- Acura RDX ECU part numbers 37820-RWC-A55
through 37820-RWC-A74 (2007-2011)
- K23A1-RDX ECU flash program 7200 rpm REV limit - $295
This upgrade information form
must be sent if you wish to reflash your stock
Hondata does not sell direct - all sales and payment must be conducted through Hondata dealers.
This reflash was tested on a
mechanically stock 2007 RDX. This is a
must have upgrade. Power was gained
everywhere, from a strong increase in low
end torque to a good increase in top end
power above 5500 RPM.
- Rev limiter raised to 7200 rpm.
- 10-20 Hp gain
everywhere - 26 Hp at peak.
- 33 ft lb torque at 3300 rpm
Click picture to enlarge
RDX Boost changes
In stock form, the RDX runs
13-14 psi of boost until 4500 RPM,
decreasing to 8 psi at 6500 RPM.
Hondata raises the boost
level about 1-1.5 psi under 4500 RPM and
raises the boost level 3.5-4 psi at redline. As
a result the turbo spools faster at lower
RPM leading to better off the line
Tuning and performance notes:
The Hondata reflash raises the boost a
little, advances the ignition a little and leans
the mixture a little. Reflash owners have
reported an improvement in fuel economy, but this has not
The RDX is very sensitive to fuel quality.
You must always run the highest quality fuel.
The ECU is constantly monitoring knock and will
advance or retard the ignition to suit. Poor
fuel, hot intake temperatures, hard loading on a
dyno, and high speed running can cause knock. As
a result the ECU will retard timing (and reduce
the power) until conditions improve.
RDX owners in states that run higher octane
than the 91 found in California may well see
more performance than shown here.
If you are dyno testing it is unlikely you
will get enough air across the intercooler. If
the air gets too hot the ECU will retard the
ignition, in addition to retarding the ignition
from any knock. Reset the ECU by unplugging it
for 30 seconds to reset the knock learning.
The increased rev limit only functions in
Testing was done on the Church Automotive
Dynapack 4 wheel drive dyno.
How will the reflash work with
At the time of writing there were no intakes
available for the RDX. Air fuel ratio is largely
determined by the mass air flow sensor located
in the intake. Any intake which does not alter
the pipe diameter surrounding the mass air flow
sensor (and thus the air fuel ratio) should work
The reflash will work safely with an exhaust
How do I get the reflash?
You will need to remove the ECU and send it to Hondata
through a dealer . Unlike reflashes for other Honda models you will not need to send the key and immobilizer; just the ECU. Fill out this form and contact a Hondata dealer. Hondata does not sell direct. All ECUs must be sent to Hondata for reprogramming. No Hondata dealer has the equipment to reprogram this ECU.
How do I remove my ECU?
The ECU is located on the inner fender beside
the air box. Unclip the three wiring
connectors. They are released from underneath
the plug. You will need a 10mm socket to remove
the bolts holding the ecu in.
For further identification, see the ECU picture
at the top of this page.
How long does it take to get my ECU back?
Turnaround is 1-2 business days. If the ECU
arrives in the morning it is almost always sent
out the same day. ECUs arriving mid to late
afternoon ship the next day.
Can I send in a new or used ECU?
Neither a new or used ECU will function with
your car until the immobilizer system has been
programmed to match your keys. This is something
only an Acura dealer can do. A new ECU will also
require a VIN number to be programmed into it.
Again this is a job for your Acura dealer.
What if Honda comes out with an ECU software upgrade?
If a dealer erases your ECU and installs a
newer Honda program, you may send your ECU to
Hondata to restore the program. Hondata
charges $75 which includes overnight shipping
and handling for any program upgrade.
Will this affect my warranty?
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.
Review by Turbo & High-Tech Performance Magazine
Review by Import Tuner Magazine
Hondata RDX Reflash Review
Turbo cars have always been great for tweaking a
bit more horsepower and torque from the factory.
Enthusiasts with Audis, Subarus, BMWs, Porsche,
Mercedes etc. have long been able to purchase
ECU software upgrades to increase their car’s
When Acura released the RDX, I was confident
that the leader in Honda tuning technology,
Hondata, would eventually release an RDX
specific reflash. Hondata recently sent me a
reflashed ECU to try in an otherwise stock RDX.
Installation of the ECU is very straightforward;
a few 10mm bolts, a plastic cover and some
connectors. The swap took me 10 minutes and I’m
pretty slow. Enthusiastically I jumped into the
RDX, twisted the key and the car started right
up and settled down to a normal idle. No
stumbling or missing, no check engine lights. It
felt like stock which is a good thing.
Driving around gently, I could feel boost
building much earlier and throttle response was
more responsive. Once up to operating
temperature I headed for a favorite back road to
start flogging the car more. A few things were
apparent: there’s a massive increase in low end
torque; the tachometer pulls hard from as soon
as boost builds. Midrange is slightly stronger
than stock, which was great to begin with, but
the top end is my favorite part of this reflash.
The stock RDX runs out of power above 5500 RPM,
but with the Hondata reflash power builds strong
right to redline. On the highway I found the new
found power especially impressive in passing
situations. The driver can choose to boost or
rev and either way the job is done nicely.
Passing cars around 4,000 RPM under boost is
especially entertaining, as the RDX just scoots
past them very quickly without fuss. In the back
of their minds I could imagine them saying “what
the hell was that?!” Call me crazy but I also
noticed on the highway an increase in mileage
which is always welcome.
With the reflash Hondata has been able to
transform the RDX into a much more capable
machine. The reflash is also very conservative.
After talking with Hondata, it became readily
apparent that these guys aren’t a bunch of
yahoos cranking boost and fuel trying to make
huge horsepower; everything has to be done
properly, like it should have been from the
Before the flash I was averaged as per
the RDX computer around 17.4 mpg (13.5 L/100Km).
After the flash I am now seeing around 19.4 mpg
(12.1 L/100Km). And I always boost and rev
several times a day =) The RDX also seems to use
much less gas when driving hard now. It really
likes 94 octane fuel!
For anybody interested in giving their RDX the
edge it lacks from the factory, the Hondata RDX
reflash is probably what you’re looking for.
It’s that good.