TRIFECTA Performance

After getting past what proved to be one of the biggest challenges we ever faced - figuring out how to get into the E90 ECM in this truck, we delivered a comprehensive calibration for the new 3.0L Whipple supercharger. Complete with TRIFECTA’s exclusive 10sp automatic transmission shift recalibration support (for the new T93 controller), this truck is a force to be reckoned with on the street. We found 555 horsepower at the tire on the dyno, and 534 foot pounds of torque! Complete mod list consists of the SC kit from Whipple, IAT relocation module from DashLogic, a cat-back exhaust system, and our calibration. A big shoutout to: CarbConn in Kirkland, WA for the install, support, and dyno. DashLogic for providing the “IAT Sensor Breakout” module (SensorTap) that’s required to relocate the IAT sensor to the intake manifold on these E90 applications. And finally, the customer for his confidence and patience while we worked through the challenges of this project!

Introduction In recent years, GM has been augmenting the driving experience for some of their vehicles with a variety of technologies which modify the natural noise from the powertrain and from the vehicle as it travels down the road. The idea behind these technologies is to enhance the sound of the vehicle, as experienced by the driver, while utilizing exhaust systems that meet certain noise requirements. Mechanical Engine Sound Enhancement On some of the 6th Generation Camaro vehicles (2016 – present Chevrolet Camaro), there is what GM refers to as an Air Cleaner Resonator assembly. Effectively, this is an isolator with a tube that plumbs into the throttle intake just prior to the throttle body, with the other tube (on the isolated side) being piped directly into the passenger compartment. Here, the objective is to pipe some of the “intake noise” into the passenger compartment to augment the driver experience. Electronic Engine Sound Enhancement (ESE) On the 2016 – 2019 Cadillac ATS-V, and the 2014 – 2019 Cadillac CTS VSport, an electronic form of ESE was implemented. Using a sophisticated array of microphones, real-time data from the vehicle, and application specific software in the entertainment system, the natural sound of the twin turbocharged engine is enhanced and broadcast through the speakers in the passenger compartment in real-time. Active Noise Cancellation Most late model GM vehicles include some form of active noise cancellation, even in applications which do not have electronic ESE. Again, using a sophisticated array of microphones located in various locations of the passenger compartment, specific software algorithms, the entertainment system can broadcast certain frequency tones through the speakers in the passenger compartment which reduces the level of road noise heard inside the vehicle. Undesirable Aspects of ESE and Active Noise Cancellation While the vast majority of GM vehicle owners will probably never even know their vehicle has ESE and/or Active Noise Cancellation, there are some that may consider these features to be undesirable. Performance enthusiasts will frequently modify the exhaust system on their vehicles as a means to customize the driving experience by increasing and tuning the exhaust sound of the engine. Unfortunately, both ESE and Active Noise Cancellation can, in some cases, negatively affect the driver’s experience by applying the “fake engine sounds” in a manner which does not sound natural with the exhaust modifications. The same can be said of Active Noise Cancellation, as it works to reduce perceptible noise external to the passenger compartment. There is also a subset of human population that are incredibly sensitive to noise cancellation technology. In some cases, the symptoms can be severe, which include dizziness, nausea, eardrum pain, and headaches. The causes of these symptoms in sensitive individuals still are not fully understood, but the general solution is to not use Active Noise Cancellation technologies. Disabling ESE and/or Active Noise Cancellation Unfortunately, as far as we know, GM does not provide any means to disable either of these technologies. For some applications, the entertainment manuals do reference the ability to adjust whether the system changes the volume level of audio playback based on vehicle speed, but nothing about either ESE or Active Noise Cancellation. TRIFECTA is, however, pleased to announce that, through our calibration products, we can disable ESE and/or Active Noise Cancellation as a pair! We’ve recently tested this on both of our Cadillac ATS-V vehicles, which have the Borla exhaust system, and we’re proud to say disabling this feature does indeed provide a more natural sound from the exhaust system inside the vehicle. Available immediately for all Cadillac ATS-V and CTS VSport customers! More applications to be available later!

