The World of Anti-Lag Systems: Understanding Turbo Lag and Its Effects

When it comes to high-performance engines, particularly those used in racing cars, one of the most critical components is the turbocharger. The turbocharger is designed to compress air into the engine's cylinders, increasing power output and efficiency. However, this increased airflow can result in a phenomenon known as turbo lag, which refers to the delay in responding to throttle input. This lag is caused by the restriction imposed on the intake manifold, where a mandatory restrictor limits the amount of air that can enter the engine.

The additional emissions and higher temperatures generated by this restricted airflow put a heavy load on the entire exhaust manifold and turbine. As a result, racing cars rarely need to replace their turbos after every single race, as this would be extremely costly. In fact, the system isn't very reliable, but if you want to win the race, why not? Turbo lag can be a significant issue in regular passenger cars as well, with some estimates suggesting that an ALS (After-Load System) can handle around 1,000 miles. However, this is still too many zeros for most production vehicles.

In reality, turbocharged engines used in production vehicles don't come pre-packaged with ALS systems due to the high temperatures and stress that they impose on the turbine wheel. The temperature of the turbine wheel can reach an astonishing 2,000 degrees Fahrenheit, making it a common sight in racing cars and performance vehicles only. Another type of ALS is the secondary air injection or inlet bypass system, commonly used in rally cars like WRC vehicles.

This system uses a throttle bypass valve that directs air from the compressor through the intercooler directly into the exhaust manifold, bypassing the engine. The wastegate valve is solenoid-controlled to accurately control airflow, while the ECU delivers the correct fuel mixture. This setup provides fresh air to the exhaust manifold, reducing the heat generated by the turbine and minimizing the risk of overheating the engine. In essence, this system allows the turbine to blow into itself through the exhaust manifold.

The anti-lag system is a safety feature that helps prevent damage to the engine during acceleration. When the driver takes their foot off the gas pedal, the throttle valve closes, but the fuel-air mixture remains enriched by the bypass valve. This ensures that the ignition timing is not rolled back too much, allowing the turbine to continue spinning and reducing the risk of engine damage. The system also prevents overheat of the engine due to minimal roll-back of the ignition angle and reduced enrichment of the mixture.

Modern racing cars have developed advanced systems that control the aggressiveness settings in the anti-lag system, allowing drivers to select the optimal throttle response based on conditions and terrain. These systems can be divided into two groups: soft and aggressive. The ones used in Toyota-Mitsubishi race cars are quieter compared to those using Ford and Subaru cars, which have higher noise levels and aggressiveness.

When you see a car shooting flames from the exhaust pipe during a racing event, it's often difficult to determine whether it's anti-lag or a two-stage rev limiter at work. The engine needs a rev limiter to prevent damage to engine components from over-speeding. This system limits the maximum rpm that an engine crankshaft can reach to reduce damage and failure. The limitation consists of two different maximum rotation limits: the first is usually below the red line of the tachometer, providing launch control, while the second is located at the edge of the red field to prevent the engine from running out of gear.

When you approach one of the rev limiters during acceleration, the car begins a safety procedure. The computer also controls the ignition delay of the mixture, and the unburned fuel from the cylinders is directed into the exhaust manifold directly into the turbine. This results in a loud bang-bang-pop sound, accompanied by flames shooting out of the exhaust pipe.

Throttle control and anti-lag systems may appear similar but are two separate systems that serve distinct purposes. In conclusion, understanding turbo lag and its effects, as well as the various ALS systems used in racing cars, can provide valuable insights into the world of high-performance engines. Whether you're a seasoned racing enthusiast or just a car enthusiast, learning about these complex systems can only enhance your appreciation for the technology that powers modern vehicles.

