The 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.  2020 Update: due to being in the weather, this camera stopped working.

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 an
d 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 (see update below for August 2019)

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.

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 Youtube

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:

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 here for a video

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.

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)
Delta T
Prior to run
No cover
Scoop taped shut
No cover
No 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.

August 2019 - Artisan Spirits Side Skirts
A short time after purchasing this car I started to look at aero enhancement kits. One that stood out was from Artisan Spirits, especially the side skirt. All the others seem to have a horizontal shelf design (like the ones I installed above) which I felt break up the lines of the car. However, the AS ones had to be shipped from Japan and were not painted. So I decided to settle instead on the ones from CF500.

In 2019 a member of the Facebook page on the RC F decided to part out his car. He had a set of AS side skirts and they had been painted gloss black and then covered with carbon fiber wrap. Since they were protected this way, I reasoned they would be in good condition and bought them.

Image from Vivid Racing site of the AS Side Skirt.  These continue the curves and
creases of the body and I like the way they flare out on the bottom.

I wrote AS in Japan and other distrubutors but none would send me installation instructions (the seller had long discarded what he had). Once I removed my old ones and test fitted these I decided to make some brackets to be able to freely position the skirts without drilling new holes into the car. The brackets, which install into the rear wheel well, also allow me to lower their position a little and rotate the bottom edge outwards. These brackets are made from aluminum and then painted gloss black. Since all the forces will be in the plane of the sheet (which is clamped between the sideskirt and the car), bending of the metal sheet will not be an issue.

Aluminum panels made to allow custom fit of the side skirts

I am very pleased with the appearance of the car at this point. Hard to see in the pictures that they make much of a difference, but in person the whole package looks great. The design and profile of this side skirt is quite different than the one from CF500. For one thing, the bottom edge is painted and faces the ground. So to protect this surface, I wrapped it with clear Suntek film.

Sketch comparing the profile of the AS and the CF500 side skirts.

The figure above shows a sketch of how the designs of the two side skirts compare.  On the right is the old one from CF500.  Due to its thin Carbon Fiber design, they were very floppy when pushed in the direction of the red arrow.  I filled them with expanding foam and painted the bottom with black rubber paint to improve them.  The AS ones on the left do not have this issue as it is like pushing on a box beam.  The green area is the Suntek film.

Side Skirts installed onto the car.

November 2019 - Helper Springs for the Rear Wing
Since this Summer, I started noticing that my rear wing was not working properly.  It would rise very slowly and sometimes not go down when I stopped the car.  Cycling it while parked would be very unreliable.  I decided to remove the extenders to return the car for service at the dealer.  Once I had the extenders and the wing completely removed, it worked just fine, and I theorized it may be due to the weight of the assembly.  With only the stock wing back on, the mechanism worked a little better.

The dealer found that the control unit had gone bad and they replaced it.  I was a little skeptical at that assessment.  It worked somewhat better after the service, but it still continued to rise very slowly and you could hear the motor really slow down while it did it.  I guess I could have just used the system that way until it would perhaps fail and then get a new motor, but I also wanted to put my extenders back on.  I found that simply placing the extenders on top of the wing was enough weight to cause the wing to no longer rise and work.  The motor was simply too weak to push the weight up, and I had to either forgo the extenders or think of a fix.

One requirement of any mod I would make here is to have it be reversible.  After some consideration, I hit on the idea of adding a pair of springs to compensate for the weight of the assembly.  The stock wing (non carbon) is about 6.5 lbs, and the extender kit (four bolts, and two caps) were 14 oz.  I went to the hardware store and after lots of brain storming and tests came up with the idea below.

Diagram of the helper spring installation.  The view is toward the passenger tail light
from inside the trunk.  Note that I taped a flag onto the shaft to show its
two different positions.

The wing is operated via a drive shaft that rotates about 45 degrees (when facing forward, it pitches up).  The mod consists of a lever that clamps onto the drive shaft, and a spring then pulls on the lever to form the assist mechanism.  Based on the capacity of the spring (about one pound), and the length of the lever, I would estimate the torque assistance to be about 4 to 5 inch-lbs.

Parts used for the assembly. Obtained at Home Depot.

Video of helper spring in action

I have had this assembly in place for the past few weeks and it appears to work extremely well.  The rise and fall time is now well matched and it the mechanism works smoothly and silently.

