AEM Performance Electronics Water Methanol Injection System Evaluation


In the past, when adjusting the onset of older systems, we had to resort to things like taping the water line to the windshield to see when in our driving cycle the pump would come on.  That was a pretty lame way to verify the operation but with early crude systems that was one of the simplest ways to check operation.

As a final safety measure and as a tuning aid, we added AEM’s optional flow gauge.  The flow gauge reads the actual water flow in cc’s per minute so you know exactly how much water the engine is getting.  Since we are using the medium size 315cc/min injector nozzle we selected the 0-500cc gauge for best resolution.  AEM sells a 0-500cc and a 0-1000cc gauge. The AEM gauge uses an inline flow meter to actually measure flow going to the engine.  In the past we had fitted water systems with pressure gauges but this was not entirely effective for detecting nozzles that were starting to clog because the system would still generate pressure, just a little more pressure.  The AEM gauge will actually tell you in real time what your flow rate is.

AEM water flow gauge
Bryan Kono of Afterhours Automotive built this very clean mount for our water flow meter.  We did not want a ricey and cop attracting pillar pod so Brian fabbed this up out of aluminum and powdercoated it satin gray. This fits the meter into our ash tray area, it’s cool because we don’t smoke or let anyone smoke in our car.  You can even easily put the ash tray back in.  The meter should be mandatory for any water injection system because it really aids tuning and is a great safety device.  It also has a 0-5 volt output so it can be data logged!

This real time flow rate is handy when tuning and to ensure everything is working properly.  The AEM flow gauge has some cool features like a 0-5 volt output for flow rate data logging, a full 320 degree needle sweep for high resolution, an overflow warning light in case of some sort of failure that causes too much flow like a line popping off or springing a leak and seven different display colors to match your interior instrument lights no matter what kind of car you have.  The AEM gauge will work on most water injection systems on the market.  Having messed around with water injection systems a lot I really appreciate this gauge.

For our initial evaluation, we set up the AEM Water/Methanol injection system on Project EVO IX to inject water only, beginning injection at 10 psi of boost and having the full water volume in by 20 psi.  We have our boost mapping set to spike at 24 psi and taper to 21 psi by redline so we would be getting the full volume of water through the rev range.  Our EVO is tuned using the stock ECU with ECU Flash and we do our logging via EVO Scan.  Our engine has really good oil, coolant and intercooling and we are tuned somewhat conservatively so most of our pulls have no to very little knock count.  We sometimes register a knock count of 4 if we do repeated pulls with heat soaking and most tuners agree that the EVO ECU starts to pull timing if the knock count exceeds 3 or so during any single period of wide open throttle operation.

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