The Hondata K-Pro ECU
By Conrad H. Blickenstorfer ()
1. Introduction
1.1 What is the K-Pro ECU?
The K-Pro ECU is a specially modified Honda ECU with an USB interface to a notebook PC running Windows XP. It is currently available for the Acura RSX base model and Type-S, the US Civic Si and the Euro Civic Type R. K-Pro ECU Manager software allows the setting of cam angle, ignition advance, fuel, and a variety of other aspects. The purpose of the K-Pro ECU is to fine-tune the Honda ECU for best possible engine performance under various operating conditions and with various engine configurations.
1.2 Who should use it?
Anyone who wants to a) take full advantage of modifications, from simple bolt-ons to extensive engine work, by tuning the engine specifically for those modifications, b) monitor the engine via datalogging, and c) learn how numerous variables inside the engine relate to one another and how they are influenced by making changes to fuel delivery, ignition timing, cam angle settings and other variables.
The K-Pro is far more than just another performance modification. It is a tool to monitor and change the operation of the ECU which, in turn, monitors and orchestrates the operation of standard “conventional” modifications such as less restrictive air intakes, headers, intake manifolds, cams, exhaust systems, and even super and turbochargers.
Unlike those “passive” modifications, the K-Pro is an “active” modification. Its operation must be learned and understood. If used properly, the K-Pro is key to unlocking the true potential of a Honda engine. If not, it may become an incomprehensible source of frustration. It may even harm the engine if inappropriate changes are made and uploaded into the ECU. A prospective K-Pro user should therefore expect a learning curve. Those unfamiliar or unwilling to learn K-Pro operation and the principles behind it can still use the K-Pro to good advantage, but they should expect paying a tuner to tune the car properly. Tuning may be necessary not only to get the best possible performance, but also because the base K-Pro calibration may cause the engine to knock. That’s because unlike the Hondata reflashes which are safe one-size-fits-all maps, the K-Pro calibrations are much more aggressive because, after all, K-Pro users can always modify the calibrations to make them fit their engines.
Those willing to spend the time learning the K-Pro will find it an incredibly powerful tool for unlocking the true potential of their engines. Those do not feel up to it and do not want to foot the expense of having a professional tune their K-Pro can always resort to Hondata’s static ECU reflashes.
1.3Ordering Process
Your car’s ECU will have to be sent to Hondata’s facilityin Torrance, Californiabecause the ECU needs to be modified by Hondata. The modification requires actual soldering and other work on the Honda ECU. The upgrade needs to be ordered via a Hondata dealer as Hondata does not sell to the public directly. If you order from a local dealer, they may take the ECU out of your car and send it to Hondata, then reinstall it for you. You cannot use the car while the ECU is at Hondataunless the dealer lets you borrow a K-Pro ECU.
Even though the Acura RSX uses an immobilizer system that is keyed to the ECU, you do not need to send the immobilizer (a ring-shaped plastic contraption that wraps around the ignition key lock) and a car key (the car key has a transponder in it that communicates with the immobilizer) to Hondata as you do when you have your ECU reflashed by Hondata.
You can also order the K-Pro upgrade from a dealer that is not local. If you do it that way, the dealer will send you a box with a Fedex shipping label, the required paperwork for you to sign, and ECU removal instructions.
1.4 What you receive
I ordered my ECU upgrade via ClubRSX.com. They sent me a box via UPS. I sent my ECUvia Fedex to Hondata on Monday, March 29, 2004 and received the modified ECU back via Fedex from Hondata on Thursday morning, April 1. The package included:
-The modified ECU with a big Hondata sticker on it
-K-Pro Manager software and USB drivers on a CD
-Installation instructions
-My immobilizer and car key (I erroneously had sent those as well)
-A six-foot USB cable
-2 silver Hondata stickers
-A ECU board jumper for nitrous applications
The modifications included installation of a 1.75x4.5 inch Hondata-branded daughterboard. This required soldering a couple of connectors onto the motherboard. I analyzed the daughterboard because I was curious as to what it does. The two main chips on it are:
A Microchip ( PIC16F877A, which is a $5 20MHz 8-bit CMOS FLASH-based microcontroller (RISC CPU) that uses Microchip’s PIC architecture and has 35 single-word instructions. It is designed for automotive applications and can handle temperatures between -40 and 85 degrees Celsius. It has 14,336 bytes of program memory and is primarily used for analog to digital conversions.
A FTDI ( FT245BM chip, which is a USB FIFO device. FTDI specializes in converting legacy peripherals to USB. ECUs normally communicate to external OBD readers and other diagnostic tools via serial connection, so the FTDI chip probably enabled Hondata’s USB interface for much faster communication.
In addition, Hondata made a small cutout in the rear wall of the ECU housing to accommodate a standard USB connector.
