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Hondata Reflash: 02-04 RSX (Base): Automatic-A1
Hondata Reflash: 02-04 RSX (Base): Automatic-A2

Hondata Reflash: 02-04 RSX (Base): Automatic

Part Number: K20A3-A

5 out of 55 out of 55 out of 55 out of 55 out of 5 3 customer reviews

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The K20A3-auto program advances the ignition, alters the cam timing and optimizes the fuel for a cold air intake, adding 5-10 ft lb across the rev range.

This program was tuned specifically for a cold air intake, as they give the best power gains. The reflash has been tested with race headers and test pipes and both are safe to use.

This reflash is not suitable with nitrous due to the aggressive ignition advance.


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.

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

This car was tuned 91 octane pump gas - which we recommend. As the ignition is advanced there will be less tolerance for poorer quality fuels.

The extra low down torque as illustrated on the dyno chart, may in fact be due to the torque multiplication effect of the torque converter. With an auto transmission, very little time is spent at low RPMs. Most medium throttle openings will bring the engine to about 3000 rpm very quickly.

We do not modify the shift points. These are left at stock. The higher rev limit is accessable in the sportshift mode

When intake, headers and exhausts are added, the power peak is moved above the stock Honda redline. Extending the redline in this case, even if the power peak was not increased will increase your average power.

In the dyno chart above, a shift from 6700 rpm to 5500 rpm (stock rev limiter) goes from 132 HP to 122 HP - an average of 127 hp.

A shift from 7200 rpm (raised rev limiter) to 6000 rpm (140 hp to 132) will give you an average of 136 hp - a 9 hp increase over the typical rev range used under full acceleration.


Any 2002 to 2004 Acura RSX with an automatic transmission with ECU part numbers PND A51- 59, and 306.


  • 7 Peak HP gain depending on the dyno and modifications (results will vary)
  • 5-10 ft lb torque across the rev range
  • Power peak raised 400 rpm from stock.
  • Rev limiter raised to 7300 rpm.
  • 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: K20A3-A
CARB Approved: No

Customer Reviews

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

3 Total Reviews

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Most Recent

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

Worth Every Penny

By Thomas on 7/8/2016

This Hondata reflash is by far the best money I have ever spent on the rsx. I completely agree with everyone who says that this is how the rsx should be from the factory. The torque is VERY noticeable; first gear (0-40mph) just flies which makes daily driving and launching from a stop MUCH better. 2nd and 3rd gear also have so much more usable power that freeway pulls are much more enjoyable. Kseriesparts does not disappoint. They give you instructions on how to mail Hondata. It was a very simple process. I mailed my ECU, Key, Immobilizer, and paperwork on tuesday morning and got everything back on thursday. Hondata is very fast with their turnaround. Thank you for the great customer service and product. 110% satisfied, because this reflash, bang for buck, surpassed my expectations. Do not hesitate if you have been looking for more power in your base.

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


By Jordan on 5/28/2012

Can you ship to Canada?

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

Reflash (7300rpm)

By pongoro87 on 9/7/2011

a MUST for base autos!!!!!

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