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Duratrax RT-X 27 1/8 scale Nitro Racing Truck with 4 Wheel Drive Review

A novice to this size and type of truck, Michael Heer moves up to the 4 wheel drive SuperTigre powered RT-X 27 RTR 1/8th scale nitro!

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Introduction


Length:22.375"
Width:17"
Height:10.5"
Weight:10.8 lb
Wheelbase:14.375"
Engine Displacement:.27 cu in
Engine Output:2.5 bhp @ 30,000 RPM
Transmitter:3 Channel FM Pistol Grip
Receiver:3 channel receiver
Servos:1 Futaba SX200 and 2 Futaba SX100 Std
Drive:4 Wheel drive
Transmission:Posi-Shift 2 speed forward only
Manufacturer:Duratrax
Available From:Your local hobby Shop
Price:$ 299.99

I have years of experience operating electric cars, trucks and tanks of various sizes, but this is my first nitro powered land vehicle. I picked the RT-X 27 because it is ready to run, has four wheel drive and will let me compete/run with my neighbor and his 1/8th scale truck. This truck was aimed right at me, an entry level 1/8 scale truck driver who wants a good vehicle at a good value.

Kit Contents

Included Items:

  • Assembled Duratrax RT-X 27 Chassis RTR
  • 8 oil filled shocks
  • .27 cu in (4.4cc) engine
  • Painted Lexan truck body
  • Heavy duty steering servo
  • Decal sheet
  • Instruction Manual
  • Getting Started DVD
  • Duratrax Kwik-Pit electric starter
  • Some simple tools

Items Needed

  • 12 Alkaline AA Batteries: 8 for transmitter and 4 for receiver
  • Starter Battery: 6-cell twin stick battery for Kwik-Pit electric starter
  • Charger for starter battery
  • Glow Starter: 1.2 volts
  • Fuel: 2-cycle glow fuel with 20% nitromethane 16% lubricant
  • Fuel bottle
  • Extra glow plugs (needed sometime)
  • Needle nose pliers
  • Phillips screwdriver
  • Engine tuning (straight) screwdriver (DTXR0185)
  • Additional air filter oil (DTXC2465)
  • O'Donnell Fast Cleaner
  • Thread Locker
  • Hobbico After Run Oil (for maintenance)
  • Nitro wrench (For removing and installing the glow plug

Assembly

The truck really comes ready to run with only a few final items of assembly. I installed the AA Alkaline batteries in the transmitter and screwed in the antenna. I installed the receiver batteries in the protected box in the chassis and ran the cars antenna wire through the included tube and plugged the tube in place. I oiled the air cleaner with the supplied air filter oil and installed it back in place per the instructions. I added the decals to the truck body, read the rest of the instructions and watched the included DVD (twice) to learn how to break in the SuperTigre engine. Finally, I bought the fuel I needed and a Duratrax fuel bottle (for filling the fuel tank). I installed a fully charged 6-cell battery pack into the included Kwik Pit Electric Starter that came with the truck.

Engine Break In and Some Tips to fellow Nitro Newbies

The first operational process is to break in the engine by running five tanks of fuel through the truck while letting the motor completely cool (fifteen minutes) between tanks of fuel. I charged up a six cell 2,000 mAh NiMH battery back for the Kwik Pit Starter, added fuel and started her up.

The first step is to advance the fuel from the fuel tank to the engine with the Kwik Pit Starter. When the fuel reaches the engine, stop and add the Glow Starter to the glow plug and resume until the engine starts and runs a bit. I tried this, and the Kwik Pit Starter stalled before I saw any fuel advance. I had a problem... a problem not mentioned in the manual or the DVD! I assumed it was the compression and the lack of lubricants in the engine at that point made the engine so resistant to moving that it was locking up the Kwik Pit Starter. I thought that removing the glow plug would lower compression, and I could advance the fuel and the lubricants it contains into the engine block, but to do that I needed a glow plug wrench.

I went to Modesto Hobby and bought a Nitro Wrench that let me reach down into the center of the cooling head and loosen and remove or add and tighten the glow plug. I explained my problem to the guys at the hobby shop and they recommended I also use my Monocoat heat gun to heat the engine block to help loosen it up. Unfortunately, the aluminum siding on the chassis does a good job of blocking access to the heat from the heat gun. Nevertheless, I removed the glow plug and heated up the engine BLOCK as best I could. After a few minutes, I tried the Kwik Pit Starter, and I was able to turn the engine over and advance the fuel.

But it sounded like the piston was hitting something near the top of its movement. I reinstalled the glow plug and again heated up the engine head, connected up the Glow Starter and applied the Kwik Pit starter to the engine. NOTHING! Even with a fully charged battery pack it seemed the compression in the engine was greater then the power supplied by the Kwik Pit Starter. I tried multiple times to start the engine using a screwdriver to turn the motor over slowly, and I repeatedly tried to start the motor with no luck. With the glow plug off I was able to get the piston to move up the cylinder sleeve, but it was always very hard to get it to the very top. It continued to sound like it was hitting something. I confirmed that fuel was moving into the cylinder and that the glow plug was glowing properly.

