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I frequently spend a lot of time on planes so I thought I’d use a couple of sleepless flights to write up and share my IS-C story…Maybe some of you will find something useful buried in this lengthy post...or maybe some of you will think I'm nuts...everyone's mileage varies.
Although I’m comfortable with working on my 65 and 67 classic cars, I’ve always been hesitant to do mods to newer cars—hence I've leased my daily drivers and traded up every 3 years. After the lease was up on my first 350C, I couldn’t find anything with the right balance of performance, reliability and price so I sought out a 2015 in the configuration I wanted. I was lucky to find a new 350C F-sport in Matador Red but even luckier to find a lot of people sharing their experience and knowledge on these forums—what works, and what doesn’t. This post is a compilation of what I've managed to do with all that knowledge...so far.
The odd years: 2015 was the last year for the IS-C. Lexus had already moved on to the 3rd gen IS Sedans in 2013 and seemed to begrudgingly sell the IS-C until 2016. Today most auto parts suppliers will insist I need a 3rd gen part or accessory and sometimes they’re not aware of any convertibles after 2012. And of course none of them are interested in updating their systems based on feedback from their customers. I’ve learned to research, question, download manuals and make my own decisions.
Wear and Tear: PAINT PROTECTION FILM- The one thing that annoyed me about previous cars (my last IS350C, GS350 and Infiniti G35’s) was how badly beat up the front nose got after 3 years of bugs and rocks. On this car I broke down and had paint protection film installed when it was new. Was it worth it? Probably not. It took several days with a local installer and although the front nose has worn better, it’s not impervious. Rocks and debris have penetrated and chipped the film from the front part of the hood. Plus wax tends to build up on the edges and has to be carefully removed. I suspect it will take heat and adhesive remover to peal this stuff off some day.
The ride: COIL OVERS and SWAY BARS- At some point I started to look at lowering one of my classic cars with coil overs and I wondered what existed for my C. Starting from scratch, I struggled to understand differences between C and Sedan, between 2nd and 3rd gen. I knew I didn’t want an aggressive drop or a much rougher ride than the existing F-sport shocks, so I chose Megan Racing EZ2’s. They’re not the same quality or level of others on the market but suit my needs for now. I found them listed as: Megan Coilover Damper Kit Fits IS250C IS350C Convertible 10-13 MR-CDK-LI09C-EZII (Again you’ll notice 10-13 with no acknowledgement of 2015). I ended up lowering the front by 1 inch, and the back about ¾.
Even with such a small drop, I’ve had a couple of “check headlight system” warnings show up. The High Intensity Headlamps have an automatic leveling system that gets a little confused when you lower the car. I found the remedy in searching these forums is to simply adjust the sensors at the left front and rear suspension. These determine the front-to-back leveling of the car and tend to reach their end stops when lowering—problem seems solved for now.
The F-sport sway bars were fairly straight forward. Although there are other manufactures (like Sikky), I can’t imagine there’s much gained/lost between manufacturers. The Lexus part # PTR02-53100 came with new bushings and had great instructions with all the torque specs. The rear sway bar provided the most improvement in handling—but of course was more involved to install. (B.T.W. Having a lift makes any installation far easier than lying on the ground—but that is another story!)
Once suspension upgrades were completed, I drove it for about for a week to ensure I had the ride dialed in where I wanted—only then I took it into the shop for wheel alignment. In reading the forums, I noticed many prefer brands like BC Racing, Fortune, Tein or even lowering springs for a more aggressive ride—I just wanted some drop so my IS didn’t look too much like my 4x4.
Camping: TOWING- Alright I’ll admit it…towing with my IS-C sounds crazy right? But what could be cooler than pulling up to a campground in an IS-C with a camper attached? You can set up camp and then venture out with the top down.
Lexus says their cars are not suitable for towing—actually it’s hard to find any manufacturer that says you can tow with a car these days. I've heard all kinds of reasons...maybe it's due to lawsuits from wreck-prone-idiots getting into trouble, or manufacturers unwillingness to do the engineering for the few that want to tow, or they just want to sell me a truck. Well, I have a truck…but I want to tow a tiny camper with the top down. And while my 67 convertible is cool looking, it doesn’t have air conditioning…or ventilated seats. In fact the 67’s curb weight is about 500lbs less than the IS with a 50-year old transmission, less HP, less torque and drum brakes. I knew there had to be a solution as my teardrop only has a 120lb tongue weight and is 1050lb dry—nothing compared to the larger boxes I see people towing with lightweight-top-heavy-short-wheelbase SUVs. This one is so light, I’ve been able to move it around by just picking up the front and dragging it.
