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Can I drive around with my muffler detached?

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Jzero

Lifer
Oct 10, 1999
18,834
1
0


<< At the end of the day, who do you think is going to be in better shape? Someone breathing normally or someone that has had to exhale into a balloon? >>


You say that as if a machine could get stronger from working harder.



<< It's a shame your little import job can't handle it. >>


From everything I've read, if you've got a little 4-banger, you'll get better efficiency and performance if you have some degree of backpressure.
Edit: Note above post--if the engine is tuned properly :) Also cut a line b/c in reality he's not actually giving any advise, just making a statement which makes me guilty of "arguing for the sake of arguing"
:)
 

BooneRebel

Platinum Member
Mar 22, 2001
2,229
0
0


<< At the end of the day, who do you think is going to be in better shape? Someone breathing normally or someone that has had to exhale into a balloon?

You say that as if a machine could get stronger from working harder.
>>

You misunderstood me. I meant better shape breathing normally as in the guy blowing up a ballon will be totally exhausted from the work, not that he would be in better shape from exercise. Just responding to hoihtah's analogy explaining why backpressure was necessary. But to be fair I've got V8s in both of my trucks so I don't relate as well to you with the 4-bangers.

But for those of you that are performance-minded: If you are concerned about your car being tuned for backpressure and you remove some of that backpressure, then you should consider tuning your car to reflect that reduced backpressure. Just like you'd tune it after adding a new intake system, etc.
 

Jzero

Lifer
Oct 10, 1999
18,834
1
0


<< You misunderstood me. I meant better shape breathing normally as in the guy blowing up a ballon will be totally exhausted from the work, not that he would be in better shape from exercise. >>



Ahhh now it mkaes sense!
 

Fritzo

Lifer
Jan 3, 2001
41,499
1,658
126
WHAT???? I CAN'T HEAR YOU!!! SOME IDIOT IS DRVING AROUND WITHOUT A MUFFLER!!!
 

Thegonagle

Diamond Member
Jun 8, 2000
9,773
0
71


<< Actually I thought 4 bangers need more back pressure. It's the big V8's the benefit from the straight exhaust. Or am I the one who is backwards? >>

I dunno, I was towing a car with a Dodge 360 that had straight pipes, and I thought they probably killed the low end torque. That thing felt pretty gutless. Later I towed with another Dodge 360 that had a stock exhaust, and I thought it was probably a little better.
 

spanky

Lifer
Jun 19, 2001
25,716
3
81
i've had two big holes on the pipes to both sides of my muffler for a few months now. i guess the fact that there is actually a muffler there throws the cops off. :p
 

PsychoAndy

Lifer
Dec 31, 2000
10,735
0
0


<<

ZV

EDIT: In all engines, completely removing the exaust will result in an increase in power at W.O.T., but backpressure (in certain amounts) is beneficial to low-end torque. As for it creating valvetrain problems, I'd want to know just how many of the people who removed the muffler then needed new valves 5000 miles later were also spending 90% of their time at or beyond redline after removing the muffler. Sounds to me kind of like saying that using Hoosier racing slicks causes cars to wear out faster, only people who race (and thus heavily stress) their cars use Hoosier racing slicks, and only people who are going to punish their engines remove the exaust system. There are too many other variables to pin it conclusively on a lack of backpressure.

EDIT #2: Just rememberd this, I know that open headers can lead to burnt valves but I'm not quite sure why. I'd always thought that burnt valves stemmed from excess heat. Anyone care to enlighten me?
>>



well, wouldnt open headers allow the engine to suck in more air therefore causing leaner, hotter combustion?

<---engine newbie
 

LAUST

Diamond Member
Sep 13, 2000
8,957
1
81


<< well, wouldnt open headers allow the engine to suck in more air therefore causing leaner, hotter combustion?

<---engine newbie
>>


It depends on what the CAM was desighned for, most of the new Z06 gets it's increase in power because they were able to make a more aggressive CAM because the new CAT's flow a lot more CFM's

Many older cars engine's were not desighned for much backpressure like new cars since CAT's didn't come around till about 1977~

When someone "Uncaps their headers" on a car that was build with CAT's and newer more restrictive Mufflers they will lose lowend that effects milage and 60 foot times.
 

Zenmervolt

Elite member
Oct 22, 2000
24,510
11
81
<<well, wouldnt open headers allow the engine to suck in more air therefore causing leaner, hotter combustion?>>

Headers are on the exaust end, not intake, so open headers won't cause more air to come into the chamber, they just make it easier to get the burnt gasses out of the chanber. At least, that's my understanding.

ZV
 

LAUST

Diamond Member
Sep 13, 2000
8,957
1
81


<< <<well, wouldnt open headers allow the engine to suck in more air therefore causing leaner, hotter combustion?>>

Headers are on the exaust end, not intake, so open headers won't cause more air to come into the chamber, they just make it easier to get the burnt gasses out of the chanber. At least, that's my understanding.