Introduction: Turbocharger Bypass (or blow off) Valves Unless it’s an extreme racing application, gas engines utilizing a turbocharger typically need some way to “blow off” the boost pressure in the event there’s a sudden reduction in power request from the driver. Consider the scenario where an engine that is operating under full boost pressure, the turbocharger is spinning at full speed, and the driver suddenly takes their foot off the accelerator pedal. In order to slow the engine speed down, the throttle blade will close. However, the turbocharger is still spinning at full speed and continuing to compress air. Eventually, the compressed air behind the compressor will build up so much pressure that it will push back through the compressor (this is called compressor surge). Compressor surge can destroy a turbocharger in short order, so to avoid this scenario, automakers incorporate a mechanical valve that diverts the compressed air coming out of the compressor outlet back into the compressor inlet. Old School: Pressure-Mechanical bypass valves Bypass valve found on 1.4L Turbo (RPO: LUJ/LUV) Historical bypass valves were pneumatic-mechanical devices. They would use the pressure supplied to the intake manifold while the engine is under boost to push the bypass valve closed, and keep it closed. If the pressure in the manifold drops because of a throttle closure, the pressure from the compressor would push the bypass valve open to avoid compressor surge. On most modern applications, there’s also a bypass control solenoid that allows the ECU in the vehicle to disable the pressure signal even if there’s positive pressure in the manifold. It might do this because of a boost control system failure to ensure the engine is not allowed to develop any boost. One drawback to the legacy system is its complicated and failure-prone. There’s plumbing from the manifold to the control solenoid, and more plumbing to the bypass valve assembly itself. It’s always possible the bypass valve itself could fail, as well. Modern Era: Electronic bypass valves Bypass valve found on 1.4L Turbo (RPO: LE2) The newer turbocharger designs from General Motors aim to reduce system complexity by utilizing an electronic air bypass valve on the turbocharger. Here, a self-contained electromagnetic-mechanical device attached directly to the turbocharger compressor housing can bypass the air by simply receiving a signal from the ECU. One of the two pins is connected directly to a fused +12v source, and the ECU controls the ground pin. The default position (unpowered) results in the valve staying closed (through spring pressure). In order to open the valve, the ECU supplies the ground signal, which energizes the coil and pulls the plunger against the spring to open the valve. GM 2.0T (RPO: LTG) and 1.4T (RPO: LE2) engines use the electronic bypass The 2.0T LTG engine made its debut in the 2013 Cadillac ATS, and 2013 Chevrolet Malibu, and so far as we know, is the first application to use the electronic bypass valve. Later, in 2015, the overseas Chevrolet Cruze arrived with the 1.4T LE2 engine which also uses the same electronic bypass valve. In 2016, the US and other global markets received the 1.4T LE2 engine in the Chevrolet Cruze and certain models of the Buick Encore. 2016 was also the first model year of the Gen6 Chevrolet Camaro that has the LTG as an option. Virtually every known “next generation” GM turbocharged engine design at the time of writing has, or will have an electronic bypass valve, including: 1.2T RPO: LIH 1.35T RPO: L3T 2.0T RPO: LSY 2.7T RPO: L3B 3.0T RPO: LGY 4.2T RPO: LTA Limitations in the OE electronic bypass valve design The OE bypass valve relies on a relatively weak spring to keep the bypass valve closed when it isn’t energized by the ECU. While it may be adequate for OE boost levels, performance enthusiasts that are looking for higher boost or are using a modified turbocharger may run into issues with the bypass valve leaking. The other limitation related to the return spring is that when there’s a transition from an open bypass event to closed bypass event, again, it relies on this spring’s ability to push the valve closed. GFB (GoFastBits) DV+ bypass valve upgrade kit Several aftermarket companies have approached solving the limitations in the OE electronic bypass valve in various ways, but GFB has taken a unique approach. With the DV+, rather than just beefing up the original design, they redesigned the entire valve control system to leverage the compressor boost to open the valve during an open event, and to hold the valve shut when it’s supposed to be closed. In our testing, we have not observed any issue with the OE bypass valve being blown open by excess boost. We compared boost levels on the OE bypass valve versus the DV+ (as well as another aftermarket bypass valve upgrade) and found no differences. This isn’t to say that as the vehicle components age, they won’t develop problems. In fact, we’ve seen a few LE2 engines lately appearing to not hold boost correctly, and we’re looking into whether the bypass valve might be causing the problem. Where these valves can really shine, particularly the DV+, is during bypass open-to-close transitions. Not only does the piston have a stiffer return spring, but the piston travels a shorter distance, and the valve design leverages the compressor boost to get the valve closed more quickly. This results in a noticeable improvement in boost response when going from off pedal to on pedal. Installation of the valve is straightforward. Simply remove the OE valve by disconnecting the battery, disconnecting the electrical connector, and removing the three screws that attach it to the compressor housing. After partial disassembly of the OE valve, the DV+ is assembled on the OE coil assembly and is reattached to the turbocharger with the three new bolts they provide with the kit. Installation took approximately 20 minutes and required no tuning changes. Conclusion The GFB DV+ is a great modification if you’re looking for the best performance you can get out of your 2.0T LTG or 1.4T LE2 engine! It’s a simple, low cost way to improve the vehicle’s boost response. For this application, the part number is T9363 and is available at any of GFB’s distributors. Link: https://gfb.com.au/products/blow-off-and-diverter-valves/dv-plus/t9363/ NOTE: The web site does not list the LE2 as compatible with this product, but we have tested and confirmed it is, on our development vehicles.

