I only have the right tail pipe open when I start my car. Both tail pipes eventually become open. That would imply that the flap is indeed open, however despite having both tailpipes open, it is quieter, according to the BMS description. I’m quite unsure if the flap controls anything other than the tail pipe in the muffler, though.
When both tailpipes are open, the engine is quieter since the wastegate has closed (it is open during initial start-up for about 20 seconds) and all of the exhaust is running into the turbo, which muffles the sound. The exhaust flap’s sole purpose is to lessen exhaust noise during cold starts and while driving at highway speeds. With an MPE or other aftermarket exhaust, it is more obvious.
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However, once the car reaches operating temperature and the cats are all warmed up, the door stays closed until you press the WOT button. Surely there is another explanation.
My 335 is not mine. My 328, which I own, is devoid of that feature. It may therefore be used for purposes other than simply warming the cats. I suppose it’s for sound because I think there’s a method to unplug something and keep it open all the time. If my guess is true, it opens up for a lively exhaust noise after a certain rpm.
just for the sake of sound. Just listen to the difference at idle if you bypass it (either via software, a golf tee, or by removing the in-trunk cable). I used it for approximately a week before becoming tired of the annoyingly loud and unfavorable idle sound.
When starting up, the exhaust should be kept as quiet as possible, especially in the morning or garage. Because BMW, in all their cleverness, would rather that you didn’t wake up your children or neighbors than that your sports car have a sporty-sounding exhaust.
lol You don’t need an aftermarket exhaust if you think the golf-tee modification is too loud. In comparison to an aftermarket exhaust, the golf-tee modification is quieter.
My own was unplugged the day I got the car. It is in the trunk, to the left of the panel. I adore that gurgle sound you make when you let off the gas at a stoplight. “Your automobile sounds a lot different when you’re standing outside compared to riding in it,” a buddy remarked to me. adore it
It’s under the car, next to the driver’s side exhaust tip, not in the trunk.
Functions of Exhaust Gas Flaps
They are utilized for a wide range of tasks, both with diesel engines and spark-ignition engines.
By adjusting the volumes and pipe lengths of silencers, acoustical optimization can alter exhaust noises.
One of the two tailpipes on the rear silencer of the new BMW 7 series is fitted with an exhaust gas flap, which ensures that the twelve-cylinder engine’s “sound” is consistent across the whole speed range. Below: a 7-series BMW
A significant reduction in the capacity of the necessary silencer can be achieved by carefully arranging the exhaust gas flaps in the exhaust system. As a result, it is possible to reduce both the weight and the amount of space needed for the overall system.
Exhaust gas flaps are used in emission control to redirect the flow of the exhaust gas. By doing this, they activate the HC (Hydrocarbon) absorbers or more quickly raise the operating temperature of the starter catalyst.
DeNOx catalytic converters are a more current type of emission control. These ensure an optimal effect and a long catalyst service life by causing a portion of the exhaust gas flow to be diverted through a cooling zone by an exhaust gas flap.
It is possible to increase efficiency in some specific characteristic areas by adjusting the exhaust gas back pressure. An exhaust gas flap in the exhaust system is another way to accomplish this.
Exhaust gas flaps are precisely sized to suit the high requirements in the exhaust gas system; they must endure gas temperatures of up to 950degC while accurately closing and remaining movable for the duration of their service life.
The exhaust gas flaps provided by Pierburg are made of high-alloyed, corrosion-resistant steels combined with ceramic elements to ensure optimal operation even in the corrosive environment present in the exhaust tract.
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The turbo does actually have a waste gate. It entirely opens upon launch to assist the Cat in warming up for approximately 20 seconds, and after that it functions as you would anticipate.
The only purpose of an exhaust valve is to reduce noise. It can close at low speeds in compliance with EU regulations, at specific RPMs to reduce drone or boomy noises, or in specific driving modes.
You can unplug it if you wish. It will definitely generate a background code, although BMW don’t typically laugh at this.
What does an actuator for an exhaust flap do?
A form of actuator called an exhaust butterfly valve is used to muffle or lessen noise produced by some applications. Due to their frequent use in automobiles and motorcycles, these valves are frequently connected with the automotive sector.
Engines run more quietly at low RPMs and start more quickly and smoothly when the exhaust butterfly valves are functioning properly. Additionally, for a cleaner start, the heat from the exhaust manifolds will preheat the fuel-air mixture.
However, there are a number of circumstances in which exhaust butterfly valves can fail. Let’s examine some of the frequent mistakes that could cause problems in more detail, along with the best ways to handle them while service.
Why are there exhaust valves on BMWs?
The valve, which is a component of the BMW Active Exhaust, only serves to reduce noise. to keep the valve open, to disconnect the pump using the electric connector in the trunk. The MS 41.1 module controls how the exhaust flap operates.