"WEBVTTKind: captionsLanguage: enwhat is bang bang it has nothing to do with popcorn or loud gunshot noises but everything to do with turbo chargers in a recent video i talked about turbochargers and how do you address turbo lag today we'll talk about anti-lag and how it minimizes turbo lag time so hop in and let's go for a ride people who like turbochargers love the boost it gives their engine large turbos give you high top end power but one downside is that they're much more laggy meaning there's a delay before you achieve full throttle and boost in port the reason is because the larger the turbine wheel the greater the rotational inertia which means more time is needed to spin its wheel let's say you're rally racing or drifting you let off the gas for a moment the turbine slows down so then you press the gas but you don't get immediate boost you need to gas again and again or do something else to get the turbine back to working speed but you're losing time and why because the moment you squeeze the clutch to change gear you remove your foot off the accelerator this means that the throttle valve at this moment closes the intake system and the fuel air mixture loses its richness and oxygen less oxygen so less force of explosion in the cylinder which means less torque hence the slowdown and speed and when you press the gas again it's like the turbine is saying wait a minute let me think about it but you want immediate response to the press pedal without any delays or hesitation and while yours is still thinking a competing car with an explosive bang passes by you and that's because of his anti-lag system which minimizes his turbo lag time so that he can press his gas and get immediate boost the anti-lag system or als requires an air bypass and ignites a mixture of air and fuel in the exhaust manifold or turbine housing and not in the engine cylinders that's the secret sauce behind als okay now wait a minute to understand als we need to briefly rewind and recall how a conventional turbocharged engine works so the fuel air mixture explodes when the piston is closed to its maximum top dead center thanks to this we get the most efficient combustion of fuel the engine produces the greatest power when during the exhaust stroke the piston ejects the burnt mixture from the cylinder through the exhaust belt it passes through the turbine wheel and therefore spins it the turbine wheel in turn transfers inertia to the compressor which forces pressurized air into the combustion chambers of the cylinders the intercooler also helps to further compress the air before it enters the cylinders it cools the ambient air before feeding it to the engine this allows even more air to be fed into the cylinder in one cycle because chilled air is more dense and takes up less space the result is that a more powerful explosion happens in the combustion chamber of the cylinder more boom which means more power but this is only as long as the driver is pressing the gas as soon as he lets off the gas the throttle valve slams shut like a door and as a result the turbine doesn't get fed and loses spinning speed to avoid turbo lag you need a way for the turbine to not lose its spinning speed one method to achieve this is to cause an explosion directly in the outlet manifold right in front of the turbine this type of anti-lag system is called throttle bypass or throttle kick this is how it works when you let off the gas sensors transmit information to the engine electronic control unit or ecu as a result the anti-lag system shifts the ignition angle towards the delay by 40 degrees or more then the injection control system changes the composition of the fuel air mixture enriching in it with oxygen at the same time throttle valve is constantly kept open by 30 when the piston already drops down to the bottom dead center then the spark plug ignition delay is triggered and the exhaust stroke begins this re-enriched mixture has not yet burned out completely so all this mixture ready to explode is pushed through the valve into the exhaust manifold there on contact with the hot pipes of the exhaust manifold the remaining fuel explodes naturally combustion continues in the cylinder so the engine doesn't stall the main volume burns out already in the release as a result these explosions maintain high pressure and accelerate the turbine's rotation even when the throttle valve is nearly closed in other words no slowdown in turbine at low engine speeds and therefore no need to try to get the turbine back up to a higher speed and now when you press the gas again the fuel ignition advance angle returns to the desired parameters and your car doesn't experience turbo lag immediate acceleration anti-lag systems were first used in the early days of turbocharged cars in formula one racing around the mid to late 1980s until fuel restrictions made its use unusable it later became common in rally cars do the increased turbo lag from the mandatory restrictor at the intake manifold anyway all this would be all very good if it weren't so bad because there's one problem since our fuel burns practically in the outlet all this heats up to incredible temperatures the additional emissions and even higher temperatures places a heavy load on the entire exhaust manifold and the turbine in fact it's so damaging that racing cars in the world rarely championship typically need to replace their turbos after every single race and that's not cheap how'd you like to have to change yours after every time you drove the car actually the system isn't very reliable either but if you want to win the race then why not what about als in a regular passenger car how many miles do you think the turbo can handle maybe a thousand miles nope too many zeros maybe a hundred still too much after all with an als the temperature of the turbine wheel can reach 2000 degrees fahrenheit that's why we see als usually in race or performance cars and why production vehicles with turbocharged engines don't come pre-packaged with als another type of als is the secondary air injection or inlet bypass you see this often in rally cars like wrc vehicles in essence it uses a throttle bypass which looks like this a special bypass valve is placed directly in front of the throttle valve which directs air from the compressor through the intercooler directly into the exhaust manifold bypassing the engine the wastegate valve is solenoid controlled so it accurately controls airflow while the ecu delivers the correct fuel mixture all this will be done by the control unit depending on the conditions that you need to enable anti-leg that is now the turbine will blow into itself through the exhaust manifold