XRAY - Model racing cars

Hi,

I'm after some options for what to do when the grip levels at a track change. Here is my setup for when the track is high grip:

xform/index.php?act=view&ID=891&setup=t2_007

Here is a video of the track so you can get an idea of the layout.



Now, that setup above is brilliant, the car is responsive through the chicane, full on through the sweeper and tight through the S. But this is when the track is grippy, loads of rubber & additive down and dry to boot.

The problem is we have had a lot of rain and all the grip has gone. With the setup above, the car just can't get any substantial grip. On entry to the hairpins it will understeer and mid corner the rear end will snap out. The rear end is also tail happy on the sweeper mid corner. But all of that is controllable with a careful trigger finger, leaving the worst part as the 90 degree corner onto the main straight where it just power slides if you are in anything less than a straight line. Others don't seem to have this problem as much, but I'm the only one running a 007 so I have to figure out a setup for myself. I have tried the basics - stiffening the front, softening the rear, lowering the roll centres - but all that tends to give me is more entry understeer.

So, I am suffering from entry understeer, mid corner oversteer and exit oversteer. Any suggestions to try out would be greatly appreciated.

Thanks,

Tim.

Thanks guys, I'll give those a go and let you know how I get on.

Hi Pete,

I am doing the SLCC at Southampton so it would be good to do a comparison of setups - cheers.

I incrementally tried the changes suggested. Softening the springs to 15lb on the front, 14lb on the rear, changing the droop from 5 front & 4 rear to 4 front & 3 rear and increasing the camber to 2 degrees. The outcome was to move the oversteer from mid corner to corner entry

I'll keep trying with a generally softer setup and see if it improves.

Tim.

Hi Tim,
We have used a narrower front track width to good effect, to be honest we altered this last round at Eastbourne, and then our problems began, should have left well alone and kept it narrow. Steering seems far more consistent this way - .75 narrow good overall - full narrow mega aggressive change of direction. Also agree with the soft springs.
See you at Southampton
Phil

Interesting. My problems at the start certainly were aggravated by going for a shorter wheelbase and wider trackwidth. I am now back on 259mm wheelbase but it was suggested that I stay with my wider trackwidth. I think based on your comment, I might try a narrower width this week and see what the effect is.

As an aside, we were running a T1R previously, with a front diff and now run a solid axle on the T2. Have you considered trying a front diff? I am no expert in this area but the idea of a diff at the front just seems OK to me and I can't say we have yet got the T2 running as fast as the T1R . We are still half a second off the fastest time we set which was the last time we used the T1R, at the SLCC at Bashley. I admit that with the weather and the amount of rubber going down, the grip on that day would l have been serously more than normal.

Hi Pete,
we started about 5 years ago with a T1R, then used an FK04, now we use a T2, and I can honestly say that even on our best day with any of the old T1's, our T2 is about a lap and a bit faster over 5 minutes. I think we have come to the end of the road for things to do with this car to make it really quick like the other top runners, so maybe a T2 008 is on the shopping list, if not then a good 007. We used to run a front diff, but it just isn't aggressive enough going into a corner under brakes and challenging for position like a spool is. We will be in 19t at Southampton, come and find us, maybe we found something that works that you may have not used yet or missed.
All the best
Phil

Hi Mark,
We wanted to try that at the open day but never got round to it. Did you run pro squat in the high or mid rear roll centre positions?
Many thanks
Phil