How is the exhaust valve’s opening controlled?
A single exhaust valve is positioned in the center of the cylinder head of two-stroke crosshead engines. A cam positioned on the camshaft hydraulically controls the valve’s opening and shutting.
A piston inside the exhaust valve is operated by lube oil (from the engine’s LO system), which is displaced by the hydraulic pump and pulls the valve open. A non-return valve directs air at 7 bar to the underside of a piston that is fastened to the valve spindle. The air beneath the piston is compressed as the valve opens. When the hydraulic pressure is released, the compressed air expands, aiding in the valve’s closure. A tiny amount of oil is introduced to the air for lubrication. The exhaust valve guide is likewise airtight. This stops exhaust gas from seeping up the guide and keeps it cool and lubricated. Extra oil that gathers at the air spring cylinder’s bottom is emptied into a collection tank.
A valve rotator is attached to the valve spindle. As it passes, the exhaust gas’s kinetic energy slightly twists the valve. This helps prevent the buildup of deposits on the valve seat and maintains the valve at a constant temperature.
> Molybdenum chrome metal valve spindle with a stellite coating welded to the seating face
Exhaust valves close for what reason?
How much exhaust gas is still in the cylinder at the beginning of the engine’s input stroke depends greatly on the timing of the exhaust valve closing (EVC). In addition to having a significant impact on the contents of the cylinder at the beginning of the inlet stroke, EVC is one of the parameters dictating the valve overlap.
EVC timing typically occurs between 5 and 15 degrees after TDC. Internal exhaust gas recirculation (EGR) is largely eliminated with this timing in order to preserve full load performance.
When positive valve overlap is present, the EVC signifies the conclusion of the exhaust stroke and valve overlap time. After TDC of the exhaust stroke on fixed cam engines, the exhaust valve normally closes between 8 and 20 crank-angle degrees.
Because it can affect how long the overlap time is, the location of the EVC has an impact on how much trapped residual gas there is. Early EVC will reduce residual at low loads and high pressure gradients from the exhaust to the inlet manifold, which will improve cycle-to-cycle variability. Early EVC can therefore enhance idle quality. The engine’s capacity to scavenge exhaust gases at high engine speeds is reduced by early EVC. For fixed cam engines, the late EVC reduces low-speed volumetric efficiency by 0.15% to 0.35% per degree of retard, according to Ref. EVC timing is a compromise between high engine speed performance and idle quality.
Late EVC utilizes the ram effect’s advantages at high speeds and loads, which could aid in the combustion products scavenging process. By trapping burned gases in the cylinder (early EVC) or by allowing backflow into the cylinder when the inlet and exhaust valves overlap, the outlet valve approach also aids in the preparation of the mixture under all engine circumstances.
Using late valve timings in SI engines reduces pumping work, according to Ref, because of the dethrottling effect. The effective expansion ratio and expansion work can be increased thanks to the delayed outlet valve shutting, without significantly affecting the exhaust pumping work. Increased compression work results from the higher pressure that is attained during the inlet stroke.
How can my BMW be made louder?
- Get a more compact muffler. The smaller your muffler, the louder your automobile will be because they are made with loudness in mind.
- Place a specialist exhaust assembly in place. The most straightforward approach to increase your engine volume is to modify your exhaust system.
- Purchase a bigger downpipe. These increase the volume of your car by lowering the exhaust’s backpressure.
- Your exhaust system’s resonator has to be removed. This alters the tone of your car, causing it to make deeper sounds.
Just keep in mind that some counties and states have restrictions on how loud your car can be. Check your local laws such before making any alterations to your vehicle.
Why not spend a little more time using the Jerry app to learn more about your insurance alternatives while you’re already learning about your car’s modification options? Jerry is a qualified insurance broker who can assist you in locating the greatest deals on the protection you require. You may make adjustments at any time, receive prices instantly, and text an agent with any queries you may have. Each year, $887 is saved by the typical Jerry user.
The exhaust valve should open when?
The piston rises once again during the exhaust stroke, forcing the exhaust gas out the open exhaust valve. Before the piston completes its power stroke and reaches BDC, the exhaust valve opens. Just before BDC, the exhaust valve opens, allowing some of the pressured exhaust gases to escape before the piston even begins its upward stroke.
When it goes upward, it lets go of the extra pressure and aids in lowering the piston’s pumping losses. When the piston begins to descend the cylinder during the suction stroke, or a few degrees after the piston reaches TDC, the exhaust valve closes. The inlet and exhaust valves are now both open for a brief period of time, resulting in a “overlap.” By better “scavenging” or evacuating the leftover exhaust gases from the engine cylinder, this “overlap” aids in this process.
What Is Valve Timing & How Does It Impact Engine Performance?