Here's Mugen:
Mugen has been a busy company. They successfully redesigned the 1/8-scale on-road MRX-3, introduced a new 1/10-scale gas truck and now released an updated version of the MTX-2. A few years ago, the choice for a high-end nitro touring car was simple. It was either a Serpent or a Mugen. Now, the field has grown to a point where everybody has a nitro TC in their lineup. Banking on the big victory at the IFMAR 1/8-scale On Road Worlds, Mugen kicked some of that winning design over to the MTX-3. Whoever thought hand-me-downs were bad just may have to rethink that theory when they get behind the wheel of Mugen Seiki’s latest nitro touring car.
Features
Chassis • The MTX-3 gets a new 3mm aluminum chassis. While new, it’s not radically different than the pervious chassis. The most noticeable difference is the plastic tray in the center. It now places the receiver pack at the lowest possible center-of-gravity. Weight reducing cut-outs in the chassis are found in the front and rear and these also allow debris to exit the chassis, reducing the chance of a pebble jamming up the driveline.
On the flipside, the MTX-3 looks considerably different thanks to a rework of electronics placement. The new upper deck loses the plastic molded deck in favor for a stiffer and cooler looking carbon fiber upper deck. It now only provides mounting area for the throttle servo and the fuel tank, which still sits off-center. A plastic receiver box attaches to the right side and unfortunately isn’t sealed and is open to the road allowing wires to drag if you don’t secure them properly.
A plastic brace stretches over the engine and hits the back bulkhead and gets rid of gear-stripping chassis flex. Optional aluminum parts will add some extra strength, but the plastic will do the job just fine.
Suspension • At first glance, you may not notice that the suspension is all-new. Enhancements to geometry and material thicknesses make for a more durable, better handling package. Up front, the new geometry lays the shocks down on a new carbon fiber shock tower. The new angle makes the compression more progressive, giving more steering. The front pivot ball suspension has been tweaked with beefier arms and a slight increase in length for better stability in the turns. You still can adjust camber, track and toe with a few twists of the wrist or moving a few clips. Caster is adjustable with the movement of the clips that are now measured in millimeters. The stock setting is 2mm, and to adjust for higher traction tracks you can move them all to the rear or if there is less grip, all the way forward for better performance. A blade-style front sway-bar, previously an option, is now standard in the kit.
Following the front suspension down the track is an all-new rear suspension. The suspension borrows design features from the MRX-3. The new rear hub allows the adjustment of roll-center. This is one of the more dramatic tuning options that will eventually work its way to every on-road car on the market, if it’s not there already. Adding shims will add rear traction and stability. Removing shims will raise the roll-center and give the rear less bite. New to the kit is adjustable anti-squat in three different degrees that are not disclosed by Mugen, but we’re guessing 0-, 1-, and 2-degrees. The B spacer is in the middle and you can either go up or down by what we guess to be one degree increments. The rear shock tower is now carbon fiber, which lays the shocks inward much like the front. A rear swaybar is standard on the back to keep the chassis level in the corners.
The shocks look much the same, but they are lifted from the 1/8-scale MRX. They still feature double seals and a bladder cap. The threaded bodies make adjusting the ride height a snap. The only visible difference is in the two-piece cap that now uses a plastic insert. The kit includes 600wt (60wt) oil for all four corners. The only difference, front to back, is the rear pistons are 2-hole and the front pistons are 1-hole.
Drive Train • Starting off, the drive train has a new centax-style clutch. This type of system allows the easy adjustment of clutch engagement. The standard 2-speed transmission is also the preferred clutch-type that gives smoother shifts and is also adjustable for how hard it shifts. The rear main shaft splits power to the rear gear differential and to the new side belt. This side belt positioning is different than the previous car’s routing. Mugen explained the older layout caused unwelcome drive line friction with the belt rubbing against the chassis. As an added bonus, the new location also makes belt maintenance easier. Once up front, another drive shaft directs the power to the front one-way unit. This allows the car to have faster corner speeds by letting the wheels freewheel when off-power. Just in case you want a full differential instead of the one-way, the kit includes the front housing for a differential, but requires the outdrives and internals for completion. From either the front or back, power is sent to the wheels with old-school dog bones. In the rear, this would be acceptable, but up front, and on this caliber of car, it just isn’t. Bad Mugen! The whole drive train rides on metal-shielded bearings. Basically, if it moves, it’s on a bearing.
Stopping is achieved by a single disc, internally ventilated rotor. A Japanese throwing star looking disc is sandwiched between a set of steel discs to form a single unit achieves the ventilation. If you are ever attacked at the track, you could disassemble the brakes and use it as a weapon. Two brake pads on either side of the steel calipers provide extra stopping power.
Steering • Keeping to the low CG theme of the new car, the servo gets moved flat on the chassis and a center point bell crank system, with built-in servo saver, gets the wheel direction duty. The bell cranks offer adjustable Ackerman by swapping out horns to either A, B or C units. Adjustable turnbuckles connect the bell crank to the steering blocks and can be a pain to adjust with the 1-hole adjustment point.
