Team Academy STR4 Pro II by Murdock
Built to be competitive against Yokomo SD, Tamiya TB Evo, HPI Pro4, and other shaft drive greats. Design and manufactured by Academy who is known for their detailed scale models. The STR4 Pro II was Academy’s flagship touring car manufactured to date. Retail box includes nice purple aluminum parts, adjust shocks, carbon fiber main chassis & upper deck, and sway bars.
Tuning this car was somewhat challenging, and not for novice drivers. Shaft cars are not as easy to tune comparatively to belt cars. All my belt cars with just a locked rear end would all drift fine but not perfectly on their maiden runs. Shaft cars are a lot more trial and error. I knew when I first ran the car is had potential, but needed a lot of tuning. My initial issues were chassis balance. There was a weight bias to the right side with all the electronics. With some weights and exactly 2 battery cycles I found the balance I was after. Then came dealing with the suspension. Most of this was done in parallel to chassis balance. I think I’m close to the sweet-spot so I posted new settings below. Basic ideology was soft in front to control and bit, and slightly stiff in the rear to easily break loose. I ended up disconnecting the rear sway bar.
Once dialed in the car drifts nice. For this chassis I have to always stay on the throttle slightly more then half, and blip the throttle to full gas to kick the rear end out more. You can really feel the double one ways under braking giving the e-brake effect, and when you let off the throttle making the rear end feel lofty. There is some torque steer, and the car pushes a bit while drifting. It felt like it had slight under-steer.
Gearing: Final drive = 6.63
Front: One Way with bevel gears
Center: Shaft drive with Center One Way
Rear: Locked with bevel gears
Spur: 80T 48 pitch
Pinion: 28T 48 pitch