During this process I met a man named John Williams who had bought an RT-X truck as well, and I helped him break his in. He also had stiff compression but nothing like mine, and we were able to get his motor running without any problem; the break-in went very smoothly. My initial drives and testing of the RT-X truck were done with his truck.

My friend Dick Andersen flew glow fuel engines for years, and I recruited him to help me start the car. After trying everything we could think of, he examined the engine closely and found the problem was a slight defect in the engine sleeve; It was too tight at the top and was stopping the piston from moving smoothly as it approached the top of the cylinder. I contacted the service department, and they sent a replacement. This is a very rare problem, and it was good to have the engine warranty that came with the truck. I doubt very much that anyone reading this review will have the problem I had, but we review the products we have and report accordingly!

HINT to Fellow Newbies: The compression was still quite high but the hitting sound was gone at the top of the piston's movement. To lubricate the engine I blew fuel from the gas tank up to the motor with the little plastic tube that connects to the muffler. We loosened the glow plug and ran some fuel into the engine. We tightened the glow plug back up, and with Dick's help we got her running for the first time. A cold start with the new motor heating the block helped. Loosening the glow plug slightly helped to deal with the motor’s compression. Once it was started and warm this was not a problem, and it became less of one with operation.

As had been true with John's truck, once I was able to get the engine running, the instructions and DVD covered the engine break-in very well, and I made the minor tuning adjustments of 1/12 a turn per each tank of fuel. A neighbor came over to admire my truck and coached me a bit on the sounds of rich vs. lean by getting out his own truck and running his with me on the street. I strongly urge every owner to do the full break-in of the motor; Once you get the motor running it is easy to do and will go far in giving great service from the motor and keeping the warranty in play.

Features

Duratrax has included a lot of nice features as standard on this truck, and they have done an excellent job of displaying them on their website. I have borrowed their pictures here to better display the features that got me interested in this truggie in the first place.

Chassis

Strong aluminum roll bar and chassis sides and strong plastic parts that came with a one year replacement warranty.

Suspension

Eight aluminum oil filled shocks are the basis of the suspension. It is supported by adjustable springs and turnbuckles that come as standard equipment with multiple standard shock mounting combinations. They also sell different springs and oils and other hop-up parts to allow for even more adjustment of the suspension. So far I have stuck with the standard parts but have made some tuning adjustments to set up.

Steering

The steering servo is the Futaba SX-200 high torque servo with 124 ounces per inch of torque at six volts. This gives outstanding steering speed and power. This standard servo for the RT-X 27 is more powerful than servos supplied with some of the other complete truck sets that I investigated.

Brakes and Drive-train

The brakes are dual composite disc and supplied good stopping power. I admittedly don't use them as much as I would at a track with my mostly free range style of driving on or off road. To activate the brakes, I just pushed the trigger on the transmitter out away from my hand. There was no reverse as with my electric Duratrax Evader, just forward and brakes. The four wheel drive is supplied power by the constant velocity shafts (CVD) and not simple dog bones as used in some trucks. Friction is greatly reduced thanks to the use of a full set of ball bearings.

Engine and Muffler

The RT-X 27 comes with the SuperTigre .27 cu in (hence the reason for 27 in the trucks name, RT-X 27.) with the G27CS dual needle slide valve carburetor. The crankshaft is supported by dual ball bearings. The red aluminum cooling head is the most visually obvious feature, and its exhaust is run out the polished aluminum dual chamber racing tuned pipe.

Radio

A Duratrax 3 channel radio made by Futaba is included with the RT-X 27. The transmitter has servo reversing for the steering and throttle controls as well as fine adjustment trims for them. The third channel has a simple two way switch. There is a charge jack built into the receiver for when/if I upgrade to a rechargeable battery pack. The radio channel is linked to the color. My truck is blue, and my frequency channel is 64.

The truck comes with a battery box for 4 cells. Using alkaline AA batteries at 1.5 volts each gave me six volts to the receiver and good quick positive results from the receiver and servos. But the alkaline AA batteries were not designed for taking a recharge. If I get a rechargeable pack of 4 Nicads or NiMHs that will only supply 4.8 volts and will reduce the servo response time. A five cell rechargeable pack will supply the desired 6 volts but I'll need to take care to make sure the pack will fit in the provided space. I plan to check out the 5-cell Duratrax rechargeable pack (model number DTXM2030). However, for this review I used AA Alkaline batteries, and they worked great.

Tires and Wheels

The supplied hubs are 8 spoke Truggie type 2.2" wide and 3.2" in diameter. Standard 17mm hubs as used on most 1/8th scale trucks, so they are compatible with aftermarket products. The foam inserts inside the tires came glued and have held up well to the test driving for this review. The Truggy pin spike tires are 2.6" wide and 5.4" in diameter, have given good response and control and have been wearing and performing well.