History of Big Wheels No, we’re not talking about the toy trike you used to have when you were a kid, we’re talking about turbo wheels, and making them BIGGER! When it comes to mods for a turbocharged engine, upgrading the compressor and turbine wheels inside an OE frame turbocharger is an easy way to get decent performance gains without much hassle. Custom “ground-up” designed turbo kits that utilize standard aftermarket turbochargers can yield impressive power, but they tend to be expensive, and in some cases require modifications that are not reversible. For enthusiasts looking for decent gains with a drop-in part need to look no further than a turbo with upgraded wheels! First, it was the Compressor Wheel The first big wheel turbo kits for the 1.4T addressed the compressor wheel size. These turbos utilized a custom machined compressor wheel and compressor housing to increase airflow on the intake (cold) side. Several companies have experimented with different compressor wheels sizes, but in many cases it was hard to justify the cost vs performance gain. Exhaust Flow Challenges On this particular engine, exhaust flow has always been a challenge. The OE turbocharging strategy aims to eliminate turbo lag as much as possible in order to make the vehicles drive as similar to a naturally aspirated engine as possible, which is what most people are used to. This requires a relatively small turbocharger (from a wheel size perspective). Small turbochargers spool very quickly and provide peak boost at a lower RPM, but there’s a trade-off: the cost is having less than spectacular high RPM performance. This is because as engine RPMs rise, so do the exhaust flow requirements, and a turbine wheel size that’s optimized for low to mid RPM operation suddenly becomes a restriction at high RPM. Next, it was the Turbine Wheel Compressor wheels (compared to turbine wheels) are relatively easy to make bigger. In most cases, you take a block of billet aluminum and cut a new compressor out of it. Turbine wheels, on the other hand, are much more challenging (and expensive) to make because they need to be made out of materials that can tolerate the excessive heat of the exhaust stream. The other challenge is whether the OE turbo frame can be bored out enough to accept a larger compressor and turbine wheel. And beyond that, yet another challenge is the core itself. The OE turbocharger on this engine can spin in excess of 250,000 RPM. Installing a larger compressor and turbine wheel adds weight to the rotating assembly, which adds stresses to the shaft and bearings. And now, it’s all about the (exhaust side) A/R “A” what?? A/R. The “internet” defines this separately as “Aspect Ratio”, “Area / Radius” and “Area Ratio”. The short of it is that the A/R describes the ratio of the area of the turbine inlet to the radius of the wheel itself. There’s an A/R characteristic on the compressor side as well. It’s the radius of the compressor wheel compared to the area of the compressor discharge. Modern day big wheel turbo offerings now offer all three upgrades: compressor, turbine and modified A/R to improve exhaust flow characteristics. Supporting the Community As the premier tuner of the 1.4L turbo engine markets, TRIFECTA considers it their duty to provide ongoing calibration support for quality parts that are popular with the community. When the big wheel V2 came out – the first modified OE frame turbo with an upgraded turbine wheel - we jumped all over it. More recently, we were approached with an offer to receive the updated exhaust housing for the V3 turbo, which includes the A/R change. We were excited to have this opportunity! 2016 Chevrolet Sonic 1.4T Manual Transmission Test Vehicle We have several 1.4T equipped vehicles in our test fleet, but for this development process, we chose our 2016 Sonic as the test vehicle mainly because it’s largely stock. We pondered the question: How would a turbocharger like this perform on a vehicle that has few other modifications? Can we make a case for this turbocharger as a “sooner” rather than “later” upgrade? (we plan to add more mods to this vehicle and re-evaluate gains at each mod) Vehicle Specs: 2016 Chevrolet Sonic LT 1.4L turbo (RPO: LUV) engine Manual transmission TRIFECTA ECM and FPCM calibration 60lb Siemens-Deka fuel injectors RacerX cold air intake system Spec upgraded clutch WaveTrac limited slip differential ~22000 miles on the vehicle Installation Notes Well, there’s not much to note! This turbocharger is a drop-in replacement for the OE turbocharger. It took a DIY mechanic about 4 hours to do. The turbocharger replacement procedure calls for new gaskets and seals, but given the relatively young age of this car, we reused all of the gaskets and seals without issue. The only item we needed was some coolant to replace the coolant lost when disconnecting the turbocharger’s coolant lines from the block. Dyno Test Notes After installing the turbocharger, we took the car over to our local dyno. All pulls were done in 3rd gear, and were performed on a Dynojet 424xLC2 chassic dynamometer (with the load cells disabled). For turbocharged applications, we provide results as UNCORRECTED. Below are some highlights from the dyno sheet: Vehicle Config Max HP Max TQ HP Gained vs stock TQ Gained vs stock Stock turbo / cal 132 156 – – V3 / cal – 2000 RPM 44.6 117.2 - 5.1HP - 13.39TQ V3 / cal – 2750 RPM 78.8 150.5 - 0.87HP - 1.65TQ V3 / cal – 3000 RPM 95.2 166.7 + 8.18HP + 14.29TQ V3 / cal – 3750 RPM 170.6 239.1 + 66.54HP + 93.27TQ V3 / cal – 3892 RPM* 182.5 246.3 + 75.47HP + 101.85TQ V3 / cal – 4183 RPM** 193.0 242.3 + 82.4HP + 103.1TQ V3 / cal – 4891 RPM* 203.5 218.6 + 79.01HP + 84.9TQ V3 / cal – 6000 RPM 190.2 166.2 + 64.4HP + 56.28TQ * - PEAK HP and TQ RPM samples ** - Maximum gain vs stock (HP AND TQ) Additional Notes: Stock turbo / cal configuration includes upgraded clutch and Wavetrac LSD All V3 samples include TRIFECTA calibration V3 is ZZP Big Wheel V3 turbocharger Discussion of Test Results In general, we were quite impressed with the results. This particular dyno is notoriously “stingy” and we managed to break 200WHP and hit almost 250WTQ. We noted a slight drop in power below 3000 RPM (likely due to the increased exhaust flow required to spool the turbo), but by around 2750RPM, the power levels were almost the same. The power curve is surprisingly flat. We expected to see the power take a nose-dive at higher RPM, but with proper calibration we were able to get the power to hold decently - past 6000 RPM. We have further dyno results that show a smoother curve at higher RPM, but we chose this dyno chart to highlight the gains. For a vehicle that has so few mods, it performs amazingly. We would, however, caution that anybody planning on purchasing this turbocharger also upgrade their clutch – slippage on the stock clutch at these power levels is almost certain. We also noted that we could not achieve a manifold pressure much beyond 280kPa. The pre-throttle body pressure can rise as high as 310kPa, but even with the throttle body wide open, the manifold pressure would not rise beyond 280kPa. We believe either/both of the following are true: 1. Throttle body is causing a pressure restriction, and/or 2. There’s turbulence inside the intake manifold disturbing airflow. If this issue is resolved, we believe the peak torque numbers could rise even higher, though high RPM horsepower numbers aren’t likely to change much. Fuel injector upgrade is a requirement for this turbocharger. At the time of writing we had only evaluated the 60 lb/hr Siemens-Deka fuel injectors, but we suspect 42 lb/hr or larger will be necessary. This vehicle has the OE intercooler and exhaust system (including the OE catalytic converter). We used the wastegate actuator provided with the V2/V3 turbocharger. We plan to retest the vehicle with additional modifications. Calibration Availability The V3 turbocharger is popular this season. A number of our customers have either installed it or are planning on it. At the time of writing, our calibration is still under development but is largely complete (past 90% completion). TRIFECTA customers may contact our support team and request calibration support for the V3 at this time. As always, any future refinements will be available to our customers at no charge.

