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51 votes
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What is the point of the exhaust?

Safety, comfort, noise and space are the things that come to mind. Safety Exhaust gasses are hot as hell. Hot enough that we put heat shields all over the exhaust line. In engines, we are actively ...
Becuzz's user avatar
  • 666
44 votes

What is the point of the exhaust?

Well, we can have a pipe going out the front of a car as in this design here: or its heavier predecessor: Arguably, the aerodynamic properties are not optimal in both, but here is a similar approach ...
the-wabbit's user avatar
40 votes

Is it possible for a vehicle to be manufactured without a catalytic converter?

You don't have to have an catalytic converter, they aren't required for the operation of an engine. Catalytic converters use chemical reactions to reduce the pollution in internal combustion engine ...
GdD's user avatar
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29 votes
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Why have I had to replace so many exhaust pipes?

Another cause of rapid exhaust system rusting is driving patterns which don't warm up the vehicle thoroughly. In this case, a "thorough" warmup means the entire exhaust is hot enough to ...
DavidRecallsMonica's user avatar
23 votes
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What's the purpose of having the cat right after the exhaust manifold

The main purpose of putting it right after the manifold is heat. The cat functions best when hot. Placing it as close as possible to the manifold helps the cat heat faster and stay hotter, which ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
22 votes

What does exhaust smell on oil and transmission dipstick mean?

First of all you're not smelling CO (carbon monoxide) as that is an odorless and colorless gas. What you are likely smelling are combustion byproducts and that is not at all uncommon in the engine ...
jwh20's user avatar
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21 votes
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What does pie cut exhaust mean?

This is a term used to describe the shapes of the pieces of tubing used to create exhaust pieces with very hard turns. Imagine an apple pie. Now cut it in 8 individual pieces (triangles). You can now ...
race fever's user avatar
  • 3,353
21 votes
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How does condensed water get sent out of an exhaust system?

If there was ever that much water in the muffler such that it was sloshing around, it would be a sign of catastrophic failure in the engine, such as a blown head gasket and the "water" would actually ...
Edward's user avatar
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19 votes
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Is an exhaust pipe broken at engine connection fixable by a DIYer?

Can I just put the pipe back in and do something to seal them together again? Or do I need to replace that section of the exhaust pipe or the entire exhaust pipe? You can attempt welding. It's not ...
vidarlo's user avatar
  • 724
17 votes
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How should I remove this corroded nut without rounding it?

The tool Thanks to you all for your many good suggestions, but I thought I'd share how I actually got these nuts off today. First, more PB Blaster, and then while I was at the auto parts store ...
Edward's user avatar
  • 2,857
15 votes

Is it possible for a vehicle to be manufactured without a catalytic converter?

That will depend on the market regulations for the target country ie which country that vehicle will be sold in. Cars built to be sold in Europe & US have to meet stringent regulations as regards ...
Solar Mike's user avatar
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14 votes

Motorcycle exhaust rattling / clunking / popping / burbling on deceleration

Sounds like a lean condition Here's something to chew on regarding identifying a lean or rich condition on a motorcycle. Symptoms of Lean or Rich carb settings on a motorcycle What I believe you ...
DucatiKiller's user avatar
  • 32.9k
14 votes

What is the point of the exhaust?

Several things; Exhaust coming out the front is dangerous. If the fumes are ingested into the cab the driver may be harmed. Normally a car is driven forward. If the exhaust is coming out the back ...
vini_i's user avatar
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14 votes
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What is this yellow powder on my exhaust manifold?

IMHO that powder is either: Dust, that got "burned" by the hot exhaust manifold and transformed into some yellow-looking substance. Sulfur, as the color has a striking resemblance to sulfur. The ...
Martin's user avatar
  • 8,458
13 votes
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How does raw fuel damage the catalytic converter?

A catalyst is a chemical that contributes in a chemical reaction but remains unchanged after the whole reaction is complete. In a catalytic converter platinum is the catalyst that converts unburned ...
BillDOe's user avatar
  • 1,512
13 votes

Is it possible for a vehicle to be manufactured without a catalytic converter?

