The ability to manipulate the brains behind Porsche's 996 and 997 chassis is about as old as 1999's totally revised 911 itself. Like any automaker that's got to concede to legions of emissions regulations and safety appeasements, both cars' electronic control modules allow room for improvement. That is, if you're the kind of person who thinks more power and better drivability make life better.
AEM Infinity E46 M3 Standalone Programmable ECU
| A 996 Turbo and 997 GT2 Infinity-equipped pair tucked away at Laguna Niguel, California's Vision Motorsports. The 996 incorporates its original MAF sensor, which allows for VE-based tuning; however, the GT2 is producing upwards of 650 whp and now features a speed density-based system.
Want to turn up the boost pressure and keep the engine's air/fuel ratio happy? There's hardware for that. Not satisfied with the factory rev-limit? That and a whole lot more can also be changed. But you already knew that. As it turns out, just about anything can be fiddled with. All you need is access to all sorts of expensive equipment and, until recently, the wherewithal to hack into your computer every time a change has got to be made.
| The Infinity system is made up of the ECU itself, an available plug-and-play sub-harness, and an adapter box that communicates with the cars' CAN bus systems.
We're talking about reflashing, which, until not that long ago was about the only thing standing between you, a bone-stock computer, and a complicated, standalone engine management system that typically meant all sorts of sensors would have to be swapped and complex wiring surgery would have to be performed.
Not anymore. And that’s partly because of AEM’s Infinity EMS. AEM’s famous for it’s plug-and-play engine management solutions for all sorts of makes, and now offers systems for Porsche’s 996 and 997 Turbo models with manual transmissions. The company, which began life as a tuning shop in SoCal in 1987, later culminated into the maker of all sorts of indispensable tuning wares, like adjustable camshaft gears and intake systems designed to draw fresh air from outside of the engine bay. Today, the Hawthorne, California-based company is famous for its electronics.
| AEM makes its plug-and-play applications in chassis-specific enclosures that mount in the factory ECU's original location.
INFINITY VS. THE REFLASH
For the guy searching for a moderate power bump on the same car that he schleps back and forth to work, a reflashed ECU makes a whole lot of sense. Most developers offer software upgrades that'll give him exactly what he needs, allow him to pass an emissions test, and never let a Honda Civic with an engine swap come close to embarrassing him. Except that's part of the problem. A reflashed ECU will give him exactly what he needs, today, sure, so long as the mechanical underpinnings of the twin-turbo, 3.6L powerplant he's got aren't switched up too much. Upgrade those turbos, for example, and it's back to the reflash guy for new software.
| Speed density-based systems that do away with the factory MAF sensor are often employed when searching for significant power gains. Here, the GT2's turbos have been upgraded for larger units and the bottom end is made up of forged internals. AEM's Infinity is suited for higher-end applications like this, as well as entry-level engine programs that retain many of the stock components, if not all of them.
SETTING IT UP
AEM's done more than just about anybody to make the process of integrating a stand-alone engine management system into so many late-model chassis less threatening. It should be noted that less threatening does not necessarily mean street legal though, as the Infinity is legal only on racing vehicles in CA and CA-emission compliant states. Elsewhere, it’s best to check your state laws before considering adding one to your car.
| AEM's Infinity software includes VE-based tuning tables (left) that decrease setup time and make changes as easy as setting a target air/fuel ratio and watching what happens. Most other systems are based off of slightly more complex injector pulse-width characteristics (right).
Compatibility with every last one of the 996 and 997 turbo's applicable sensors is mostly to blame for that along with sub-harnesses that plug directly into, for example, the chassis' wiring harnesses and CAN bus connectors with nary a splice or drip of solder. Until now, integrating a stand-alone engine management system into the Porsche's CAN bus system meant having to deal with all sorts of seemingly unrelated ancillaries, like dashboard electronics, A/C, power windows, and door locks. Mess up what you thought was wiring that led to an oxygen sensor, for example, and your satellite radio might go out of commission.
The fully-sealed Infinity can be mounted anywhere, but AEM designed the case to fit in the factory ECU’s original location. The party starts by gaining access to the factory computer and its five connectors, which plug directly into AEM’s adapter box that sorts out CAN bus duties. A sub-harness connects the adapter box to the Infinity, which can be connected to a laptop to load the firmware and available base map. All that’s left is to turn over the ignition and drive it or open up the software and start making adjustments.
| All sorts of information can be logged directly to a laptop, which can speed up tuning time and reveal exactly what's going on at any given point.
