View Full Version : whats that thing called that keeps the turbo spinning???
\\'angan
01-06-2008, 04:32 PM
i am looking for something, forgot whats its called though, its like 3 letters it uses as a abbreviation, anyways i am trying to get one, what it does is keep the turbo spinning all the time at a certain speed where you have instant power, pretty common on scoobys and evos. and ya i know its extremely bad for the turbo i dont plan on driving the car that much.
ALS
Anti Lag System
all you hear is
pow pow pow POWPOWPOWPOWPOWPOWPOW
chyeaa
\\'angan
01-06-2008, 04:44 PM
ALS
Anti Lag System
all you hear is
pow pow pow POWPOWPOWPOWPOWPOWPOW
chyeaa
awsome thank you sir ....i have been searching for hours, anyways why do you hear the pows, are you talking about backfires???
yup
you know it
scoobies and evos have ALS battles sometimes
i laugh
panama DRIFT
01-06-2008, 04:54 PM
Anti-Lag System, ALS, is a system used on mainly turbocharged (http://en.wikipedia.org/wiki/Turbocharged) racing (http://en.wikipedia.org/wiki/Racing) and rally (http://en.wikipedia.org/wiki/Rallying) engines (http://en.wikipedia.org/wiki/Engines) to eliminate turbo lag (http://en.wikipedia.org/wiki/Turbo_lag). It was used in the early days of turbocharging in F1 until fuel restrictions made its use unsuitable. Later it became a common feature in rally cars due to the mandated restrictors on the turbocharger inlet. Because of the pressure (http://en.wikipedia.org/wiki/Pressure) drop across the restriction, the pressure ratio for a given boost level is much higher and the turbocharger (http://en.wikipedia.org/wiki/Turbocharger) must spin a lot faster to produce the same boost as before. This increases turbo lag (http://en.wikipedia.org/wiki/Turbo_lag) significantly compared to unrestricted turbochargers.
An ALS system requires an air bypass, and generally this is done in one of two ways. The first method is to use a throttle (http://en.wikipedia.org/wiki/Throttle) air bypass; this may be an external bypass valve or a solenoid (http://en.wikipedia.org/wiki/Solenoid) valve which open up the throttle 12-20 degrees (http://en.wikipedia.org/wiki/Degree_%28angle%29). This allows air to bypass the closed throttle and to reach the engine. The second method is to use a bypass valve which feed charge air directly to the exhaust manifold (http://en.wikipedia.org/wiki/Manifold_%28automotive_engineering%29).
The throttle bypass/throttle solenoid system is combined with ignition (http://en.wikipedia.org/wiki/Ignition_system) retardation and slight fuel enrichment (mainly to provide cooling), typically ignition occur at 35-45° ATDC. This late ignition causes very little expansion of the gas in the cylinder; hence the pressure and temperature will still be very high when the exhaust valve opens. At the same time, the amount of torque delivered to the crankshaft (http://en.wikipedia.org/wiki/Crankshaft) will be very small (just enough to keep the engine running). The higher exhaust pressure and temperature combined with the increased mass flow is enough to keep the turbocharger spinning at high speed thus reducing lag. When the throttle is opened up again the ignition and fuel injection goes back to normal operation. Since many engine components are exposed to very high temperatures during ALS operation and also high pressure pulses, this kind of system is very hard on the engine and turbocharger. For the latter not only the high temperatures are a problem but also the uncontrolled turbo speeds which can quickly destroy the turbocharger. In most applications the ALS is automatically shut down when the coolant reaches a temperature of 110-115°C to prevent overheating.
An ALS system working with a bypass valve which feeds air directly to the exhaust system can be made more refined than the system described above. Some of the earliest systems of this type were used by Ferrari (http://en.wikipedia.org/wiki/Ferrari) in F1. Another well-known application of this type of anti-lag system was in the WRC version of the 1994 Toyota Celica GT-Four (http://en.wikipedia.org/wiki/Toyota_Celica_GT-Four) (ST-205). Four brass tubes fed air from the turbocharger's Compressor Bypass Valve (CBV) to each of the exhaust manifold tracts, in order to provide the necessary air for the combustion of the fuel. The system was controlled by two pressure valves, operated by the ECU. Besides the racing version, the hardware of the anti-lag system was also installed in the 2500 "Group A homologation base WRC method car" street legal Celica GT-Fours. However, in these cars the system was disabled and inactive. The tubes and valves were only present for homologation (http://en.wikipedia.org/wiki/Homologation) reasons.
Today's WRC (http://en.wikipedia.org/wiki/World_Rally_Championship) cars also use anti-lag systems which feed air directly to the exhaust system. The reason is that these systems are more refined, more effective with advanced computer control, and also quieter. Today this kind of system has reached such a refinement that it’s even possible to use the system in a road car. A recent example is the Prodrive P2 (http://en.wikipedia.org/wiki/Prodrive_P2) prototype. The system works by bypassing charge air directly to the exhaust manifold which acts as a combustor when fuel rich exhaust from the engine meets up with the fresh air from the bypass. This will provide a continuous combustion limited to the exhaust manifold which significantly reduces the heat and pressure loads on the engine and turbocharger. With the latest anti-lag systems the bypass valve can not only be opened or closed but it can actually control the flow of air to the exhaust manifold very accurately. The turbocharger is fitted with a turbo speed sensor and the engine management system has a map based on throttle position and car speed which is used to find a suitable turbocharger speed and boost pressure for every condition. When the engine alone can’t provide enough exhaust energy to reach the turbo speed/boost demanded by the management system, the bypass valve opens and exhaust manifold combustion begins. This not only reduces turbo lag, but it also allows boost to be produced at very low engine speeds where boost was previously limited by compressor surge or exhaust energy. With relatively high boost at low speeds, this makes the low end torque superior even to large naturally aspirated engines. The system is quite loud and is banned on some rallies because of the noise it produces.
thank you wikipedia :)
\\'angan
01-06-2008, 04:55 PM
hey would you know if while it is installed on your car, if you can disable it for daily driving?
panama DRIFT
01-06-2008, 05:00 PM
you wouldnt need to disable it, some of the newer ALS systems are computer controlled, everything wikipedia has about ALS is in my first post
bejota180sx
01-06-2008, 05:05 PM
ive always wanted to run a ALS
if u find anything about what you want to run
post it up here...
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