XRAY - Model racing cars

Hi all, i am driving Xray T2-009 rubber spec, with few modification and now using Internal ratio 1.9. Our home parking lot track condition is very challenging. It's bumpy, dusty, a long straight ahead, and high speed sweeper, along with techincal slow corner inside (U Turn). Without using Sorex tire, its almost impossible to race. I have tried Sweep tire 36 & 40R where our normal weather temp is 32 -34c degree, its almost undrivable. Car will tend to slide or spin exiting corner when try full throttle. Anyhow, does anyone can discuss or maybe give me a guide of setting up T2-009 rubber on our local track condition? For example: shock oil (cst), spring, roll center position, camber, toe in , toe out, wheelbase, etc

Thanks

It would help on this one if you either posted your setup or tell us what you have changed from the kit setup in the Instruction manual. Can you clarify tyre comment - do you mean it is OK with Sorex but not with Sweeps? What turn engine are you using?

OK thats better

I am focussing in your statement that the track is bumpy. If that is the case then try...

1. I am not familiar with HPI springs but if you have used 500 cst to match the springs then I think your are sprung way too hard for a bumpy track. Depending on how bumpy it is at various points this could be causing your understeer on entry and oversteer when you apply the power on exit. If you have the kit XRAY springs also, 2.8 front 2.6 rear, fit them and change to 350cst

2. I have not used prodive but I have used prosquat, very recently, to hold the rear on exit. It certainly improved the grip but made the whole ride very bumpy so I removed it.Our track is bumpy and I suspect (but don't know) that one might only want to use prosquat/dive on a smooth track. Maybe your track is smooth and using prodive/squat is making it seem bumpy

Go back to kit setup


3. Your ride height for a bumpy track is probaly a bit low and you may well be bottoming out. I would try another 0.5mm front and back.

Having increased your ride height, slide your ride height guage slowly under the chassis, from the rear pointing down the centre line until the rear wheels JUST leave the surface. If the increase in ride height, ie your uplift, is 2.5 or more then for the moment you have enough uplift/droop. Do the same for the front.

If you are reading less than 2,5 reset your downstops 0.5mm ie 4.5 and 3.5 - a couple of playing cards are about 0.5mm, put the guage on top of those and set to 4.0 and 3.0

4. More droop helps on a bumpy track. Do away with the cards and change set to 4.0 and 3.0

Make one change at a time and see what happens. If it does not make it worse leave the change on and go to the next one. Don't dismiss them immediately.They will change the handling of the car and you need to adapt to that first before assessing whether it has made it better or worse - especially I think with number 1 above. You will compensating ,most probably, for some poor handling so you need to un-compensate first!

I think I would be inclined to make the changes in the sequence 3,1,2,4

Report back

OOh foam spec car. When you swapped the chassis and top deck over did you put all the screws back as per the foam spec setup? I am thinking that with the springing also you probably have a very stiff car, which for a dusty bumpy asphalt track you don't want. Set the chassis plate to the EU spec screw settings and if the EU kit setup has any stiffenning screws in the top deck (I can't remember), probably at the front if it does, take them out. Err do that before no.3

hey

you can give my setup a try, had trouble with the same track conditions, there arnt to many setups out there to look at, with low traction and technical.

this is my current setup and still working to improve balance, got so much steering still, and finding it hard to transfer that to push.



id go back to what works. i did a bit of looking and its all most weird how almost everyone runs the 6Front and 5Rear down-stop, and 0 front and rear roll-centers, or there about as a base. (i leave those set and fiddle with everything else, that's my theory anyways)

cheers

ok the white springs should be ok for the rear, but the light purple might be a bit too hard 30lb, if you have something softer, as i think the limit would be 25lbmax for on road.

yeah the 350cst front rear will work, not sure on the alu shock piston holes, would have thought all that they would of changed is the shock body personally? you could start with 3 f/r and go back to 2 for front depending on car handling.

best to see what local guys are running.

Bradles, i have done the suggested adjustment sequence 3 then 1. So far so good. I adjusted my ride height, downstop to 5mm front and 4mm rear. For the shock, at the front i use 550cst light-purple spring, and for the rear, i use 350cst with white spring. So far i havent made any changes for my roll-center. It is now still using pro-dive & pro-squat. I Noticed after a fast straight ahead, entering a fast sweeper, off-throttle it understeer until i apply some throttle to gain back the steering. Any adjustment that i must looking into? Just for your info, the rear side of my car, no stabilizer is installed. Thanks

to fix off power under steer at corner entry you will want to put the rear anti roll bar back on. or you could swap to a softer front roll bar instead, and leave rear off.

Bradles, the anti rollbar for the rear does help. I am wondering how to make the car sharp turning at the U-Turn corner technical track? Any recomendation? Ackermann settings maybe? Currently i am using "5 Step out". Should i change back all my roll-center position to standard 0mm for both front and rear?

yeah i would try the roll centers back to front and rear 0. see if it helps.

where you have the ackerman it should be ok for what you are wanting, you can also fiddle with the amount of spacers under the steering link. ive used 1mm, but tried 2mm last week, and might go back to nothing just to compare the feel.

see how it goes.

Good weekend. Parts arrived. Changed up rear spring from White to 2.6 and front from ligh-purple to 2.8. Its all good. High Speed sweeper, the rear will have a bit of slide at corner exit and i can do full throttle at the straight earlier than before. My car used to be have too much grip at the rear where it understeer big time at corner exit on power. Current shock oil in front 550cst using 2.8 spring and rear 350cst with 2.6 spring. All these shock oil thing confuses me. I may try 550cst for front and rear and see how it goes. Some local racer uses 700cst for the front shock and rear 500cst. They have fast steering respond. Temperature here is between 32-35c degree.

Re-setup my T2 exotek with Spec-R gear diff running LRP SXX TC Spec 4 Turn. Shock oil in front 550cst with Xray 2.8 spring and rear 350cst with xray 2.6 spring. Camber both end -1.5 degree with Muchmore V absolute 32R premount tire on Asphalt parking lot track with temp 40-45 degree. Felt the front softer than rear, dont it is right or wrong, but i see some improvement. High speed Sweeper out, i gain enough steering and after a high speed straight sweeper in, off power, my car don't understeer as before, it just nice where i can drive faster speed sweeper into infield. Very happy with that. I do found out my T2, dont have much droop. As Paul suggest to set both ends with 3mm droop. I have met 2 local racer and both using different method of setting their droop. It confused me. Does anyone know how to do it? Does droop really help? On what situation?