The TOW BAR: The first questions I wrestled with was can the chassis handle it and where can I find a tow bar? As it turns out, Lexus did sell a tow bar kit for the 2nd gen chassis in Europe years ago. Its rated capacity was around 1600kg (or 3500lbs) so I felt encouraged. I even managed to find the installation manual for the Euro kit online (it involved drilling and sawing which initially discouraged me).
Eventually I sought out tow bar options from one of the most popular trailer companies online and they insisted my 2015 could use a Drawtite tow bar designed for 2013+ IS sedan models—WRONG! The 3rd gen chassis is way different. On my own, I found the only tow bar that fits the IS-C (all years) is the Curt 11047. (Plus I found it on Amazon way-cheaper than what they were selling it for.) Although both of these are Class I hitches rated at 200lb tongue weight/2000lb towing capacity, the Drawtite did seem stronger. Unfortunately Curt has the only option that fits the IS-C (or 2nd gen IS).
The Curt does require trimming the exhaust heat shields a bit, but doesn’t require drilling/sawing into the body. In looking at the design, it also doesn’t seem to distribute the load as well as the old Euro kit from Lexus but is plenty strong for my purposes. It attaches to the 6 bolts holding up the exhaust hangers (3 on each side). The one thing I noted during installation is these bolts seemed far beefier than needed to hold up the mufflers and tailpipes so I looked back at the old installation manual and noticed Lexus originally only had two and used them for their kit as well. (Although they did add a third bolt on each side you that you had to drill holes for.) Based on all this, I have to wonder if these were also engineered for a kit and then never used for anything more than the exhaust.
I may end up putting some reinforcements in if I feel or see anything concerning. But my conclusion is if you want to add a receiver for a bike rack on the back, or maybe even tow something very light, the Curt 11047 is the only option. Be sure to use stabilizing straps for bike racks. And if you plan to tow, recognize you're on your own(as far as Lexus is concerned), learn how to tow safely, and make sure you’re back is clear when you override the sensors to put the top down.
TRANSMISSION: Here in sunny Florida, heat is a consideration when towing. After some research, I discovered the IS did share the same A760E tranny found in many other Toyota vehicles (like the Tacoma). Yes, the ECM controlling shift points is different and some vehicles had optional transmission coolers, but then I’m not really looking to tow a huge load. I decided before I go down the transmission cooler path, I had to have a way to measure the cars vitals--including transmission oil temp. This led me to the next challenge.
OBD2 MONITORING: There’s a lot of live data that can be obtained from the Toyota ECMs. Since it’s not practical to drive around with the Toyota TIS tool hooked up with a laptop, I had to find another way. After yet another round of research (as well as some trial and error), I found 2 good/viable options: ScanGauge 2 and OBD Fusion. Since I only need it as a part-time tool, I decided to buy a cheap OBD2 to Bluetooth adapter for $10, the OBD Fusion app and the 2015 Toyota OBD Fusion add-on for an extra $10. It enabled me to retrieve coolant temp as well as A/T Oil temp. Other tools (like Torque) would only retrieve the standard SAE OBD codes which did not correctly retrieve the A/T information or any Toyota-specific ECM data.
A couple things worth noting: I did try all the custom PID’s I could find for Torque Pro but nothing worked. Plus I have both iPhone and Android so I was able to compare different tools/interfaces. The iPhone requires very specific and more expensive Bluetooth OBD2 adapters (like OBDLink’s MX+). Fortunately the OBD Fusion app exists on both platforms and works reasonably well.
BRAKE LIGHTS AND TURN SIGNALS: This was relatively simple—although I did have to get creative as my camper has a 7-way plug. With some difficulty (and scratched up hands) I installed the Curt 56142 kit without major disassembly of the trunk. This kit has y-adapters to the rear tail light harnesses so no modifications are necessary to wiring. I cut a chunk out of a rubber plug in the trunk floor near the spare tire and ran the wires through and around the body and splash guard. I did have to buy a separate 7-way socket and mounting bracket as well as splice a few wires. I tapped a constant 12 volt battery line off on an open fuse socket at the fuse panel for the retractable top.