As is usually the case with USB peripherals, the USB driver must be installed before the ECU is plugged in for the first time. After that, the ECU can be connected to the computer even if it is not in the car. The PC will then recognize it and install the proper driver. When it first came back, I simply connected the K-Pro ECU to my notebook and installed the USB driver. Then I put it back into its mounting bracket in the passenger footwell of the car and reconnected the various cables.
1.5Initial calibration and calibration libraries
The Hondata K-Pro comes with a number of calibrations for various engine configurations. The term “calibration” refers to a complete set of cam angle, ignition, and fuel tables, as well as additional settings that can be made with the K-Pro. Those calibrations are starting points for tuning. Some, especially those for near stock engines, work quite well as is. Only road and dyno testing can tell how well a calibration performs in a given car. Calibrations are actually standard ASCII text files and can be viewed in any word processor or text editor. It is not recommended to change calibrations via text editor. However, you can use, for example, Microsoft Word to view calibrations or compare different calibrations with Word’s compare feature. This is a lot easier than eyeballing it.
When I received my modified ECU back there was no information about what kind of calibration Hondata hadloaded onto the ECU, if any. And since the version of the K-Pro ECU Manager software available at the time when my ECU came back could only upload calibrations to the ECU but not download one that was already in the ECU, I had no way of knowing what was in the ECU. This was not a very good situation as a customer’s car might have modifications that may not get along with whatever maps are loaded by Hondata. An email sent to Hondata tech support inquiring as to what calibration was loaded onto my ECU when it was modified yielded a “we do not know what calibration was loaded.” Given that my system was serial number 67, it was hard to believe that Hondata did not know. This situation was addressed in the K-Pro ECU Manager version 1.09 which allowed downloading of calibrations from the ECU into the notebook computer.
Further, while the Hondata K-Pro system ships with a set of pre-configured calibrations, none of them is the actual Honda factory calibration, the one the car had when it was first purchased. Hondata announced on the ClubRSX.com bulletin board that a factory calibration would be included, and this happened with revision 1.08 of the ECU Manager software. Hondata stated that this calibration, called “k20a2-stock,” was close to, but not identical, to the factory calibration. I wondered why Hondata does not include an actual factory calibration. The answer is that the K-Pro tables are different from the factory tables and it is not possible to create an exact factory calibration with the K-Pro. As is, the “stock” calibration does not return the same CVN (Calibration Verification Number) as the stock ECU. The Calibration Verification Number is a checksum value that changes if modifications are made to the ECU. At this point it is not used for anything, but in the future authorities may use the CVN to determine whether an ECU has been modified or tampered with.
For the same reason, Hondata also cannot include the standard “Hondata 4” calibration that the company used to reflash customers’ ECUs before the programmable K-Pro system became available. While existing K-Pro customers receive a more than fair discount when they “upgrade” to a K-Pro system (reflash = US$599, K-Pro = US$999, K-Pro for reflash customers = US$500), they therefore lose the Hondata 4 reflash they already paid for. If nothing else, it would be educational to be able to compare “Hondata 4” with the calibrations included in the K-Pro libraries. The lack of having either the exact factory or the Hondata 4 calibrations available is one of the few drawbacks of the K-Pro. For example, a customer may wish to start from the factory settings and tune from there. Or the supplied calibrations result in knocking and the customers wishes to temporarily revert to the factory or the older Hondata 4 settings. Having those two calibrations would enable customers to analyze those maps, determine the differences and changes, and then modify the K-pro calibration(s) to work on a particular engine.
Making things somewhat more confusing is Hondata’s calibration naming convention. The K-Pro initially came with two “stock” calibrations, one for all stock engines and one for all stock engines with a Cold Air Intake. However, those two calibrations are not “stock,” but dyno-tuned sets of maps that, in essence, replace Hondata 4. Theversion 1.0.8 “factory” calibration that approximates the stock Honda settings was confusingly namedd “k20a2-stock,” replacing the tuned “k20a2-stock” of earlier versions. Starting withsoftware version 1.0.9, a “k20a2-stock-tuned” calibration was added.
It’s important to realize that most, but not all, calibrations are the result of extensive development and tuning by Hondata. This applies especially to the stock/tuned calibrations. Other calibrations, especially those for highly modified engines are to be seen as rough starting points for tuners. That makes sense as a highly modified engine requires a careful professional tune for best engine health and performance more so than a stock or near-stock engine.
1.6 Uploading calibrations and maps
Since most people will upload and perhaps modify calibrations and maps before they have a full understanding of the K-Pro software, I’ll mentions some do’s and don’t’s. First, there is a difference between the uploading of a new calibration and the uploading of a few changes to an already loaded calibration. The initial upload of a calibration takes about 30 seconds and the engine must be off for that. If you make changes to a calibration while the notebook is connected to the ECU, uploading those changes only takes a couple of seconds and can be done while the car is running. Changes to fuel tables take longer to upload than changes to ignition tables. That’s because fuel tables are 16-bit (as they must accommodate large values) while the ignition tables are only 8-bit. In general, it’s best to upload changes with the engine not running.
