XRAY - Model racing cars

March 2005 Update: In order to make the forum easy to navigate I have removed the Announcment status of these threads to a regular posts:







Click on any of above links to visit the related threads.

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January 2005 Update: XRAY has sufficient amount of spare parts for XB8 and majority of all back orders were in last weeks cleared. If anybody will have problems to find any spares, please contact XRAY support and customer service team at info@teamxray.com where you will get contacts where to look for the parts locally.

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If you face with any of these problems, please make sure to email Xray directly at info@teamxray.com instead of posting your question at this forum, so Xray can make sure to contact you directly and solve the problem for you:

1.) I am missing some part in my kit - please contact Xray who will have it delivered to you. Please check the code number printed on the vinyl bag in which the part supposed to be and with your request, email this number as well.

2.) My battery pack does not charge - please contact Xray who will advise how to proceed.

3.) My diff pins have wrong flat spot - please contact Xray who will have the pin replaced for you.

4.) I am looking for composite spare part - Xray has extensive stock of all composite parts and there should be any shortage. If you have problems to get a composite spare part, email Xray who will advise where to get it.

5.) I am looking for steel spare part - Sever special spare parts such as drive shafts, gears, and diff parts are in shortage of the first weeks. Please have this part ordered through your local hobby store, who will get it as soon Xray will start exporting these products.

6.) I broke the pistons - Exchange the pistons for some other in the set and make sure to adjust the downstop properly. Most of the cases when pistons break happen due non-proper downstop setting. Read the Instruction manual how to set-up the downstop properly. If you have any questions, please post them in the General XB8 forum.

7.) The pins on the flywheel are coming loose - Use super glue to fasten the pins.


If you have any of the above problems, please email to Xray at info@teamxray.com who will advise you all the details how to proceed.

Gear mesh adjustment



It is very important to ensure that your XB8 has properly adjusted gear mesh. Proper gear mesh gives with sufficient play between the spur gear and clutch bell gears, and will minimize the risk of teeth breakage.

How can gear teeth break on the spur or clutch bell? If you have improper gear mesh between spur gear and clutch bell, there is very little play between the teeth. After a large jump there is an increased possibility of chassis flex in the middle; this causes the teeth to move and engage more and if there is insufficient play then breakage will occur.

To minimize the risk of teeth breakage, adjust the gear mesh so there is more play rather than less play. When the chassis flexes, the teeth have sufficient play and do not block or get stuck.

To adjust gear mesh, release the motor mounts from the bottom of the chassis, adjust gear mesh as appropriate, and then firmly retighten the motor stands. From time to time, check that that there is still sufficient gear mesh. Remember to always set the gear mesh on the looser side rather than tighter.

Eccentric caster bushings



If you experience a problem from the I.A.C eccentric bushings (Integrated Adjustable Caster) beginning to turn around and get loose, follow this small trick. Polish the hinge pins on which the front C block is mounted. Use a bit of grease and apply it to the polished pins, especially the area that is inserted into the eccentric bushing. Tighten the screw that holds the eccentric bushing from outside of the arm sufficiently so the eccentric bushing does not have any play.

Oils to use in differentials

From David Joor

To give the car a bit more steering entering the corner while maintaining stability exiting, we suggest using these XRAY oil combinations
Front = "5000"
Center = "7000"
Rear = "3000"

If the track is extremely bumpy/rutted, try taking the center diff down to "5000" from the above suggested diff configuration. This will allow the front to pull the car more making it easier to drive and keep the nose down more when hitting bumps.

Another tip that the US team has been running is a "5000" in every diff, however this will make the car push/understeer but will handle the bumpy style tracks very well. The main change is the "5000" in the rear diff and this will lock the rear of the car into the track very well.

Front kick-up vs. upper arm roll-center eccentric bushings

From David Joor

It isn't exactly spoken very clearly about how the upper arms should be positioned in relation to the kickup. So I would like to clear this up for everyone. Justin Mann and I debated over which setting was correct and I believe he won so here is the data that should give the least amount of bind to the upper arm through the compression stroke, I have found this to help keep everything functioning normally and the life of the turnbuckle is extended.