sounds like a great idea right with this system when you let off the gas the throttle valve closes but the fuel air mixture remains enriched by the bypass valve so the ignition timing is no longer rolled back so much because we provide a certain amount of air to the manifold past the engine and it continues working while the enriched mixture burns out the exhaust manifold and spins the turbine of course it will be hot there again but not as hot as the first type of als because fresh air enters the exhaust manifold bypassing the engine and so it is not as hot also we don't overheat the engine much because we don't roll back the ignition angle much and the mixture doesn't get enriched as much so in principle this setup is much cooler and that's how this als works in many modern racing cars the turbine blows into itself today modern race cars have special systems that control the various aggressiveness settings in the anti-lag system this allows the driver to select the appropriate throttle response based on conditions and terrain in general they can be divided into two groups soft and aggressive the ones used in toyota mitsubishi race cars are quieter compared to those using ford and subaru cars which have high noise levels and aggressiveness okay so now you're a bit familiar with als so when you see two cars racing simultaneously shooting from the exhaust pipe with flame and roar you might think here it is anti-leg but don't jump to conclusions maybe it's the two-stage rev limiter working how's that the engine needs a rev limiter to prevent damage to engine components from over speeding this system limits the maximum rpm that an engine crankshaft can reach to reduce damage and failure the explosions of diesel engines can be especially appealing heavy pistons can break the connecting rods pierce through the engine demolish the cylinder head or punch the engine block with fragments of the connecting rod that's why the limiter stops rotational speed from going beyond what the engine can physically withstand this limitation or cutoff consists of two different maximum rotation limits the first is usually below the red line of the tachometer basically it's the launch control which is the launch procedure its operating principle is based on the car engine's ability to maintain torque when a throttle is open and the clutch is squeezed to the maximum at this moment of ignition when the engine reaches a large number of revolutions the driver stops holding the clutch pedal and the launch control button this lifts the speed limit and instantly increases torque therefore the first rpm limit is set to ensure optimum grip at the start the second one is located at the edge of the red field and is just so that the engine doesn't run out of gear so when you add gas and approach one of the two rev limiters the car begins a safety procedure like turning off the fuel or closing the throttle since the computer also controls the ignition delay of the mixture like the anti-leg where does the unburned fuel from the cylinders go that's right into the exhaust manifold directly into the turbine and that's how you get the bang bang the pop and exhaust flames throttle control and anti-leg might appear similar but they're two separate systems and it can sometimes confuse people if you enjoyed this episode please like the video thank youwhat is bang bang it has nothing to do with popcorn or loud gunshot noises but everything to do with turbo chargers in a recent video i talked about turbochargers and how do you address turbo lag today we'll talk about anti-lag and how it minimizes turbo lag time so hop in and let's go for a ride people who like turbochargers love the boost it gives their engine large turbos give you high top end power but one downside is that they're much more laggy meaning there's a delay before you achieve full throttle and boost in port the reason is because the larger the turbine wheel the greater the rotational inertia which means more time is needed to spin its wheel let's say you're rally racing or drifting you let off the gas for a moment the turbine slows down so then you press the gas but you don't get immediate boost you need to gas again and again or do something else to get the turbine back to working speed but you're losing time and why because the moment you squeeze the clutch to change gear you remove your foot off the accelerator this means that the throttle valve at this moment closes the intake system and the fuel air mixture loses its richness and oxygen less oxygen so less force of explosion in the cylinder which means less torque hence the slowdown and speed and when you press the gas again it's like the turbine is saying wait a minute let me think about it but you want immediate response to the press pedal without any delays or hesitation and while yours is still thinking a competing car with an explosive bang passes by you and that's because of his anti-lag system which minimizes his turbo lag time so that he can press his gas and get immediate boost the anti-lag system or als requires an air bypass and ignites a mixture of air and fuel in the exhaust manifold or turbine housing and not in the engine cylinders that's the secret sauce behind als okay now wait a minute to understand als we need to briefly rewind and recall how a conventional turbocharged engine works so the fuel air mixture explodes when the piston is closed to its maximum top dead center thanks to this we get the most efficient combustion of fuel the engine produces the greatest power when during the exhaust stroke the piston ejects the burnt mixture from the cylinder through the exhaust belt it passes through the turbine wheel and therefore spins it the turbine wheel in turn transfers inertia to the compressor which forces pressurized air into the combustion chambers of the cylinders the intercooler also helps to further compress the air before it enters the cylinders it cools the ambient air before feeding it to the engine this allows even more air to be fed into the cylinder in one cycle because chilled air is more dense and takes up less space the result is that a more powerful explosion happens in the combustion chamber of the cylinder more boom which means more power but this is only as long as the driver is pressing the gas as soon as he lets off the gas the throttle valve slams shut like a door and as a result the turbine doesn't get fed and loses spinning speed to avoid turbo lag you need a way for the turbine to not lose its spinning speed one method to achieve this is to cause an explosion directly in the outlet manifold right in front of the turbine this type of anti-lag system is called throttle