This project reminds me of an idea I had earlier in the year where I was wondering about using a linear actuator to raise the rear wing in a manner similar to the LFA.  I would need two of them on each end of the wing.  It turns out that there are four holes in the top deck of the trunk that these actuator rods could go through, and it could be a mod that could be added and removed without exterior modifications.  I purchased one actuator as a test, but did not pursue the project any further.

Linear actuator commonly available on Ebay. They can support many
hundreds of pounds in compression, but the bending load is unknown.

February 2020 - A/V Jack Connection
I did some investigating on how to feed an audio/video signal into the main dash display.  It turns out that there are several standards for the "4-pole" A/V plug in the armrest compartment as the following diagram from Rocket_Scientist shows.

Two possible pinouts for the A/V plug.  The RC F uses the BOTTOM format.

It turns out that I have cables from both types in my spare parts bins, and I used the top type initially.  The video was very distorted and there was a lot of hum.  I then dug up the second one and it worked fine.  Using my meter, I 'buzzed' out the connections and that confirms the match to the above two diagrams.

In addition to different pinouts, the two cables have different looking
4-pole plugs.  The compatible one is on the BOTTOM.

To mirror my iPhone, these are the components I used.

It is possible to mirror the phone on the dash display.  To do this, I used the above components.  The top is a Lightning to HDMI converter ($15), and the bottom is an HDMI to A/V converter from Ebay ($9). 

Phone mirrored on the dash.

In order for the video to be displayed on the dash, the A/V needs to be selected (under Media), and the footbrake (E-brake) needs to be pushed down at least partially to activate the sensor switch.  In the future, I may look into a camera that gives me a view of the right edge of the car to better avoid curbs when I turn (some also add a camera to the front to avoid hitting th lip).  I could then select the camera with one pushbutton ("Media" button on dash), and then another switch that temporarily closes the E-brake button.  This would not have any effect on braking, but it would produce an annoying beeping tone.

March 2020 - trunk spoiler
After adding the rear wing extenders, I have always felt the very back end missed something.  So I have been looking for somthing to finish that area.  I like this one from Nia, but the price ($550) was a bit higher than I wanted to pay.  During the COVID-19 pandemic we were staying home a lot and it is during that time that I found this inexpensive ($55) trunk spoiler from Dealer Choice Parts.

This sequence shows 1) with no trunk lip, 2) with, 3) spoiler extended

As you can see in the above sequence, the new spoiler lip is wide enough that it may interfere with the stock wing if the extenders were not present.  Update: this spoiler lip is wide enough that it does interfere with the stock wing (from FB exchange).

Video on Youtube

April 2020 - Red Stripe

The red pin stripe was added by using 1/4" vinyl tape.

June 2020 - Phone Holder
A problem that many have is how to hold the phone for use while driving.  I need it mainly for running nav apps such as Waze.

I had the following requirements:
After some positioning, I realize that making a simple bracket out of sheet aluminum that mounts by the clock in the dash was the best option. 

The bracket simply slides into the gap above the clock.

It is super easy to drop the phone in to the holder. 

October 2020 - Matching Rear Spats
When I received my Artisan Spirits side skirts, they did not include the rear spats (part behind the rear wheel).  I tried buying only those small parts from Artisan, but received no reply.  After some routine checking on Ebay for RC F parts, I found that someone had started making replicas (seller: carbon_aero), and that the rear spats were available separately.  I paid about $300 for the pair.  Although the carbon fiber weave is really nice, it does not match the gloss black.  I will use them that way for now.

rear spats

Installation was not trouble free, but neither were the authentic side skirts.  I am super happy with the way they round out the sides.  I used 1/4-20 threaded rods and stainless nuts to mount them and that allows them to be adjusted. 

At this time I also placed the 'F' badge on the side skirts.  These were inexpensive and from Ebay.  The bottoms are concave and I was concerned about the poor contact with the double sided adhesive.  To address this I filled them in with hot glue.  They are a good match to the authentic emblem.

November 2020 - Mirror Caps
These cover the sideview mirrors and are made from carbon fiber and were bought from another member of the RC F Facebook group.  I am not a big carbon fiber fan, but since the car is black, they blend in well.

April 2021 - High performance air filter

K&N air filter

During the install of the K&N filter, I found that the air box has a carbon filter that covers half of the air filter (odd that it is just half), but the thinking is that it does not impede performance.  Typical improvement with the K&N installed is small, perhaps 2%, but due to the large engine it means a gain of about 10hp.  With the Borla, the heat shield, and this, it should put me at the 500hp mark at the crank.