TOWING BRAKE CONTROLLER: So the reason I needed the round 7-way socket is that my Little Guy Silver Shadow camper actually has brakes—a huge safety feature that I would’ve added anyway. I started to research brake controllers but didn’t want another wiring project on my car. Albeit expensive, I found 3 wireless options:
Autowbrake: I’ve used Autowbrake on the car hauler and it works well although you get no feedback and no way to adjust trailer brake power from inside the vehicle. The cool thing is it physically attaches to the trailer and automatically turns off if the tow vehicle has a controller. The downside is it does need to be hard-wired on the trailer.
Curt Echo: I purchased this relatively new product that is a cylindrical appliance that attaches in line with the trailer harness. It connects via Bluetooth to either an iphone or android for adjustments and manual braking. Although it works well for me, I’ve read some feedback that this controller has random issues. My suspicion is many people are unaware of what their factory 7 way plug is doing and it adversely affects the performance of this controller. So far, it works well for me. The only concern I have is there’s no way to secure it so I need to be careful about leaving it attached when the car/camper is parked unattended.
Tekonsha 90250 Prodigy RF: This is my backup option if the Curt doesn’t work in the long-term. Like Autowbrake it attaches to the trailer but has no additional wiring. It also has a remote that plugs into a cigarette lighter outlet that allows for adjustments similar to the Curt.
TOWING TESTS: After establishing a baseline for my coolant and A/T Oil temps in the hot south Florida weather, I hooked up the camper. I was nervous and drove a bit conservative but didn’t feel the car struggling or twisting whatsoever. I drove on both expressway, and back roads with stop signs and traffic lights. And what was the difference after hours of tests? Nothing…In 90+ degree weather the A/T Oil temp peaked at 206.4F both with, and without the trailer connected. The coolant never exceeded 195 in either case. The only thing I could feel was a little extra bounce on the back end when going over bumps at high speed. My conclusion at this point is I feel fairly confident that I’m not over-stressing the drivetrain or chassis. All I have left to do is plan a few camping trips.
ANCIENT NAVI SYSTEM: One drawback to buying the last of the 2nd gen cars is that I miss out on some of the new technology. I’ve owned several cars with navigation and even though they eventually added Bluetooth and some integration (Lexus Enform), they fall well short of keeping up with advancements in the technology industry. On occasion, I researched upgraded head units but quickly dismissed them due to questionable integration or the non-stock look of the products. And then by accident, I found forum members discussing the Gromaudio product.
This Android-based upgrade is somewhat pricey ($600) but doesn’t change the stock look of the car or impact the functionality of any controls. The only visible addition is the GPS antenna on my dash—which is smaller than my toll pass. After reading through the hundreds of posts (both good and bad), I decided to give it a try. Most of the negative posts were from early adopters and since it’s basically like an android tablet, my expectations were already managed.
Once again I was faced with the odd year challenge. Lexus has conflicting information out there regarding the non-ML Navi systems in 2015. Although it looked identical to my 2012, they did change the Navi in 2013+ and had incorrect information about the 2015 posted. I submitted the question to Gromaudio and received an immediate reply: I needed the Gen7 version. I was a bit skeptical after my adventures with other parts but I ordered it anyway. The good news is they knew their stuff. It fit and performed exactly as advertised!
Installation was what I expected—there are a number of videos to help with removal and some tools & techniques needed to ensure you don’t damage the dash. I hid the grom box in the glove compartment and until I switch to the Aux input, I can’t even tell anything is installed.
One of the coolest benefits is that it seamlessly integrated with the cars built-in microphone and navi touch screen. I was even able to install the Curt Brake control and OBD Fusion apps. Performance is acceptable—although it could be better. Connecting to my hotspot and the OBD adapter can be slow at times but is rock solid once it syncs. I changed the default launcher app to Agama Car Launcher for a nicer customized look for the home screen.
Having an open platform Android compatible device in the car offers a lot of customization opportunities and really advances the Navi beyond what’s available in current cars. Of all the upgrades, this is the one stands out. Thanks Gromaudio!
WHAT’S NEXT?: At the moment, I’m focusing on the resto-mod of my 65. I may look at more suspension changes to tighten up the Lexy a bit more. While I don’t want to lower it any more, better coil overs, control arms, bushings and stickier tires may be on the menu…who knows? Right now it’s a fun car to drive in sport mode with the top down.