ZV
>>


Yep, and Headers over stock Manifolds do flow much better also,

When I replaced my stock Exhaust Manifolds with my Headers it really wasn't a huge noticable increase in the beginning, but after driving for longer times is the biggest pay-off, the headers weigh about 1/4 of what the POS cast Iron manifolds did ones did, mine are ceramic coated so the heat disapates faster... with that combination my engine doesn't suffer as much from being "Heat Soaked" as they did with the manifolds.

My need for the better flow also comes with having a Supercharger tho ;)
 

Cyberian

Diamond Member
Jun 17, 2000
9,999
1
0


<< EDIT: In all engines, completely removing the exaust will result in an increase in power at W.O.T., but backpressure (in certain amounts) is beneficial to low-end torque. >>

Can anyone explain this to me?
Intuitively, I would think that tuned headers with no cat or muffler would produce the most power at any RPM.

(I read about the balloons, but I really didn't see the parallel) :)
 

Zenmervolt

Elite member
Oct 22, 2000
24,510
11
81


<<

<< EDIT: In all engines, completely removing the exaust will result in an increase in power at W.O.T., but backpressure (in certain amounts) is beneficial to low-end torque. >>

Can anyone explain this to me?
Intuitively, I would think that tuned headers with no cat or muffler would produce the most power at any RPM.

(I read about the balloons, but I really didn't see the parallel) :)
>>

I'm not entirely sure about why backpressure helps out low-end torque, but I know that it does in most cases. However, the gains are generally seen at W.O.T. because that's when the most air is moving through the engine. At lower engine speeds an optimised exaust isn't necessary because the engine is not moving enough air to max out even the stock system, but at W.O.T. the engine is moving a lot more air and all that air has to go somewhere. It's not volume of air being moved that's the problem, it's volume per unit of time, higher RPM increases volume per unit of time and therefore requires more "flow" from the exaust than a stock system can give. Unless the stock system is intentionally restrictive (for example the LS-1 V8 in the Camaro vs the opened-up LS-1 V8 in the Corvette) there will probably not be much (if any) benefit to an open exaust until 3,000-4,000 RPM because the extra flow rate isn't needed until then.

ZV
 

KokomoGST

Diamond Member
Nov 13, 2001
3,758
0
0
I don't think you'll have to worry too much about the noise level, especially with so many dumb@$$ riceboys running around with their bumblebee Honduhs. Your Sentra doesn't depend on backpressure, rendering all this backpressure talk all moot.

Not too many cars depend on backpressure in the way that's been discussed in this thread and backpressure may not even be generated by the actual muffler, it might be in the various bends in the exhaust system. Only one car comes to mind for me when I think of a car that NEEDs specific backpressure, the 2000+ Civic.

All other cars, the only problem with too little restriction/backpressure in the exhaust is flow stagnation which will rob you of power. This happens when your pipe volume is too big and your puny engine don't spit out enough exhaust to effectively push their exhaust in the system out of the pipe. A reason why a 3" inch exhaust system is dumb on tiny NA engines. For turbocharged engines... it's usually, the bigger the better since they spit out a lot more exhaust at a higher flow velocity (because they are inhaling more) and need increased volume to reduce backpressure on the turbo's exhaust turbine. Superchargers have a need for larger exhaust piping for similar reasons, but they aren't exhaust driven so they don't need quite as large of an exhaust system.

So Cyberian is actually right, with the right size dump tube, no cat or muffler would generate the best horsepower even if low end torque is lost from less backpressure. There will be greater maximum gains and gains throughout the powerband as well.
 

veryape

Platinum Member
Jun 13, 2000
2,433
0
0
Sure you can drive around without your muffler attached, and you can also get tickets up the ass as long as you do so. They make them for two reasons, one is so that you don't annoy everyone within a square mile with the obnoxious sound emminating from your car, and the second would be the most important, which is pollution. You will be ticketed almost as soon as you back out of your driveway without a muffler, as cars are quite loud without them. Go ahead though, and bring a camera and post it so we can laugh as you are pulled over and ticketed. We'll pay the ticket costs, promise.

Sorry, didn't read your whole post. On the matter of bothering your car, no, not having a muffler will not do any damage to your car. If anything you will add a bit of horsepower without it since the muffler and exhaust system restrict your engine.
 

RU482

Lifer
Apr 9, 2000
12,686
2
81


<< Can I drive around with my muffler detached? >>



Sure, but if you drive by my house, YOU WILL DIE!!!!!!!
 

yakko

Lifer
Apr 18, 2000
25,455
2
0
I remember when the muffler on my Scirocco came apart. It was great. I had more power and it was loud as hell so driving through parking lots fisjing for alarms was fun.
 

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