Kickup: Front Upper | Rear Upper
1down: 1up | .5up
1down: .5up | 0
1down: 0 | .5down
1down: .5down | 1down

So this is just an example, here are the rule of thumbs. Justin Mann and I built this up on the premise that 0 kickup placed the lower and upper hingepins were parallel using all 0 bushings. We also did testing on which caused the arms to be the most free (this is what we debated on, thanks Justin)

KICKUP | RULE FOR FRONT UPPER BUSHING POSITIONS
1up (-3.0) | front bushing should be .5 lower than rear
.5up (-3.5) | front bushing should be .5 lower than rear or same
0 (-4) | front bushing should be same as rear
.5down (-4.5) | front bushing should be .5 higher then rear or same
1down (-5) | front bushing should be .5 higher then rear

Using front brace with adjustable engine mount

Using both front and rear aluminum braces will make the chassis very stiff in the front and rear, and flexibility will be transferred to the middle of the chassis. This flexibility in the middle of the chassis will increase the risk that the teeth on spur gear or clutch bell will break if gear mesh is incorrectly set and there is insufficient play.

To minimize the risk of spur gear or clutch bell teeth breakage, we suggest using the optional adjustable engine mount, which will stiffen the car in the middle of the chassis.

Please note that even if you use the adjustable engine mount, you must adjust proper gear mesh and set a rather large amount of play between the spur gear and clutch bell.

Steering Throw Modification (Increase)

By David Joor

There has been a couple of people asking me how I get the extra steering in my car. I have been explaining it but it seems that pictures are what everyone wants these days, lol. So here you go, this is what I have done. The only thing to note that I don't have pictured is if you are using the stock knuckles, you will need to remove the lower bracing on the knuckle that will hit the arm when you steer at full droop. All you have to do is lift the front of the car off the ground and turn your wheels, find where it hits and cut it off. Now remember this is not covered by any Xray affiliate, if you cut your arm too far and it breaks then it is not Xray's fault, so you your best judgement. Enjoy...



Notes:There are two cuts to look at to increase overall steering throw. The caster block has a slight cut so the knuckle can swing further. The cut that is on the arm is to allow for the extra steering when running a lot of droop with either the soft arms or modfied hard arms.


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Notes: This is a birds eye view to better understand the cuts made with a dremel sanding drum.


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Notes: You can see the extra throw that you get with this shot.


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Notes: This is the space available at full droop and full steering lock, notice that there is never a bind.


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OPTIONAL: Notes: If you are using the 3d Acermann steering plate than you will need to cut a tad bit off the corners of your front upper suspension holder - rear because the nut will hit it. If you take the top plate off and your tank, you should be able to remove it with a Hudy 2mm ball end wrench. By looking at the aluminum option part available, it appears you will need to take off material on that as well if you want the extra steering throw.


Click to enlarge

XB8 Building Tips

Created by Michael Giorgi
What to be aware of when buiding and running a new Xray Xb8 kit

1 ) When filling the diffs with silicone oil, make sure to only fill them to where the pins cross for the syder gears

2 ) If you choose the optoin to not use the O-rings in the diffs. Make sure its only the four small o-rings that you do not install. Make sure that the two bigger o-rings are installed to create a seal for the silicone oil

3 ) make sure you grease the shaft of the outdrive when installing it into the diff cup and gear

4 ) make sure you grease the o-ring that seals both sides of the diff for a better seal

5 )When installing the diffs make sure they are installed in the bulkhead correctly and the gear facing towards the milled out section of the chassis. As per instructions

6 ) When installing screws into plastic, only screw until the screw stops with a decent seal. Going further can risk stripping the plastic

7 ) When installing electronics make sure you route the wires into the radio box under the radio tray before installing the tray.

8 ) Make sure you install the antenna throught the hole in the top of the radio box plate before installation

9 ) When tightening the fuel tank thorugh the grommets, only tighten until the screw touches the top of the seal on the grommet. It is ok for the fuel tank to have some play in it when installed correctly

10 ) When installing servos only tighten the screws for mounting until they just seat onto the grommets. Same as instruction #9, You want the servos to be seated good, but not too tight

11 ) When installing engine mount, make sure the line of the engine is perpendicular to the spur gear

12 ) Make sure gear mesh has a decent amount of lash in it when installed correctly. You should be able to hold on gear tight and have the other make a slight click, click noise.

13 ) Make sure that if you choose to install the optoin aluminum front knuckles and choose to use thread lock on them, that when installing the thread lock, you put it into the screw hole on the knuckle and not on the screw, to prevent any leftover threadlock for getting dryed up in the bushing, and causing binding

14 ) When building the shocks the object is to put the oil in the shock and seal it up without having air get inside. To help do this install the oil and move the shaft up and down until there is no air left in the oil. Then install the cap with the bleed hole facing upward on a 45 degree angle and slowly spin the shock body holding the cap and bleed hole stationary. Excess oil will bleed out and this will prevent air from getting in.

