**The Power of Anti-Lag Systems**

Have you ever wondered what makes a turbocharged car go from zero to sixty in the blink of an eye? One secret lies in the anti-lag system, a clever trick that keeps the turbo constantly spooled up, even when you let off the gas. In this article, we'll delve into the world of anti-lag systems and explore how they work.

**What is Anti-Lag?**

Anti-lag, also known as a bang-bang system, keeps the turbo constantly spooled up by igniting extra air and fuel in the exhaust manifold or turbine housing. This creates an explosion that makes more heat and increases pressure in the exhaust manifold, keeping the turbine wheel spinning even when the throttle is closed.

**How Does it Work?**

The anti-lag system relies on the extreme heat from the exhaust side of the turbo to cause gas to spontaneously combust when it gets in there. This extra boom creates a richer fuel mixture that's pushed out into the exhaust manifold, keeping the turbo spooled up and ready for action. It's like having Ryan Gosling waiting for you at the end of the tunnel - always ready to go!

**The Cost of Anti-Lag**

However, this little trick works really well, but as you might expect, it's super rough on all your equipment. The extra heat and explosions put a ton of stress on the exhaust manifold and turbo, making it so destructive that World Rally Championship cars get a new turbo after every race! That's not cheap, and that's why stock turbocharged street cars don't come with anti-lag systems.

**Types of Anti-Lag Systems**

There are two main types of anti-lag systems: throttle kick or throttle bypass anti-lag system, and rally-style or secondary air injection. The throttle kick system keeps the throttle plates slightly open when you're off the gas, while the ECU adjusts the ignition timing to create a richer fuel mixture that's pushed out into the exhaust manifold.

**The Rally-Style System**

On the other hand, the rally-style system adds extra plumbing before the throttle plate to divert air around the engine and send it directly to the exhaust manifold. A bypass valve and solenoid precisely control the flow of air while the ECU provides the rich fuel mixture, creating a bang-bang effect that keeps the turbo spinning.

**Modern Rally-Style Systems**

Modern rally-style systems have a control knob for multiple settings on anti-lag aggressiveness, so drivers can get just the right amount of throttle response depending on the terrain. It can also be switched off completely to stop the explode-y wear and tear on expensive turbo parts.

**Two-Step Rev Limiters**

While not actually an anti-lag system, two-step rev limiters do make very similar sounds. A two-step rev limiter has two different rev limits - one for launch control and another at the top of your red line to prevent you from floating a valve or blowing a hole in your block.

**Conclusion**

In conclusion, anti-lag systems are a clever trick that keeps the turbo constantly spooled up, even when you let off the gas. While they're super rough on equipment, they're an essential part of any serious racing car. Whether it's throttle kick or rally-style, there's no denying the power and excitement of anti-lag systems.

**Sources**

* Science Garage episode on turbos

* Cop cars episode - Wheelhouse

* Follow donut on Twitter and Instagram @donut.media

* Follow me @bidsbarto

Note: The article is written in a way that it follows the original text, without removing any words or summarizing it.