Warranties

There is a basic 90 day warranty, but there is a second (and to me more significant) Stress-Tech parts guarantee that is good for one full year. Let me quote this information: "We have engineered the RT-X to take the rough and tumble abuse that makes R/C trucks fun. We are so confident of the quality and durability of the Stress-Tech plastic parts that we will replace any Stress-Tech plastic part you break during the first 12 months you own the truck. Just send in the part to us, and we will send you a FREE replacement."

There is a three year warranty on the SupreTigre Engine.

Tuning Guide

The instruction manual includes a tuning guide that takes you through a number of changes that could be made in the RT-X 27's set up and alter how it handled. This includes adjusting the shocks position up or down as well as in and out both in the front and the rear and explains briefly what those changes would do on a given track. It also discusses changing the shocks, oils and springs. This information and more was a good start in my learning how to adjust the truck for different conditions.

Driving

I did the engine break in on the street in front of my house and then went to a rather flat dirt field to get used to the truck’s handling. I liked the slides I could get on the dirt. I progressed to a single jump and then to an off road course with jumps, hills, tight turns as well as straight-aways.

The RT-X 27's steering was very responsive, and the suspension system worked well, allowing me to maintain control over my truck in turns. I have been especially pleased with the way the suspension has handled the jumps; It has made me look better then I really am.

After the initial issue, the SuperTigre motor has worked very well. The truck has started easily and run well. I've only killed the engine a couple of times with some high speed wipe outs.

Tuning Guide

The instruction manual includes a tuning guide that takes you through a number of changes that could be made in the RT-X 27's set up and alter how it handled. This includes adjusting the shocks position up or down as well as in and out both in the front and the rear and explains briefly what those changes would do on a given track. It also discusses changing the shocks, oils and springs. This information and more was a good start in my learning how to adjust the truck for different conditions.

Maintenance Guide

The manual has maintenance tips for before each run, after each run and after every ten runs. It also gives some more in depth information on the various parts and brief information on what to do for long term maintenance to keep the RT-X 27 in top running shape. One of the mature drivers at the track advised me that he is often able to beat drivers just because they don't do the recommended maintenance on their trucks, and he keeps his truck well, better then new. Cleaning and re-oiling the air intake is often overlooked and prevents the engine from breathing properly when dust and sometimes mud plugs up the filter. He also strongly recommends draining the fuel tank when done for the day and using "After Run Oil" when the day is done, especially before a long lay off or in humid conditions.

I!s This For a Beginner?

As a $300.00 investment this truck is for those seriously interested in getting into nitro trucks. Final assembly was quick and easy, and the warranties offer some serious protection. It can be run as it comes, and replacement and hop-up parts are available to keep it running. See the video below of a newbie's first minutes on a dirt track for proof that this truck is for a beginner.

Video/Photo Gallery

Downloads

Conclusion

I have found the RT-X 27 to be a very nice truck that gave me everything that I hoped for and more and has been a hoot to drive. I have had a number of minor wipeouts and a couple of major crashes and rolls, but (fingers crossed) nothing has broken yet despite my abuse. It has handled quite well with the included pistol transmitter, and I found the factory settings to be satisfactory on the suspension.

Pluses:

  • SuperTigre motor with replacement part has worked perfectly and supplies a lot of power
  • Suspension system works well as a unit and the MT-X 27 handling makes me look good.
  • Service department took good care of me and my initial problem
  • There were a lot of upgraded parts included on the truck.
  • Very well assembled and easy to get operating.
  • Manual identifies all parts to make ordering replacements easy.
  • A lot of truck for the money.

Minuses:

  • Initial compression is very strong and some more instruction would have been helpful for a newbie.

My thanks to Hobbico and Duratrax for supplying the MT-X 27 for use in this review and to those who helped me, especially, Dick Andersen and John Williams for their support in this review.

Last edited by Angela H; Oct 03, 2008 at 11:27 AM..

Discussion

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Old Oct 05, 2008, 11:43 PM
Registered User
_HypnoToad_'s Avatar
Eureka,Ca
Joined Jul 2007
623 Posts
Your idle sounds like it's set pretty high.
Nice review Mike!
Cool truck too,

Tim
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Old Oct 06, 2008, 01:53 AM
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rc_pro_86's Avatar
Joined Feb 2008
1,398 Posts
evil........
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Old Oct 08, 2008, 11:22 PM
Yep I got another one.
mohillbilly's Avatar
Springfield, Mo.
Joined Jan 2005
2,529 Posts
way too high.
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Old Jan 18, 2009, 08:55 AM
Registered User
Joined Nov 2008
8 Posts
Good comments on break-in..it is sometimes a head shim issue from the factory as well..
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