Yes, in theory. The government doesn't care how your engine hits the required emissions numbers. As an engine designer, you get a tabula rasa, and are free to build any system that will do the job. ...
Harper - Reinstate Monica's user avatar
13 votes

Why have I had to replace so many exhaust pipes?

3 in 4 years? That sounds like the engine mounts were loose or broken and putting undue strain on the pipe. Another possibility is hitting the exhaust on sleeping policemen - are the roads in good ...
Solar Mike's user avatar
  • 34.6k
12 votes
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Do naturally aspirated engines need back pressure in the exhaust pipes?

Pressure drop is to flow as voltage drop is to current With all else equal, removing the resonator or muffler will reduce the restrictions in the exhaust pipe. This means that the ability of the ...
Zaid's user avatar
  • 39.2k
12 votes

What is this yellow powder on my exhaust manifold?

If your engine was running / exhaust manifold hot; the yellow is then zinc oxide. It would result from a galvanized steel manifold which has naturally oxidized. At room temperature the ZnO is white , ...
blacksmith37's user avatar
  • 3,688
11 votes
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What is the muffler? How does it work?

A muffler is a harmonically tuned chamber that is designed to reduce the noise created by the combustion process. Mufflers are usually designed with specific sound frequencies in mind. When a ...
MooseLucifer's user avatar
  • 6,007
10 votes

My feet turn black

Cabin filters on modern cars use something called activated carbon (or at least some of them do) which is basically two paper / cotton sheets either side of a fine layer of carbon particles. It looks ...
Steve Matthews's user avatar
10 votes
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How much room do I need to avoid carbon monoxide poisoning?

Is your Check Engine Light on? That's a rhetorical question, what I mean to say is that if your ’04 Forester is in good tune, it really should not produce that much carbon monoxide. Also, there are ...
SteveRacer's user avatar
  • 12.4k
10 votes

How should I remove this corroded nut without rounding it?

A lot of localised heat to the nut will help. A 1/2 inch spanner/wrench is slightly smaller than a 13mm, so that may still work after heating. If you can’t get a splitter on it, you could drill a line ...
HandyHowie's user avatar
  • 25.4k
9 votes
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Making a custom exhaust

Possibilities Yes! Absolutely you can have this done. The quality of work may vary depending on the level of experience of the shop you commission to do the work but you could end up with something ...
DucatiKiller's user avatar
  • 32.9k
9 votes

What is the point of the exhaust?

The exhaust also creates a pressure differential, which can help scavenge exhaust gases from the chamber. So a properly tuned exhaust will therefore increase the fuel efficiency of the engine. Whilst ...
Damien's user avatar
  • 91
9 votes

2004 Taurus - Help Identifying the leaking component

The left descending pipe is (or comes from) the exhaust manifold, and ends in a two-bolt flange. The flange bolts to a matching flange on the front end of the exhaust pipe, which runs aft from the ...
DavidRecallsMonica's user avatar
8 votes

Is it possible for a vehicle to be manufactured without a catalytic converter?

No Telsa has a cat. While you could bolt one to a Tesla it would serve no purpose.
Loren Pechtel's user avatar
8 votes

What does exhaust smell on oil and transmission dipstick mean?

Smelling AT fluid is (or did ) give a good hint of the transmission general condition , but it requires experience. The clutches and bands have material like brake pads and if they slip, they heat ...
blacksmith37's user avatar
  • 3,688
8 votes

What does exhaust smell on oil and transmission dipstick mean?

If the motor oil has a distinct smell of exhaust fumes, it might also mean that the cylinder head gasket has become leaky. Transmission fluid should never smell of exhaust gases, but can get a certain ...
WooShell's user avatar
  • 180
8 votes

How should I remove this corroded nut without rounding it?

As you don't care about saving the nut you have a few options. In addition to the good solutions mentioned in other answers I have a few suggestions: One of the handiest tools out there is locking ...
GdD's user avatar
  • 17k

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