Team Losi XXX-S: Drop your weapons
Gonzalez, George M
The engineering staff at Team Losi started with a clean computer screen when they set out to create the new XXX-S (Triple-XS) touring car. Their goal was to design a car that would be more efficient and easier to tune and maintain, and that would make it through a five-minute race without getting tweaked. On-track performance, however, was always the most important design criterion, and it was hard for chief designer Gil Losi Jr. not to grin when he filled me in on the prototypes latest successes. Triple-XS prototypes have been tested on tracks around the U.S. and the world, and early reports tell stories of faster lap times and shattered track records.
The preproduction Team Losi Triple-XS touring car shown on these pages accurately represents the final production cars. Unfortunately, this vehicle is not a “driver,” so we’ll just have to wait patiently for the production vehicle to be released before we can properly evaluate its performance. But features such as its completely sealed, single-belt drive train, quick-access spur gear and diffs, adjustable front and rear hinge-pin angles and roomy chassis layout with flexible battery mounting are sure to make the Triple-XS a very hard act to follow. Judge for yourself.
FRONT SUSPENSION
The Triple-XS has the same bottom-loading Hard Body aluminum body shocks as the Street Weapon, but you won’t find any other suspension parts from the Weapon’s parts bin. The shocks are bolted to a molded shock tower with several upper shock and inner camber link mounting locations to choose from, and the long suspension arms pivot on steel hinge pins that are held in place by separate front and rear suspension-arm mounts, Depending on which mounts you use, you can select one of three front anti-squat settings (0, 2, or 4 degrees). Steel turnbuckles are used to adjust camber, and optional hub carriers give you several caster options. The front and rear width is at the ROAR/ IFMAR-legal 190mm. Front swaybar mounts are molded into the suspension arms, and the bulkhead is ready for the soon-to-be-released optional swaybars. The production Triple-XS will sport a foam bumper in addition to the sleek-looking molded unit shown here. The production kits will also include a body, but Team Losi has not decided which one to include. The Triple-XS has adjustable body mounts and is 190mm wide, so finding replacement bodies will not be a problem.
STEERING
The Triple-XS features a conventional dual-bellcrank steering system. Each bellcrank arm pivots on metal bushings, but racers can add bearings for even smoother performance. After years of testing, the designers found that most racers preferred the maximum Ackerman position on the Street Weapon’s bellcrank arms and rarely used the optional mounting positions. For this reason, there aren’t any optional steering-link mounting holes on the bellcrank. The best news is that the Triple-XS features 8/32-inch axles and includes both Losi-style and 12mm hex hubs. That means you can bolt all standard, zero-offset, 12mm wheels onto the Triple-XS, and you can still use your Street Weapon rubber from last season. The production kits will include Lost mesh wheels, racing tires and shaped inserts.
REAR SUSPENSION
The rear suspension-arm mounts can be changed simultaneously to provide toe-in and anti-squat adjustment. MIP CVD axles are provided in the front and rear. The axles are not swept forward or rearward as they are on some other models, and the neutral drive-shaft angle increases efficiency and improves handling. According to Team Losi, you can access the front and rear ball differentials in less than four minutes by removing six screws. The diffs use the same balls, rings and thrust-bearing assemblies as Losi’s popular Triple-X and Triple-XT off-road vehicles. This is a blessing for the Losi faithful and makes it that much easier for Joe Hobby Shop to stock parts. The Triple-XS is equipped with large, 42-tooth front and rear diff pulleys. An optional 41-tooth diff pulley will be available to provide over-drive or under-drive capabilities. An optional front one-way further broadens the ratio-tuning horizons. Setscrews that are threaded into the front and rear suspension arms allow down-travel adjustment. You can easily access the setscrews from under the chassis. The production kits will include a droop gauge for more accurate down-travel adjustment.
SINGLE-BELT DRIVE
The single drive belt is routed around both the front and the rear diff and then pinched between the large-diameter main drive pulley and a bearing-supported idler pulley. According to Team Losi, the large-diameter pulleys have a greater loadcarrying capacity that reduces belt fatigue. The larger pulleys also have more tooth engagement to prevent belt deformation.
The drive belt’s routing system is designed for maximum efficiency. Because the drive belt actually tightens itself under load, it can be set very loosely without the risk of it skipping. The drive train and wheels spin on high-quality sealed bearings.
Although the drive train may seem complicated, it’s actually very simple. It has very few parts compared with other touring-car models, and all of its components, including the spur gear and diffs, can be accessed easily. The drive train is also completely sealed against the elements.
CHASSIS
The Triple-XS features a molded semi-tub chassis made from the Losi’s figid, tough Stiffezel composite (stiff-as-hell, get it?). The long cover that runs down the center of the chassis need not be removed for maintenance; it was designed as a separate part because, if molded as an integral piece, it might have affected the main chassis tweak.
As you can see, the motor is mounted on the left side of the chassis. It is just slightly rear of the chassis’ centerline, unlike the Street Weapon’s motor, which is slightly in front of the centerline. The large opening in the chassis allows the motor to be mounted flush with the bottom for the lowest possible center of gravity; it also allows exposure to cooling airflow.
Spacers installed on the outer hinge pins allow you to move the front and rear axle carriers forward or rearward to adjust the vehicle’s overall wheelbase. This is a powerful feature that makes the car adaptable to both large and small tracks and low- and high-bite conditions.
BATTERY TRAY
Seven battery slots are molded into the chassis’ right side to allow a 6-cell battery pack to be positioned forward or rearward to adjust weight distribution. For added convenience, you can flip the molded battery strap to accommodate either side-by-side or stick packs. Check out how the wires have been neatly routed behind a gap in the chassis behind the spur gear-sweet! Unlike the prototype shown here, the production vehicle will have a 48-pitch spur gear and main drive pulley molded as a one-piece unit. Optional spur-gear/d6ve-pulley clusters will be available for tuning versatility, as will an optional universal spur-gear mount that will allow you to use aftermarket spur gears (including 64-pitch gears). Gearing shouldn’t be a problem because the Triple-XS drive train is designed to accommodate the full spectrum of pinion- and spur-gear ratios. A small rectangular “window” molded in the chassis tunnel lets you inspect the pinion/spur-gear mesh: the opening is sealed with a removable rubber cap. The belt tensioner is directly in front of the spur gear and is easily adjusted without disassembly. The buttonhead screw directly above the rubber cap is used to adjust belt tension.
ELECTRONIC MOUNTING
The electronics are neatly arranged on the left side of the chassis. The wires from the ESC are routed through small channels molded into the chassis and then secured with screws that keep them away from the motor. Standard size electronics are used on the prototype to show how roomy the chassis is. You can also see the cam-style aluminum motor mount and locking clamp system, which is similar to the Street Weapon’s motor-mounting system.
THE VERDICT-SO FAR
Does the Triple-XS have what it takes to outperform its competitors in the hotly contested proelectric TC segment? Until production cars start to hit the track, we can only speculate. Losi has certainly held nothing back in creativity and innovation and seems to have thrown out a lot of what most of us take for granted as basic TC design elements. It would have been easy to crank out just another two-belt tourer; instead, Team Losi has stuck to some unique designs that just might point to a better way to build a touring car. We’ll have to drive a production car to confirm that. In the meantime, the Triple-XS looks like a real threat; it has already bettered some long-standing track records in prototype form, and it joins the HPI RS4 Pro 3 (reviewed in this issue) at the vanguard of competition electric sedan designs. This summer’s TC season will be the hottest ever!
SOURCE GUIDE
TEAM LOSI
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Copyright Air Age Publishing Jul 2001
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