Lexus RC F

After driving the VR-4 for 25 years, I needed to search for a replacement.  In terms of very high performance coupes with four seats, there are of course the American ponies and some European models.  In the end, I bought a 2015 RC F for the large displacement engine and the loud body contours.  It was a leftover from the previous year and was available at a good price.

March 2016
Test drove and bought the Shark.  Named by my daughter due to the fin on top and the side gill vents.  I was originally only going to test drive this particular car, but they offered to allow me to take it home for the week.  Well after driving it a few days, I was completely hooked on how it felt and resolved to buy it.

May 2016 - PPF
First mod was to wrap the front of the hood, grill and side fenders with Suntek Paint Protection Film.  This particular type is designed to use the heat of the Sun to remove slighy hazing and scratch marks.  I bought the film on Ebay (vendor "mykodesigns".  I also received my NASA plates this month (visible in images below).

Suntek PPF wrap on the hood.  You can see the faint line to the right of the hood scoop.

I was able to do a good job on most parts even though it was my first time wrapping a car.  However, the complex front end with the head lights was a challenge, and I could only wrap it by doing it in sections.  I do have a seam right at the sharp edged running light.  I tried again in 2017, but still could not do it in one section.  

July 2016 - First Ceramic Coat
I used the 22PLE Ceramic coat for this first go around.  It took four hours to do this job, and the main time demand was the buffing of the paint to correct any flaws in the finish.

August 2016 - Red Calipers
I decided to paint my brake calipers red by using high temperature paint and clear.  Since they are Brembos, I obtained some high-temp decals from an Ebay vendor.  

Brake Calipers painted with high-temp paint and clear
2019 Update.  The paint has not faded in the three years since.  When I added a small touchup to repair a nick, the color was the same.

October 2016 - Dash Cam
I decided to select a dash cam that would allow me to mount it in the grill.  I didn't want a movable device cluttering up the cabin.

Dash Cam integrated into the grill.

There is a large fuse box in the front driver side corner of the engine compartment.  I found a switched feed and plugged into that for power.

October 2016 - Embroidered Patch
After some searching, I realized that no one made an RC F patch.  I worked with the online vendor The Studio.  They had the best price and did not charge me an increase despite the changes I made at the last minute.

Patch that was designed and custom made.  Note the
matching red DashMat that fits the Lexus RC.

January 2017 - LED interior lights
These are for example the trunk, door and interior lights.  From Ebay vendor jdmautohaus.

April 2017 - Aero Kit
I like the low wide look.  But instead of actually lowering the car with after market springs, I decided to add a ground effects kit.  The kit includes a very aggresive splitter lip, the side skirts and the rear spats.  I installed this system myself without adhesives so that it can be easily removed, cleaned, buffed, etc.  The kit was from CF500 in Boca Raton, FL.

In the year after (2018) I removed the sideskirts and filled them with expanding foam from the bottom followed by black rubber spray.  Due to the carbon fiber material, I found them to be a bit too flexibly, and the foam added stiffness and rigidity.

June 2017 - Aruba Rocks! Apparel Sponsorship
Working with the company CEO, I added decals for several photo shoots in return for apparel (active wear, hats, etc) for the family.  

April 2018 - LED lights
I installed LED bulbs into my reverse lights.  Rated for 1600 Lumens from  Also installed projector lights in the door as shown below.

June 2018 - Borla Exhaust
The 5 Liter V8 is one of the reasons that I selected the RC F.  However, I find its stock exhaust to be we way too quiet.  From the tests others have done, a HP increase of about 20 hp is expected.   This brings my system to 485 hp range.

Installation of the Borla took two hours of labor.

Cold start video from Facebook post

With the system installed, I would get infrequent Check Engine Lights with the P0430 Code.  A post on the Facebook group recommended the replacement of the exhaust gaskets (which were reused from the stock ones).  This was done in Jan 2019, and I will update this page if I get any more CELs.

Driving the car now with the paddle shifters is really much better with the Borla.  I can make the car growl and pop on downshifts.  It is just so fun and almost like playing a musical instrument.

