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Hondata Reflash: 2006-2011 Honda Civic Si-A1
Hondata Reflash: 2006-2011 Honda Civic Si-A2

Hondata Reflash: 2006-2011 Honda Civic Si

Part Number: K20Z3-06/09Si

5 out of 55 out of 55 out of 55 out of 55 out of 5 1 customer reviews

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The 06-11 Honda Civic Si reflash advances the ignition, alters the cam timing and optimizes the fuel adding up to 25hp and 29ft/lbs of torque across the rev range.

The reflash lowers the VTEC point to 4500rpm, advances the cam angle and raises the rev limit to 8500 rpm.


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. The instructions are towards the bottom of the page.

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.

Additional Information

Below 4500 rpm the K20Z3 is always on the low cam

Above 5800 rpm the K20Z3 is always on the high cam

Between 4500 rpm and 5800 rpm the K20Z3 is on the low cam at part throttle switching to the high cam at full throttle.

This one reflash will work well with a variety of aftermarket performance parts. It will work well with:

  • An intake
  • Cat-backs (as long as they are less restrictive than stock)
  • A race header*
  • A combination of intake and race header

(*Note that current race headers eliminate the catalytic converter and will generate a check engine light. This engine check light is for emissions and will not affect the car's performance. Race headers are for offroad use only)

You must have a minimum of an intake or header.

It is not designed to work with a stock 2006-2011 Civic Si and will lose power between 4500rpm and 5600 rpm if installed.

The 06 Civic employs a mass air flow sensor that automatically adjusts the air-fuel ratio for increases in air flow from correctly designed intakes and race headers. Intakes for this car are critical. The intake - in particular the size and shape of the piping around the mass air flow sensor is the primary determinant of fueling for this car. If you have any problems in running rich or lean, then you must retest with the stock intake. Race headers will not cause this engine to run lean.

The VTEC switch point on this reflash is very smooth - much smoother than previous reflashes. With a stock air box and race header the switch point is virtually undetectable. For the reduction in VTEC "kick" and aural stimulation, we apologize, but this is the path to maximum power.

Power is gained in the midrange from 4700rpm to 6300 rpm. Power gains above 6500 rpm are negligible, although the higher rev limit will raise average power a little.

As this reflash will work with a combination of aftermarket parts we have two examples of the effect of the same reflash on two 06 Civics. (Both Civics dynoed at about 195 stock HP)


US and Canadian 2006-2011 Civic Si with K20Z3 engine ECU part number 37820-RRB-A04 to 37820-RRB-A14

Mexican Civic SI ECU part number RRB-X11


  • 4500 rpm VTEC point
  • Rev limiter raised to 8600 rpm.
  • 15-25 Hp gain midrange
  • 15-29 ft lb torque gain midrange


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: K20Z3-06/09Si
CARB Approved: Yes

Customer Reviews

5.0 out of 5.0 5 out of 55 out of 55 out of 55 out of 55 out of 5

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5.0 out of 5.0 5 out of 55 out of 55 out of 55 out of 55 out of 5

Hondata Reflash

By Kent Donahue on 6/6/2008

I received quick responces to my questions from CLUBRSX. Getting the Hondata Reflash for my 07 Civic SI through CLUBRSX was an easy process and the Reflash was worth every penny.

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