11 February, 2003

The CARTRIX BMW Z3!

After the latest acquisition of the Cartrix Boxster, I knew that I wanted to try another selection from them. The BMW roadster looked like a logical choice, the problem was choosing ONE of them! Well, needless to say, my family stepped in and "solved" the problem...

We decided on 4 of them! There are plenty of times that I recommend getting 2 of every car for a more even racing field. We decided that we wanted 4 so that we each had a car we could tune and race against one another. When they arrived, we were pleased to find all of them intact and ready for us to start racing. Something that I should have mentioned before, is that the boxes these models come in also double as handy parts pins. I thought this was a nice idea, and have to give a thumbs up to Cartrix for them.

All the finishes on the models were very well done, and we found no dirt, runs, or fades in the clear-coat. We chose a mix of 2 convertibles, and 2 hard top versions. Mold lines were clean throughout all our models, although there were some gaps present on the hard top versions where they connect at the top. Although not adorned with racing liveries, our drivers are dressed for the track, complete with helmet. The interiors are nicely done, and we felt Cartrix did a good job on what detail there was provided.

Wheels and tires were again a fair effort, however the tires did require some hand tuning to get them true on the wheel. As with all of our models, we sanded these tires to get them as round and true as possible. This helped a great deal on the Boxster, and it repeated itself here. Up front we find the guide, with its double-braided set-up, and although they do have some play to them, it isn't enough to warrant any changes...at least for our home racing uses. The front wheels are held in place by brass post axles, which seem to be very durable, and had minimal free-play.

Underneath you see 4 screws on the chassis, however only the 2 screws in the rear secure the body to the chassis. The other 2 screws near the front are used to secure the motor mount to the chassis. Once the body is removed, we discover that there are some differences between this model and the Boxster. First of all, this model utilizes the front motor configuration, instead of a sidewinder, also a second magnet pocket is included so that you can either move the provided bar magnet closer to mid-position, or if you like, you can add a second magnet.

The magnet is held in place, along with the complete rear end assembly with one screw as shown in the photo. This magnet is nearly identical to the Fly B73 bar magnet, and provides plenty of magnetic down-force. Because of this similarity, I decided to try a Fly B73 magnet in this front pocket to see if it would fit, and it fits perfectly. The motor is the FX-Sport, rated at 17,000 rpms. This motor seems to have plenty of power for this model, and so far in our testing, it has provided some great acceleration with no excess overheating. When you remove the motor, be careful not to bend the shaft to far, or you will bend the spring. If you do, simply bending it back in place by hand does the trick with great results.

The drive-line consists of 3 brass bushings, 2 for the axle, and 1 for the motor shaft. This is where we find some flaws, that seem to be consistent in all 4 models. These bushings are loose in their chassis mounts, and will spin freely unless you add some adhesive to secure them. Now this is something that many of us have grown used to in the Fly front motor versions, so I can't knock Cartrix too hard here. Although I did find that some of the bushings seemed to be a little large on the inside diameter, causing a fair amount of free-play between the axle and bushing. This was not found on all models tested, but out of 12 bushings, 3 were found to have this excess play.

 As stated, we are used to these kind of problems related to a front motor configured car. For those new to the hobby, you might as well get used to doing this maintenance, as it has been with us for quite some time. On these metal bushings, we use regular Super Glue and add a few drops on the tops of them, and allow it to flow all around the bushing where it sits in the chassis. Once this is dry, oil these bushings, and you will most likely find a smoother, more reliable model racing car, and I highly advise you perform this on all front motor models BEFORE ever letting them see the track. And allow me to stress that with these metal bushings, OIL THEM frequently ok?

Now when it comes to performance, once these bushings are secured, this car is VERY smooth. We were happily breaking these cars in with hardly a sound from the drive-train. Once we ran these cars for about 50-60 laps, it was time to start racing, and as much as these models are smooth, they were FAST as well. In fact, these models are rockets thanks to the strong magnet, and you speed crazed enthusiasts should be happy with the top speed.

Braking was crisp, and acceleration was very acceptable. We found that you can still recover from a spin rather easily, even with this strong magnet. My oldest son seemed to find he could punch out of the corners and get the "tail wagging" rather nicely, and still get her straightened out soon enough to beat me to the next corner!

All in all, these 1/32nd scale versions are quite a handful of fun. They do require some work to get them to provide the best results, but if this doesn't bother you, then you will find some fast and reliable models in your stable. We are happy with all 4 of them, and can advise those of you looking for something different to give them a second look. These cars would be great for the younger drivers, and beginners alike, so if you get frequent newcomers to your track, these would be great additions as well.

Harry

As always, feel free to email me at wiseone@yhti.net about this article or just the hobby in general.

Or better still, drop into the Home Racing World Message Forum and let us know your thoughts. 

A thanks goes to Slot Car World for providing me with these fun models.