52

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 trying to remove heat. Adding more from the exhaust goes completely against that and would increase overheating. Also, would you want a hot exhaust pipe near ...


51

It signifies that the car is running absolutely correct. Here is the reason why: A gasoline (petrol) molecule is made up as such: C8H18 (or 8 Carbon atoms and 18 Hydrogen atoms) Energy is obtained from the combustion of it by the conversion of a hydrocarbon to carbon dioxide and water. The combustion of octane follows this reaction: 2 C8H18 + 25 O2 → ...


46

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 where aerodynamics have been considered for sure: other designs (like trucks) do account for aerodynamics by putting the exhaust tubing behind the relevant ...


20

The supplied gas values suggest a rich run condition and possibly a non-functional catalyst. Using a mixture calculator for the supplied gas values shows that the mixture is 6.4% rich. CO elevated is the key indicator as it is not present in lean combustion in significant amounts. NOx is produced in significant amounts in lean combustion and requires ...


14

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 this gives the least chance of the fumes making it inside the cab. Mufflers are large components. Often there is not enough room inside the engine compartment to ...


13

The recall is not to remove the cheating logic; it is to actually make the engines meet emissions requirements so they do not violate the law any more. From Autoblog's initial article on the scandal: Volkswagen intentionally installed software in nearly a half-million diesel vehicles that helped the cars evade substandard results on emissions tests, the ...


13

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 hydrocarbons into H2O and CO2. If there is too much unburned hydrocarbons going into the catalytic converter, it greatly increases the temperature inside the ...


11

They aren't better for the environment But efficiency is often confused with emissions. The average person would think that because diesel engines are more efficient and burn less fuel, they must be less harmful to the environment. I think few can be more authoritative than the folks at Bosch on why diesel engines are so prevalent (emphasis my own)¹: No ...


9

Every gallon of fuel your vehicle burns produces a gallon of water out of the exhaust. If the weather is cold you will see it as steam. If the rear of the exhaust system is still cold even in warm weather it will be for a short time after start-up, you will see the drips. On a hot engine/exhaust you will not see any drips from the tail-pipe. If there are ...


9

tl dr: By adding a throttle plate, it creates the vacuum needed to draw in gasses from an EGR valve. Since diesel engines are designed to run lean, they don't need throttle plates to run. They utilize the amount of diesel fuel needed to keep the engine running and to provide the work needed to do the job required of them. One of the inherent issues with ...


9

Gasoline is a pretty toxic liquid. And it evaporates pretty easily. The Carbon Cannister is a system to help keep toxic fumes from gasoline out of the environment. So here's how it works. You fill your car up with gasoline at the gas station. You add a gas cap to seal off the tank. Cool, no evil fumes can evaporate from your gas tank and contaminate ...


9

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 an engine without an exhaust would make more power, it would also consume more fuel.


8

Gasoline is made in large batches. Each batch has a number of attributes that should be met; Octane, specific chemistry, volatility, contaminates, ethanol content, and others. The output is dependent on the crude that went into the refinery and the processes the refiner has at hand to process it. Refineries vary in there capabilities. There are over 60 ...


7

Open up the hood and look at the emissions control system label. That will indicate whether it meets California emissions standards or not. Also, at least for California (Not sure about other California-standards states), you can register a 49-state vehicle in California after you move there if you previously registered it in your previous home state.


7

As a vehicle technician for BMW I can assure that it is good for your engine to get rid of EGR. EGR systems are there to improve the exhaust gas quality and slightly win a few miles on a tank (in theory). What really happens is quite different. Your oil will become polluted quicker, your manifold / intake will get clogged by excessive amounts of soot and ...


7

Looking at the description of the California O2 sensor for your car, the only thing different on it (besides the internals) is the electrical plug. The wrench which you tighten it down with is 7/8", which means the sensor bung should be the same size as well. I don't think there is any real external difference between the California and non-California sensor....