15 ) When installing sway bars make sure that when you tighten the two setscrews in the sway bar that they are tight enough to take up slack, but not to tight to cause binding. It is easier to acheive this with the shocks uninstalled.

16 ) When installing body, try to mark out the mounting holes for the engine and mounts before painting the body. You can write with a magic marker on the top side of the body, then after painting , ream out the holes, then peel off the protective coating

17 ) Body holes will be a little different from the factory marks in the body, so be aware of that when drilling mounting holes

18 ) When building center diff mounting support and brake system. Make sure to leave about .5mm of play inbetween the brake disks and pads to prevent binding

19 ) Make sure that all moving parts are not binding before final isntallation. If they are go backwards with the installation steps until you can find out what is causing the binding and fix the problem

20 ) When installing the setscrews to hold in the pins on the outer rear arms, make sure to only tighten them until the sit upon the plastic arm, and not to tighten them in until they stop. Doing this will prevent the pin to be under stress and prevent binding

21 ) When installing the trunbuckles into the plastic arms and ends, make sure you pay close attention to the instructions, becuase the arms and turnbuckle ends are prethreaded, and installing the wrong end will cause the prethread to be stripped

22 ) When installing the shock boot, be sure to apply some oil to where the endcap for the bottom of the shock will be installed to prevent the boot from ripping

23 ) When building the sway bars start with the end of the sway bar flush with the endcap that supports the sway bar on the ends. If you have to go further than 5mm's in on the bar, it is suggested to upgrade to the thicker sway bar and start with the ends flush again, and so on.

24 ) When tightening 3mm locknuts, tighten until they are seated. These nuts do not require any additives to stay tight. They have nylon in them to prevent from unscrewing. Once they become easy to put on and you feel no resistance, install an new one and start again.

25 ) When installing the muffler mounting bar, be sure that it is not binding or rubbing against the steering bellcrank, and that the steering is free to turn.

26 ) When installing the clutch, make sure that you shim behind the flywheel until there is only .5mm of play left at the end after the clutch bell. Shimming in front of the clutch bell excessivly will cause unnecesary strain on clutch bearings

27 ) Before installing clutch bearings, be sure to rid them off excess oil in them which can casue slippage and overheating of clutch parts. To do this, either blow both sides out with a air gun compressor, and wipe of with nitro cleaner when done. Or take of shields and spray lightly with nitro cleaner, and do not regrease when finished

28 ) When isntalling linkages onto throttle be sure that you adjust the bellcrank on the slide of the carburator to be facing straight ahead towards the front of the engine to reduce unneccasary binding on the linkage

29 ) When installing throttle horn, make sure that when at nuetral position, it is facing 90 degrees perpendicular with the chassis, to leave enough room to fully turn left and right equally, and do the same with the throttle horn. Face parralel with servo length, to leave equal room for left and right turning while in neutral position

30 ) When building and making adjustments, be sure to make equal adjustments to both sides of the car when there is an optoin for left and right adjustment.

31 ) If using the muffler support/protector ( 35 8720 ) make sure your muffler doesn't rub the M3 Nuts. It can cause damage to muffler or even wear a hole in it. Either dremmel down the excess screw sticking out, or move the pipe over out of the way of them.

RCAMERICA Team Setup Tips 2006

Written by David Joor

The Wheelers, Castleberry, Tang, Starr, and Myself got together 2 weeks ago at a track for 4 days to test on the car. Here are the things we have come up with to help the car on our tracks in the United States. I can't promise that I will be able to respond to a lot of questions because I am hardcore into my racing right now. I just wanted to show you guys what was going on in our heads.

Diffs Try 335 cps or 333 cps, maybe surprised with the result. 5 in the rear locks the car in on exit, the 3 in the center puts more power to the front tires on exit so the rear stays planted, and the 3 in front doesn't give as much exit steering but it is balanced by it pulling the car out of the corner from the center giving it the power, it also allows the car to rotate into the corner.

The RCAMERICA Team are ranging from 233, 331, 333, 345, and 335. The car reacts well to the light oils.

Caster
Run the car with the least amount of kickup almost all the time. The car transfers a lot of weight to the nose off power and noses sometimes off of jumps when there is a lot of kickup. The Wheelers tried running 16 caster and it was incredible because like the diff setup the car rotates so well at low speeds, doesn't over-steer coming out of corners, and pushes at high speed making it feel more stable. Just watch out for high speed ruts

I tried this at the Ice Breaker II this weekend and it didn't feel as good as it did at our test track but the Wheelers ran this at CRCRC so it does work.

