XRAY - Model racing cars

Raced my t4 14 for the first time over the weekend on a UK tarmac track and found the rear end very loose off power I set the car up using the supplied stock set up sheet for tarmac.any suggestions on set up advice welcome to help reduce this? During qualifying I added more rear droop and added 40wt shock oil and this helped quite alot put still a bit loose I was going to run without a rear rollbar as I've done this years ago but not sure its advisable with newer cars? Also noticed that most set up sheets now have the car using both front and rear springs/shock oil the same where as years ago we used to run stiffer springs and thicker oil up front but that don't seem to be the case nowadays why's that? I jus need bringing up to speed on latest trends in tc racing. Any help gladly received thanks

More rear droop should have actually made it worse, surprised you found that helped. I run 4 rear and 5 front (with ~6mm ride height) as my standard setup and rarely have issues with that. What ride height and droop are you now running?

Thicker diff oil will reduce off-power steering. Give 2k a try. Also try going to 1mm shims on the rear inner links, that usually calms it down on entry and is what most people run.

I wouldn't remove the rear roll-bar. If anything going thicker often gives more rear grip on entry; a 1.3mm rear bar might help.

Also consider getting the centre post (306516-O), this gives a lot more rear grip and stability, although usually requires other setup changes to get some steering back.

i found widening the rear helped,i run 2.5 rear toe in with the rf i use the 1mm outer insert,the rr i use the 0.5 outer insert these are still on the std centerline
if its low grip add shims to the rear inner camber links,ive ran up to 3mm when the grip was low

if you can post a set up sheet it would be alot easier to help

You don't say what track this is for, someone might be able to give more specifics on a setup.

Wider rear tack as mentioned, but just use the +.5's or +1's to keep 3deg rear toe.

I would also consider dropping the rear upper link to 1mm on the inside.
1.3mm rear roll bar might also help.

Skiddins

Thanks for the reply guys, I'm running the std tarmac set up .the only difference being 3k diff oil.I was only running 3mm on rear droop so I changed it to 4mm droop all round and found it helped as when I came off power all weight shifted to front so the extra droop kept the rear wheels in contact with the tarmac which gave better rear end grip.I also use 40wt shock oil all round as when I had 30wt in the car was bottoming out as the track was bumpy in places ( Broxtowe tarmac track). At that track we used to run without rear antiroll bar as it gives the car more rear grip but not sure if you need to do that with today's cars we used to do it with old mi2 schumacher but things may have changed since then.also we used to run cars with stiffer front end eg stiffer springs up front along with thicker oil although looking at some set up sheets spring rates and oil kept the same back and front.will try some of your suggestions hopefully will get better. And was running 6mm ride height.That optional steering post wouldn't it stiffer the chassis?
Thanks again guys anymore help gladly recieved

If you're running the full tarmac setup, does that mean you've got 4mm bumpsteer spacers? If so reduce it to 2mm (not sure why they specify that many, no one runs more than 3mm, and 2mm is more standard).

Broxtowe is mega bumpy so the extra droop probably gave more grip by keeping the tyres on the ground over the bumps.

When using the motor mount post you remove the layshaft screws, so you end up with a bit more flex overall, and more flex at the rear which is what changes the balance. I'd definitely recommend it for Broxtowe as it also seems to help over bumps.

Cheers dale yep prob got 4mm spacers on so will reduce down to what you've advised.will look at that post a prob invest in one for more flex.Broxtowe is my local track so will be set up for mostly running there.would you run thinner rollbar on rear for more grip? And are the stock springs ok or would you change em? Thanks

Here's my Clubman setup for the T4'13 at Broxtowe running 13.5 from last year.

It was a bit loose in the finals when the track got hot, but up until then it was pretty good.



My best lap was a 14.83, don't know how that compares with what your going for?

Although the springs on the sheet are progressive's the kit 2.5's should be fine, they've worked for me almost everywhere as a safe starting point.

Cheers skiddins will have a look and take a few pointers from it my times weren't as quick as yours but will be working on it thanks again