Rally style Anti lag systems, set up and tuning
After such positive feedback to our last post (click here for the Intro to Anti Lag) explaining the basic functions and design of multiple types of Anti lag systems aka ALS we are back again to provide a LONG overdue follow up. I will go over the 2 most popular Anti Lag Systems that we commonly set up and tune on both shop and customer cars; Throttle Bypass ALS and Secondary Air Injection ALS.
What if something as simple as the flick of a switch meant your turbo would deliver any amount of boost you desire from idle to redline? Power bands and torque curves from your turbocharged engines that give big block V8’s a run for their money. This is no fantasy, with the help of anti lag mid to large turbos can be kept “spooled” creating a very usable power band.
Starting with a quick review, Anti Lag systems are used to build boost on turbocharged engines in situations where the engine’s exhaust cannot provide enough energy to spin the turbine wheel at the desired rate to create boost on the compressor side of the turbo. IE: Low rpm, low engine load and low throttle openings (lifting during a corner on the circuit). The only factor limiting the shaft speed (aka turbine rpm) is a lack of energy in the form of pressure and heat from the exhaust pre turbine wheel. This problem is most commonly addressed by introducing a combustion event pre turbine wheel leading to a dramatic increase in energy (heat/pressure) which intern increases turbo shaft speed leading to the BOOST we all love so much.
Already familiar with anti lag but worried about damaging expensive parts? Don’t be, a correctly set up and tuned Anti lag system will not lead to premature failures. Contrary to wide spread rumors throughout the internet started by people who more often than not have no hands on experience Anti lag systems can be set up from mild to wild and tuned for aggressively or with reliability in mind. Of course when we are working with a professional race team (HUGE budget) a turbo may only need to last for 30 min. or 1 race and we can tune VERY aggressive. For weekend warriors and even street cars the balance is easily shifted to provide years of reliability with boost on demand using ALS turned on or off with an arming switch.
These days almost everyone is familiar with “drag” style Anti lag tuning which is basically a second rev limiter aka 2 step rev limiter that is tuned to adjust both ignition and fuel trims when activated just before “launching” the car. So what do you do about turbo lag caused by lifting off the throttle through a corner or turbo lag when shifting? This is where the “rally style anti lag” comes into play. While a drag style ALS is pretty straightforward to set up and tune the rally style ALS requires far more attention to detail to ensure there is no damage to any mechanical components IE: exhaust valves, turbo manifold and turbo.
Over the years our team of tuners and engineers have been hard at work fine tuning 2 types of “rally style ALS” to provide the boost response needed for rally/rally cross, drifting and even circuit racing at a competitive level. The simpler of the 2 systems is most commonly referred to as a Throttle Kick ALS or as we call it Throttle Bypass Anti Lag kit. The second type of system is a Secondary Air Injection system (AKA SAS) This type of ALS introduces air from the compressor side of the turbo into the exhaust manifold pre turbine wheel. The SAS ALS system offers some huge advantages when compared to the “throttle kick ALS” however SAS also requires extra hardware and an advanced EMS to properly tune the ALS.
Using a “throttle kick ALS” keeps things simple and does not require all of the extra hardware associated with SAS anti lag. The down side is you must pass all air and fuel through the engine in order to get the air/fuel mixture into the turbo manifold for combustion. This adds extra stress to a few engine components in particular the exhaust valves. When properly tuned the “throttle kick/bypass anti lag” is incredibly effective AND reliable. Brewed Motors is currently using the “throttle kick ALS” on our 4g63 powered Galant Vr4. Check out the pictures, links and Video to see the throttle bypass style anti lag system in action. The Throttle Bypass rally style Anti Lag kit features all the fittings, line, wiring and solenoids required for installation. There is no need to modify the throttle body this system is fully functional without opening the actual throttle plate any further so you can retain a smooth idle with the ALS off.
The Secondary Air Injection anti lag system or SAS has proven to be one of the most effective and efficient anti lag systems and is widely used throughout motorsports. While this system works great it does require specific hardware, IE: Valves, control solenoids, boost/ vacuum can, lines, fittings and a proper Engine management system to control everything. One of the largest benefits to the SAS anti lag systems is the fact the air used to create combustion in the exhaust manifold completely bypasses the engine which means much less stress on the exhaust valves. Brewed Motors is currently using the “secondary air injection ALS” on our KA24-T powered wide body S13. This SAS rally style Anti Lag system is also set up on a switch so you can easily turn the system off on the street. In order to use the SAS anti lag kit you will need to weld the supplied fittings (2pc) to your exhaust manifold these fitting will then be connected to dual 15mm stainless steel hard lines leading to the ALS valve. This AL valve is controlled by the ECU using a series of vacuum solenoids and a vacuum can. You can also order Velocity Element aka VE turbo manifolds pre fit with our anti lag system!
If you find yourself fantasizing about running an Anti lag system on your turbocharged engine don’t hesitate to drop us a call or email. Brewed Motors is currently offering a number of different Anti lag systems and tuning packages to provide you with the fast spool, boost response and performance our customers have come to demand. Both the Throttle Bypass and SAS Anti Lag systems deliver reliable boost and huge gains in response; contact our team of tuners if you need any help deciding which kit is right for you. **If you also need your ECU tuned after the ALS is installed ask about our “Power packages” that include a complete tune for your new ALS. **
Brewed tuned Vr4 running a mild throttle bypass ALS for extra slippery conditions