Sway Bar
Try the 2.6 in the front if the car is a little difficult to control, it will also improve the car through technical sections because it is more stable and response left to right but will push more on high speed long turns.

Rear Toe
Don't be scared to try 4 degree rear toe, however when the car breaks loose be ready to counter steer.

Shocks
We are all now running 1.4's in the front and 1.5's in the back. The front ranges from 500 - 600 xray oil and the rear 400 - 500 but typically 450. The Wheelers and I are also now using the Xray dark blue springs in the front and the light blue in the back. This suspension allows once again for the car to be more stable off power and it jumps higher and more level. Whatever springs you use just try the next range up in stiffness on the front from that company.

Length
The Wheelers like running the car short lately (rear uprights all the way forward).

XRAY XB8 Diff Supplementary Sheet

XRAY XB8 supplementary sheet how to fill-in oil into diff.

VERY IMPORTANT: You have to follow these instructions.

These instructions apply for XB8, XB8-TQ and XB8R.

XRAY XB8R CVD Drive Shafts Supplementary Sheet

XRAY XB8R supplementary sheet how to build & fix the CVD drive shafts.
VERY IMPORTANT: You have to follow these instructions.

These instructions apply for XB8R and for XRAY CVD Drive Shafts.

More downtravel modification

To achieve more downtravel of the front suspension, please follow this handy tip to easily modify the chassis.


This is standard out of the box chassis. The highlighted area shows where the chassis needs to be slightly filed.


Using a file, slightly file the highlighted area under an angle on both left & right sides from the top of the chassis.


The edges of your finished chassis should look like in the shown picture.



Safety Precautions:
• Practice using the file first before making this modification.
• Wear safety glasses and gloves.
• Perform this modification in a safe area away from small children.

XB8 Tech Tip: Pistons Assembly

The latest XB8 shock pistons have been improved for maximum efficiency of movement inside the shock body.


When installing the pistons, very carefully remove the pistons from the parts tree using a sharp hobby knife.


Use the knife to remove any excess material from the piston, but DO NOT remove any extra material from the shock piston itself.


Use the XB8 Shock Shims (#358040) above and below each piston. Secure to the shock rod using a M2.5 self-locking nut.


When installing the piston, tighten the self-locking nut securely but not excessively. If excessive force is applied, the force on the nut will distort the piston and negatively affect the free and smooth movement of the shock piston.


The self-locking nut is gently tightened. The piston remains undistorted and fits inside the shock body perfectly, ensuring smooth movement of the piston.


The self-locking nut is overtightened, causing distortion of the piston. This will negatively affect the free movement of the piston in the shock body.

Now available world wide - the original authentic , developed & designed by Ing. Juraj Hudy.






The set of high quality German made pins for off-road drive shafts are available too:
for XRAY XB8

TECH TIP: Securing Shock Lower Mounting Screws

To prevent loosening of the shock lower mounting screw, we suggest installing a flat-head self-tapping screw (e.g., SS 3.5x8) in the beside hole. The head of the self-tapping screw will secure the shock holding screw and prevent it from backing out. This should be done on all four lower arms.

TECH TIP: Front & Rear Diff Gear Mesh Adjustment

In the event that the composite diff bulkhead allows too much diff side play, this may create non-optimal gear mesh between the diff spur gear and the pinion drive gear. This is easily resolved by inserting 1 or 2 of the included thin shims behind a diff outdrive ball-bearing, depending on how much play there is.

THE LOCATION OF THE SHIM(S) DEPENDS ON WHETHER YOU ARE TRYING TO CLOSE OR OPEN THE GAP:

XB8 EC Supplementary Instructions



The XB8EC chassis has been updated in the recessed area below the engine to increase the strength and lifespan of the chassis. Due to this design change, the engine screws protrude very slightly beyond the chassis; this effect is intended and has no negative effect on performance or longevity.






STANDARD 2 HOLE PISTONS

The standard set of 2-hole shock pistons features 1.3, 1.4 and 1.5mm holes, both STRAIGHT and CONICAL. When using any of these 2-hole shock pistons in the XB8EC, we suggest using thinner shock oil. For the basic set-up, we suggest the following configuration:

FRONT shocks: 1.4mm, 2 holes, straight - 350cSt shock oil
REAR shocks: 1.5mm, 2 holes, straight - 350cSt shock oil

Please note that using the standard pistons in the XB8EC shock you need to use much more thinner oil than what you may be used to with the XB8TQ.

