Hello guys, I noticed not many people know how to set the VTEC window in Kpro, or understand how it even works. We just set it to where we want to and go with it. So here's a lil guide on how it works. It's easy!

Here is our Parameters window and Table. The VTEC window settings use Kpa to determine where to set the threshold, so I changed the way the table displays to coincide with the settings.

Basicallly, if you didn't already know, the Kpro ecu uses the Speed-Density method to determine how much air is flowing through the intake manifold, and the O2 sensor is used in closed loop mode to correct it. This means the computer is guessing at how much air is going into the cylinders and all it's using Manifold Absolute Pressure (MAP sensor!) to determine where on the fuel table it is at, and that dictates how much fuel is going in the engine.

What that means right now is the Kpa numbers are just a measurement of vacuum/boost, and for the purpose of this instructional, that's all we need to know. The higher the Kpa, the higher the pressure is in the manifold, ie, the harder you step on the gas, the higher the manifold pressure (from absolute vacuum, to atmospheric for NA guys).

So, notice the first threshold settings, 3800 RPMs and 96 Kpa, lets draw a line on the table to demonstrate how this works...

Pretty simple right? What this means is any pressure above 96 Kpa (pretty much WOT) AND above 3800 RPMs will put you in VTEC.

Now lets look at the second settings, 5500 RPMs and 30 Kpa. Lets draw more lines.

Well look at that, a WINDOW!
What this means is at 30 Kpa, which is with almost the throttle closed, and over 5500rpms, you will be in VTEC, this is your partial throttle VTEC setting.

So we made this nice lil window right? Lets draw another line that connects those 2 thresholds...

This line represents the variable VTEC threshold that could occur anywhere between those 2 settings. If you were able to see the tracer on Kmanager move through the Kpa and RPMs, as soo as it crossed that line you would be in VTEC. What this means is if you were cruising at about 4200 RPMs, you would not be in VTEC, but as soon as you stepped on it and the manifold pressure crossed that line, you would get VTEC.

So lets clean up this table and show you where you would, and would not be, in VTEC.

This is how the ECU determines when you cross into VTEC, lower boundary is always where WOT VTEC occurs, and upper is where it would be if you were just partial throttling through traffic or something.

In the tuning world, you would set the lower boundary where the low speed cam and the high speed cam (primary and vtec, respectively) cross in power on a Dyno. This setting can be different depending on how you built your engine. Honda typically sets VTEC a little higher so you can FEEL it, a sales gimmick to show you that the technology exists. Nothing more, nothing less. You wont feel a "kick" when you have a properly set VTEC threshold.