To that end, if any of our tech-savvy followers or customers want to help us fight Covid-19, we invite you to join our Folding@Home team! Folding@Home is, in a nutshell, a method of crowd-sourcing CPU cycles to help researchers simulate how new drugs might interact with the virus. The more CPU (and GPU) cycles people can donate, the faster researchers can go through iterations which may accelerate the path to a vaccine! For more info on Folding@Home, visit: https://foldingathome.org/ Our Team Number is 252535! https://stats.foldingathome.org/team/252535

TRIFECTA products are only installed using EZ Flash software With the exception of in-person dyno tuning, all TRIFECTA products are installed using a Windows based application that runs on a Windows PC, or inside a Windows virtual machine (VM). This application is called EZ Flash, and the splash screen will look as follows: In some cases, TRIFECTA has provided “rebadged” versions of EZ Flash to resellers, however, at present, none of those resellers are active. TRIFECTA products are only installed using EZ Flash, and never installed using any other piece of software. TRIFECTA products are only installed using a USB to OBD-II adapter Over the years, TRIFECTA has supported only four different types of USB to OBD-II adapter for installing its products: The “black box” which is a retangular box with a USB connection on one side and a 15pin D-Sub connector on the other side, which the OBD-II cable attaches to. (pre-2010, no longer supported) Special version of the Tactrix OpenPort2 USB to OBD-II adapter. (pre-2010, no longer supported) The “red cable”, which is a special version of the OBDLink SX OBD-II diagnostics tool. It is a one-piece assembly with a USB connector on one end of the cable and an OBD-II connector on the other end. It may carry the TRIFECTA logo, though some units in the field will say OBDLink SX (see below). The “black cable” which, like the “red cable” is a one-piece assembly. It carries the TRIFECTA logo and the model number TFEZ010U (see below). Illustration: TRIFECTA “Black Cable” Illustration: TRIFECTA “Red Cable” TRIFECTA calibrations are never installed using stand-alone handheld devices or any other “flash cable”. TRIFECTA will vigorously investigate alleged instances of sales of “fake” product Individuals or entities that choose to engage in the activity of selling products or services that are advertised as TRIFECTA products or services, and that are mutually understood to be genuine TRIFECTA products or services by both the buyer and seller, but are in fact not genuine TRIFECTA products should be aware that they are likely: Violating various laws regarding fraud and misrepresentation Causing damages to the TRIFECTA brand Displacing profits that TRIFECTA was entitled to Exposing themselves to substantial civil monetary penalties Exposing themselves to criminal penalties TRIFECTA will vigorously defend its brand, will investigate all alleged instances of fraud, and, when appropriate, refer the results of its investigation(s) to authorities if it believes a crime has been committed. Contact us if you have concerns If you are located in North America, and you believe you were sold what was represented as a TRIFECTA product or service and you have a reason to believe it was not an authentic TRIFECTA product or service, please contact us via email at: genuine@trifectaperformance.com

If you are a current TRIFECTA customer, we offer this update to you at no charge! Contact us for details: https://www.trifectaperformance.com/contact Applications: 2014--2019 CTS V-Sport 2016--2019 ATS-V

This car is equipped with a Manual transmission, and will join our Automatic transmission ATS-V in development duty, ensuring we are able to faithfully serve owners of both gearboxes as we continue to push the limits of the ATS-V!

What is “Lean Cruise”? From the late 1990s through the mid 2000s there was this mysterious feature enabled in some non-US V8 (LS1) engine software calibrations that was purported to improve fuel economy. Some of the aftermarket calibration product suites referred to it as “Lean Cruise” and what it did was it allowed the vehicle to operate at fuel mixtures leaner than stoichiometry (14.7:1 air to fuel ratio on non-ethanol gas) under certain light-load conditions (such as steady state cruising) – generally up to 17:1 or 18:1. How does “Lean Cruise” improve fuel economy? “Lean Cruise” has positive impacts on fuel economy, but not largely for the reason most people think. It's widely believed that running a leaner mixture means less fuel is being consumed, and hence the fuel economy improves. This is true, but it is by far the smaller effect versus another: reducing pumping losses. Pumping losses occur, particularly on large displacement engines while the engine is under light load because a gasoline engine's power output is currently regulated by a throttle blade (though newer engine designs are beginning to use variable valve lift technology as an alternative). In the steady-state cruise scenario, the throttle blade needs to be mostly closed to maintain a specific vehicle speed. Because the throttle blade is mostly closed, the pistons operating on the intake stroke are literally fighting against the throttle blade to pull a full cylinder's worth of air in but cannot. “Lean Cruise” reduces pumping losses because it requires the engine to operate with the throttle blade opened further than it would otherwise if it were operating at stoichiometry. The engine cannot generate power as efficiently at leaner mixtures, so the engine needs to be operated under a higher load at the leaner mixture. Naturally, the LS1 engine was a perfect choice to implement “Lean Cruise” on. “Lean Cruise” is not allowed by US EPA / CARB regulations “Lean Cruise” was only enabled in certain non-US software calibrations where the emissions standards allowed it. Running the engine at a leaner mixture increases combustion chamber temperatures and dramatically increases the amount of “oxides of Nitrogen” (also known as NOx) emissions. The other emission-related issue is that the catalytic converters used on modern day vehicles, (also known as Three Way Catalysts) require the engine management software to oscillate the fuel mixture between slightly lean and slightly rich in order for it to be able to do its job. TWCs cannot function properly if the fuel mixture is run in the ranges that “Lean Cruise” utilizes. Newer engine designs lose the pumping losses benefit from “Lean Cruise” Remember what we said about pumping losses? GM's answer to that issue was to solve it using two other technologies (though only one of which is relevant to the LF4): 1. Variable valve timing (VVT), and 2. Active fuel management (V4 mode on the V8 engines). The LF4 enjoys a great benefit from VVT because both the intake and exhaust camshafts can be independently phased. Under light load cruising conditions, the engine