XRAY - Model racing cars

I received yesterday the x-ray's gear differential. I replaced the two spec-r. The X-Ray's seems to work better, also because don't leek.
But for the price I think that the "output shaft" (I didn't know if I write it correctly) should be made in metal

The outdrive adapters will be made from hudy spring steel as option parts - #304971 (should be available within few weeks).

I see that people use either using 700 oil or 1000, is this the shock oil? Part # XRA359270 for 700cst. Just confirming before I try it.

Yes, try the #359270 700cSt oil.

Which Oil should I fill in for Modified?
I have the SP 4.0R.
In the Setup sheet from Hagberg by the Euro he take also the 700 Cst.
I see also by Juraj Hudy that he takes 1400 Cst by the Euro.
But by the Spec-R Diff. we take 2000-3000 Cst only in Stock Class with 13,5 turn they take 1000 Cst.
Is the Xray diff so different by the Oil?
What will be when i take the 3000 oil in Xray Diff?

Regards Christian

If you want the same effect as in the Spec-R diff, you should use a little bit harder oil because of different geomtry of the housing.

I use 3000 most of the time. At the Euros it was better to have it softer becaus there was understeer with hard oil.

The reason some drivers use very soft oil is because of drivers preference. If you like 2000 or 3000 oil in the Spec-R diff, you should probably use 3000 in the XRAY diff.

And in a smalltrack, with low traction and rubber tyres? I'm trying the 1.000.000 in the front and 500 in the rear anc it's not so bad , but I'm open to all suggestions

It is always a good idea to check if the spool in front gives you better times, even if you think your car is good with diff in front.

Low traction means usually that it is a good idea to use a thinner oil. But it depends on more track characteristics.
Hairpins with straights means harder rear oil, so you can accelerate earlier and harder.
Having a nerveous rear end on throttle can mean that you are too hard or too soft.

Do you race on carpet or asphalt?

It's an asphalt track.

In this winter photo you can see the curves where I suffer a bit more than other pilots:
http://s1111.photobucket.com/albums/h47 ... G_1407.jpg

But in the last test I was pilot with the less experience and I'm trying the rubber tyres in this period, instead my friend with TC6 is a better pilot and he drives with rubber since a lot of time. We had 10.5 motor. The third pilot had the T3R (not really like mine. His car is "stock") with foam tyres and a 7.5 (and more experience )

If you have all the oils and you can invest 2 hours I recommend the following test-series for the diffs:

1) Do a test run with your normal configuration (in this case 1'000'000/500)
2) try 2000 in the rear
3) if 2) was better try 3000, if not try 1000
4) Test Spool in the front and keep it if it is better
5) if not, try 200'000 to 500'000 in the front

I recommend a procedure like this for racing in high competition on each track. At racemeetings it is a good idea to work together with more drivers to find the perfect combination.



Now to your track:

You should try harder oil in the rear (around 1000 or 2000). Gives you more smooth feeling on throttle, more steering on throttle and more stabillity through the part in the middle of the picture. But you have to test.

At 10.5t you already have to break for the turns so you should also try the spool in front. This will help a lot at the end of the straight.

But you will have to test it yourself if you like it, and if it is good on your track.

I tested the solid axle before, also with ball bearing anch Spec-R, but in seems to be slow in the direction change (or not so much feeling...). Probably it's also because I prefere to drive the car into the curves releasing the throttle, not with a strong breaking. I don't know it's because I used a 1/8 glow rally car for a lots of years. With the 1/8 I use the front thorsen, so the drive is probably just a bit different. With the 1.000.000 in front (50mm axles) it seems to be nice, but the problem is in the rear (52 mm axels) that sometimes overturns. I'm also trying thew tires. With MuchMore I had some overturns, instead with sorex it seems to be easiest to drive (the test I talked before was with MM tyres).
BTW I'll try at least the 1.000 in rear (I've it at home) and then others, when I can go to my reseller
Thanks

Last Weekend i drive with my new Xray diff with 3000cst with SP 4.0 and it Works great.
Today i take a 2000cst and it wasn't so good to drive.
The tail was oversteering and breaks sometimes out.
Now i take again the 3000cst, it works much better.

The diff from Xray is better then Spec-r, no leak by Xray diff.
Only the O-Ring is damaged after disassemble.
The diameter is about 3mm to big and you must
take a new one.

Regards Christian

I use it without the O-Ring for a few weekends now, without problems.