After months of reading forums and searching for stereo upgrades for my 2015 RC 350 F Sport’s stereo (Not ML), I finally decided to start a build of my own. I figured since many of you are discussing this, perhaps I should share the progress of my build - if only to share ideas and lessons learned with all of you.

Truthfully, the highs in my RC didn’t sound that bad when properly tuned - what I needed to do was fix the mids and low end right away. So, I got started with adding subs and an amp.

Step 1: Get power to the trunk

I started with a T-Spec Breaker, which I have used many times with good success. However, after two failed units, I moved on to a breaker from Rockford Fosgate. I temporarily installed the breaker using zip ties - just to ensure I liked the placement and no issues were presented (like another failed breaker). I’m waiting on an order of ABS and then I’ll machine a new bracket for this.



Getting the power wire pulled to the trunk wasn’t anymore difficult that most cars - in fact I found that the panels and back seat of the RC were much easier to remove than other cars. It’s almost like someone put some thought into building this thing.

Step 2: Mount Amplifier, Line Output Converter, and Obtain Signal






Apologies, I forgot to take a photo of where I tapped into the factory amplifier. The factory amplifier is located on the right side of the trunk - exactly opposite of where I’ve mounted my amplifier in these pictures. To prepare the factory signal for the amplifier, I ultimately chose to install an Audio Control LC2i - my personal preference. Don’t knock the mounting, I didn’t have any material other than MDF to build a bracket. I’ll upload a picture of the LC2i with the final bracket install when I tear the trunk apart again. Anyway, the LC2i came in pretty handy later when I was trying to correct the weird rolloff that Lexus limited the factory subwoofer to.

The amplifier I’m using is a Kicker CXA1200.1. I already had the amplifier from a previous build and the fit was too perfect to argue with. I hope to replace this with an Audio Control amplifier someday - but not just yet. I also installed the remote for the amplifier into a factory “blank” location on the driver side dash as show below:




I’ll get into some headunit modification that I did and the subwoofer box and beauty panel build in the next post.

 

As I mentioned in my last post, I made a few modifications to the head unit in my RC. First, I didn’t know if any of you have experienced this, but I bought my RC used (certified) and the screen had an anti-glare coating that was scratched in unbelievable ways. BY FAR the most annoying thing about the car when I first bought it.

So, I got a wild hair one day, pulled the screen from the car, and took some Meguir’s PlastX to it with a buffing wheel. Slowly but surely, I removed the anti-glare coating and actually found the screen not only more attractive, but easier to see in daylight. I’m not sure what that coating was for, but its gone for good!

Before: Who/What does this!?




After: This is how it was supposed to look all along!



After I could actually see the screen, the frustration of not doing my research and buying a car without Apple CarPlay started to weigh on me. A good friend who drives an IS-F is also a Lexus enthusiast, recommended I look into GROM Audio’s VLINE adapter. If you have no idea what I’m talking about, strap in, your life is about to change.

GROM Audio built a small Android device that runs Android Oreo (at the core). Then, they utilize an auto-launching app call Dashlinq that, essentially, creates a UI that is driver-friendly. GROM sells kits for the RC that include all wiring harnesses and integration adapters needed for their device to sit inline between the factory head unit and the amplifier and screen. Once installed, you can change the source to AUX on the head unit and the GROM adapter will be displayed on the screen. Impressively, GROM was able to fully integrated with the trackpad, home, menu, and back buttons. So yes, you get full control of the unit with the Lexus controls on the console as well as the steering wheel.

Now, in fairness, to get Apple CarPlay to work, you do have to either install a new USB port in the center console (that can connect to the VLINE’s MFI certified USB port, or you can elect to run a USB cable directly to the VLINE module itself. I chose the install a new USB port in the center console - replacing the cigarette lighter that I never use.

With this installed, I’m happy to report that I have a full functioning factory headunit, complete with CarPlay.




Now, in fairness, there are a few bugs that GROM hasn’t worked out yet - at least in my case. Making calls works, but has significant echo for remote callers. As a work around, I leave my phone connected to the factory head unit via Bluetooth and the factory head unit is smart enough to override the VLINE when a call comes in and automatically switches back to VLINE mode (AUX) when the call ends.

In addition, I occasionally get a flicker on the screen - which only happens once or twice when I start the car and then doesn’t appear again.

I have open tickets with GROM for both of these issues and their support team is extremely responsive. In fact, they’ve sent me multiple code trains and firmware packages to resolve bugs along the way. These are the only two outstanding issues I have.

Oh, and if you’re wondering if this supports Android Auto, the answer is yes - but that’s just gross.