control module (ECM) sets the camshafts for more “overlap”. “Overlap” is the amount of time both the intake and exhaust valves are open. By setting both valves to be open, instead of fighting against the throttle blade, the intake stroke can pull exhaust gasses back into the combustion chamber, thus reducing pumping losses with the added benefit of inducing Exhaust Gas Recirculation (EGR) which is also beneficial for controlling emissions. The other way VVT can help reduce pumping losses – a technique that is also used on the V8 engines, is by retarding the intake valve event such that it begins as late as possible after top dead center (ATDC). This effectively shortens the length of the intake stroke, and the engine spends less time fighting against the throttle blade. Active fuel management (AFM) further reduces pumping losses by effectively shutting off 4 of the 8 cylinders (though newer AFM designs allow for shutting off up to 7 cylinders). It does this by disabling the camshaft lifters on 4 of the cylinders, so those cylinders are no longer fighting against the throttle blade. This feature doesn't exist in the LF4, but newer V6 engine designs like the LGW, LGX and LGZ all can disable 2 cylinders on the fly. “Lean Cruise” was removed from OE software “Lean Cruise” disappeared from OE software when the newer series of engine controllers was developed starting with the Gen IV V8 in 2005. In 2006, the L76 engine was introduced. This was a 6.0L engine that had VVT – the first of its kind. Later variants of the Gen IV V8s such as the L94 and the L99 used VVT primarily to improve fuel economy by reducing pumping losses. It is clear that GM found better results with VVT than using “Lean Cruise” without having to maintain two different emissions standards and software calibrations for various regions. Any modern “Lean Cruise” implementation would require some trickery Because “Lean Cruise” as a feature hasn't existed in the operating system of the engine controller since around 2004, any implementation that attempts to mimic the effects of it would require some amount of trickery. It's certainly possible to calibrate the ECM to go into open loop fuel mode, and command leaner mixtures, but what are the possible side effects of that? One is that many of the ECM's diagnostics won't run if the commanded EQ Ratio isn't 1.0 (stoichiometry) and in closed loop fuel control mode. O2 sensor self tests, EVAP purge events, sensor plausibility checks are just a few examples of diagnostics that require the ECM to drive the mixture specifically to test that the engine is operating properly. Another IS that it cannot operate in closed loop fuel control mode if the commanded mixture isn't EQ Ratio 1.0. The fuel trimming system is designed to detect deviations in actual engine performance vs predicted engine performance, and provide a feedback-based correction mechanism. One more is that the TWC (catalytic converters) cannot operate properly while closed loop fuel control is disabled, and the vehicle would produce emissions in excess of the limits allowed by the US EPA and CARB. And last, running the engine at leaner-than-stoichmetric fuel ratios would cause combustion chamber temperatures to rise. Direct injected (DI) engines are already prone to a phenomenon called “stochastic pre ignition” (SPI) in which the fuel charge ignites too early. While the LF3 and LF4 seem to be relatively immune to SPI, it has been known to cause pistons to break between the ring lands on other GM turbo engines. The likelihood of an SPI event occurring would be increased by both increased combustion chamber temperatures and running a leaner mixture. A lopsided trade-off between benefit and concern As stated in the introduction, we won't be offering “Lean Cruise” on our products because we don't feel the trade-off between benefit and concern is a good one – largely because we have failed to find any substantial benefits at all. We have experimented with mimicking “Lean Cruise” in the newer engines and we haven't found any substantial fuel economy gains. We can't speak for claims that others are making but when we measured actual fuel consumption changes, the improvements were within the range of statistical noise. And this makes sense: when you consider the largest benefit “Lean Cruise” offers is reduction of pumping losses, the LF4's engine design itself (smaller displacement, turbocharged, independent VVT) does far more than “Lean Cruise” did back in the LS1 days. We'd also challenge anyone who is using a “Lean Cruise” tune to check actual MPGs versus what is reported on the instrument cluster. If a modern “Lean Cruise” implementation is reliant on trickery, it stands to reason this would skew the ECM's ability to estimate the fuel economy as well. Having said all of this, aftermarket engine calibration remapping is a dynamic process. We continuously challenge our previous notions in the light of what we learn along the way. It is possible one day we will make a discovery that changes the trade-off between benefit and concern.

The Sonic cousin: Buick Encore / Chevrolet Trax In a quest like this, the first thing to do is figure out which parts can be borrowed from other vehicles that have the feature you want. It turns out the Chevrolet Sonic, Chevrolet Trax, and Buick Encore all share something in common: the chassis. Known as the GM “Gamma II” chassis, it started in the US in 2010 as the Chevrolet Spark. In 2011 the Chevrolet Aveo was introduced. In 2012, the Aveo was renamed as Sonic, and in 2013 the Buick Encore and Chevrolet Trax were introduced with optional AWD. The Sonic, Encore and Trax use the 1.4L turbo MPFI engine (RPO: LUJ/LUV). Borrowing the AWD System For our project, we obtained a 2015 Chevrolet Sonic RS and an AWD Chevrolet Trax. The Chevrolet Trax has a transverse mounted 1.4L turbo engine, mated to a 6 speed automatic transmission. A transfer case attached to the transmission sends power to a rear differential via a propeller shaft. An ECU (Rear Differential Clutch Control Module) controls the amout of torque transferred from the propeller shaft to the rear differential. Not as easy as it Sounds Given these vehicles are all “Gamma II” chassis vehicles, we just need to unbolt the AWD system from the Trax and install it in the Sonic, right? Not quite. To name just a few challenges: We had to cut the spare tire well out of the Sonic to make room for the rear differential. We had to swap the rear suspension from the Trax in its entirety because the Sonic suspension doesn't have a provision for the propeller shaft. The propeller shaft will need to be shortened. Maybe a Rally Spec car instead of a Hot Hatch One other issue we've run into so far, is that the Trax suspension sits higher than the Sonic suspension. The overall ride height will be about 1.5” higher than the original suspension. Maybe we should make this into a Rally spec car instead of a Hot Hatch!

