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Hondata Reflash: K20Z1 Engine Swap-A1
Hondata Reflash: K20Z1 Engine Swap-A2

Hondata Reflash: K20Z1 Engine Swap

Part Number: K20Z1-05-06 Engine Swap

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This reflash is so that you are able to use an 05-06 RSX-S ECU when you do an K20Z1 05-06 RSX-S engine swap.

The K20Z1 Engine swap reflash lowers the VTEC point to 4000rpm, advances the cam angle and raises the rev limit to 8600rpm.

This reflash requires a cold air intake, race header, and 54psi of fuel pressure.


You are responsible for paying for and sending your ECU to Hondata. You can send your ECU as fast as you would like and shipping costs normally start at $10.00 for ground and $60.00+ for next day air. We recommend using an express service (2 day or next day) through FedEx or UPS because they have the least amount of delivery problems, provide proper insurance, and have good package tracking. We recommend that you do not use USPS because of delivery issues. You are not sending your ECU to K Series Parts you will be sending it to Hondata directly and we provide all of the instructions on where it needs to be sent once your order is approved.


After we approve your order we will send you two emails, one email will be a Hondata form and the other email will be instructions for shipping and what items need to be included. Orders submitted by 3:00pm Mountain Standard Time Monday to Friday are normally approved same day. Orders places after 3:00pm MST or on Saturday and Sunday are processed the next business day.

Hondata normally reflashes ECU's the same day they receive them but they do get busy and it might take an extra business day. We recommend that you plan on a 3 day total turnaround time from the day that Hondata receives your ECU.

Return Shipping

Hondata uses K Series Parts FedEx account to next day air the ECU back to you once the reflash has been installed. This means that you do not have to pay for return shipping. Your ECU will arrive by 3:00pm the day after Hondata completes the reflash installation. Hondata does not provide us with a tracking number or notification when they ship the ECU back to you.

ECU Serial Number

The serial number is located on the ECU. Hondata has provided instructions on how to remove the ECU.

California Customers

Not legal for sale or use in California on any pollution controlled motor vehicles.

International Customers

K Series Parts cannot sell reflashes to customers outside of the United States per Hondata request. The shipping address must be a US based address.


Any 05-06 RSX-S ECU

  • 37820-PRB-A13 through 37840-PRB-A16
  • 37820-PRB-4050
  • 37820-PRB-4150
  • 37820-PRB-3060


  • Maximum power gain 52 hp at 5500 rpm 42 hp peak (over stock)
  • Maximum torque gain 50 ft.lbs torque at 5500 rpm (over stock)
  • VTEC window from 4000 to 5000 rpm
  • 8600 rpm rev limit, increased from 8300 rpm
  • Throttle response improved
  • Rev hang reduced
  • Emissions systems disabled
  • Immobilizer disabled
  • Idle speed raised for smoother idling with solid engine mounts
  • Fully dealer compatible - works with all Honda scan tools and equipment


Any increase in RPM limit is at your own risk. If you suffer engine damage that is related to excessive revs Honda / Acura will not cover your warranty.

With regard to aftermarket parts, the law is that warranty coverage cannot be denied simply because such parts are present on the vehicle, or have been used. For more details read the K series FAQ.


Honda may not cover mechanical damage to the engine under warranty resulting from exceeding the factory red line. Hondata & K Series Parts will not cover any damage as a result of installing this product.


Brand: Hondata
Part Number: K20Z1-05-06 Engine Swap
CARB Approved: No

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