bypass or throttle kick this is how it works when you let off the gas sensors transmit information to the engine electronic control unit or ecu as a result the anti-lag system shifts the ignition angle towards the delay by 40 degrees or more then the injection control system changes the composition of the fuel air mixture enriching in it with oxygen at the same time throttle valve is constantly kept open by 30 when the piston already drops down to the bottom dead center then the spark plug ignition delay is triggered and the exhaust stroke begins this re-enriched mixture has not yet burned out completely so all this mixture ready to explode is pushed through the valve into the exhaust manifold there on contact with the hot pipes of the exhaust manifold the remaining fuel explodes naturally combustion continues in the cylinder so the engine doesn't stall the main volume burns out already in the release as a result these explosions maintain high pressure and accelerate the turbine's rotation even when the throttle valve is nearly closed in other words no slowdown in turbine at low engine speeds and therefore no need to try to get the turbine back up to a higher speed and now when you press the gas again the fuel ignition advance angle returns to the desired parameters and your car doesn't experience turbo lag immediate acceleration anti-lag systems were first used in the early days of turbocharged cars in formula one racing around the mid to late 1980s until fuel restrictions made its use unusable it later became common in rally cars do the increased turbo lag from the mandatory restrictor at the intake manifold anyway all this would be all very good if it weren't so bad because there's one problem since our fuel burns practically in the outlet all this heats up to incredible temperatures the additional emissions and even higher temperatures places a heavy load on the entire exhaust manifold and the turbine in fact it's so damaging that racing cars in the world rarely championship typically need to replace their turbos after every single race and that's not cheap how'd you like to have to change yours after every time you drove the car actually the system isn't very reliable either but if you want to win the race then why not what about als in a regular passenger car how many miles do you think the turbo can handle maybe a thousand miles nope too many zeros maybe a hundred still too much after all with an als the temperature of the turbine wheel can reach 2000 degrees fahrenheit that's why we see als usually in race or performance cars and why production vehicles with turbocharged engines don't come pre-packaged with als another type of als is the secondary air injection or inlet bypass you see this often in rally cars like wrc vehicles in essence it uses a throttle bypass which looks like this a special bypass valve is placed directly in front of the throttle valve which directs air from the compressor through the intercooler directly into the exhaust manifold bypassing the engine the wastegate valve is solenoid controlled so it accurately controls airflow while the ecu delivers the correct fuel mixture all this will be done by the control unit depending on the conditions that you need to enable anti-leg that is now the turbine will blow into itself through the exhaust manifold sounds like a great idea right with this system when you let off the gas the throttle valve closes but the fuel air mixture remains enriched by the bypass valve so the ignition timing is no longer rolled back so much because we provide a certain amount of air to the manifold past the engine and it continues working while the enriched mixture burns out the exhaust manifold and spins the turbine of course it will be hot there again but not as hot as the first type of als because fresh air enters the exhaust manifold bypassing the engine and so it is not as hot also we don't overheat the engine much because we don't roll back the ignition angle much and the mixture doesn't get enriched as much so in principle this setup is much cooler and that's how this als works in many modern racing cars the turbine blows into itself today modern race cars have special systems that control the various aggressiveness settings in the anti-lag system this allows the driver to select the appropriate throttle response based on conditions and terrain in general they can be divided into two groups soft and aggressive the ones used in toyota mitsubishi race cars are quieter compared to those using ford and subaru cars which have high noise levels and aggressiveness okay so now you're a bit familiar with als so when you see two cars racing simultaneously shooting from the exhaust pipe with flame and roar you might think here it is anti-leg but don't jump to conclusions maybe it's the two-stage rev limiter working how's that the engine needs a rev limiter to prevent damage to engine components from over speeding this system limits the maximum rpm that an engine crankshaft can reach to reduce damage and failure the explosions of diesel engines can be especially appealing heavy pistons can break the connecting rods pierce through the engine demolish the cylinder head or punch the engine block with fragments of the connecting rod that's why the limiter stops rotational speed from going beyond what the engine can physically withstand this limitation or cutoff consists of two different maximum rotation limits the first is usually below the red line of the tachometer basically it's the launch control which is the launch procedure its operating principle is based on the car engine's ability to maintain torque when a throttle is open and the clutch is squeezed to the maximum at this moment of ignition when the engine reaches a large number of revolutions the driver stops holding the clutch pedal and the launch control button this lifts the speed limit and instantly increases torque therefore the first rpm limit is set to ensure optimum grip at the start the second one is located at the edge of the red field and is just so that the engine doesn't run out of gear so when you add gas and approach one of the two rev limiters the car begins a safety procedure like turning off the fuel or closing the throttle since the computer also controls the ignition delay of the mixture like the anti-leg where does the unburned fuel from the cylinders go that's right into the exhaust manifold directly into the turbine and that's how you get the bang bang the pop and exhaust flames throttle control and anti-leg might appear similar but they're two separate systems and it can sometimes confuse people if you enjoyed this episode please like the video thank you\n"