Next post, subwoofer box build and beauty panel!

 

Alright...

As a reminder, when I started my build I wanted to reuse equipment from my previous build (F-150). I also wanted to maintain as much trunk space as possible since I travel extensively for work and need to fit a suitcase in the trunk 3-4 times per month. As a result, I decided to stick with the 2 Kicker CompRT 10” subs that I had in my truck.

I reached out to Mark at CarAudioFabrication for a box design, sent him some measurements, and got a PDF design a few days later. Unfortunately, I’m not perfect and I freakin’ measured wrong. /smh

I took Mark’s plan, and my modified measurements, and rebuilt the box to not only fit but to provide the proper air-space to the subs. Here are a few pic of the final steps of the box build:








If you’re wondering what the weird bars are on the subwoofer box, those came in handy when I went to mount the beauty panel. For the sake of cleanliness, I’ll post that separately in a second.

 

I thought about playing it cool and saying the beauty panel went together beautifully - but honestly, I must’ve built this d**** thing 15 times before I was happy with the result. The most critical part, and perhaps the only part I got right the first time, is copying the profile of the trunk to MDF.

Here’s a pic of that completed:




I won’t bore you with the details of how to do this as there are tons of YouTube videos that teach the technique far better than I could.

I’ll also spare you the dozens of renditions that failed. Just know this, I used my router table A LOT. All of the upholstery was done by me, and my wife’s Cricut machine gets full credit for the embossed F Sport logo. I used her fancy-pants crafting goddess machine to cut out the logo on adhesive backed foam and stuck it to the panel before I upholstered that trim ring. Yes, it worked, yes I’m shocked, no I don’t think I could ever do it again.

Here’s how the final panel came together:

 

And now friends, you’re caught up.

To be truthful, I sound dampened the trunk and rear quarters while I had everything torn out, but that’s boring to look at and not exactly a feat to get excited about.

So what’s next?

Well, I’m considering replacing all interior speakers with Focal (component set up front, coaxial speakers in the rear). I love the sound of Focal speakers and have used them in my two prior builds. BUT, I’m actually very happy with the sound of the system as-is. I just feel like its almost rude to come this far and not replace the speakers too - especially since I’m going to sound dampen the doors anyway. Besides, building custom brackets to install everything would be fun!

Anyway, I’d love some feedback from those that have installed aftermarket speakers - was it worth it, was there an audible difference, what size speakers did you use, etc.?

Happy modding!!

 

Nice work man

 

Wow. This is absolutely beautiful. Im really interested in the Grom thing. Can you link me to it? How was the install?

 

Here you go: https://gromaudio.com/store/vline/le...n-upgrade.html

Make sure you select your year/make/model/nav options so that you get the right harness.

The installation is pretty straight forward. You have to remove the factory head unit, disconnect the wiring harnesses and install the VLINE harness in between. Then, you have to do the same with the screen. Both are pretty easy to get out but if you get stuck, hit me up and I'll make a video showing how to do it all.

I installed the VLINE module behind the glove box using a velcro strap to attach it to another BCM module back there - although I'm not 100% sure what module I strapped it to. GROM actually recommends you install the unit under the seat but I didn't think the harness had enough slack and I love the out of sight, out of mind approach. Anyway, let me know if you decide to do it - I've really enjoyed it!

 

Thanks! It's been a fun project so far.

 

You should definitely make a how to diy video. That would be awesome!

 

I’ll see what I can do!

In a hilarious turn of events, one of my best friends was driving down the 101 a week or so ago in a blue IS-F and we’re pretty sure he saw you and gave you a thumbs up. Oddly, he’s the guy who turned me onto GROM Audio and is one of the best car audio fabricators I know. If that was indeed you, he said he’s willing to meet up and show you the GROM module, etc. Just PM me if you’re interested.

 

Yes that was totally me!!! How funny!

Definitely interested. I'll send you a PM!

 

Any concerns with the amp overheating ? I installed an HD 1200/1 JL Amp & 2 12"W6 subs and it overheats in about 5 minutes of playing it loud. Stereo shop said it had something to do with the Lexus wiring?

 

I haven’t had any overheating issues with my amp. I run a Kicker CXA1200.1 and have taken long road trips between Nashville and Jacksonville have never had an issue...

 

Dude, I love the cleanliness of this setup! I am wanting to add a sub in my RC too as I came from an IS with the ML system and definitely miss the kick along with some of the clarity/definition in other portions of music(but not going to down that rabbit hole.... again). I had a powered sub setup from Rockford Fosgate in a VW I owned awhile back and am considering going that route again just for simplicity of installation, but this is definitely catching my eye..