehicle is a Mk1 Ford Kuga with the Volvo drivetrain from the XC90/70/Focus ST225 etc. The final setup after a number of iterations is a straight pipe to the stock rear box with a, electronic cutout valve just before the same box. I removed the mid-exhaust free flow muffler after watching your video as I was unhappy with the lack of mid-to-high frequencies. I now have what I was looking for - a quiet motorway cruiser when necessary or a gloriously loud 5 cylinder noise (to my ear) at the push of button. Thank you.

[@ESISTTIGER]

Straight through setups with 2 straight through are reasonably quiet just cruising a bit notey and get louder depending on rpm and engine load

[@tiitsaul9036]

Big difference between types of mufflers is weight. Straight through mufflers are a lot lighter than own style mufflers.

[@1982mmag]

whats the ideal sequence of combination??, straight through then baffled or the other way round? the car has a total of 3 mufflers, and as you said currently all straight through, very very loud boomy tone

[@TassieLorenzo]

Usually the baffled muffler is placed at or near the end, but I don't think it matters that much. A question of putting the mufflers wherever they fit. :)

[@1982mmag]

@@TassieLorenzo thanks for beautiful explanation- you saved a lot of people a lot of trail and error with their setups

[@pjimmbojimmbo1990]

Chambered Mufflers were invented long before the Turbocharged Covair came along. Also the muffler Chevrolet used on the Turbocharged Covair is a lot different externally and internally than any of the "Turbo Mufflers" being marketed

[@dupajasiu920]

Indeed very interesting video. I would appreciate to get some more info, which chamber how is calculated to delete certain frequencies. For example I want cut out resonance 2k rpm and at 3k rpm. How do I calculate.. ?

[@TassieLorenzo]

You can look at the Helmholtz resonator equation, or also try a quarter-wave tube, using the quarter-wave equation. The catch is you need to be able to estimate the exhaust gas temperature accurately at that position in that exhaust. More follows... A quarter-wave tube to cancel 2000rpm on an inline-six engine will probably be pretty long, around 1000mm. To convert engine speed from rpm to Hz in a piston engine, 2000rpm on an inline-six engine is f=rpm/60*cylinders/2=2000/60*6/2=100 Hz, with the divided by 2 being for a four-stroke engine that only fires every second revolution. For an inline-four 2000rpm is 66.67 Hz. For example, assuming an exhaust gas temperature of , the speed of sound is c=SQRT((1.4*8.314*Temp in Kelvin)/(0.02857)) from the natural gas law and using air as the gas. Assuming 200 deg C, it's 473 deg K (add 273) which gives 439 m/s. There one wave length is lamda=c/f where f=100Hz and c=439m/s, which gives lamda=4.39m. Therefore a quarter of a wavelength (in order to give an anti-node and thus cancellation of noise), is lamda/4=4.39/4=1.10m. So it would be around 1100mm (not easy to package!), thankfully it doesn't need to be the full diameter of the exhaust, even 1.5" or 1.75" would work. Usually a J-pipe design is used to allow it be tucked up close to the exhaust. For 3000rpm on an line-six, it would be 730mm. For a helmholtz resonator, you take that speed of sound c, and put it in this equation: f = c / (2*pi) * sqrt (A / (lc * V ) ) where A is the cross-sectional area of the inlet tube, lc is the length of the inlet tube, and V is the volume of the resonator chamber. The calculation is very, very sensitive to the temperature of the exhaust at that point and thus the speed of sound, c. It can tricky to work out what the temperature at that point of the exhaust is (ideally you would measure it somehow, drilling a hole where you want to branch off the quarter-wave tube or Helmholtz resonator and using some kind of temperature probe I guess).

[@PhillyDee215]

Cool video😎. I have a GM 3.8L supercharged cammed aluminum heads etc.....what's the quietest but yet free flowing non restrictive muffler?

[@TassieLorenzo]

Thanks! You could try Vibrant Streetpower oval mufflers 5"x9"x15" (or something even bigger if it will fit). vibrantperformance.com/catalog/index.php?cPath=1021_1031_1053_1110 The alternative reversed-flow style mufflers will be quite a bit quieter at idle and part throttle, but about the same under load as straight-through mufflers like the Vibrant.

[@jorgeguzman659]

@@TassieLorenzo Can you give some options of reversed- flow style mufflers? I can’t seem to find any

[@TassieLorenzo]

@@jorgeguzman659 Hi Jorge, there are few on the Summit Racing or Jeg's catalogue like say the Dynamax Super Turbo. If you mean a complete system, most of the European systems like Milltek or Remus tend to be some kind of baffled muffler system. But depending on the size of your engine, the best bet is the OEM muffler from a larger engine, if it will fit the vehicle, as they tend to be both good quality and cheap as no one wants them (they've usually upgraded to something aftermarket).

[@mindmythfilms1428]

Very nice video!!! So i would like one that has like a deeper base but that growls when you step off the gas :) Anyone any tips?