2. The K-Pro ECU Manager software
The Hondata K-Pro ECU Manager software runs under Microsoft Windows. Hondata officially supports only Windows XP although the software also works with earlier versions of Windows. There is no Macintosh or other version even though it is possible that the software might work under Virtual PC on a Macintosh. The ECU Manager borrows heavily from Hondata’s earlier s100 and s200 Series software. Those who are familiar with those applications will be right at home with the ECU Manager. However, the ECU Manager is also different. For example, it combines datalogging and ROM editing into one single application. And at this point, the ECU Manager is still missing many of the Hondata s100/200 Series’ features.
The notebook computer does not need to be connected to the ECU to run the K-Pro ECU Manager software. In standalone mode, you can use the ECU Manager to analyze datalogs and make changes to calibrations. However, the notebookneeds to be connected to the ECU in order to a) communicate with the ECU, b) upload or download calibrations, or c) log data.
2.1 The main views of the K-Pro
The K-Pro software is built around two main functions: a) viewing and modifying the tables that contain the cam angle, fueling and ignition advance values the ECU uses, and b) datalogging so that you can capture, view and analyze what the engine does when it is running under various conditions.
The following sections describe the main functions of the K-Pro software.
2.1.1 Tables
The K-Pro Manager software has various windows to show information. The central one is “Tables.” Tables (Windows>Tables) consists of two side-by-side displays. On the left is a data table where the rows are engine rpm levels and the columns are manifold vacuum and pressure levels. On the right is either a two or three dimensional graphical depiction of the data table. Through the Tables window you can view and modify a total of no less than 26 tables. They are:
-2 cam angle tables (low-speed cam and high-speed cam)
-12 fuel tables (6 each for cam angles between 0 and 50 degrees for low-speed and high-speed cam)
-12 ignition advance tables (6 each for cam angles between 0 and 50 degrees for low-speed and high-speed cam)
In all tables, rows represent different rpm and columns different manifold vacuum. Each cell therefore represents the cam angle, the fuel value, or the ignition advance valueat a specific engine rpm/manifold vacuum intersection. Each table has 20 rpm rows and 10 vacuum columns, plus an additional three “pressure” or “boost” columns used by turbo or supercharged engines.
What is the significance of the different vacuum/pressure columns? This is very important for understanding the tables and how they relate to tuning:
-Columns one and two represent deceleration.
-Columns three and four represent idling
-Columns three to seven are the cruising range.
-Columns eight to ten are the full throttle “power” columns.
-Columns 11 to 13 are boost columns.
Rows always have the same unit, rpm, and everyone is familiar with that. Columns however, representing vacuum and pressure, can be shown in several different units:
-psi (pounds per square inch),
-bar,
-kPa (kilopascal), or
-Atm (Atmospheres).
The relationship between those units is as follows:
1 psi = 0.069 bar = 6.89 kPA = 0.068 Atm.
And conversions are as follows:
1 psi = 0.06895 bar
1 bar = 14.50326 psi
1 psi = 6.8948 KPa
(The K-Pro has a Settings control panel where the units can be set either to mbar, kPa or Inch in columns 1-9 (the “vacuum columns”) and to no less than five different units in the “pressure columns” 10-13: mbar, kPa, bar, kg/sqcm, or psi. I generally use kPa because the datalog and sensors windows, unlike the Tables window, by default display vacuum and pressure in kPa.)
So what does it all mean? In naturally aspirated engines, full throttle means the throttle plate is completely open and manifold pressure is the same as outside atmospheric pressure. 1 atm is 101.3 kPA, and that is roughly the value in column 10. Boost columns 11-13 generally display boost in psi because that is usually what turbo or supercharged boost is measured in. Problem is that, again, the sensors and datalog windows, by default, display the MAP value not in psi, but in total kPA. What does that mean in kPA?
Column 11 = 4 psi = 101.3 + 27.56 = 128.9 kPa
Column 12 = 8 psi = 101.3 + 55.12 = 156.4 kPa
Column 13 = 12 psi = 101.3 + 82.68 = 184.0 kPa
While using kPa for vacuum and psi for boost makes some sense, early K-Pro users with boosted engines hadto get used to using kPa or mbar because that is how the K-Pro datalogs displayed the data. Even under boost, there weren’t any data points that showed, for example, 4 psi of boost. Instead the sensor display showed 19 psi, which equals atmosphere plus 4 pounds of boost. This was changed in rev. 1.0.11. A new unit now displays boost the commonly accepted way.