Why Not to Change Your Car’s Muffler

Why Not to Change Your Car’s Muffler

rev up your engines, today I’m going to talk
about why you shouldn’t change the muffler on your car, and to explain
why, we’ll have a little history lesson, in 1897 the Reeves Brothers of Columbus Indiana
patented the first modern muffler system for engines, now mufflers do exactly what
their name says, they muffle sound, making it quieter so engines aren’t loud and
obnoxious, here’s my wife’s Lexus when you rev it up a little, rev it up, okay it’s about 42 decibels, not that loud, and
here’s my Triumph motorcycle that doesn’t have any mufflers, it’s a racing setup
they look like mufflers, but there’s nothing inside, okay that’s 110 decibels, and
as you can see on a decibel chart, the Lexus is quieter than a speaking voice,
while the motorcycle, hey it’s up there almost as loud as a pile driver, which is
112, so if everyone with all their vehicles took the mufflers off, and
either put straight pipes with no muffler, or a fake muffler that had no
baffle plates inside, it would be really loud outside, now yes mufflers do
restrict the power of an engine some because it restricts how fast the
exhaust gas can leave, but if you’ve ever gone to a racetrack,
last year I went to the Indianapolis 500 and man, that is loud, those babies don’t
have any mufflers on them at all, I couldn’t hear for a couple of days, I didn’t wear
any earplugs or anything I wanted to experience the whole thing, you could
feel it in your chest, everywhere I mean those babies are loud, and I know a lot
of young guys, especially with Japanese cars, they’re taking their mufflers off,
throwing them away and they’re putting on those little free flow mufflers that sounds kind
of like bees when they’re driving down the road, and if you listen closely to a
lot of them, you’ll hear that they don’t sound like they’re running right, and
that’s because they aren’t running right their cars were made to run correctly
with the muffler system on them, the gas is made to flow at a certain speed, the
oxygen sensor measures how much residual oxygen is in the system, they store some
of that oxygen in the catalytic converter, and if you take the muffler
off and you make the system flow a lot faster, that messes with the
anti-pollution system, it can also mess with the air fuel ratio that the
computer gives the fuel injectors and they actually can end up running worse,
if you take the original muffler off, now I have to say that this Mustang that I
just tested out, it’s got a great sound just listen to it but guess what, that baby was designed by
engineers, they spent a lot of time having to make the sound that they want,
having it work with the anti-pollution system to make it legal, and even to have
it pass the decibel ratings, there are certain ratings that cars can have to be
sold in the United States, now I know people are going to say, Scotty you’re a hypocrite,
your motorcycle back there, hey you took the mufflers off of that, but hey I
got fancy software in a computer, it’s an English motorcycle and the English are nuts
about modifying motorcycles, so there was a great website where I could just
download different patches for what exhaust you put on, and reprogram the
computer, so it would run perfectly and that’s why I see so many guys driving
around in Harley’s that backfire and even sometimes Ferraris that backfire,
they change the exhaust system but they don’t reprogram it to run correctly, so
then they run really badly, even though they make a lot of noise, hey they’re
not running right and that’s not what you want, a loud car that doesn’t run
right, now when I was young mechanic in the sixties, hey it wasn’t that hard to
change your muffler out and put a freer flowing system, because they had
carburetors, they have jets in them that allow more or less fuel and air to come
in, and you could re-jet the carburetors to compensate for putting a
free-flowing exhaust in, anybody with a little time and a little imagination
could do it, but modern cars they’re all fuel-injected, they have air fuel ratio
sensors, that are very sensitive you can’t just change the exhaust system of
the car, even just putting a free-flow or a muffler in is going to mess with all
that computer software and usually the check engine light comes on, they don’t
run right, you get worse gas mileage, so it’s not a smart thing to do if you’re just
planning on making a little bit noise with your car, and really even if you
have all the equipment in order to reprogram it and know what you’re doing,
you only get a very minimal power gain by taking the muffler and changing it
it, doesn’t make all that much difference for actual power, so now you know why you
shouldn’t take your stock muffler off and put on one of those performance
mufflers, and I’m sure there’s going to be plenty of people that are going to put those loud mufflers on and think it sounds cool, but at least I
can say I warned you about it, so if you never want to miss another one of my new car repair videos, remember to ring that Bell!

