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All Turbo Charger Anti-Lag Systems (ALS) – Reducing Turbo Lag for Turbochargers.

Anti-Lag Systems (ALS) – Reducing Turbo Lag for Turbochargers.

Anti-Lag Systems (ALS) – Reducing Turbo Lag for Turbochargers.

Turbochargers provide substantial power advantages and fuel savings to conventionally aspirated engines. This has earned turbochargers a good reputation and car manufacturers have adopted them as a standard component in their latest automobile designs. However, turbochargers all suffer from a common design flaw – turbo lag.

Anti-lag systems were first adapted for use in Formula One racing from the mid to late 1980s and later on in rally cars, due to the mandated use of restrictors, which lowered the maximum pressure and thus top speed of the vehicles. As turbochargers rely on pressure to spin its turbine, restrictors significantly lowered their performance which also translates into more turbo lag.

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Types of Anti-Lag Systems.

Essentially, an anti-lag system works by diverting gases to exhaust manifold (the space just before the turbocharger but after the engine). These gases then mixes with excess fuel (caused by the ECU telling the engine to spew more fuel than it can burn, which then leaks out into the exhaust manifold) resulting in a high fuel/air mix.

When this fuel/aor mix comes into contact with the hot surface of the exhaust manifold it explodes – thus keeping the turbocharger running. However, because the exhaust manifold isn’t designed for combustion it is likely to be damaged over time along with the turbocharger.

There are two main systems:

1. Throttle Bypass.

Consists of an external bypass valve that shuts the throttle, causing air to bypass it and move to the exhaust manifold. The combustion of the air/fuel mix inside the exhaust manifold causes high pressure and temperature to exit the exhaust valve and directly into the turbocharger, keeping its turbine constantly spinning at high speed, and thus eliminating turbo lag.

2. Inlet Bypass.

More advanced than the Throttle Bypass, the Inlet Bypass system comprises a bypass valve located just before the throttle valve, diverts gasses directly into the exhaust manifold via brass tubes.

Get Turbo Charged and Enjoy More Power while Using Less Fuel. Contact your local Turbo Supplier

Other ways to reduce turbo lag.

Aside from ALS other methods used to reduce turbo-lag include:

1. Adding Nitrous Oxide.

Injections of nitrous oxide increases the amount of oxygen available to combust fuel with and thus substantially increases the power output of an engine. The massively increased gas pressure helps reduce turbo lag.

2. Increasing Compression Ratio.

Gas pressure is what spin turbocharger and thus increasing the compression ratio will help turbocharger turbines spin up more quickly. However, gas compression ratios are limited by the durability of the turbocharger, and if too high can damage them.

3. Narrowing Powerbands.

Narrowing the powerband causes engines to rev up faster and thus providing a constant airflow to the turbochargers, which translates into reduced turbo lag. It is also an inexpensive alternative to getting an additional low-spool turbocharger to take advantage of low gas pressures.

4. Sequential Turbocharging.

Also called a twin-turbo, sequential turbocharging involves installing a smaller, secondary turbocharger in sequence with the main turbocharger, allowing the system to take advantage of both low and high pressure conditions.