I hope some of this long story has value. Comments, thoughts, suggestions and yes even criticism welcome. I’ve learned a lot from others experiences so it’s all good. Thanks again to all that took the time to share their experiences!
This is a great post, I like it. I actually thought about doing something like you said and monitor the transmission oil temperature since it will come in handy if I'm driving my car hard on the track.
Thanks for this post. I might add that curt hitch for my bike rack. Though I'm not sure I'd want to use the stabilizing strap on the trunk, I might have to figure out a way to use it and hook it inside the trunk to keep it stable....
Holy cow!! thanks so much for sharing this.. I especially like the trailer hitch info, as I like to ride my bike and need to get it to where i like to ride, so thank you very much!!
Ok I contacted eTrailer to get their input on a IS350 convertible so they sent me this message: "Yes, the curt trailer hitch #C11372 is a confirm fit for a 2012 Lexus IS 350. " So I'm guessing both "Curt 11047" - mbski (OP) and the "curt trailer hitch #C11372" would fit out car. I don't know when I'll be ordering but maybe I'll get it sooner than later to enjoy dragging our bikes around while it's summer.
Ok I contacted eTrailer to get their input on a IS350 convertible so they sent me this message: "Yes, the curt trailer hitch #C11372 is a confirm fit for a 2012 Lexus IS 350. " So I'm guessing both "Curt 11047" - mbski (OP) and the "curt trailer hitch #C11372" would fit out car. I don't know when I'll be ordering but maybe I'll get it sooner than later to enjoy dragging our bikes around while it's summer.
Just as an FYI, eTrailer told me the Drawtite would work. I've learned to double check their advice.
Here are some pics for those who might be interested in adding a hitch. Very low profile that you really don't notice it. The greyish looking area is the black reflective tape I placed to cover the curt sticker and just for safety at night.
UPDATE ON TOWING: I just returned from my first camping trip and I'm happy to report the camper and setup performed perfectly. (Plus I received a number of envious comments at the campsite and other places I stopped along the way!) The car, transmission, hitch and brake controller all performed as expected. I estimated my trailer loaded with stuff/water weighed in around 1400 lbs with a tongue weight of 130 lbs. At some point over the next few weeks I'll get the car back up on the rack and do an inspection but from what I can tell, all worked perfectly.
I do want to make one correction to my original post, the A760E transmission is the same one used in the 4.6L Tundra and Sequoia (I said Tacoma).
And as far as the transmission temperature is concerned, here is a graph of my 3 hour drive home (with a half hour break in between). I collected a lot of data but for a simple visual I charted only coolant temp, transmission temp, ambient temp and speed (I stayed mostly around 67 MPH).
Of course with my new found confidence I'm planning my next trip ;-)
Great post! I installed the V-line and love everything about it except that when I'm talking on the phone I can't see my navigation. I've read here that some models revert back to the V-line after 30 sec. I would really be happy if there's an update or someone figures out how to get that on the IS convertible.
One thing I added to the v-line was a small trackpad. I wanted to be able to control the v-line from the console without constantly reaching for the screen. I snaked the wire under the right gray plastic molding piece and mounted it next to the cup holder. It is really inconspicuous and works well. It's a little pricey for what it is on Amazon but was well worth it for me.
Also, I mounted my box under the driver's seat. I know everyone recommends the glove box but I didn't want all that mess in my glove box. I seems to work fine for me so far.
I want to be able to cart my bikes so I'm going to go for the trailer hitch. Does it result in any permanent drop in the muffler position or is the drop only temporary for the installation? Some people on Amazon complain about the rear bottoming out heading down curbs. Have you found that to be an issue for the IS C?
Hey, great idea going under the seat. I may move mine.
For the screen switch, I think it's the lexus navi controlling the screen and preventing it from going back to the V-line while in a phone call. I haven't figured out how to overcome that yet but imagine it's possibly a Lexus setting.
I thought about potential muffler drop, but frankly I can't even tell. At most it's 1/4". The coil-overs (and even my original F-sport shocks) are so stiff there's no chance I can bottom even if I exceed the tongue weight of the hitch.
06-07-19, 06:49 PM
IS-C mods for dummies...like me
