• Hondata Reflash - RSX Type S 2002-2004 Type R

Reflash your RSX Type S (Type R specification) engine computer.

  • Fuel, igniton timing and cam timing optimized.
  • Rev limiter raised to 8800 rpm. (ITR ECU uses a 8500 rpm rev limiter)
  • VTEC point lowered from 6100 (ITR ECU) to 5200 rpm.
  • 8 peak wheel hp increase over an ITR ECU.
  • Peak power raised 200 rpm (8100-8300)
  • Peak torque now at 6300 rpm, down from 7600.
  • Significant midrange torque increases form 5500-7000 rpm
  • 15 ft/lb torque increase between 2500-3500 rpm.
  • 20 ft/lb torque increase at 6300 rpm.
  • Fully dealer compatible- works with all Honda scan tools and equipment.

This is for an ECU reflash - the ECU is not included.  Hondata does not sell direct - the reflash must be purchased from a Hondata dealer. The ECU reflash form must be sent with your ECU.


  • K20A engine or K-Series engine built to K20A specifications (ECU part number PRB A01 through PRB A08)

We do not recommend the use of nitrous or forced induction for this reflash. For these applications use the K-Pro.


  • K20A ECU flash program 5200 VTEC and 8800 rpm REV limit - $295
  • K20A Flash upgrade - $200

The upgrade price applies to any K20A2 (RSX type S) owner that already has a Hondata flash program.


Within the USA this product is legal only for racing vehicles which may never be used upon a public highway.

Sales Region US
EPA/CARB status (USA) Competition vehicles only
Model RSX
Year 2002-2004
Market US
Engine K20A2
Transmission MT
Part Number 37820-PRB-A01 to 37820-PRB-A08

The engine tested here is a JDM K20A engine with Hondata intake gasket, CAI (cold air intake) and cat back. Headers and cat were stock RSX. Also tested was a bored and tapered 64mm throttle body. The major variations this engine has compared to the US K20A2 are:

  • Cams (same lift and more duration)
  • Compression (up from 11 to 11.5)
  • Intake manifold (wider runners)

Three programs were tested.

  • The stock ITR ECU
  • The K20A2-4 flash program
  • An optimized K20A2 program

The RSX K20A2-4 program performs substantially better than the stock ITR ECU adding significant torque from 5500-7000 rpm.

The K20A program optimizes the fuel and cam timing, adding about 5 ft lb more torque for the high cam.

ECU re-tuning – Comparisons to the ITR ECU

  • 216 peak HP at 8300 rpm depending on the dyno and modifications
  • 8 peak wheel hp increase from the ITR ECU.
  • Power peak raised 200rpm (8100-8300)
  • Significant midrange torque increases form 5500-7000 rpm
  • 15 ft/lb torque increase between 2500-3500 rpm.
  • 20 ft/lb torque increase at 6300 rpm.
  • Peak torque now at 6300rpm, down from 7600.
  • Rev limiter raised to8800 rpm. (ITR ECU uses 8500 rpm rev limiter)
  • VTEC point lowered from6100 (ITR ECU) to 5200 rpm.
  • Fully dealer compatible- works with all Honda scan tools and equipment.

This is a magnified view of the torque curves seen above.

What if you have modifications?

This program was tuned specifically for a CAI(cold air intake) as they give the best power gains. All future tuningwill be done with either the stock or CAI intake.

Headers will be tested at a later date. This program should work OK with headers.

Test pipe. This will eventually give you an engine check light telling you have a faulty catalytic converter. We havenot seen this error cause any power loss.

If you have nitrous this program will probably not be suitable due to the aggressive ignition advance used.

Tuning notes

This program is a highly optimized version of the K20A2-4 program. Ignition was retarded from 1800-2200 rpm as 91 octaneand 11.5 compression caused knocking. This (and the knock sensor retarding the ignition) is the cause of the slight low RPM power drop.

Fuel was added to all high cam fuel map.Additional fuel was needed above 8500 rpm where the engine ran very lean.Part of the reason additional fuel was needed was that the Hondata gasket was providing colder air while the ECU was providing the same fuel. TheHondata gasket caused the engine to run about 0.2 points of an air fuel ratio leaner.

Cam timing has been highly optimized for this engine. The intake cam can move 50 crank degrees. 25 degrees of movementis needed to generate the best high cam power figures.

We tested a 64 mm (+2 mm) bored and tapered throttle body. It produced statistically insignificant results (+ 1 HPfrom 7500 rpm up.) We have seen combinations (short ram cold air 50 cmstraight velocity stacks on a K20A engine mounted in a Lotus.) where thebored throttle body makes a difference.

Dynojet comparison

These three programs were also tested on the Jackson racing dynojet.

Note that this car had heavy 19” wheels and tyres. The gearbox also has different ratios to the type S. The time taken to make the acceleration is longer than the Dynapack. This will also affect power readings. Dynojet testing was done the day after the Dynapacktesting that generated the graphs above.

For consistency in dyno testing we suggest you follow the dynoprocedure outlined here.

How does this compare to the Type S?

An RSX Type S with CAI, Hondata flash program and stock exhaust makes between 190-200 peak HP on the Dynapack. When examining these figures take into account that the ITR had a cat back, giving it a few more HP, and the RSX's engine had only a few miles giving it a few less HP.

You can see that the main improvements are on the high cam by the amount of 15-20 HP.

This is a magnified view of the torque curves seen above.

How would the K20A flash program work in a Type S?

Without the ITR cams this will just cause poor fuel economy and lower performance.

How would the K20A flash program work in a Type S with ITR cams?

It works very well.  In fact, it works better than the stock ITR ECU.