July 2018 - Second round of ceramic coat
The ceramic coat I applied last year is only rated for one year.  So I reapplied, but this time the 22PLE VX2 PRO version.  This is expected to last several years.

August 2018
- Clearcoat of Caliper Bridge Bolts
Although the calipers themselves are nicely painted (red), the large bolts that tie the halves of the caliper together are just bare steel and they corrode to a dirty red color.  I removed them, buffed and then clearcoated them with high temperature clear paint.

Clearcoated (and washed) bolts on the caliper.

September 2018 - Tow Hook / RBF Tag
At work, we frequently use Red Tags (aka Remove-Before-Flight tags), and I often also see painted tow hooks used as adornment on modified cars.  I thought it would be fun to combine these two into my version.  

Continuing on the red-on-black theme, I decided to add a tow hook to the front.

On nice weather days, I use this NASA themed
RBF tag instead of the tow hook.

Tow hook: Ebay
NASA Red Tag: Ebay

Use of the tow strap on the Chronos Racing car.

December 2018
- Lexon Rear Wing Extenders
As loud as the styling on this car is, I think the rear wing is a bit understated.  Even though it does move up and down with the speed, I decided to add on the Lexon Wing Extenders.  I think it looks much better now.

Video on the Wing Extenders

January 2019 - RR Racing Heat Shield
This intake mod was added from RR Racing and is good for 10 hp, bringing the system to 495 hp.

February 2019 - Carbon F logo
Also from RR Racing, this replaces the large "L" on the grill with a carbon fiber "F".  The manufacturer suggests glueing this into the grill with black silicone adhesive but I wanted to do something reversible.  I also wanted to mimic the illuminated star accessories that some Benz's have.  Since I already use the Neopixel addressable RGB LEDs for my other hobbies, I decided to use these here also.

Preliminary installation of the F logo.  The left image shows my concept
for a removable installation.

The logo is made removable by using a 1/4" plexiglass panel that is about 6"x8".  At the top I used two #6 bolts into the original mounting holes of the OEM L logo.  The thickness of this plastic allows the bottom to be wedged into a slot in the bumper.  I then drilled small pilot holes into the back of the carbon logo and used self tapping screws to screw it to this plexiglass panel.  Long 1 1/4" self tapping screws are needed for this.

Plexi glass panel with Neopixel LEDs.  The three wire cable
goes to a Flora Arduino compatible microprocessor.

The above figure shows the LEDs mounted to the plexiglass panel using silicone adhesive.  After this photo was shot and in a later revision, I mounted the top three LEDs to the back of the panel to increase the distance to the light diffuser.  The connections between the Flora processor and the LED string is as follows:
  • The red wire connects the VBAT terminal of the Flora to the +5 terminal of the first LED
  • The black wire connects Flora #6 terminal to the Data Input of the LED strip
  • Finally, the white wire connects the Flora Ground terminal to the GND of the LED.
Detail of one LED
Detail of how two LEDs are chained together on the plexiglass panel.
I used 28 AWG wire-wrap wire to interconnect the LEDs.  This kind of wire is fine enough to be easy to work with the small pads.  The LEDs above and below the center of the logo oval are 4 cm from center, and the ones to the left and right are 6 cm from center.  They are then glued down with silicone adhesive, and are thus easily removed with a razor blade and repositioned.

Translucent white plastic bonded to the F logo with silicone adhesive.  At the
top is the "Add-a-Circuit" tap that allows me to get both switched and
unswitched power from the fuse box.

Power and control lines are fed from the fuse box in the driver's side of the engine compartment (see image below).  The Flora controller is powered from an unswitched source in the fuse box (red wire in the middle).  This uses an "Add-a-Circuit" device plugged into an existing Low-Profile minifuse location.  This has two fuse holders built into it.  The first is the fuse for the original circuit, and the second is the fuse for the new circuit you are feeding.  For sensing when the engine starts, a switched power line (that also powers the dashcam on my grill) is the blue wire plugged in on the right.  

