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XRAY T4 Review

Building the XRAY T4 by Chris Lillywhite.

This is a build review primarily for someone who is an experienced racer of 1/10th scale on road touring cars or who has previously built such a car. I have included building tips along the way, although the manual also includes some very useful pointers to setting the car up as you build it, including option parts which you can purchase seperately.

The manual also very handily includes the part numbers for the option parts which makes ordering them a lot easier! :)

The Xray forum is a good place to learn as to what the option parts can do to help improve the T4's performance.

The car in the review is a top level competition kit and does not come with any electrics or bodyshell as such (Transmitter, receiver, steering servo, Li-po battery/charger and the tools needed to build the car), as these are usually chosen by the racer themselves and therefore these items will need to be purchased separately to complete the build.

I used a selection of Red EDS Hex drivers and a standard Tamiya nut wrench to build the car. These have proven to me over many years that not only are they hard wearing, but also represent very good value for money.

You will also require a sharp set of curved and straight scissors of any brand for cutting out your chosen bodyshell, and a good quality, metal hole reamer for body post holes.

Should you have any questions about what does or does not come with a kit when buying one from Fusion Hobbies, we are only an e-mail or phone call away.

Box Presentation

Upon opening the box, I saw immediately the quality of parts was very good as per any Xray I have seen. The kit design is a twin deck carbon fibre chassis, utilised for Lipo batteries and brushless motors. The kit also comes with a sheet of T4 stickers which would look nice on any bodyshell and an Xray certificate of authenticity.

The only slight issue I had with the kit quality is that one of the packets of parts had not been sealed properly at the factory, resulting in a few loose screws and fittings inside the box, but luckily, they were all correct and present.

That said, the chassis has had an enormous amount of R&D to it by Martin Hudy and his team at Xray, which can be read about here:
http://www.petitrc.com/reglages/xray/setupxrayt4/T4_MakingOf/

The parts in each step are to scale, which is very useful should you need to make sure you have the right parts for the step you are following, especially with the different size screws. The best advice I can offer is as with any kit, is take your time, do not over tighten any screw fixing and study the diagrams carefully.

Help is always at hand using the official Xray forum should you need any pointers as to how a particular step of the build should go, or general questions about the T4 @ http://forum.teamxray.com/

Team drivers are also part of the forum community at the link above to help you get the most from your car.

So you do not get confused with this review, the text for each step is below the picture/s of the step covered.

XRAY T4

The Build

Chassis

The first step of the build involves gluing the chassis edges to prevent the chassis from splitting in the event of a crash.

XRAY T4

Any superglue can be used; I used some from Poundland with some cotton sticks which make applying it a lot easier and less messy. Slightly thicker gel superglue might make this step easier as it will dribble less and give an easier application. I had a sheet of kitchen towel to hand in case of any spillage.

Gear differential and Spool

With the chassis now glued, the next stage is to build the gear differential for the rear gearbox and the spool for the front gearbox.

XRAY T4

The outdrives to the differential halves are held to the differential casing by a pin, which then affixes to the internal crown gear of the differential. The differential oil is kept sealed in by a clear O ring, followed by a silver washer.

XRAY T4

I applied a small amount of Tamiya shock oil to the O rings before fitting them as this provides a little lubrication and prevents any splitting to the O ring, although any light oil would be suitable. Two halves make up a complete differential assembly - one which holds the oil, the other acting as a cover. The larger differential casing assembly is shown in the pictures below.

XRAY T4
 
XRAY T4
 
XRAY T4

With the two differential halves now assembled with the bevel and satellite gears installed, it is now time to fill the differential with gear oil.

XRAY T4

TIP The thickness (or CST rating) of the differential oil is a very important setting for the car, so it would be useful to have knowledge of what is typically used at your local club before you assemble it, or you will need to replace the two seals and possibly the O rings if you decide to change it later on.

I use a differential front and rear as this is a preferred setting where I race at. 50,000cst front, 3,000cst rear with foam tyres, indoors on carpet.

For rubber tyres, racing outdoors on tarmac, I would suggest using a spool for the front, and 2,000cst oil in the rear differential to start with.

The differential assembly needs to be filled with oil so that it weighs 9.2 grammes as per the above picture.

XRAY T4
 
XRAY T4
 
XRAY T4

Once the differential is filled, you then need to put the thin O ring inside the other half of the differential and have the paper O ring ready with the 4 screws to join the two differential halves together and complete the differential assembly.

TIP Make sure you line up the differential halves correctly (there is a small dot on the inside of the differential) tighten the 4 screws up in the correct sequence, as per the instructions to ensure a leaky free differential!

