XRAY - Model racing cars

I know from reading the bit on the Xray site that the Snowbirds had very high grip.
Was that the reason for running abnormally soft springs and the higher upper links?

If grip was that high, why the need for front arm sweep?

From the pictures the run foam tires, right?

Softer springs maker more overall traction and more pitch from front to rear which means more forward bite which proved really beneficial with these Jaco tires.

The higher upper links made the car drive more "round" and carry more cornerspeed.

The front arm sweep is used to give more corner entry steering. I like to use it for most conditions and have done so lately in almost all races.

So the softer springs were more to do with power out of the corner?

I have tried the arm sweep but it seemed to make the car loose a bit too easily.

Were you braking much at the Snowbirds or just at the end of the straight, your car looked very flat from the video's.

Skiddins

@ Skiddins:

If you add that sweep (plow) without re-shimming the suspension arms on the pin you shorten the wheelbase and that makes a car more instabile. I experienced a more direct front and a rear that needed slight changes in settings to follow the front as it should. But that's my impression and of course I can't speak for others.

@ Alexander:

Do you mean you removed material from the alu suspension arm holder by 'Rear suspension cut 0.5mm each side'?

Yes the springs affected mostly the on-power steering.

The rear suspension is narrower by 0.5mm per side.

The car had very good off-power steering, and thus I could use the braking points to get the car to steer around corners better. Yes I was braking in most of the corners. This is how most top drivers drive today with a spool in the front. You have to drive from "point to point" and not round corners like in the old days of touring car racing.

When the shocks are shimmed out 2mm from the shock towers (both from the top and bottom mounting point) the car will have slightly less traction but will "stop" less in corners, especially in high speed corners such as the sweeper after the straight. I don't know the exact reason of this.

Hi Alex

Do you think any of your setups would be suitable for the following track, it's 35m*20m;



The layout will be different but the overall feeling will still be the same.
It's not very high grip.
It's Prima GT Carpet with Sorex 32 JB tyres.
I'll be in 13.5, the same as the video.

The only thing I can say is that when running short rear links the car was too loose, still drivable but I had to slow down a lot for the corners.

Would the Snowbirds or ETS setups be suitable or can you think of anything else to look out for?

Sorry for hassling you.

Thanks
Skiddins

OK, here's what I started with today;



This was quick but the rear was a little unstable off power.
So I tried 3.0 front springs, this improved the rear grip slightly and obviously sharpened up the steering. It was also 0.4s per lap faster.

As the rear was still not 'stuck' enough for me to push hard I started trying to mess around with the rear links.

I have gone down to 4mm on the rear upright and tried using 1mm on the rear clamps, 0.5mm, but the rear is always a bit loose.
Also tried shorter rear links with 0.5mm/4mm which did get me my fastest time of the day but was still too on edge.
Also tried lowering the rear diff which didn't seem to do anything.

My main question is what would you do to try to get the rear to stick more?
Would dropping the links down front and back and going back to 2.8 springs be better?

As it happens they have copied a layout from a previous round so this is exactly what we're racing on!



Thanks
Skiddins

i would try 900 or 1000 gear diff oil
1.3 anti roll bar
and if you do that,go with your rear shocks on 3 position
3.0 front spring and 3position

2mm shims between all shocks and shock tower and between shocks and arms(i saw that car is more stable and have more coinstant grip,car is easier to drive,more predictable)

dont use additive on whole FRONT tires,just "paint" the inner half

Skiddins, are you using any dragbrake when you write that you have a little unstable rear axle off power?