7

Locally worse, globally better Diesel exhaust versus gasoline: about 15-20 % less CO2 about 4-100 times the NOx (highly temperature dependent, mitigated by proper use of diesel exhaust fluid, ref the VW scandal) and a fair amount of soot (esp. before common rail, mitigated by a particle filter). What this means for the local environment: Local CO2 is the ...


7

The voltage being a little low (13.75 is not low enough to be considered a problem in any case) is not going to affect their RPM reading - as it's the frequency of voltage variations that is measured to get your RPMs. I'd be tempted to say your tach is out slightly. You could ask them about that. There is a smartphone app that you can use to gauge RPMs - ...


7

Adding to the excellent answers already given. An important point to note is that we need to have a catalytic converter somewhere in the exhaust a short exhaust will not have room to fit it. Then there are a host of other things car manufacturers determine while designing an exhaust system. For an engine to have optimum efficiency, the intake , combustion ...


6

since installing new 02 sensor engine light has not reappeared after clearing w/obd2 device and torque free app. TOTAL COST= ~$27 7 31 13 ordered Koolertron F-12 ELM 327 OBDII PC Car Diagnostic Scanner Electronics EggDeal via amazon $9.50 to use w/android smartphone torque free app to read & clear obd codes 8 10 12 friend sprayed hoses he knew to be ...


6

Disadvantage is that tampering with emissions systems makes a vehicle no longer street legal. Other than that, it probably won't hurt anything at all. I don't see how removing EGR will increase power though. EGR closes at high power settings anyways. The gain would be entirely from some other feature of the racepipe (perhaps it's bigger). The fact that ...


6

The federal test procedures for vehicle emission certification(FTP) is run on a dynamometer. It starts with the vehicle at an exact temperature and barometric pressure and humidity. It is run in a lab that has carefully controlled exact air conditions that are maintained throughout the test. The vehicle is kept is stored at the test temperature for hours ...


6

Combustion Chemistry from Princeton This isn't much of an answer but here is some data from a Princeton class related to Combustion Chemistry. You will see that the table you are looking for is plotted. Here is the link to the PDF. Manufacturers of Emission Controls Association Here is a study from Manufacturers of Emission Controls Association. ...


5

There are two ways to tell. Your local ford dealer can tell by decoding the VIN (the vehicle indentification number). It is usually located on the dashboard at the base of the windshield on the drivers side. If you look under the hood there is usually a sticker on the frame near the radiator that will say complies with California or 49 state emissions. The ...


5

Just to add to the other answer as I ran into this same issue, what kind of emissions do I have on my mitsubishi galant? I had this code: P0421 and I had to replace my O2 Sensor & the catalytic converter but I wasn't sure if I needed the CARB (California Air Resource Board) compliant ones or not. There is a label that identifies what type you have. I ...


5

Anti Shudder Valve Not a direct answer, but one engine component that many people confuse with a throttle plate on a diesel engine is called an "anti shudder valve". This looks exactly like a throttle body, but it only has two positions - fully open and fully closed. On an engine equipped with the device, the valve is completely closed when the key is ...


4

The diagnostic trouble code is not to be looked at as a root cause of the system failure. (example. Replacing a blown fuse is NOT a solution) In all cases there are multiple components that can cause the same code to trigger. For instance, a possible vacuum leak, or EGR problems, and even a PCV issue, could all show o2 sensor readings with tendencies towards ...


4

The car has not been driving long. As the others have said, the water comes from the combustion of the fuel. When the exhaust system is cold, it cools the exhaust enough that the water can condense. After a while of operation, the exhaust system heats up. The same water vapor is present in the exhaust, but it stays vapor and doesn't drip.


4

With the check engine light on, the car is going to be running a fixed set of parameters from the Engine Control Module. For instance Fuel Pressure will be held at max pressure and timing and spark adjustments (if done electronically) will not retard or advance. One of the reasons this happens is because the Engine Control Module is not recieving all of ...


4

Yes, it will probably be necessary to fix the problem in order to pass emissions requirements. The secondary air injection pump on the Beetle is apparently used to accelerate the transition from cold start to hot catalytic converter operation. Without this system, it will take longer for the catalytic converter to reach operating temperature. The ...


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