XRAY T4

The differential bearings then need to be slotted onto the outdrives and a small amount of oil, one or two drops is placed into each bearing.

Spool

XRAY T4
 
XRAY T4

The spool is a very straight forward part of the build, as you can see from the pictures, a long screw each end secures the outdrives and bearings into the centre part. Do not over tighten these screws and apply 1 or 2 drops of oil to each bearing.

Simple, yet strong and effective engineering from Xray is the name of the game here.

XRAY T4

Both the spool and rear differential are now built.

Central Transmission

XRAY T4
 
XRAY T4
 
XRAY T4

The next stage of the build is to install the bulkheads, which house the gear differential and spool onto the chassis.

TIP My review does not show this, but make note of the manual in which order the screws should be tightened to prevent the chassis from tweaking (getting out of shape).

XRAY T4
 
XRAY T4

Attention is now focused on building the spur gear assembly - three M3 size screws, 2 pins and circlips hold this all together.

XRAY T4
 
XRAY T4

With the spur gear assembly completed, we can now put this, the differential, bearing "cam" holders and spool into the bulkheads, coupled by two belts to join the transmission together - make sure the spur gear assembly is positioned into its layshaft housing the correct way or the belts will not line up.

Both the front and rear gearboxes belt tension can be adjusted - follow the kit settings and adjust to suit as per the manual later on if need be ensuring the "nubs" on the cam holders are seated fully into their surround and are equal in where they are positioned.

As the belts stretch with normal wear and tear, it is possible to purchase separately a belt tensioner which helps prolong the life of the front belt.

XRAY T4
 
XRAY T4
 
XRAY T4

In this stage, the upper bulkhead clamps and shock mounts are attached. 16 screws complete this, and ensures your recently built transmission does not come out of where it should firmly stay in one piece! :)

Suspension - arms and steering

XRAY T4

With the build starting to take shape, the suspension blocks need to be attached to the chassis. 10 screws attach these items.

XRAY T4
 
XRAY T4

Next, on go the wishbones and their mounting parts. As you can see, once the wishbones are put on it fuels the desire even more to get the build complete as your box of parts slowly starts to resemble a radio controlled car! :)

It is very important that the arms are able to move up and down freely. A little time spent doing this is better than having an ill handling car due to stiff, malfunctioning parts.

Also, the front and rear wishbones incorporate the use of droop screws - droop is an important setup feature and well explained in the xray/hudy downloadable setup guide and explained well in this forum topic:
http://forum.teamxray.com/viewtopic.php?f=8&t=13569&p=108341&hilit=droop+explain#p108341

XRAY T4
 
XRAY T4
 
XRAY T4
 
XRAY T4

The pictures above replicate a simple explanation as to how the steering assembly is built. The tubes allow the steering arms (complete with bearings) to pivot freely and provide the essential primary links to the front wheels and to the servo output horn. A drop, or two of oil for each bearing ensures a smooth operation. The bearings inside the steering plate are the smallest in the entire kit and therefore require very little oil.

For me, assembling the springs inside the output horn was the most difficult part of the whole build especially because the build was starting to take shape and it looked like a very simple step... after much struggling and a few cuss words, a perfect explanation was only a search away on the xray forum and helped immensely :)
http://forum.teamxray.com/viewtopic.php?f=8&t=11978&p=101227&hilit=t4+servo+saver#p101227

Voila! all of the C shaped spring clips were seated onto the servo saver assembly in seconds!!!

Top deck

XRAY T4
 
XRAY T4

The graphite top deck of the chassis strengthens up the car considerably and is attached using 12 screws. In case you are wondering, the hole in the middle of the top deck is used for the optional belt tensioner.

Driveshafts

XRAY T4
 
XRAY T4

The front and rear driveshafts are of similar construction, but note 52mm driveshafts are used in the front, and 50mm in the rear. I used a little dab of Tamiya liquid threadlock on the grub screws to prevent them from working loose after time.

If you choose to install/use an optional front differential instead of the kit supplied spool, you will need to make sure that you also use driveshaft caps on the front driveshafts.

The caps can be quite stiff on first installation, I would suggest using pliers to help carefully ease them over the end of the driveshaft pin.

Some people like to use graphite grease on the knuckle of the driveshaft, but this also helps grit, carpet fibres and other debris enter the joint and make it wear prematurely as it is an open joint. For this reason, I use a minimal amount of grease, or usually, none at all.

I really like the design of these driveshafts. They look and feel strong, serving a bullet proof link between the wheels and gearboxes of the T4.

Optional ECS driveshafts are available for this car. They are quite expensive but when used with a spool, they decrease front wheel vibration, which improves the steering.

