The ultra-competitive Thailand International Touring Car Championship TITC event saw very tricky conditions this year, with a very high grip surface & tire (Sweep D40R), as well as a technical track layout which was largely affected by bumps. Our team worked meticulously to find the right setup during the week of open practice. These were our findings:
The XRAY X4'24 carbon chassis kit configuration is what worked the best and is what seemed to have the biggest setup window throughout the changing track temps each day. The lower arms in medium material, as opposed to hard, also drove better over bumps.
Mounting the spool and differential in the low position in both front and rear made the car easier to drive, mainly in the two chicanes in the middle of the track.
The active rear shock tower provided improved bump handling and more consistency.
A wider rear offset compared to front, took away a bit of mid corner rotation, and greatly improved drivability.
A rather soft progressive front spring (2.4-2.7) made the car initially less nervous, and reduced traction rolling. A stiff 2.8 linear rear spring reduced squatting on-power, and thus, improved forward bite. We even ran a 2.6-2.9 rear spring for the "high grip" runs of the day, to lock in the rear more, and improve drivability.
Raising the front lower arm (to have the same lower RC in front and rear) reduced pitching, and stopped the car from getting onto the nose as hard in the infield section.
The motor mount setting should be considered rather stiff, with all screws used apart from the front furthermost one. This also gave better consistency over bumps.
Several elements from our 2023 TITC setup remained, such as the rear T-brace (using 2 screws) to reduce rotation, and to increase stability. A reduced rear caster setting (1.5 degrees) also provided better bump handling, as a result of the longer wheelbase.
Most importantly, gluing of the front tire sidewalls was important, 60mm in this case, to reduce traction rolling, especially on fresh rubber in the cooler conditions. We also reduced front camber to further aid this effect. I've made a video on how to glue front tire sidewalls.
Tire heating was necessary with this Sweep D40R compound tire, and to a rather high temperature. Thin additives such as Mighty Gripper V3 Yellow gave the best initial grip, but more fade. Additives with more oil content, such as Mighty Gripper V3 Orange, or HUDY Asphalt (which I ended up running) made the car feel more "in the track" but perhaps with a bit less steering.
Electronics:
I ended up running a Hobbywing ESC set-up very similar to that of Bruno Coelho RC Driver. It felt smooth, powerful, and made me have the highest recorded top speed of all drivers in the A-final (114 km/h). The optional 12.1mm rotor is a great choice for any track where you require a smoother bottom end power.
The brand new Nosram ULCG Modified Graphene 4.1 6500 packs impressed me a lot. 6000+ real capacity (when charged full from 3.3V per cell). It's simply the perfect pack for modified TC racing outdoors!
Bodyshell:
I ended up running the Xtreme Twister UL (with stiffeners), to be able to replicate the set-up of Bruno. I also tested the brand new LensBodies Ghibli 2.0. It had the same speed as the Twister. It had a bit less initial, but more mid corner steering than the Twister. The included and improved wing also provides a lot of downforce. I ran vertical body posts, which I usually prefer for modified racing outdoors on fast tracks.