[@ryancalhoun4671]

Chambered type- Flowmaster + knockoffs

[@pjimmbojimmbo1990]

Magnaflow will have a deep tone, but can really growl when you put your foot into it. They are far less restrictive than the Flowmaster.

[@Ronny.T]

Hey, awesome video! I have an aftermarket Cat-back exhaust on my Jeep Wrangler and love its deep and aggressive tone. However, I have a very annoying drone noise when cruising at highway speeds and going up steep inclines. The exhaust system currently has an 18" body straight-through muffler from AFE POWER. What would you recommend I do to try and get rid of the drone without sacrificing much of the deep and aggressive tone on acceleration? I went to a muffler shop and they told me my best bet is replacing the muffler with a Dynomax Super Turbo style muffler... Would this be my only option? I was thinking maybe if I buy a straight through muffler from a better brand such as Magnaflow It may not have the drone noise...

[@TassieLorenzo]

"I went to a muffler shop and they told me my best bet is replacing the muffler with a Dynomax Super Turbo style muffler... " That won't work in all likelihood. It'll be a quieter type of muffler but there's still nothing to cancel out the resonance. Try to find a shop that's willing to add a quarter-wave tube, a tube that branches off to a dead-end. It's designed to reflect the sound out-of-phase and cancel out the resonance. You'll probably need some way to make the length of the tube adjustable to dial in the right length.

[@lukeskywalker1840]

Smart kid....

[@smartcookie3500]

The question is, Are you SPL or SQ audiophile? Bass enthusiast myself.

[@TassieLorenzo]

Hahaha. :)

[@W0LV1E45]

what if I have aftermarket performance exhaust but is too loud and yet I want to keep the bassy sound?

[@TassieLorenzo]

You can try fitting a bigger muffler body or bigger resonator body (but still the straight-through type), if it will fit.

[@W0LV1E45]

@@TassieLorenzo I bought a chamber muffler (60 series flowmaster) to teplace the resonator (mid section) on my veloster. Hope it will work. I can't drive my car for that long or else it will irritate my eardrums for how loud the solo exhaust. Anyway its Solo Performance catback for veloster. It has rear muffler and resonator (replaced the central oe muffler after the 2nd cat).

[@shawncordeiro5078]

TRUE DUAL WITH HI-FLOW CATS AND NO MUFFLERS

[@GearheadExplorer85]

Thanks for taking the time to explain this. I was hoping you could help me at least narrow down the type of exhaust/muffler I am looking for. It will be for a carbed v8. I am pretty sure the muffler I am looking for isn't chambered (not a fan of the hollow-metallic sound). Here are some samples of the type of sound I am after: kzbin.info/www/bejne/jJS5nmyviM-nors kzbin.info/www/bejne/rJTHhpiPmZ6WeNk (fast forward to 2:40) Any idea what kind of exhaust combo I should use to get this kind of deep smooth sound. I not sure if a turbo-style or straight-through would be the best. I am guessing that a cross-over would be mandatory to prevent the popping/crackling. As an audiophile, trying to chase a specific exhaust tone is um.....exhausting XD

[@TassieLorenzo]

Hi Crockett85, Being carbed, I guess your V8 is going into more of a vintage-type car? :) A H-pipe type crossover would give more of that 1970's muscle car sound, whereas an X-pipe crossover would give a more 'modern' sound. I think a H-pipe combined with some straight-through perforated mufflers should give the sound you are looking for, to me this sounds similar to that Corvette :) : - Mustang magnaflow axleback, H-pipe kzbin.info/www/bejne/jKK2dX6XlMp6qLs - LS3 magnaflow mufflers, H-pipe kzbin.info/www/bejne/gHy7qKOGlpicfLM A smaller pipe diameter like dual 2" or dual 2.25" would probably make it sound more similar to that Corvette, depending on your power output. :) About chasing the perfect exhaust tone -- yeah, OEMs have the luxury of making lots of prototype exhaust systems, measuring the noise spectrum and subjective impressions and then adjusting things as appropriate (sometimes adding resonators to cancel out problem frequencies and things like that), whereas for private enthusiasts if it's not right the first time, it all costs money! :) Unfortunately I'm not sure there is a better way than trial and error or listening to example cars.

[@GearheadExplorer85]

@@TassieLorenzo Thanks for the feedback! I think a crossover pipe and Magnaflow combo is what I am after. This morning I actually found a video of an 80s Pontiac Firebird that sounds exactly like the Corvette in the movie. kzbin.info/www/bejne/gpKYZaajmZxsnK8 I think these cars have a single y-pipe that goes to one traverse-mounted muffler that branches out into a dual pipe. So there wouldn't be a crossover pipe. However, I imagine the place in the y-pipe where both headers converge could be replicated with an x-pipe.

[@jill1447]

The Chevrolet Corvette turbo???

[@TassieLorenzo]

Corvair Turbo en.wikipedia.org/wiki/Chevrolet_Turbo-Air_6_engine