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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!

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100 thoughts on “Why Not to Change Your Car’s Muffler

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

  3. 100% correct, computer is designed for a stock system. You are only getting better performance when you tune it , to adjust for it.

  4. 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.

  5. 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 😂

  6. 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

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

  8. 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.

  9. ‘Why not to change mufflers’

    Presents bike without mufflers

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

  10. 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.

  11. 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

  12. Not wearing earplugs to the event was extremely stupid Scotty. The thing you experienced was permanent hearing damage. With earplugs they would have reduce the noise by at least 32 DB and you still would have felt everything.

  13. You are my best info fun resource 😂 I like that man. If you don’t like what he said in all of his videos just make a deep research on the objects you are interested in.

  14. I know more about cars than this guy he is not a real mechanic changing your muffler on your vehicle will not hurt it actually helps increase horsepower along with a cold air intake

  15. Oh you mean like the dummies and put those kazoos on their Hondas. The darn things sound like a herd of West Nile mosquitoes going down the road.

  16. REAL Harley Davidsons ( Shovelhead ) run a He'll of a lot better with free flowing exhaust. So does my Chevy truck. I wish Scotty would talk more about REAL cars and trucks not computerized plastic newer junk all the time. SOME OF US ARE PRETTY GOOD MECHANICS OURSELVES WITH OLDER REAL CARS THAT MAINTAINE OUR OWN STUFF. WE MEASURE THINGS IN CUBIC INCHES NOT LITERS. V-8'S REAL STEEL REAL CHROME BUMPERS. DOESN'T SCOTTY HAVE CUSTOMERS OTHER THAN MILLINEAL DRONES THAT CAN'T EVEN FIX A FLAT TIRE ??🔞🇺🇸🈚🈳🚮

  17. So you literally say it’ll help it breathe better by expelling exhaust faster and it’ll run better then you say not to…

  18. Personally I hate all the attention seeking juvenile little baby idiots with loud cars that annoy us all and damage hearing

  19. My Integra runs the same. Im not an expert on ecus but it still has the o2 sensor and cat sensor. Hondas do sound better…. let us little horsepower guys dream scotty . But you are the most awesome honest dude and there are not many good people like you these days.

  20. You can reprogram a car too so what's the difference between me doing exhaust work and reprogramming the car vs you doing it to your motorcycle? It's ok for your bike but not the car…..got it 🙄

  21. It's called tuning. My 91 ZR1 was tuned by Marc Haibeck. Being the car has a chip Marc makes a chip special for all the mods done to the car. Including a special provision so that it will not back fire when you let off the throttle suddenly. The exhaust sounds awesome and he prefers to use the Corsa system. Corsa uses a center muffler / resonator that uses gases to cancel out loud drone at lower engine speeds but opens up at wide open throttle. Marc does his homework and excellent tuning.

  22. Scott should change his intro to…
    "Rev up your stock, muffled-exhaust engines!!…

    but not too much because you could blow it up especially if it's not my Toyota Celica, my wife's Lexus or my Motorcycle."

  23. But mine broke. 2003 Eclipse. All rusted. Pipe from muffler to rear resonator isn't even connected. So nothing even goes through the muffler.

  24. So so you hate all things done to a car cause sounds like you just conplane way to much sir and is very negative stop putting people down for having cool rides

  25. Don’t change anything ! Just imagine what it’s like living with Scotty- Nothing interesting allowed and no Fun !

  26. Or ya know set up the system and tune it to run it pretty much as he stated at the end, that's what I'm doing as I'm building a car up new intake and exhaust and then a tune once that's set up

  27. A catback won't cause these issues..since you are leaving the cat alone..no tune needed because it isn't changing any air/fuel mixtures.

  28. Guys leave this guy alone he's living in nostalgia he's old and anything new and a mod to a car is bad for him.

  29. My car has a carburetor. It didn’t come with any sensors, a catalytic converter, or any computer whatsoever. …so can I take the muffler off?

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