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Project: The Ultimate LST2 Race Truck

8/6/2007 by Gary Katzer

Copyright:© 2007 Horizon Hobby, Inc.

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Page 2: Chassis
Page 7: Performance Recap
(continued from previous page)

Performance Recap

When it came time to test this Ultimate Race LST2, three drivers were enlisted to provide feedback. Beyond just myself, Team Losi Racing’s Bill Jeric and JR Surface Team Manager Anderson Yau spent time behind the wheel. While there were several shakedown runs with the truck to break the engine in and test setups, the real test came with the truck’s first race at an RC Pro Series Event.

Anderson Yau

Anderson Yau





The LST2’s stock 427 engine and polished exhaust system delivered excellent power and easily out-ran all other vehicles down the back straight. The bottom end was just as impressive, as this combination delivered more than enough low end torque to come out of turns and take the jumps. This was my first experience with Losi Nitrotane fuel, and I must admit I was impressed; the engine ran cool and delivered excellent power through the entire power band while maintaining the tune on the carb.

Like Gary, I was surprised to experience a slight amount of push through the turns with the LST2 being equipped with 2 Z4800T servos. However, I think this can be easily remedied by either modifying the stock servo saver with a heavier spring or installing a thinner front swaybar. The Spektrum Pro Series module and SR3500 Micro receiver worked flawlessly all day long and I felt totally connected to the truck. The large volume Mega Shocks easily soaked up the bumps and jumps and helped me get comfortable with the technical layout quickly. There was one particular bump on the front stretch that had caused problems for me with other vehicles here in the past, but the LST2 drove over it each and every time as if it wasn’t even there. With no prior experience driving the LST2 and very little practice, it appeared to handle better than most of the other production trucks on the track.

Bill Jeric

Bill Jeric

The last time I raced was at the U.S. Indoor Championships in Cleveland several years ago. I normally race 1/12-scale cars which are about as different as you can get from what this massive Losi LST2 is. From the moment the engine came to life I had a smile on my face. The 427 engine delivered the stump-pulling torque people have become familiar with in the back yard, but it also had outstanding acceleration on the race track, making jumps easy to tackle. The slipper clutch worked consistently all day long, allowing the power to get put down without spinning the tires. The top speed was phenomenal as well; if this were simply a drag race, I have no doubt who the winner would have been. On an off-road, it’s just as important to get a truck slowed down. The High-Performance Brake Set provided smooth and powerful braking every time I got on the binders. I was surprised that we managed to qualify third overall at the event since I hadn’t raced in so long, but the truck’s performance was so good that it was easy to drive fast. With a little more practice and tuning, I know this truck can be a winner each and every time out.

Gary

As I did the majority of the work and testing on this truck, I must admit I was a bit nervous about its first race. During my initial testing, I felt like the truck exhibited a slight low-speed understeer. I gave the truck a little more front toe-out and raised the rear ride-height slightly; both tweaks really helped the LST2 turn better. Bill hasn’t raced much in a few years, but he’s still one heck of a driver. After handing the controls to him, he agreed that it was still a little pushy but comfortable. After the first round of qualifying, Bill was sitting second, and he backed up that time in the second round. For the third round, Anderson got behind the wheel, unaware that I had made a slight engine change. I leaned out both needles about an hour to help clear the carb out a little quicker and improve both acceleration and top end. Anderson really did well and the truck was faster. Unfortunately a setscrew backed out, which caused him to drop out of that qualifier. Between the two of them, they both managed to turn some of the fastest laps of the event and put a previously unproven vehicle into the A-Main. Not bad at all.

We made a decision that I would drive the truck in the main. While I had practiced with the truck beforehand, the track was really bombed out and I was a little nervous about how I would do. Also, we had never really done any timed runs with the LST2, so I really didn’t know how long I could stretch a tank of fuel. With Anderson as my pit man, we lined up third for the start of the 25-minute A-Main with a conservative pit strategy. I made a conscious effort to take it easy on the start and it paid off huge. On the tone, the first and second place drivers got tangled with each other, opening the door for me to sneak by and grab the early lead. As the rest of the pack battled it out, I drew away to a decent-sized lead. I was challenged a few times early on by the second-place driver but held him off until the first pit stop. We pitted the lap after six minutes were complete, relinquishing the lead. I came out of the pits in third and quickly moved into second. I was chasing the leader down when something happened to the truck. For some reason, it was undriveably loose on-power. It almost felt like it was only rear-wheel-drive and, upon inspection, that was exactly what had happened. The setscrew that held the front drive pin backed off causing the pin to fall out and disengage the front drive. This ended our race, but we still had a really positive experience.

Man, I can’t think of a project that I have had much more fun with. The LST2 platform just begs to be tweaked and played around with. For someone like me, the core racer, this project proves that you can take any vehicle to an extreme and push the performance envelope. I was very impressed with how well the stock 427 engine ran from the time break in started until the main was completed. This thing is a hoss and I loved how it performed. It provided the right balance between the acceleration and top end I needed. I was also very impressed with the suspension on the LST2 and how well it worked. I was concerned that the fixed camber might be a problem, but I never once thought "man, I wish I could change the camber." There are still a few improvements I’d like to make to this particular truck, but those are setup-related items to help get the truck to handle a little more to my liking. Overall, I’d have to say this Project: Ultimate Race LST2 definitely exceeded my expectations.