Control your Boost Turbocharged engines rely one of a few different methods of controlling the boost level. Most modern-day gasoline engines rely on a “wastegate”, while diesel engines generally rely on Variable Geometry Turbochargers (VGT). In both cases, boost pressure and airflow is the result of engine exhaust gasses passing through the turbine of the turbocharger, of which the compressor shares a common shaft. Hence, turbine acceleration causes compressor acceleration which causes boost pressure and airflow to rise. With a wastegated turbocharger, the turbine and compressor speed are controlled by allowing a variable amount of engine exhaust gasses to bypass the turbine. With a VGT, the angle and shape of the turbine vanes can be changed on the fly, which affects the speed of both the turbine and compressor. VGTs are considered to be more efficient as the turbocharger's mechanical characteristics can effectively be changed, on the fly. (As an aside, the reason VGTs aren't prevalent on gasoline engines is because the exhaust temperatures tend to be much higher, although materials technology has caught up and VGTs are slowly making their way into high end gasoline engined vehicles like the Koenigsegg One:1) Wastegated Turbochargers The remainder of this article will focus on wastegated turbochargers (specifically internally wastegated turbochargers), since that is the type that is used in on the 1.4L turbocharged engine. In the age before Electronic Control Unit (ECU) controlled engines, the original wastegated turbochargers used a purely mechanical approach to controlling the boost. A calibrated “wastegate actuator” (WGA) would use spring pressure to hold the wastegate “default-closed”. Exhaust pressure levels “pre-turbine” (in other words, the exhaust pressure between the exhaust port and the “front side” of the turbine) rise in accordance with boost levels, and once there is sufficient pressure on the wastegate to overcome the spring weight in the WGA (sometimes called the cracking pressure), the wastegate will start to open and allow exhaust to bypass the turbine. This regulates boost pressure and airflow. LUJ/LUV Turbocharger turbine and internal wastegate (wastegate closed) LUJ/LUV Turbocharger turbine and internal wastegate (wastegate open) In the age of purely mechanical wastegates, it was relatively easy to increase boost levels beyond OE design specifications – all one had to do is install a heavier spring in the WGA, and the cracking pressure would increase, which would cause the turbine to spin faster, which in turn would cause the compressor to spin faster and compress more air. Of course, fueling and ignition advance curves would have to be modified, not to mention charge cooling systems as increasing the boost would also increase the amount of heat generated from compressing the incoming air. ECU Control – A Twist on Mechanical Wastegates When ECUs started managing engine operation, engineers had to come up with a method that would allow the boost to be regulated electronically, and, additionally through a closed-loop feedback system that would allow the ECU to compensate for changes in environment (air temperature, altitude, fuel quality) as well as changes to the engine operation as it wore mechanically. The earliest turbocharged engines from General Motors utilized a similar WGA as was from the mechanical days, with a twist: the addition of a pressure reference port which could effectively lower the WGA cracking pressure by applying pressurized air. LUJ/LUV Wastegate Actuator (WGA) In this system, there is also a boost control solenoid (BCS) which is essentially like an electronic diverter valve. By providing a Pulse Width Modulated (PWM) signal from the ECU, the ECU can control how much of the boost pressure coming from the compressor is allowed to be directed to the WGA. On General Motors vehicles, the usable PWM duty cycle range is 5% to 95%, where 5% causes the maximum amount of boost pressure to be directed to WGA, and 95% causes minimal amount of the boost pressure to be directed to the WGA. In other words, when the BCS command is 5%, the lowest amount of boost will be produced, and when it is 95%, the highest amount of boost will be produced. The following pictures show the BCS on the LUJ/LUV engine: LUJ/LUV Boost Control Solenoid (BCS) The ECU determines the “desired boost” level based on myriad decision inputs, including calibrated power limits, calibrated powertrain component limits (e.g. maximum turbocharger compressor speed), driver power demand, altitude, incoming air temperature, amount of historical knock, just to name a few. Once the ECU makes a decision on the boost level, it references a calibrated table to decide how much duty cycle should be output to the BCS, and drives (commands) the BCS to that duty cycle. The ECU then monitors incoming air mass via the Mass Air Flow (MAF) sensor, the intake Manifold Absolute Pressure (MAP) sensor, the Throttle Inlet Absolute Pressure (TIAP, or “boost”) sensor, and several Intake Air Temperature (IAT) sensors to determine if the turbocharger is operating as desired. If the actual boost level is lower than the desired boost level, this is considered an “underboost” condition and the ECU will make some dynamic increases to the BCS signal to try to correct the condition. If the actual boost level is higher than the desired boost level, this is considered an “overboost” condition and the ECU will dynamically reduce the BCS signal to try to correct the condition. In an overboost condition, it may take further, more drastic measures depending on the severity of the condition such as shutting down boost entirely, closing the throttle blade, or opening the bypass valve. This is done to protect the engine and its components (more on these conditions later). The ECU employs a Proportional-Integral-Derivative controller (PID controller) strategy to both immediately correct boost control errors, and also correct predicted future boost control errors. This is the “closed loop” portion of the system. The parameters of this system are part of the ECU calibration and can be modified as needed. This article won't go into depth regarding how a PID controller works, but there's a great reference on Wikipedia (https://en.wikipedia.org/wiki/PID_controller) that describes both the method and the mathematics behind it. Advancements in ECU Turbocharger Controls Since the original boost control system design on