Rev limits and Valve springs

Based on information from TODA Japan, theType-S and Type-R have the same exhaust valve springs. However the intakeside uses F20C (S2000) intake springs for the outer spring and a Type-Rfor the inner spring. TODA also mentioned that Honda is now using singlesprings of a higher grade material for the newer Type-R's.

The interpretation here is that the stockvalves are good. We have had a test vehicle (K20A2 in a Civic Si) runningwith an 8900 Rev limit for 2 months now. In this car you change gear whenthe Rev counter points to 20 mph!

Any increase in RPM limit though is at yourown risk. If you suffer engine damage that is related to excessive revsHonda / Acura will not cover your warranty. If this of a concern, upgradeyour valve train or use a program with a stock rev limit.

Some 2002 onwards and all 2006 onwards ECUs are flash programmable. The ECU can be repeatedly reprogrammed without removing or replacing and internal components.

How do you get your ECU reflashed?

  • Fill out this form
  • Contact your dealer. All sales are made through Hondata dealers.
  • Your dealer or you will need to remove and send your ECU, immobilizer and key to Hondata.

Do I need to send the key & immobilizer?

Only for 2002-2006 RSX and 2002-2005 Civic Si reflashes. All other reflashes do not need to send a key or immobilizer. Flashing the ECU does not in any way alter the immobilizer operation.

How long does it take?

The ECU will be reprogrammed and shipped out the same day it is received. Shipping in the continental USA is FEDEX next day.

Will this affect the fuel economy?

Assuming you drive the vehicle in the same way, no. Fueling at cruise is the same as stock.

Will this affect the engine life?

Provided your engine is maintained correctly this modification should not affect the engine's life.

Will this affect the warranty?

It should not.

Federal law sets forth requirements for warranties and contains a number of provisions to prevent vehicle manufacturers, dealers and others from unjustly denying warranty coverage. With regard to aftermarket parts, the gist of the law is that warranty coverage cannot be denied simply because such parts are present on the vehicle, or have been used. (see Federal Warranty Laws for details). The warranty coverage can be denied only if the aftermarket part caused the malfunction or damage for which warranty coverage is sought.

If a dealership denies warranty coverage (more details here) , they should be willing to do so in writing. Have the dealer describe the failure which is causing your problem AND how the dealer believes the aftermarket product installed is responsible for the problem. Keep an accurate log of all contacts and correspondence in addressing the warranty denial. Hondata will provide any technical information the dealership requires.

With any increase in rev limit there is an increased risk of valve damage. To minimize your risk use the Hondata program with the stock rev limit. All reports of valve damage we have heard have been as a result of miss-shift. The Type S valve springs are good. We have tested a Type S with an 8900 rev limit in a press test vehicle for several months with no problems.

Will any settings be lost?

Your ECU will lose some idle settings and fuel trim when it is unplugged. It will relearn idle automatically if you leave it idling for 10 minutes. As you drive the car it will relearn fuel trim values in a matter of minutes.

Can a Honda/Acura dealer erase this program?

Only if another Honda/Acura update is released could a dealer erase your existing program. If Honda/Acura comes out with an upgrade you are not obliged to have it installed. If you do not wish to have the dealer program installed there is a wire you can disconnect or cut, to prevent reprogramming. The charge for restoring an erased program is $75 (cashiers check or money order) shipping included.  You can also remove pin 7 from the OBD2 port to keep the dealer from reflashing your ecu (DO NOT CUT THIS WIRE).

What about bolt ons?

Most programs have been tested to work well with a variety of intakes and exhausts. No retuning is necessary after an intake is added.  Some programs as tuned specifically for an intake or exhaust, and if so, will mention this in the reflash notes.

If you currently run nitrous, these programs will probably not be suitable due to the ignition advance used. If you want to use nitrous and this program now, you must install a nitrous system that retards ignition.

What about turbo-charging and super-charging?

Use the K-Pro or FlashPro.

What octane is recommended?

For high compression engines (K20A2, K20Z1, K20Z3, K24Z7) 91 octane fuel or better is recommended.  For all other engines there are gains from using higher octant fuel, as the ECU will automatically advance the ignition timing if no knock is detected.

The K series ECU, in order to be re-programmed must have a functioning immobilizer system. Three items must be sent to Hondata: the ECU, the ignition key and the immobilizer. The immobilizer works as normal after the ECU has been re-flashed.

Tools needed:

  • Philips screwdriver
  • 10 mm socket and drive
  • Time needed : 10-15 minutes

Removing the immobilizer (Civic Si, RSX / Integra)

Under the steering column remove the three philips screw holding on the bottom plastic cover.

Depress the bottom cover along its top edge where it meets the top cover to separate the plastic clips. Rotating the steering wheel 45 degrees can help.

Lower the steering column and remove the bottom plastic cover from over the height adjustment lever.

Unclip the green connector immobilizer connector and unscrew the securing two philips screws.

RSX ECU removal

The ECU is located in the passenger's footwell. The kick panel is removed after depressing the centers of three small plastic buttons around the front covering panel.

Unplug the three wiring connectors and remove the two front most 10mm locating bolts, plus the rear bolt. The ECU will slide out easily - if it does not, then check that the rear bolt has been loosened or removed.

K20A3 Civic Si ECU removal

The Civic Si's ECU is located in the passenger's footwell behind the glove compartment.

Unclip the lower plastic panel:

Unplug the three ECU connectors.

Remove the lower two 10 mm bolts.

Open the glove compartment and push out from behind the two bump stops. The glove compartment will drop after this is done.

Undo the last 10 mm bolt and slide the ECU down.

Hondata Reflash - RSX Type S 2002-2004 Type R

  • Brand: Hondata, Inc.
  • Product Code: Reflash - RSX Type S 2002-2004 Type R
  • Availability: In Stock
  • $295.00