Body, Tires, & Wheels • This kit doesn’t include a body, so the choice is yours. We opted for the TC standard Protoform Stratus 2.0. You do get a mean set of wheels and tires. 26mm front and 30mm rears wrapped around 12-spoke wheels.
Engine And Accessories • The kit is available with or without an engine. Only a fool would opt not to get the kit with the powerful MT-12 rear exhaust engine. It’s coupled with a free breathing REX pipe for lots of power. Having used the MT-12, I can say with confidence that you won’t be disappointed with the engine. It does require a starter box, but it’s a racecar not a weed whacker.
Instructions • The instruction aren’t perfect, but they do get you to the final stages pretty quickly. The line drawings are helpful. There isn’t much text to help you out when things get tricky. A better, more detailed stock setup would have been more helpful and some explanation of when to make tuning changes would have helped, too. I’ve seen better and I’ve seen worse, but the good part is the finished product is a joy to build.
Testing
I was excited to run this car on the big Revelation Raceway minutes from our office. The huge track would give the MTX-3 a good testing at both low and supersonic speeds. The track is asphalt and is fairy smooth. There are a few sections that get a little bumpy, but, for the most part, it would be smooth sailing. I did opt to break-in the car in front of our office and quickly found that the car is better suited for the track. Pebbles and uneven pavement aren’t good for the car.
Acceleration • See ya! Once you get the centax clutch engaging at the perfect spot and the engine is warmed up, the MTX-3 rockets of the line. I have to say that the MT-12 engine has much to do with the tremendous acceleration. The car accelerated arrow-straight and never pulled off to one direction. Like all cars, you do have to make sure you have the suspension set correctly or it will pull to one side.
Rating: 10
Top Speed • Sometimes I forget just how fast a car feels on a track with boards. In a parking lot, it’s easy to lose track of speed since there’s no real reference to judge against. Even on this made for 1/8-scale track, the MTX-3 was fast. The gearing was a little short on the back straight, but it was still a delight to watch tear down the straight.
Rating: 10
Braking • Tons of top end means once in a while you’ll have to grab a handful of brake. The car comes with a front one-way unit, which if you know anything about racing, means faster corner speed but at the expense of braking stability. The brakes will lock up the rear wheels with a good tap, but if you aren’t going straight, prepare for some end swapping. It’s a justifiable tradeoff for some, but I wish they included all the parts needed for a front gear diff. To keep from swapping ends, I dialed much of the brake out; so, even if I had to slam on the brakes the car slowed down gradually.
Rating: 6
Low-Speed Handling • The revised suspension made for a much better handling chassis than the previous car. Off power, the car had a slight push, but once you applied the throttle a very controllable over steer occurred and you could get the cat quickly through the tight sections. I left the stock setup for the testing to get a good feel for the car. With a few changes, the car could gain performance. You’ll be happy to know that the stock gear provides a great handling car.
Rating: 8
High-Speed Handling • This track is all about high speed and the faster I went, the better the car felt. The car rotated very well through some of the tight, fast switchbacks. The only problem areas were at the end of the sweeper and the entrance to the back straight because it required some braking to keep it tight. It required me to let off the gas for a second to allow the car to rotate and then it was back on the throttle. Again, these are all things that can be fixed with a few simple changes. Otherwise, the car was super stable at full clamp, never feeling light in the feet or too heavy.
Rating: 9
Rough Track Handling • On the rougher sections of the track, the MTX-3 kept its composure. It never felt like it was bottoming out or like it wanted to loop out. On the rare occasion that it was in the middle of a shift and hitting a high spot in the turn, the rear did break free only to snap back into place after the rear wheels regained full traction. If the car shifts too hard, you can easily adjust it to shift smoother.
Rating: 9
Tuning • The MTX-3 offers a ton of adjustments that can get you dialed into a track or confuse the hell out of you. It could easily be one of the most tunable cars on the market. You can adjust caster, Ackerman, front and rear toe, anti-squat, camber, roll center and track. If you can’t tune this in, it’s time for a ready-to-run
Rating: 10
Damage • You can break this car if you wanted to, but under normal conditions and use, the car will be near bulletproof. I did lose a dog bone in the break-in process due to the front track being too wide, but after that, it was a trouble free run. During testing, I clipped a few boards when I entered the straight too fast and pushed out. I also tagged some other spots on the track and nothing decided to give up. The one area that worries me is the receiver “box.” The bottom is left open and if you don’t take care of the wires, they will drag on the ground. It’s my overall impression that you will, at some point, hit something too hard and, as a result, you may break something. That’s partly due to the confidence this car instills in you to keep pushing harder.
Rating: 9
Conclusion
Mugen has always made some high quality racing kits. Their MTX series has been a solid performer on the local scene, but has never done too well on the pro circuit. This is partially due to a small race team. Thankfully for those drivers, Mugen did its homework with the new MTX-3. It incorporates some of the design features of the IFMAR Worlds winning MRX-3 and shrinks them down to a smaller size. With the amount of competition out there, the MTX-3 has a lot to prove, but it’s fully capable of winning on any level.