General Motor vehicles, two variants have come along. The first is used on the twin turbo V6 engines (RPO: LF3, LF4 and LGW). The system works very similarly to the “default closed” systems originally used, but in this case, the wastegates are “default open”. Mechanical spring pressure holds the wastegate open until boost is required. The advantage with this system is it allows for more efficient engine operation. If you consider the “default closed” system design, one drawback is the exhaust gasses are ALWAYS flowing through the turbine. Even under light duty, even where no boost is requested by the ECU, the exhaust still flows through the turbine, and the turbine still acts as an exhaust restriction, which reduces efficiency. The only way the wastegate can be opened is for the mechanical spring pressure to be exceeded, which can only happen when there's sufficient boost. The “default open” design aims to resolve this shortcoming. Instead of using positive pressure (boost) to control the WGA, negative pressure (vacuum) is used. When the WGA is subjected to atmospheric pressure, the wastegate is fully open. As the pressure supplied to the WGA drops, it starts to pull against a spring inside the WGA to close the wastegate. The negative pressure is generated by a mechanical pump driven by an engine component, and is controlled using a BCS which directs a controlled amount of vacuum to the WGA. It is essentially the inverse of the “default closed” system design. LF3 turbocharger with “default open” wastegate design This system is not without its drawbacks, however. It's significantly more complicated than the “default closed” system design because it relies on a system of vacuum pumps, lines and solenoids to control the turbocharger. Another interesting issue that has arisen on this system is the turbochargers can be noisy. The wastegate valve itself is a floating valve attached to the wastegate actuator arm. When the wastegates are open, they have a tendency to create an annoying rattling sound, and because the aim of the design was to keep the wastegates open under low power levels and at idle, the sound can be easily heard. General Motors even revised the turbocharger assembly several times in order to correct the problem. This cannot be an issue on “default closed” systems because the wastegate valve would be held against the wastegate orifice under these light load and idle conditions. But, on the very newest turbocharged engines General Motors is producing, such as the new 2.0L turbocharged engine (RPO:LSY), its larger 2.7L cousin (RPO: L3B), and the new 4.2L twin turbo V8 engine (RPO: LTA a.k.a. “Blackwing”), there's an exciting new technology being used! Doing away entirely with all of the pressure-based controls, the ECU now simply drives what is essentially the equivalent of a throttle blade actuator which directly drives the wastegate position. It also uses the “default open” design to improve efficiency. The aftermarket has not yet delved into calibrating any of these engines, so little is known about how effective this new solution is. Limitations with the Gen 1 1.4L Turbo Engine Wastegate System Now, we will discuss the specific issues with the LUJ/LUV engine turbocharger's wastegate system. The main issue we have observed is there can be quite a variance in the cracking pressure of the OE WGA assembly. Based on our years of experience in calibrating these vehicles, we can say that on average, a safe assumption is that the highest boost level that can be had on the OE WGA assembly, at sea level is around 20-22psi of boost. However, we've have also seen OE WGA assemblies that will support more than 25-26psi of boost. Our assumption is that because these vehicles, in stock form were never designed to make these kinds of boost levels, perhaps the manufacturing tolerances in the OE WGA is somewhat lax. When calibrating customer vehicles, however, we have to start with the lowest common demoninator or else our customers could end up with boost control diagnostic failures and subsequent “boost limp mode”. Collection of LUJ/LUV WGAs that all have different cracking pressures Adjusting OE WGA “Preload” a.k.a. “Playing With Fire” One of the classic (or perhaps “infamous”) techniques for changing boost levels (particularly before boost levels were managed by an ECU) was to adjust the length of the rod from the WGA to the wastegate arm. The original intent of using an adjustable rod length was to allow calibration of the wastegate but hot-rodders quickly figured out if they shortened the length of the rod, they could either restrict the amount the wastegate could open, or otherwise cause the cracking pressure to go higher (because of the additional preload on the spring). On the LUJ/LUV engine, indeed an adjustable length threaded rod is used between the WGA and the wastegate, but the factory attempts to prevent tampering by using some sort of locking compound on the threads. This isn't enough to stop a dedicated tinkerer, but we wholly recommend AGAINST modifying the length of this arm for the simple reason that it can cause the turbocharger to overspin which leads to either a failed turbocharger assembly, or a failed engine. LUJ/LUV WGA showing tamper-resistent compound on actuator arm adjustment Additionally, changing the WGA rod length will have no effect on the boost potential without corresponding tuning changes because the ECU will detect there's more boost than expected and simply respond by either commanding less BCS duty cycle, or closing the throttle. Introducing the Forge Billet WGA for the LUJ/LUV Forge is an aftermarket UK company that specializes in engineering and manufacturing aftermarket WGAs (among many other parts). They have developed a billet aluminum WGA for the LUJ/LUV engine (Forge part number FMACC14T). One of the fascinating features of their part is the mechanical cracking pressure can be adjusted through the use of interchangible springs. Through our testing process, we found their part to be incredibly consistent from unit to unit (unlike the OE WGA) and of high quality. Forge Motorsport FMACC14T w/ “Yellow” spring pre-installed When you purchase this WGA from Forge, off the shelf it includes a “green” spring pre-installed in the WGA. We found this spring to be too “light” - in other words, the cracking pressure was actually LOWER than the OE WGA. We tested the next heavier spring, which is the “yellow” spring, and found it to be a suitable