XRAY - Model racing cars

Hello everybody.

In my last race I have a serious problem:

My Car oversteed on power acceleration in fast corners.

I think the problem is that I use a diff silicone on rear with 50mm shafts and in front I use a spool and 52mm shafts ECS.

Can be caused for use a more short shafts on rear????

I review all the parts of the car without find the problem.

Regards.

The car has been working OK until the last meeting?
If this oversteer is a sudden change you need to establish was setup changes have been done to the car.
This is the first time you've used a gear diff in the rear? What oils is in it?
Have you checked your tyres? Made sure they arent coming unglued.

I would probably say that the short rear driveshafts is the main source of your issues. However, to be able to help out fully I would need to see your entire set-up sheet. If possible, please post online.

Ok, sorry I am late.

Mi general setup:

Downstops: front 6, rear 5
Roll center +-0.00 front and rear

No kick-up, No anti-squash
Oil Shocks: front 50, rear 50

Toe front º0.5 rear 3º
Camber front º1.5 rear º1.5

Chasis height: front 5, rear 5.5

Driveshafts: front 52mm ECS, rear 50mm aluminium

Tyres: Jaco 2432
Additive: Tire Tweak 2000 (all surface of the tyre front and rear)

Spur: 64p 116
Motor: 4.5 lrp octa wind

My difficult is driving with all the space of steering. I use a Futaba 3VC (too old stick radio), and to give little º for fast corners. Is difficult to me move little the sticks.
I not sure, but I can´t setup the Exponencial for the steering with this radio.

Thank you everybody.

Regards,

Thank you for your answer.

Yes I knew that. But when I configure the EXP to minus, the tyres turn little to the right. Later when I turn to the left, the tyres turn fast, but if I turn to the right the tyres turn slow. In adittion the tyres don´t are on the center.

Does happen to you???

Sorry about my english and my explanation.

Regards,

I hope for my setup:

Spool in front

Silicone Diff in the rear and 10.000 Oil

Regards,

Did you say you were using 10000 wt oil in the back? If so, this will be your number 1 reason why your losing traction on power. Go to 700-1k oil and enjoy your rear traction. Also, a little more rear camber will also help.

Hi

Something does not sound right on the radio / servo setup as skiddins says....

I run a Futaba 3PL, which sounds similar to yours - my setup method

Set ATL the ATL so you have a small (0.5mm - 1mm ) gap between the steering arm and C-hub and equal side-side (alternatively use a setup station to set the anle on full lock equally, and around 23degrees)
Dual rate - 90% - 100% by preference
Exp -30%
Steering speed 100%

Some other ideas

What roll bars are you running?

Going thinner will slow down the load transfer and the "twitchiness".

Also check that the tyres are not fouling the bodyshell (check at full lock and with the body pushed down to simulate braking)

Charles

Thank you very much everybody.

I will do all your advice.

Regards.

Hello everybody.

After do some practice, I think that problem is about 2:

- Is so thick the oil on the rear silicone diff
- Use the 50mm shaft on rear

The setup do the car very nervous.

I hope this experience will help other drivers.

Thank you, regards.

Just to add a point, if you're running a rear roll bar, you could disconnect it for a drastic change so you see the effects straight-away, or you could go to a softer one. I find that if I'm experiencing oversteer on the exit of a corner, I look more towards my geometry rather than my shock and diff setup.

Going lighter on your diff oil might make the car more nervous on corner entry under braking, but would cure your problem of corner exit oversteer as you would have less on power steering.

Overall, I would look at your upper roll center adjusters and see if you can get more camber gain as the car rolls over to give you a bit more grip, your shock angles to possibly transfer more weight to the outside rear tire, and your rear roll bar, as maybe the car is also just staying too flat through the corner and not generating enough grip in the rear when power is applied.

Just some more options to think about.

Cheers