Friday, May 11, 2007

Slot.It McLaren - review

The release of a new car by Slot.It always attracts attention. The BMW McLaren F1 GTR seems to have attracted more than usual, due to its good looks and better-than-ever performance.

The car weighs 74 grams in stock form with the magnet. Without the magnet the car weighs 73 grams ...not much difference.

As noted in other reviews the front wheels can rub on the inside of the fenders, and maybe the headlight buckets. This was not a problem on our test car. However, there are small stubs of plastic on the inside surface of the hubs where they ride against the uprights. These little bumps cause the front wheels to wobble severely. Fortunately it's a simple fix to cut them off with a knife, and makes a huge improvement.

The wheels inserts don't fit well. Either the inserts are on the very edge of the wheel and not pushed back inside the wheel as they should be, or they're pushed inside the wheel at an angle. And one of the inserts has cracks on 3 of the spokes. The look of the inserts is nice, just the assembly seems poor.

As your eye runs along the angular lines of the body you see there are small details on nearly every surface of this car. The detail on the tail is particularly interesting, crisp, and precise.

The wires run along the usual channels and under the front axle. The uprights for the front axle are quite thin.

The guide lead of the McLaren measures 100mm, which is the distance between the guide pivot point and the rear axle. With the car resting on a 1/4" rod to test the center point of the balance of the car, the balance point is about 65mm behind the pivot of the guide. In comparison, the Nissan's guide lead is 100mm and the balance point is about 66mm behind the pivot of the guide.

The gears mesh smoothly, with a 9-tooth pinion and a 26-tooth crown. The offset gear arrangement drops the motor shaft 1 mm below the axle centerline, which seems to increase cornering speed and stability.

Testing begins ...on the 61' East New York Raceway wood track. Voltage was set to 13.6v and we used a Prof. Motor 2055 controller.

In stock form (with magnet out), with stock tires and the pod tight, the first laps click off and we get a best time of 5.244 seconds. That is very, very fast for the stock tires still being on the car. The car feels slippery, but feels much better than most cars with stock tires. It handles nicely and has good balance.

Next, the body screws are loosened one turn on the rear and half turn on the front, still with tight pod screws. The car is much faster, easier, and times dropped to 5.156, with consistent 5.2's.

Still with the stock tires, the front pod screws are loosened only half a turn. The car feels not much different. Times stayed about the same. Next, the pod screws are loosened on front and rear a full turn. The pod now feels very loose. Times again dropped to 5.147. But the motor felt like it started to weaken. We stopped and lifted the rear of the car up a bit, gave it some throttle, and saw a red flash illuminate the body from inside! The motor continued to function. Off we went again. Times dropped to 5.101...guess the motor still works, eh?

Next we changed the tires to the S2's which are supplied with the car. Pod and body are still loose. A big increase in grip, and on the first lap the time dropped below 5 seconds, and on nearly every lap, for a few laps, the car rang the "faster bell" on the timer. The car doesn't seem to have any handling vices and never comes out of the slot at the front. Best time dropped to 4.765, and was solidly below 5 seconds on every lap.

Next, the tires are changed to SuperTires silicone tires (#1408) with the shoulders rounded by sanding. Times again dropped to 4.604 at best, with solidly lower times under 4.7 seconds. Down the straights the car feels very fast, much faster than with S2's.

In comparison, the Nissan 390 recently tested with SuperTires, and similar screw back-offs, did a best lap time of 4.723. Despite near identical mechanical specs, the driveability of the Nissan isn't as good as the new orange McLaren. The advantage appears to be the motor pod in the McLaren, which allows more movement of the pod out-of-the-box, as long as those pod screws are backed off.

Several orange end bell motors have been tested by Slot Car News, and the average rpm is about 23k at 12 volts, although the factory spec is only 21.5k/12v.

Of note are the large holes for the motor pod screws, which allow plenty of pod motion when the screws are backed off. The amount of pod motion is larger than seen on any previous, unmodified Slot.It car, and it does seem to help this car go fast. This small innovation is a huge improvement that will hopefully be carried on with every other new Slot It car.

The lap time with this car rival those achieved in the recent Slot.It Shoot Out held at this track, in which 20 modified Slot.It cars were raced, each carefully tuned by racers across the US and Canada. Out of the box, the Slot.It McLaren is a sure contender. A very fast car!

Thanks to Fantasy World Hobbies for the car for review.

Written by Dave Kennedy and Robert Livingston of Slot Car News.

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