choice for the LUJ/LUV in that it allows boost pressures to reach the potential of the engine and OE turbocharger closely. We could have, of course, chosen an even heavier spring (such as the “red” spring). However, there is a trade-off using a heavier spring that needs to be recognized. Not only does the heavier spring weight raise the cracking pressure of the wastegate (e.g. the MAXIMUM potential boost level), but it also, in effect, raises the MINIMUM pressure that can be made from the turbocharger when 100% of the pressure is being sent to the WGA (e.g. 5% duty cycle). The OE WGA has a minimum of around 5psi of boost, but the Forge WGA with the “yellow” spring is closer to 12psi. We chose the “yellow” spring because it's the lightest spring that can allow the maximum boost potential to be reached which in turn raises the mininum boost by the lowest amount possible. If the minimum boost level is raised too far, it can cause a clunky driving experience, because the ECU will have to manage the torque by closing the throttle blade instead of being able to open the wastegate. Forge Motorsport WGA installed on LUJ/LUV turbocharger So, what about the power? We recently performed a series of tests on one of our development vehicles. It is a 2016 Chevrolet Sonic LT, with the LUV engine, and a manual transmission. It has the following modifications: 60 lb/hr fuel injectors RacerX cold air intake SPEC billet aluminum flywheel WaveTrac Limited Slip Differential (LSD) TRIFECTA calibration Out of the LUJ/LUV vehicles we have at our disposal, this one was closest to stock configuration, and the few modifications it does have would not materially affect the power output, except for perhaps the flywheel. As expected, on the stock calibration (adjusted for the 60 lb/hr fuel injectors), this vehicle baselined at fairly high numbers on our dyno: Peak power output was 135 horsepower (HP) at the wheels (WHP), and 151 lb-ft torque (TQ) at the wheels (WTQ). Considering this vehicle is rated at 139HP / 149TQ at the flywheel from the factory, it would seem indeed the aluminum flywheel had a positive impact on power output for this vehicle. TRIFECTA Calibration with the OE WGA As started above, we consider 22psi (at sea level) to be the highest boost level that can be achieved on the OE WGA. This dyno chart shows what 22psi on this vehicle produced versus the OE calibration: Under these test conditions, PEAK gains went up by approximately 26WHP and 47WTQ. However, particularly with horsepower levels after the curve, gains are much higher than 26WHP – e.g. at 6300 RPM, the gains are closer to 45WHP. High RPM power delivery holds much further into the high RPM range than on the OE calibration. TRIFECTA Calibration with the Forge WGA and “Yellow” Spring Finally, we tested the vehicle and calibrated it to its full potential with the Forge WGA. Observe the following dyno chart: Versus the OE WGA, we gained another 17WHP, and a whopping 33WTQ! The torque gains are so impressive because this engine can really utilize boost levels higher than 22psi at the low to mid RPM range. Choosing some key RPM points, the following table summarizes the gains that were possible with just tuning and the Forge WGA: 3500 RPM 5500 RPM 6000 RPM 6300 RPM OE WGA / Calibration 146WTQ 133WHP 123WHP 115WHP OE WGA / TRIFECTA (22psi) 190WTQ(+44) 155WHP(+22) 143WHP(+20) 141WHP(+26) Forge WGA / TRIFECTA 229WTQ(+39/+83 total) 166WHP(+11/+33 total) 157WHP(+13/+33 total) 156WHP(+15/+41 total) More than just Power Believe it or not, the vast majority of calibration work required to make the Forge WGA work correctly has nothing to do with getting the big power gains. Because the turbocharger response from the BCS was dramatically altered with the installation of this part, we needed to start from scratch in dialing in the BCS table and the other PID controller constructs. We've spent about a week of total time on the dyno with various LUJ/LUV vehicles just getting everything mapped correctly. Without proper calibration work, people installing this sort of part are likely to have sporadic, or even common issues with “boost limp mode”. This is where the ECU detects that there's been an ongoing boost control problem for long enough that it shuts down the boost control system entirely. This results in a maximum boost level of about 12psi (or 5psi on the OE actuator) and a very powerless vehicle! - TRIFECTA Performance

TRIFECTA Exclusive Driver Selectable Vehicle Modes (DSVM) One of the earliest exclusive TRIFECTA product features is DSVM, formerly known as Select-A-Tune (SAT). Taking root in the days of the first 2.0L turbo DI engine GM built (RPO: LNF), SAT was a feature designed to give the driver dynamic control over the vehicle's power output. This feature was a very popular distinguishing feature of the TRIFECTA calibration. Over time it evolved into DSVM by name, and has been implemented in most vehicles that TRIFECTA offers a calibration for. DSVM and SAT are exclusive because they rely on the specific software that doesn't exist in the OE software. Some vehicles have OE DSVM-like capabilities, such as the 2014-2019 Chevrolet Corvette, but many other vehicles do not. Buick Regal GS and Sport buttons TRIFECTA has always been interested in whether either (or both) the GS and/or Sport buttons found in the Buick Regal could be tapped into to change the engine's dynamics on the fly. After some amount of research we determined that these buttons can in fact be used to select alternate automatic transmission shift profiles, but selecting alternate performance envelopes and pedal response maps seemed to not be possible with the OE software. Bringing DSVM to your Buick Regal GS and Sport button TRIFECTA is proud to announce we are opening a limited beta program for existing and future TRIFECTA customers that would be interested in being able to change the power and drivability dynamic of their Buick Regal on the fly with the GS and/or Sport button! If you have a 2014 Buick Regal, or a 2015 Buick Regal with either (or both) the GS and/or Sport button, and you would like to try this new feature, please contact us via our support system and request the “Buick Regal DSVM Beta test” and let us know which button(s) your vehicle is equipped with! Our engineers will put together a beta test calibration for you, and post it to your download page. After that you can install it, and provide feedback on how you like the drive modes! Contact Us!