Standard 2-Hole Pistons = 350cSt Shock Oil




MODIFIED 4 HOLE PISTONS

To increase shock damping action and improve handling, we suggest drilling 2 additional holes in the straight pistons. This will greatly improve the oil flow and improve shock action.

When drilling the additional 2 holes (to make 4 total) in each piston, it becomes necessary to use thicker oils (similar to the oil weights used in the XB8TQ shocks). Please note that additional holes must ONLY be drilled in the pistons with the STRAIGHT holes. Always drill the additional
holes the same diameter as the existing holes; for example, in the straight 1.3mm piston you must drill two additional 1.3mm holes.

Using the 4-hole pistons, we recommend the following basic set-up:
FRONT shocks: 1.3mm, 4 holes, straight - 500cSt oil
REAR shocks: 1.4mmm, 4 holes, straight - 500cSt oil

Modified 4-Hole Pistons = 500cSt Shock Oil






#352620 ADJ. TURNBUCKLE M5 L/R 35 MM SPRING STEEL (2)

Please note that the hardness of the front upper turnbuckles has been modified for the XB8EC kit; the new turnbuckles are purposely softer. In the event of a serious crash, the softer material will allow the turnbuckle to bend slightly instead of breaking; this will help allow you to finish the race.

TECH TIP: XB8, XT8 Diff Outdrive



All XB8/XT8 diff parts are manufactured from very high tensile steel and as such all parts are specially hardened to provide extra long lifespan and minimal wear. After the hardening process the diff outdrives and inside of the diff gear and diff case are ground to achieve a smooth action of the diff outdrives in the diff assembly. All of the parts are precisely manufactured within very tight tolerances to minimize diff oil leakage; however, if some of the parts with tight tolerances meet together and the tolerances overlap, in some very rare cases the diff outdrives may not turn as smoothly as desired. In case you experience that the car starts to behave strangely and the handling of the car gets difficult after a few minutes of running and the differential becomes very hot, we suggest that you follow this Tech Tip.




Take ultra-fine sandpaper and cut strips the same width as the diff outdrive shafts.




Roll the strip of sandpaper on the diff outdrive shaft, with the grit of the sandpaper against the shaft. Gently squeeze the sandpaper while turning the outdrive in both directions and moving it slightly in and out of the rolled sandpaper. Use a drop or two of light oil on the sandpaper (if desired) for smoother polishing. After fi nished polishing, carefully clean the diff outdrive to remove any residue or metal filings. Performing this action will slightly polish the diff outdrive shafts; do it for all of the diff outdrives. Make sure not to overdo it or you may damage the diff outdrives.




Cut a slightly larger piece from the same sheet of ultra-fine sandpaper.




Roll the sandpaper on any narrow shaft, for example a screwdriver, with the grain of the sandpaper facing outside.




Insert the shaft or screwdriver with the rolled sandpaper into the diff case and follow the same procedure, move the shaft in and out and turn inside the diff case. Use a drop or two of light oil on the sandpaper (if desired) for smoother polishing. After finished polishing, carefully clean the parts to remove any residue or metal fi lings. Perform this on all the diff cases.




Perform Step 3 for all of the diff gears.

XRAY XB8EC Chassis Flex Tech Tip



The XB8EC chassis is manufactured from premium Swiss 7075 T6 and is hardcoated on XRAY‘s own fully-automatic state-of-the-art robotic hardcoating line.

Some XB8EC drivers who were used to the XB8TQ may feel that the chassis is softer, but please note that the XB8EC chassis is not softer but rather it is more flexible due to the use of composite braces both front and rear. The XB8TQ included both composite and aluminum braces and experience has shown us that most customers installed the aluminum braces; this made the XB8TQ chassis flex less and in most racing conditions where a more flexible chassis was required the XB8TQ did not have sufficient traction. For this reason XRAY decided to include only the composite braces in the XB8EC kit, which can be used in most standard racing conditions as they provide more chassis flex, making the car easier to drive.

The extra robust was specially developed to work on the 1/8 Buggy and Truggy 17mm wheel nuts in dirty and abusive conditions. No matter how tightly the wheel nuts are locked, the HUDY Wheel Nut Tool will allow you to very easily and comfortably release the wheel nut. The special design of the oversized handle gives you superior torque to tighten the wheel nuts (helping to ensure no more lost wheels) as well as loosening them.