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Conrad's Acura RSX and ECU Tuning
Last major update: December 2006, minor update March 2023
Also check my ECU tuning blog

What's this page for?
This page, mostly compiled 2004 to 2006 when I was very active at ClubRSX.com, includes a variety of information on how to tune the Acura RSX and other Honda K-Series cars (Civic, TSX) with the Hondata K-Pro ECU.

It also contains additional information on RSX tuning and modification in general, with an emphasis on ECU tuning and supercharging. Much pertains to my own RSX Type S, which I bought new late 2003 and still have. For a complete write-up of all my mods to-date, click here. For a quickie on how to tune the K-Pro, click here.

The Hondata K-Pro
This is a rather comprehensive (17,000+ words!) description of the Hondata K-Pro ECU. It covers just about anything anyone would want to know about the K-Pro. There is basic information in there, but also information on how to tune with the K-Pro, fix knock and fueling, and some pretty technical stuff.

Hondata Seminar Transcript
These are my notes from the Hondata tuning seminar I attended in March of 2004. The notes are quite extensive and cover a) general Honda tuning principles, b) some items relating to the s200 ROM Editor, and c) the K-Pro system. Those interested should also download the seminar slides Hondata used (click here to download pdf)

Tuning 21st Century Style--The Hondata Story
I sent this this article, with pictures, to Honda Tuning Magazine and offered it to them for free. They were not interested and never even returned my emails or calls.

Tuning from calibrations
Most people will not create a K-Pro calibration from scratch. Instead, they will start with one of the many library calibrations that come with the K-Pro's K-Manager software. Most, but not all, are the result of extensive development and tuning by Hondata. However, Hondata developed them on a particular car with particular modifications. Yours may be different and by adjusting the air-fuel ratio, tweaking ignition advance, and perhaps trying out different cam angles, you can customize and finetune an existing calibration for your car. This can be done in an hour or two on a dyno. If you can't be on a dyno, you can use a datalog as the basis for fuel map tuning. I always recommend a full throttle 2,500 rpm to redline run in third gear. (see how it is done)

Advanced Tuning
This is an expanded summary of Hondata's advanced performance tuning videos. It includes my commentary and some of my own experiences.

Hondata Boost Primer
Good stuff to know for anyone who wants to turbo or supercharge their engine, right from the source.

My final NA Dyno
The graph shows a dyno tuning session June 2004 at Church Automotive Testing in Torrance, CA. Hondata's Doug MacMillan was kind enough to invite me and show me how to tune with the K-Pro. I was quite pleased with the results, but keep in mind that Dynapacks tend to read high.

My initial Comptech supercharger Dyno
The graph shows the first dyno result with the Comptech Stage 1 supercharger installed. It was done November 2004 on a Dyno Dynamics dynamometer at Comptech USA in El Dorado Hills, CA. The baseline shows stock with just an Icebox intake. The blue line is with the supercharger, using the 310 cc stock injectors. We cut off at 7800 rpm because duty cycle was at 100%.

My Comptech supercharger Stage 2 Dyno
The graph shows the dyno results comparing the street Comptech supercharger kit with the Stage 2 upgrade (3.6-inch pulley, larger injectors). It was done April 2005 on a Dyno Dynamics at Comptech USA in El Dorado Hills, CA.

Dyno comparisons: stock/Hondata 4/K-Pro/CTSC
This is a composite graph that shows the difference between stock, Hondata #4 and Comptech Icebox, Hondata K-Pro and AEM CAI, and street Comptech supercharger. The black dots show the VTEC point in each setup.

Knocking and ignition
Knock control is crucial to getting maximum power without harming the engine. As of now it is not entirely clear how the K-Series handles knocking. These are some thoughts on knocking and how the K-Pro handles knocking.

Immobilizer reprogramming
When you get a new ECU (or buy one with the reflash already on it, you need to have the ECU matched to your immobilizer and key. Click here for how it's done (Note: Have Acura do it, NOT Honda).

CarCPU review
This is a pdf file of a review I did of the CarCPU automotive computer system. I wrote it for Handheld Computing Magazine, which is one of the magazines I produce.

RSX mph/rpm calculator
Some really great person programmed this handy rpm and speed calculator for the RSX. Note: this is a Windows .exe file and downloads to your computer.

CARB regulations
What, according to the California Air Resources Board is legal and what is not. To check for specific items that may or may not have a CARB exemption click here. And to see what the California Highway Patrol considers street-legal, click here.

Images
The first customer Comptech SC installed
Comptech SC wallpaper (1024x768)
The K-Pro ECU inside
K20a2 PRB vs PRC manifold
Fixed cam angle torque curves
My Gran Turismo 4 Integra Type R

Hondata K-Manager archive
In case that for some reason you need to go back to an older revision of the K-Manager software, I have an archive of the installer .exe files. This is absolutely a last resort as it is never a good idea to go back to an older rev. Also, as of rev 1-2-0, a version checker won't let you run older versions unless you delete the version entry in RegEdit.

Some of my threads at ClubRSX.com
My threads and posts (well over 4,000) tend to be long and somewhat involved. Here are some of the more interesting ones (note that I wrote most of these back in 2004-2006, and not all links still work):

  • How to adjust fuel in K-Pro
  • Hondata reflash and K-Pro FAQ
  • How to locate and eliminate knock
  • Drag racing contemplations
  • Will Hondata get me better gas mileage?
  • Air temperature correction calculator
  • Lean protection explained
  • Boost comparison turbo versus supercharged
  • Auto Meter boost gauge install
  • Blower RPM calculator
  • Aftercooler considerations
  • Pre 1.1 calibrations need retuning
  • Mugen SS DIY and data
  • The cam and ignition tuning predicament
  • Supercharger intake manifold considerations
  • Older calibration? Upgrade!
  • K-Pro intimidating to many users?
  • Cam angle comparison
  • A day of tuning at Hondata
  • Some Eaton Supercharger facts and figures
  • ITR manifold installed/impressions
  • How open, exactly, is our open loop?
  • AEM CAI installation: here's the scoop
  • Datalog: Icebox versus AEM CAI
  • Hondata IMG installation
  • The K-Pro Business Model/Predicament
  • Icebox facts and figures, dyno
  • What's legal in Kalifornia
  • Fujitsubo PG: decision, purchase, install
  • Getting started with my new 2004 Type-S (1st post)

    A day at Sacramento Raceway
    Pics from a great Sunday at the Sacramento Raceway drag strip. Hot cars, including several RSX's, and some REALLY hot babes.

    AEM CAI installation manual
    For all those folks who get a AEM CAI but have no installation manual, here are scans of each page of the manual. Warning: the manual that comes with the AEM CAI is confusing and low black&white quality, so the scans are no better.

    2005 RSX ECU pinouts
    A31P - B24P - C22P - D17P - E31P
    Terminal overview
    These are the pinouts for the 2005 ECU (copyright Helms manual).

    Progression of my mods
    This is a list of the progression of mods I installed, why I decided to do them, and what my experience with each was.

    Useful links
    Quaife
    Eaton Superchargers
    Magnuson Superchargers
    Club RSX
    Acuity RSX shortshifter