May 2021 - Stop/Start Button
A cosmetic enhancement from is a machined aluminum red Stop/Start Button.  It is a good match to my red interior.

August 2022 - Mirror Power Tap

View of connector above the rear view mirror with the cover removed

In the 10-pin connector above the mirror, there is present: unswitched power (top left, above the blue), switched power (blue), and ground (purple wire to the right of the blue wire).  I found that using 24 gauge pins from a D connector worked well to tap this without splicing.  I simply attach wires to the pins and insulate them with some heatshrink.  This is then inserted into the back of the connector and can be done without demating it.

Two-wire cable with pins inserted into the back of the connector.
This taps the Switched Power.

August 2022 - Dashcam
I installed a AZDOME "4k"dash cam to the above power tap.  One requirement for me was no display.  This unit was quite inexpensive at less than $100 and had a front and back camera.

I had a 12V to 5V switching converter available that fit into the wire cover.

5V converter installed and everything is very clean with the cover installed.

Sample image of a car 20 feet away. 
Full view at top (reduced in size to show FOV)
and cropped native resolution.

June 2023 - F-Wing
RR Racing developed a spoiler enhancement that really captured my attention as it closely resembles the configuration of the Track Edition, but that maintains the function of the active aero.  It not only sets the spoiler up higher (somewhat cleaner air), but also adds side plates that I think act similar to winglets.

When I first received the kit, I was a bit concerned about the additional weight on the stock spoiler mechanism.  At this point, my spring mod had been in place for four years, and it has worked flawlessly ever since.  Before their installation, the active spoiler worked eratically.  I temporarily taped the new support beams onto the back edge of the spoiler and saw that it was only able to very slowly deploy upwards.  So the first thing I did was to increase the pull force of the springs by shortening them by 2/3.  The spring has about 30 turns, and I removed 10.  This increased the pull force so that actuation time was more even between rise and drop.

I then installed the kit and I think it looks really nice with it.  Fortunately, I have a black car, and it all blends in with the existing look.

Shark with RR wing conversion
Spoiler enhancement attached.

Some tips /observations for the assembly:
- Guard against dropping a bolt or socket into the lid of the trunk.  This is easy to do as you are working through holes in the trunk wall.  If a socket gets hung up on the edge of the hole and pops off your driver, or if you drop a bolt, you are in for a world of problems.  That occurred to me as I dropped one of the spoiler bolts into the trunk lid wall but was fortunately able to retrieve it after a harrowing hour of work.  So to prevent this from happening again, I put a magnet into the socket to hold the bolt and taped the socket to the extension so it would not pop off.  I also feel the best way to remove the bolts is to do so with the trunk almost closed so that if it drops, it will fall into your hand.
- As you can see below, the cover plates did not exactly line up with the mechanism.  This caused the plate not to sit flat on the actuator.  I initially did not think this would be a problem, but after I mounted everything, there was enough of a twist between the two posts that the mechanism would not smoothly rise and fall.  I addressed this by using a round file to open up the bottom hole.  By the time you read this, RR may have fixed this issue.
- If you have a stock spoiler (vs an aftermarket long tail), be sure to remove the rubber bumpers on the bottom.  The best time to do this is once the spoiler is completely removed and you can flip it upside down.  It took me a long time scraping the residue with a plastic card and alcohol.  Just take your time and be thorough so that the plates have a good place to adher to.  I stuck the unneeded bumpers to the underside of the metal trunk lid so that they don't get lost and I see them if I decide to undo this mod in the future.
- At this point it is a good idea to replace the stock spoiler bolts with M6x1 fasteners hex head fasteners.  Previously (when adding the Lexon extenders), I striped the heads on several of the stock bolts and had to drill them out to remove them.  I believe they were the JIS standard and easy to strip.  I have heard of others doing this when replacing the spoiler mount.
- It is possible to swap the end plates.  I think it actually looks better that way, but I decided to follow the way the Track Edition is configured.

The true test of a proper install is to see if the mechanism is able to work at 55mph when the air is pushing down on it.  Running a test shows that there is enough asist in the spring to allow the spoiler to work and it rises nicely in my rear view mirror.  Fortunately, it is high up enough to not block my vision out the back, and it looks cool to see the entire curve of the spoiler in my mirror.  Rafi from RR Racing let me know that this mod has been tested to 170mph.

Alignment of cover plate
The cover plate over the mechanism did not have the
correct hole spacing and it did not sit flat.  Both plates had
this issue and this introduced a twist into the spoiler.

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