Friday, April 17, 2009

A Tale Of Two Porsches

SCX surprised everyone back in 2007 when they first introduced the Audi R8 Pro Car. Here was a mass producer of slot cars bringing a car to market that was loaded with goodies: setscrew wheels and gearing, adjustable chassis, interchangeable motor pods, and lightweight racing body. What surprised me even more? Getting beat at my club by a race tuned SCX Audi R8. Then, last year SCX introduced the Pro Porsche 997. Is it really any better than the standard SCX Porsche 997? How does the Pro Porsche compare to Porsche 996/997 models from other slot manufacturers? Let’s find out!

Let’s start by looking at what comes in the box. The Porsche 911 GT3 Cup Pro (50590) comes attractively packaged in a box that could double as a pit case in a pinch. Inside the box are the Porsche’s chassis, body, motor, extra motor pod for boxer type motors, an extra guide, some extra braid and screws, and an extra mechanical brake shoe. The body is decorated in a racing livery from the Carrera Supercup. Also included is a glossy covered booklet: Driving And Maintenance Guide. Interestingly, the guide is illustrated with photos of the Pro R8. Fortunately the Porsche’s chassis has adjustments identical to that of the Audi so the instructions do apply. The guide book lays out in simple terms how to assemble and adjust the Pro car. While more experienced slot racers might take car setup for granted, someone new to the hobby will find this to be a valuable resource. The booklet goes one step further and presents a few basic racing strategies. Again, this will be useful information to someone new to the hobby. If you’ve bought a Pro Car and haven’t read the manual (tucked under the foam rubber packaging) it really is worth a look.

Putting the car together is a snap. Only two screws hold the body onto the chassis. A closer look at the body screws shows that SCX has sweated the smallest details of this car. The smooth shank of the body screws allows the body to float without interference from the screw’s threads. SCX has also provided more a highly adjustable chassis for the Porsche Pro Car. The adjustments include front axle ride height, motor pod float front and rear, as well as the usual adjustments afforded by setscrew wheels and gears. SCX even includes a hex driver to help get the job done.

At the heart of this car is SCX’s potent RX4H motor. This powerplant has been tested to 26,000 RPMs! A far cry from the mild-mannered RX42B that came installed in the standard Porsche. Let’s pay the standard car some attention.

While at first glance the standard and Pro Porsches look quite similar, they are in fact two totally different cars. Where the Pro car sports a half pan interior, full front axle, and RX4H motor, the standard car has a full interior, front stub axles, and RX42B motor. I know that a lot of slot racers aren’t a big fan of stub axles since the performance advantage of independently rotating front wheels is normally lost by the play inherent with this type of design. SCX has made the effort to get it right.

There is minimal play on the front wheels of my test car, and both wheels spin freely. I suspect that the stub axle design is a result of SCX designers making room for the digital chip and lane changing mechanism. Another benefit of this design is that there’s lots of room for weight placement which is a boon to non-magnet racers. Other differences to note between the two cars are the Pro car being 2.4mm wider than the standard car, and the standard car uses 5 screws to hold the body on vs. the Pro car’s 2 screws. The Pro car is also 5g lighter than the standard car, tipping the scales at 75g vs 80g. While the standard car does not have an adjustable motor pod, it does have SCX’s excellent 4 post motor pod design which effectively decouples the drivetrain from the body/chassis. The standard car also features functioning headlights and tail lights.

As good as both of these SCX cars look, they are destined for a life on the track, not as shelf queens. The Pro car ships without a traction magnet whereas the standard car has a typical SCX adjustable bar mag. Out of the box the standard car pulled 85g yielding a 9.044s fastest lap around my 22m test track. A quick adjustment with a screwdriver boosted magnetic downforce to 293g and saw the lap time plummet to 7.278s. For the sake of comparison I tested a few other Porsche 996/997 models in my collection with magnets.

Here’s how they stacked up with traction magnets in place:
• 6.610s – Scalextric Flying Lizard Porsche 996 (comes stock with a hotter Sport Plus motor)
• 7.278s – SCX Porsche 997
• 7.503s – NINCO Porsche 997
• 8.343s – Scalextric Red Bull Porsche 996

When it came time to remove the traction magnets, I first tested each SCX car with stock tires, and then once again after fitting S2s. The lap times for the Pro car dropped from 9.375s to 8.204s, and went from 11.657s to 8.871s for the standard car. With a bit of weight added I was able to get the Pro car down to 7.784s, and the standard car down to 8.274. I then fitted S2 tires to my comparison cars and recorded some hot laps with each of them.

Here’s how the SCX cars stack up in non-magnet trim against the competition using an S2 control tire:
• 7.278s – SCX Pro Porsche 997
• 8.274s – Standard SCX Porsche 997
• 8.548s – Scalextric Red Bull Porsche 996
• 8.959s – Scalextric Flying Lizard Porsche 996
• 9.328s – NINCO Porsche 997

Clearly SCX has raised the performance stakes with these Porsches. While hobbyists will pay a premium for the performance of the Pro car, the standard SCX Porsche is an excellent value for the money. It can be made into a competitive race with only a bit of ballast and a better set of tires. For someone looking to make the step to a better performing car, the Pro car is an excellent choice. The range of setup options will be beneficial to someone just starting to learn about slot car tuning, and will give the seasoned racer an excellent platform to build on.

Van LaPointe

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