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The David Jun TNX

Who ever said to leave a RTR gas truck well enough alone? Well, today we are here to tell you that you don't need to leave it alone as we can't help ourselves. Here at Tamiya America we love to tinker. By definition, those of us who enjoy the world of R/C relish in our pursuit to improve our rides. The following will be our adventure in what David Jun did to get his personal ride ready for the Proline Maxx Challenge race held this past May as well as share with you the TNX owner the options that are available already in the R/C market that will compliment your new TNX.

TNX Product Page (Specs, videos, pictures and more.)

Engine

First, we should be perfectly clear that the O.S. .18 engine was completely left alone. The TNX is so light for its size that the powerful stock engine has a perfect power to weight ratio. Our best recommendation is to carefully break it in as described in both the owner's manual and the new DVD included in all TNX boxes. To insure clean fuel reaches the carburetor a high volume fuel filter is placed between the fuel lines. To lighten up the on board starter system a bit the stock starter system was replaced with an Ofna shaft start system (OFN 50000 starter unit), (OFN 50009 backplate). In addition, the Ofna system requires a larger oneway bearing for the backplate, so Tamiya part# 7684015 was used.

Tires and suspension

The truck pictured here is sporting new wheels and tires to help it transverse your typical groomed off-road racetrack. The tire/wheel and insert chosen were the Proline Bow-Tie #1079-00 mounted on Proline Velocity #2660-04 wheels. The inserts inside are the Racers Edge medium gray. Next David chose to try Prolines' new Powerstroke suspension system. The system was a near perfect fit, but a slight modification to the by- pass shock body was needed to ensure a perfect fit. The bypass shocks were filled with Tamiya 500 weight oil (# 53444) and the coil spring shocks were filled with Tamiya 300 weight oil (#53443).

Radio gear and weight balance

David has been using Futaba radio gear since his early days of R/C and chose to use his new 3PK. With this in mind he elected to give both the throttle servo and steering servo an upgrade. While the standard steering servo is high torque, David wanted to increase it further as well as increase the transit speed. You can never have enough transit speed or torque in just about any R/C application. He chose the Futaba Digital S9451 to do the job for both. As you will notice in the photos in this set up guide, David made a modification that will often

go unnoticed. In stock form the receiver compartment is located near the front of the chassis and the battery compartment is located just behind it. To facilitate a better balance from front to rear David swapped the compartments so that the heavier battery compared to the receiver is further forward. This swap helps in putting weight forward to keep the nose down on the truck while making jumps. Speaking of batteries, a Peak Performance 1200 Mah NI-MH Blitz battery is used to power the servos and receiver. To protect the digital steering servo from breaking its gears, a heavy-duty servo saver was installed made by Ofna.

Body

The stock pre-painted body was used. A couple of simple modifications were implemented to add cooling to the engine and down force to the truck. A piece of Lexan was mounted to the rear trunk to add the down force and a square cut out was made to the front of the window for cooling.

Final touches

Gas racing of any kind involves pit stops and to help out your pit guy we recommend putting a loop using a tie strap on your fuel cap. This will make it easier for your fuel guy to open the tank in a mad rush and it will make for a fumble free pit stop.

We hope this in depth under the hood look into David Jun's TNX has proved helpful to our monster truck customers and we will be posting further recommendations as new products hit the market.