Steering arms and camber links assembly

Part A - Assembling the steering arms and driveshafts to the C hubs

XRAY T4
 
XRAY T4
 
XRAY T4
 
XRAY T4

The driveshafts exit the differential (or spool) output and pass through a C hub and upright, or a steering arm. The front steering arms use an upper and lower screw and bushing to pivot the steering arms - the rear hubs use a single screw at the top with a shim (which is shown later). Be careful not to over torque the tiny hex screw. I installed the screws to the steering arm bushings in the next stage, as at this point the bushings are floating loose.

Part B - Connecting camber links to the steering arms, C Hubs, rear uprights and driveshafts to the car

XRAY T4
 
XRAY T4
 
XRAY T4
 
XRAY T4

I was getting rather excited at this stage as I could sense there was not much left of the kit to build - the hubs fitted onto the pivot pins very securely and this gave me a good indication as to how strong Xray kits are.

XRAY T4
 
XRAY T4

Part C - Connecting the pivot balls to the outer steering ball joints

As I was planning to race the car on carpet, I used a 1mm shim between the top of the pivot ball and the ball joint as per the manual, completed with an m3 12mm screw. If you are planning to race on asphalt, start off with a 4mm shim and a longer screw to make up the difference.

XRAY T4
 
XRAY T4
 
XRAY T4
 
XRAY T4
 
XRAY T4

Part D - Attaching the front and rear anti roll bars

The front anti roll bar is 1.4mm thick, the rear is 1.2mm. To make them easier to identify, the front one has 4 stripes on it, the rear has 2 stripes on it.

The next stage involves assembling the anti roll bar mounts and attaching them and the bars to the chassis and wishbones. The front and rear anti roll bars are attached to the wishbones with 28 and 27mm ball joint links, make sure not to muddle these up as it will more than likely affect the handling of the car.

The middle of both front and rear anti roll bars attach to the lower bulkheads with a double cap screw, grub screw and plastic support fixing.

Make sure there is a 0mm gap between the end of the pivot ball and the anti roll bar wire, but more importantly that both wishbones travel up and down when moved - if not make sure that both down stops are the same and that the anti roll bar is flat.

Different strengths of roll bars are available to suit different track types as an optional part. I personally only use the kit front anti roll bar and none on the rear but this is because I race indoors on foam tyres - but more importantly this is what works the best for me.

Suspension assembly

XRAY T4
 
XRAY T4
 
XRAY T4

The first picture of my review shows an exploded view of a front or rear shock absorber on an Xray T4, also showing 2 types of piston and spring as these can differ when building the car for the first time depending on the type of track you use the car on.

The front shocks are built using 2.7 rating springs, the rear 2.3-2.6 rating and are marked as such at the end of each spring. The kit springs are progressive in action which are more suited to asphalt tracks with rubber tyres.

For carpet racing with foam tyres, I would suggest a linear type spring.

The T4 shock absorbers are smaller in size compared to the T3 but work just as well, if not better and have the benefit of weighing less.

Because of the reduced size and more importantly, length standard sized 1/10th on road springs will not fit onto these shock absorbers. They are a 2013, unique design of spring size for touring cars.

I would suggest looking at only Xray T4 springs or Spec R for alternative spring options - Although possibly 3racing also sell springs which will fit the T4.

When building the T4 shock absorbers, be careful not to scratch the shock shaft when screwing the ball joint onto the end of it as this will more than likely ruin the O-ring inside the shock after time and will result in a leaky shock absorber.

I used a piece of folded up kitchen towel on the shock shaft whilst screwing on the ball joint.

The rebound process is also another important setup feature when assembling them - I use 100% rebound on front and rear but other settings may be better for you. It is discussed in some detail here:
http://www.rctech.net/forum/electric-road/540410-shock-rebound.html

Front bumper assembly

Part A, Lower mount and body posts

XRAY T4
 
XRAY T4

The lower part of the front bumper is attached to the chassis with 2x10mm screws, 1x8mm screw, two composite braces and an M3 nut.

The body mounts attach with 10mm screws. Very straightforward, nothing difficult to report on here...

Part B, Fitting the upper bumper mount, foam bumper, bodyshell height adjusters and front shock absorbers

XRAY T4
 
XRAY T4
 
XRAY T4

The foam bumper fits over the two body posts that were fitted in the previous step. Then, the upper brace and two 8mm screws secure the foam in place.

The height of how the bodyshell sits on the car is very simply adjusted via a pin and a composite O piece which the pin sits into and pivots freely back and forth. I really like how Xray have constructed this part of the car and the pieces fit together very well.

