Installing and Tuning the AEM Infinity EMS – Honda S2000


Time to get ready to start the car up.  You can simply go to AEM's technical support web site and download a base map for your car.  This takes care of the sometimes tricky things to figure out like cranking enrichment and warm up curves.  The base map at least gets you in the ballpark.
Tony has bigger power plans coming together in the near future so he has installed and wired some switches for map selection and traction control trim.
Once we got the car started which only took a few minutes, it was time to strap it down and do some tuning.
The first thing we tweaked off the base map was the VE table or tables in the case of this car. To get the fastest possible response with the least lag during VTEC switch over the car runs two maps, one for the high rpm cam lobe and one for the low rpm cam lobe.  The maps are switched at the set VTEC switchover point.
The high and low cam VE tables are shown here. When tuning you tweak the VE or volumetric efficiency maps so you can reach your target lambda or air fuel ratio with minimal correction from the EMS.  A good trick is to tweak your VE table for a lambda correction of around 0.02.  That way if you have a problem with your wideband, it will failsafe slightly rich.  In the lower left part of the screenshot you can see the datalog of target vs set lambda.  VE based load calculation is more accurate than stuff like Alpha N or Speed Density as it is not as prone to errors due to changes in conditions or the engine's state of tune.
Here is your target lambda table.  This is the air fuel ratio that the Infinity EMS will try to maintain.  Having this table is a lot more straightforward than going by injector pulse width.  Again the lower graph shows the target lambda against actual.  You can set lambda correction limits which is important in case you have an O2 sensor failure or develop an exhaust leak ahead of the sensor during a race.
The ignition map is pretty straightforward.  What is notable is how much ignition advance the Honda F series engine likes on over run.  Maybe this is a strategy to cool things down?  Also of note is that you can change the break points of all of the maps to gain more resolution in areas that you might feel the need to have it.  


  1. Hey, I just came across this article while trying to setup my own Infinity on my S2000. How are you switching maps with VTEC activation? The user manual for the infinity is kind of vague on that point. I see you have separate VE tables. Do you also have separate lambda maps and ignition maps? Thanks for any input and guidance you may have.

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