Factory boosted engines like those from Audi, BMW, Jaguar, Mercedes-AMG, Porsche and VW constantly retard ignition timing under full throttle to battle hot intake air temperatures and poor fuel quality alike, all in efforts to reduce detonation. Whatever the cause of detonation, these issues have made water and methanol injection systems highly desirable in high performance boosted applications. First, methanol has an effective octane rating of 107--enough said. Second, the fine mist of water mixed into the system uses heat to evaporate, bringing down the intake charge temperature--thus, combustion temps--further reducing engine detonation. This allows the ECU to keep ignition timing optimal for peak performance.
In the April '09 issue we performed a methanol injection upgrade on an Audi A3 2.0T. The 12-hp gain we saw there was basically a 12-hp recovery from lost horsepower due to ignition retard from the factory software, over which we essentially had no control. In other words, with the injection system turned off, ignition retard resulting from either not having enough octane or high intake air temps--given AWE's software tune against knock--was costing us that 12 hp. As stated in that article, had the car not seen ignition retardation to begin with, the 2.0T wouldn't have seen the power gains it saw.
But what if you did have control over your software with a stand-alone engine management system, and the ability to increase timing when shooting methanol into the engine? Much like tuning for high-octane race fuel, this is where the benefits of a methanol injection system are maximized. To see how much more power we could safely extract, we took this supercharged E36 M3 with stock compression to our friends at Evosport, the well-known BMW tuner that specializes in forced induction.
Although there are a variety of systems available, Advanced Engine Management, AEM, recently released its own stand-alone water/methanol injection system. It features a dash-mounted indicator showing current system status and a low fluid warning, and comes with three different sized jets to match your power requirements. And while AEM reports no more than 50 percent methanol-to-water mixture should be used, we've heard reports of users running 100 percent methanol through the pump without worry.
Last, for cars capable of using it, the system also features AEM's Boost Safe, which lets you retard ignition timing or reduce boost if the system runs out of fluid or detects an error.
Since the car was already equipped with an Evosport/AEM fully programmable plug-and-play engine management system (EMS), Evosport, working in conjunction with tuning expert Gary Karamikian of GK Systems, was able to make full use of AEM's Boost Safe feature using a laptop.
The beauty of the system in this particular car is the way Evosport wired it, giving Karamikian total control through the AEM EMS. First, taking it several steps beyond AEM's boost-sensitive trigger, he programmed it to shoot methanol at a specified throttle position and RPM, as well as load, making sure it only comes on when really needed. Second, as long as the system doesn't detect a low level, a system error, and all the AEM EMS parameters for knock are met, Karamikian set the car to run a more aggressively tuned map with leaner fuel mixtures and 3 degrees more ignition. Testing revealed this combination still gave him the safe knock voltage he previously didn't want to exceed--essentially a non-detectable level.
1995 BMW M3
Engine: 3.0-liter I6, dohc, 24-valve
Transmission: Five-speed manual
Testing octane: 91