Then, the front shocks are installed. Ensure you are fitting the two assembled units with 2.7 rated springs.

At this part of the instruction manual I felt that the assembly was not very well explained. The pivot balls have threads inside of them and an Allen key design on one end of them.

This allows the shock absorber to be attached to the wishbone and upper mount without having a typical screw head at the end of it, except on the upper mount where it essential to keep everything in one piece.

Although the front bumper assembly looks strong, I would seriously consider purchasing the optional upper bumper brace and fitting before using the car. The part number is 301215.

This part strengthens the front bumper considerably and prevents the chassis from breaking in a heavy front end impact. It is also much cheaper than replacing the most expensive part in the whole kit - the main, lower graphite chassis!

I do not know why Xray did not include this part in the kit as I would say it is an essential item to purchase before using the car for the first time.

Attaching the rear bodyshell mounts and shock absorbers

XRAY T4
 
XRAY T4

The rear shock absorbers attach in the same way as the front shocks and the rear body mounts are fitted to the rear shock mount with an 8mm M3 screw.

Servo Installation

XRAY T4
 
XRAY T4
 
XRAY T4

Nearing the end of the review now, the servo is installed.

In this review I am using a Futaba S9550, I chose to use this servo as it is a slim size, lightweight and has relatively good performance.

Most of the 2013 design cars have a very similar layout as to how they house the servo in the chassis and in my opinion it is an improvement over the older, traditional style where only two plastic posts are used.

The aluminium and graphite parts used in this step not only look very nice, but provide a very strong assembly and protect the servo a little too.

Final steps - installing the rest of the electrics and wheels/tyres of your choice

XRAY T4
 
XRAY T4

Finally, the speed control, motor, battery, receiver, wheels and tyres are fitted.

In this review I am using a Tekin RS Pro Speed control, Tekin Redline 13.5 Type S (Gen 1) motor, Futaba receiver, Turnigy 2S 5.0 Lipo battery, Futaba s9550 servo and Enetti 42 and 40 shore foam tyres.

Although the pictures do not show how long each part of this review took, I would say installing all of the electronics onto the chassis takes a considerable amount of time to get them fitted well and looking good.

The more important element of how long it takes to build the kit is that everyone's skill level is different, I deliberately did not rush the build of the kit so that everything was shown in step by step form, and to ensure a good fit of every single part.

An average time from start to finish including the electronics would be approximately 7 to 10 hours.

The speed control in particular takes a while to get just right as all of the wires need to be cut to size, then tinned with solder and fixed into place at the right angle

The T4 is a high specification 2013 model chassis, however should you wish to tune it further, a full range of genuine option parts for the T4 can be found here:
http://www.teamxray.com/teamxray/news/newsdesc.php?news_id=738&kategoria=738&catName=Product&newsTitle=New%20XRAY%20T4%204S%20Spring%20Sets

Should you wish to purchase this kit, or a similar one, please contact us for product prices and further information.

Since writing this review, the T4 has been improved on even further, with the release of the T4 '14 - Although it looks similar to the T4, several improvements have been made including a narrower chassis, modifications to the wishbone mounting structure and closed layshaft bulkheads as standard to name a few of the improvements. I personally think that both the T4 and the T4'14 are both very competitive cars to race with and in some circumstances there will be no difference in performance between the two cars.

However, to a large degree this really depends on your driving and car setup ability - and the track that you race at.

I have been in the hobby of r/c cars for 17+ years now and it is still very much a learning curve every time the car goes on the track.

To summarise, the T4 is what you would expect from a well established r/c company - A high specification car which demands precision building for optimum results. Top level touring car racing is similar in some ways to Formula 1, it is not for the inexperienced or weak minded!

However, the car itself can be setup to suit a wide range of end user skill levels, (not everyone has uber quick reflexes) but in any case, (except the front bumper area that I mentioned earlier), the car is very strong.

As a result, Xray have made sure the car can be driven in a more friendly manner for the less abled racer, yet still produce a competitive setup.

Yes, the T4 is a car that can be driven by pretty much anyone - but its best performance will only be achieved by those who can understand every element of the car - and there is usually a lot to learn with any new car.

Part of the fun of r/c racing is unlocking a cars performance and making every second of your lap the faster than the second before it! :))))

I hope you have enjoyed the review and I will be happy to answer any questions you may have about the kit, or the review.

I have deliberately not mentioned in too much details as to the setup I use with this car as it is a very personal element of r/c car racing. I do not use team driver setups at all when racing, but do sometimes note particular elements of their setups, and use them for my own experimentation as it is very rare that you will find a setup that is 100% to your own liking.


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