Tuning: Charting the Map!

After some teething issues I finally found out why the car wouldn't start! It was because of the increased size of the intake that the MAF sensor was now mounted on.

So before we go and adjust the MAF map, let's have a look at plotting a tuning course by checking out some basic maps!

Okay! Before we begin, I just wanna let you all know that the stuffs I'll go through is quite generic and will need to be tailored to your application. Don't forget to read and fully understand the AEM FIC manual! It outlines all the fundamentals!! So go and read that noa!!!

Also, if you have some ideas of your own, please comment and share so we can all broaden our knowledge!

Cool! First off, on the X-axis, map out the break points for your monster's RPM. So put the minimum RPM on the left hand side and set a maximum RPM on the right hand (but also allow for over engine speed, so you can tune for that). You can either manually set each individual RPM break point or simply highlight the cells, right-click and in the context menu select "calculate". This will automatically calculate and distribute the values from the minimum and maximum you set earlier. Pretty useful feature!

Alright! We need to get our bearings before we can plot out our map! You need to know the transition between vacuum and boost, this will determine the scale of your load axis (i.e. boost/MAP). Remember, the AEM FIC reads in absolute pressure so don't put in zero as the transition break point! To determine the transition break point simply connect up the FIC, put your car in accessories but don't start it! Check out the reading on the boost gauge, that will be your current absolute atmospheric pressure.

For me it's about 15 psia (the "a" after psi is absolute). Atmospheric pressure varies depending on your elevation in the world, so make sure you have the right one for you!

Now, if I had a Naturally Aspirated (NA) motor, at wide-open throttle, the maximum pressure that would be read from the MAP sensor would be 15 psia.

For a turbo motor, as the pressure approaches 15 psia, the turbo is spooling up and begins to make boost when the pressure exceeds 15 psia.

Now because you only have a finite amount of cells, you want to maximise the resolution and number of cells you can tune. For a NA tuning map, it may look like the following:

Note that this basically applies to all your maps (ignition, fuel, MAF, O2, analogue). At the red arrow you would want to put your current absolute atmospheric pressure. This is basically the transition point between vacuum and boost. You can change the Y/X-axis values by double clicking on them.

By setting up your NA map sorta like the above, it maximises the number of cells you can tune under vacuum and give you lots of load break points (Y-axis) thereby increasing your resolution. There is also an atmospheric "boost" buffer, should you drive closer to sea level, where you may even see increases in atmospheric pressure, so you should account for that.

Now for a turbo map, it's almost the opposite. You want to have lots of cells for the boosted sectors but also have enough cells in the vacuum portion so you can tune non-boost driving, which is pretty much most of the time (e.g. cruising). You may set it up sorta like this:

Here, I allowed three break points (0, 5 and 10 psia on the Y-axis) to tune vacuum or non-boost mode and allowed a crap tonne of cells for boost mode. The more cells you have, the more resolution you can put and the finer you can tune.

By resolution, I mean, the number of break points you can have. For example, if you have 5 break points, you can only put in, say 5, 10, 15, 20, 25. But if you have a higher resolution, say 10 break points, you can split it up to more finer points; 2.5, 5, 7.5, 10, 12.5, 15, 17.5, 20, 22.5, 25. Now you have more numbers to play with and tune at finer points.

I like to have lots of break points for the boosted section so I can pin point rich/lean spots more easier and tune to a finer degree.

So then when you begin to map out your boost map, it may look like something like this:

As the motor's RPM increases, boost may start to be produced at say, 1,400 RPM and say max boost occurs at maybe at 5,250 RPM. Additional variances are added at the higher boost and RPM values as things can get quite hairy at that end. Obviously, this varies from application to application so you'll need to tune accordingly. When you tune, you'll find that some patches of the map require more or less fuel/MAF/O2 etc so different cells may be adjusted. Not always you will get a smooth map so don't worry.

Also, you will find different parts of the map, your monster will pretty much never get to or very unlikely to reach. For example, the bunch of cells on the top left and bottom right of the map. No way you motor would get to max boost at 0-350 RPM; and no way it'll be in total vacuum at max RPM. Be prudent and put in conservative values anyway just in case something crazy happens!

Now, the AEM FIC software comes equipped with a feature to map out a basic map. Do try this and see if it works for you! It is a pretty good starting point! Check out the manual for further details!

Next we'll have a look at correcting that pesky MAF map that preventing the lil'monster from starting at Boostworx! So stay tuned!