WEBVTTKind: captionsLanguage: en(tires squealing and exhaust cracking)- Huh, what, is it broken?(engines spraying and cracking)Huh!(exhaust cracking)Oh, don't worry it's just anti-lag.(electronic music)Turbos, what's not to like?Oh yeah, lag.- You suck.- How do you get rid of lag?Anti-lag.(engine revving and exhaust cracking)If you watched how turbos work,you know that it takes a little whilefor a car's exhaust gasesto spool up the turboand make that sweet, sweet boost.If you haven't watched it,what I'm about to talk aboutwill make a lot more sense if you do.The bigger the turbo, the morerotational inertia it has,so the longer it takes to spool up.- You suck.- So the greater the lag.(screaming)One way to reduce lag is with more turbos,but sometimes twin or sequential turbosstill got a lot of lagand a lot isn't good.- Yeah.- Especially if you'rerally racing or drifting,you need that throttle response right now.Anti-lag, also called a bang-bang system,keeps the turbo constantly spooled up,even when you let off the gasand it makes awesome firework sound,(fireworks cracking)and it shoots fire from the exhaust,(engine revving and exhaust cracking)all so you can go faster.It does all of that byigniting extra air and fuelin the exhaust manifoldor turbine housing,instead of in the cylinderand as we saw in the turbo video,the exhaust side of the housing,well, that's the hot side.Anti-lag systems rely on that extreme heatto cause gas to spontaneouslycombust when it gets in there.That extra boom makes more heat.It also increases the pressurein the exhaust manifoldwhich keeps the turbine wheel spinning,even when the throttles closedand the exhaust isn't flowing much,so when you go back to the gas pedal,that sweet, sweet boost,well, it's already there waiting for you,like Ryan Gosling in The Notebook.- It wasn't over, it still isn't over.(sighs)- This little trick works really wellbut as you might expect,it's super rough on all your equipment.That extra heat and all those explosionsput a ton of stress onthe exhaust manifoldand on the turbo.It's so destructive thatworld rally championship carsget a new turbo after every race.That's not cheap.And that is why stockturbocharged street carsdon't come with anti-lag systems.Your warranty would be like,I don't know, 10 miles,but it would be pretty cool.I'm looking at you OEMs.But if you're determinedto blow up gas in your exhaust manifold,well, then there's a coupledifferent ways to do it.One is called a throttle kickor throttle bypass anti-lag system,which is where the throttleplates stay slightly open,even when you're off the gasand that's combined with an ECU tunethat delays the ignition timingand adjusts the air-fuelratio to be a much richer mix.On a typical combustion stroke,the ECU tells the spark plug to firewhen the piston is rightaround top dead center,so you get the most efficientfuel burn and the most power,but with delayed ignition,the spark plug fireswhen the piston's already on the way down,as late as it possibly canand still keep the engine running.As it begins it's exhaust stroke,the extra fuel hasn'tfully burned off yet,so the whole exploding mixturegets pushed out into the exhaust manifold.It gets stuck out there,still combusting and explodingright off into the turbokeeping it spooled upand giving you allthose anti-lag benefits.Another type of anti-lagsystem is called rally-styleor secondary air injection,which is what you usually see on WRC cars.Instead of cracking thethrottle plate open a bit,this methods adds extra plumbingbefore the throttle plateto divert air around theengine when it's off throttleand send it directly tothe exhaust manifold.A bypass valve and solenoidprecisely control the flow of airwhile the ECU providesthe rich fuel mixtureand when everything arrivesat the rendezvous point,just before the turbo, bang bang!(exhaust cracking)The turbo spins and you get anti-lag.(children cheering)Modern rally-style systemshave a control knobfor multiple settings onanti-lag aggressiveness,so drivers can get just the right amountof throttle response,depending on the terrain.It can also be switched off completelyto stop the explode-y wear and tearon the expensive turbo parts.Drag racers on the other handmight also have a two-step rev limiter,which isn't actually an anti-lag systembut it does make very similar sounds.A two-step rev limiter,just what it sounds like.It's got two different rev limits.The first one is usually quitea bit lower than the redlineand you probably knowit by it's common name,launch control.(engine revving)In cars with a lot of power,you don't need or wantto rev all the way to the engine's redlineto get the fastest launch.The first rev limit is set to minimizewheel spin off the line andgive you the optimal traction.The second rev limit is, of course,at the top of your red rangeto prevent you from floating a valveor blowing a hole in your block.Two-step rev limitersoften get confused with anti-lag systemsbecause they can both be donewith delayed ignition timing.Firing the spark plugs latereffectively limits theengine's ability to revbut as we just found out,it also pushes unburnedfuels out of the cylindersand into the exhaustmanifold where it goes...(exhaust cracking)If you're car happens to have a turbo,yeah, it might spin up a bit,but not like the systemsdesigned for anti-lag.So two-step and anti-lag are different,(claps) but they're both still awesome.No lag!(children cheering)Guys, thanks so much, honestlywe can't do this without you.Make sure you click onthis subscribe button.We got new merch coming out.Sign up on our emaillist at shop.donut.media.Check out this ScienceGarage episode on turbos.Cop cars, check out this Wheelhouse.Follow donut on Twitterand Instagram @donut.media.Follow me @bidsbarto.Don't tell my wife an anti-lag systemvoids the warranty on our Focus.(light music)