About the Author: Michael Flood


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  2. Yeah I don't know if I agree with any of this because I've never had a problem with an aftermarket exhaust system on any vehicle I've ever owned.

  3. I have had mustangs where I would put on after market pulleys heads intake and exhaust the car would definitely be faster with the mods. I do know that changing the exhaust offered almost no HP gain the other mods were more significant. I think the point of this is simple you can change the exhaust but you won't really gain much HP if any so what is the point other than to be loud and obnoxious.

  4. today i was ordering straight pipe but after this i think i wont. i really dont wanna see check light on my lexus is

  5. you should say what you must do when changing a muffler. if you take your car to a shop and tell them to change the muffler and reprogram it it won't damage your bike nor car and doesn't cost that much

  6. I wish I would’ve known this before I put flow masters on my challenger 2010 and also my Chevy Silverado 2002

  7. This guy is that grandpa that tells you to keep your car all stock straight from the dealership 🤦🏻‍♂️😂

  8. The little pipe right after my gasket fell off of my car I know I needed a new muffler but should I get the whole exhaust System replaced and if so where can I find a exhaust system it is a 1999 Ford Explorer xlt with a V6 engine and I’m pretty sure it’s 4.0L

  9. Or you do a full straight pipe with no cats and aftermarket header. Stock headers kill hp and cats plug up and kill hp but if you get a good ecu tune like Hondata in a civic you will gain 50-80 hp with a full system and a tune

  10. Did ambience agency paid you to tell this. if you are a expert , theres diference btw motorcycles and cars….

  11. This info is false!!! The only time you get a cel is when you remove the cats! Not mufflers! Get it together scotty boy!

  12. Well cars are mass-produced and there is a price point of profitability. If they started putting on a lot of the better aftermarket equipment the price for a car would be a lot higher than perhaps the average person would want to pay. You can buy a very nice exhaust system that might be better than the installed original exhaust. But you may have to adjust your computer to allow the sensors to properly manage the cars air and gas flow. bottom line you can make a car sound a whole lot better and still have the engine work correctly

  13. Scotty really doesn't know what he's talking about lol, especially when he talks about the backfiring harleys and ferraris, I mean really scotty you dont even know why cars with turbo atilag systems make flames pop

  14. Watched this video yesterday, today took my mufflers off car sounds fantastic runs better no engine lights 👨🏼‍🔧

  15. 100% correct, computer is designed for a stock system. You are only getting better performance when you tune it , to adjust for it.

  16. I learned this lesson when I developed a hole in the muffler in an 84 Mustang. Performance (power) went to pot until I got it fixed.
    There's definitely something to the engine air flow calcs, especially in the exhaust system.

  17. What about muffler, cold air intake and then have it tuned or just muffler and tuning? I really wanna make my Kia noisy, I wanna hear all 4 cylinders 😂

  18. Your info is totally wrong… Should really do some internet searching… Before making false statements lol … I have a lexus IS 300 which I installed a greddy rs exhaust have it for a year now and my car runs perfectly fine no check engine light no wierd feeling it runs smooth …. Car breaths perfectly fine and the air flow is better than having a stock exhaust which contstricts the air flow … Your still stuck in the 70's hehe we live in a new era

  19. I can only guess that Scotty's neighbor probably didn't let him sleep last night, with his/her aftermarket flowmaster! 😂

  20. Hey Scotty, while I was on the hwy some truck ran over some metal scrap and threw it under my car. I couldn’t turn or brake and ended up running it over but it punctured my transmission Pan and it dented my muffler and broke by the exhaust. I was wondering if I would be able to use a JB Weld or some type of muffler cement to patch them up temporarily or if they would need to be replaced. I recorded a video of the damage and posted it on my Page, can You check it out and Please give me some advice?
    I’m on Parole and I Really need this vehicle.

  21. ‘Why not to change mufflers’

    Presents bike without mufflers

    On a side note, his voice makes me want to kill myself

  22. When you said you went to the Indy racing and was partially deaf for a days after I know what you mean. That's what it's like when I watch/listen to one of your videos.

  23. I put a performance muffler an it run good around slot of mustangs. Challenger's corvette.have those loud muffler an they run fine an sound good

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