WHAT IT DOES
The Infinity’s ability to adjust all sorts of parameters in search of a whole lot more power is comprehensive but, even without so much as a single tap of the keyboard, improvements are there. According to the people at AEM, that’s because of the Infinity’s 32-bit, 200MHz processor and real-time operating system. Laguna Niguel, California’s Vision Motorsports helped confirm all of this, performing back-to-back dyno pulls on a 2001 996 Turbo with no changes made beyond the addition of the Infinity and its pre-loaded base map. Here, nearly 7 whp were uncovered, all before AEM’s InfinityTuner software had even been massaged.
| All of the engine's sensors and parameters can be easily set up or modified through the InfinityTuner software's setup menus.
But nobody here’s interested in parting ways with just south of $4,900 for a measly 7 whp and without ever delving into the software. That is, after all, what separates systems like the Infinity from a reflash. Aside from its processing speed, the Infinity’s ability to adjust air/fuel ratios based upon the engine’s volumetric efficiency on MAP-based applications is one of its most notable characteristics (the Infinity Porsche 997/996 PNP application retains the factory MAF-based system though, so no MAP sensor is required). As opposed to more conventional injector pulse-width-based tuning systems where all sorts of variables have got to be pinpointed before tuning can even begin, VE-based tuning requires very little information up front beyond the engine’s approximate airflow characteristics and what air/fuel ratio you’d like to arrive at. Go ahead and tell the Infinity the desired air/fuel ratio, and watch it adjust its tables to suggested values that you can either continue to tweak or leave alone. In other words, VE-based tuning tells the fuel injectors what to do instead of you telling the ECU what they’re supposed to do. That means tuning’s now gotten a whole lot easier for everyone.
| Expect small gains even with AEM's start-up base map. The Infinity's ultra-fast, 32-bit, 200MHz processor and real-time operating system mean operations happen quickly, resulting in gains like these, especially when compared to other slower stand-alone engine management systems.
Unlike most reflashes that don’t allow toggling back and forth between different states of tune or stand-alone systems that require a separately wired and mounted ancillary switch to do so, the Infinity features built-in map switching that, because of AEM’s integration with Porsche’s CAN bus system, can be selected through the factory cruise control buttons on the fly. Here, eight different states of tune can be selected right from the steering wheel, allowing for dramatic changes in engine performance, octane type, and more, depending on the circumstances and any previous tunes that may’ve been saved. Mode changes are confirmed at the tachometer where the needle briefly indicates, in increments of RPM, which tune has been selected. For example, a quick flip of the needle to 2,000 rpm means mode two has been chosen.
The Infinity includes all sorts of ways to extract an engine’s full potential, but it also includes all sorts of ways of getting that done without blowing anything to smithereens. Its built-in knock-sensing capabilities are part of that. Here, the engine’s original sensors are retained, however, what happens once pre-ignition is detected is entirely up to you. Decrease boost pressure or ignition timing, add fuel, or make just about any other change you see fit should detonation begin to rear its ugly mug. Other failsafes include over-boost and lean protection, and with the appropriate sensors from AEM that communicate with the ECU through the provided expansion port, oil pressure, coolant temperature, and fuel pressure protection. Set up the parameters, and if trouble happens, the Infinity will immediately adjust the fuel supply, limit engine speed, or cut ignition timing, depending on what exactly is going on.
| A few minutes later and a little more boost is all it takes to safely generate another 60 whp.
But melted pistons and broken ring lands will never be as glamorous as complete VarioCam Plus control, built-in traction control, and the ability to calibrate drive-by-wire throttle controls to behave however you’d like. Which is exactly what the Infinity’s capable of. Here, the ECU monitors wheel speed using existing ABS sensors and, depending upon the rate of speed from one wheel to the next, adjusts power accordingly by limiting ignition timing, fuel, or throttle angle. Turn it on or off, again, using the factory cruise control buttons. AEM’s drive-by-wire controls are even more impressive, allowing complete behavior control from pedal to throttle—something no reflash is capable of. Adjust the throttle curve and response rate however you’d like and, for endurance racers, for example, limiting power based upon throttle movement is easy and safe.
WHAT YOU GET
Buying AEM’s Infinity now means not paying for a whole bunch of add-ons later. The system includes built-in wideband oxygen sensor controllers that you would’ve needed anyways for fine tuning, data-logging capabilities that mean you won’t need a recordable dash, as well as boost control and traction control capabilities that eliminate at least two other bits of hardware that you already wanted. All of a sudden, the Infinity seems affordable, especially when considering some of the other stand-alone systems often used on the 996 and 997. It’s also compatible with both chassis’ MAF sensors and electronic bypass valves as well as the 996’s boost solenoid, and is fully compatible with the 997’s variable-geometry turbos. By the time you read this, AEM will have likely released the NA version for the 997 too.
The ability to fine tune Porsche's 996 and 997 chassis' electrical hardware for better performance is nothing new. But the way in which all of that can be done has been forever changed.