Both of these feeds need to be downregulated from 12V to 5.  There are two options for this.  One is a 12V to USB power converter, and the other is a LM7805 linear converter.  The latter is small enough to be wired inline with the wire, or on a circuit board.  I used one of each because the dashcam was an older project.  Once converted, the unswitched power is connected to the battery terminals of the Flora controller but the switched power needs to have a 2:1 voltage divider to to ensure that we do not exceed 3.3V on the logic input for the Flora.  I used a pair of 2.3k resistors for that.

The inside of the fuse box showing how I tapped in for power.
Red wire is unswitched 12V and blue is switched 12V.

Since each LED is RGB and completely addressable, any pattern is possible.  When the car is not running a red 'heart-beat' pattern runs.  The brightness is ramped up fast/slow as needed to accentuate the effect.  As soon as the car start event is detected, a white animation runs that spins a few turns while the car starts up.  It then stays on solid white while the car runs.  See below for a video.  The code that runs on the Flora Arduino micro is available as Shareware (a fee of $35).  Contact me if you want a copy of it.

The heart-beat pattern runs for three hours after the car is shut off and draws about 40mA.  Once the LEDs are shut off, the standby current is only 15mA.  In practice this effect is really best seen at night as the white diffuser is very bright during the day.

This writeup should be enough for you to build this project yourself.  One aspect that can be a bit daunting is procuring, wiring and programming the Flora processor.  If you wish, you can purchase this module (programmed) from me for $50 (shareware fee included).  Contact me if you want to pursue this option.  Other custom components may be available as well.

Project Links

May 2019
- Hood Scoop Tests

As you can see above, the RC F has several functional air scoops (unlike the GR Supra, which has over a dozen fake ones).  The hood scoop in particular has an internal cover that looks like a rain guard.  From the start, it felt to me that this guard would obstruct air flow and I removed it by popping out the trim clips.

View from under the hood with the rain guard covering the hood scoop.
You can see the small opening in the top right for air flow.

This is with the rain guard swung away, revealing the exterior scoop.

In May 2019, there was some debate on the Facebook group if this removal was a good idea or not.  The counterargument was that the small opening would create a Venturi, which would actually help draw air out of the engine bay.  I decided to run a test with a remote temperature sensor to get some data on this question.

I did five runs on a sunny spring morning on the East Coast US with the hood temperature sensor mounted just aft of the scoop opening (see image above).  The readout was then placed at the base of the driver's side A-pillar so I could observe the temperature as I was running.  In addition to this hood sensor, I also used the built-in ambient air sensor of the car, and a separate hand held temperature/humidity monitor.  

After letting all three sensors settle overnight in my garage, I first took baseline readings on all three.  I then drove for half hour to the test road to get all coolant and oil temps to the normal range.  I then did a run with my standard configuration (no cover), then with the hood scoop taped shut (so non-functional scoop), and then next the stock configuration.  I finally finished with two runs of the no cover configuration to see if conditions were consistent.  All runs were done in S+ mode (so no Atkinson cycle), and at a sustained speed of 70 mph.  The data is summarized below.

Ambient (car sensor)Under Hood (wired sensor)Ambient (hand held sensor)Delta TComment
7375.173.92.1Morning baseline reading
75128.37553.3No cover
78123.545.5Scoop taped shut
81129.848.8Stock config
81134.853.8No cover
83138.055.0No cover (60 mph)
All readings in F

As you can see above, and to my surprise, the best reading was with the scoop taped shut.  Now in full disclosure, there was a small opening as the tape pulled away from my paint (ceramic coated and waxed, so very slick).  While driving, I could see the tape bulging out and up, indicating either lift from the air flow above, or positive pressure below.  By the time I had stopped, there was a small opening pealed up.

But the second surprise is how much worse the no-cover configuration was.  It was a consistent 53F rise with the 70 mph runs and slightly worse at the lower 60mph speed run.  Presumably , in the case of the latter, the lower speed meant lower air flow.

In the light of this, I have put back my rain cover.  It is possible that at even higher speeds, the stock configuration would win out over the no-scoop configuration. This result reminds me of the RR-Racing find that the stock intake is already very good.  The only improvement they could justify was the intake diverter.  Lexus must have done testing on the design already.  As a final note, I have always liked seeing the blue intake runners when the hood is closed.  I guess I will now have to unfortunately do without that.

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