XRAY - Model racing cars

Hello my fellow XRay fans! I'm absolutely loving my XB8 except for one problem... Whn I'm accelerating, the rear end wants to come around (fishtailing). Here's my setup (what I can remember anyways ) :

Shocks

- oils F: 50 wt, R: 40
- pistons straight 1.5 holes
- Springs = RMV soft progressive rate springs

Diff Oils

- Front Diff = 7,000
- Centre Diff = 10,000
- rear Diff = 5,000


Rear Suspension Geometry

- 0* anti-squat
- 0.5* negative camber
- top shock postition = 2nd last outside-top hole
- bottom shock position = inner-most hole

I'm running an RB Mods RB C6 BB with a 13 tooth CB and an Orion V6 Adjustable Clutch set to emulate the operation of 1.1 clutch springs.

Everytime I come out of a corner, straighten out and hit the throttle the tires spin and the rearend wants to swing out to the right. Now this happens everytime the tires spin and I'm pointing straight. I want to eliminate this fishtailing. Does anyone have any suggestions? I was thinking abouty maybe adding more Anti-Squat. What I don't want is to make my buggy push. I love the way it turns. I want to keep that quality intact and eliminate the fishtailing.

Any help would be greatly appreciated!!

regards

speed metal

What is your rear toe-in setting? Try using 2 degrees toe-in with 2 negative of rear camber. I would try going down 5k,7k,3k on your diffs to tame the power output the C6 BB. The use of the orion clutch to simulate 1.1 springs setting plus the 13 tooth clutch bell may be tooO much since you already have such a high powered engine. So try to bring it to 1.0 springs in effect. What type of tires are you using on what type of track as well? Thses could also play a major factor in the handling of your buggy.

The use of 7K, 5K, 3K in the diffs may require regular maintenance due to the fact that you've got a beast of an engine strapped into a light buggy. Hope it works out.

i would also strip down rebuild the back end just to be sure there is nothing binding and the bearings are ok etc. ITs just a but strange how it is getting worse.

I had an exactly the same problem with my XB8TQ and C5 BB engine.
I haven't found any solution, that would solve the problem right away, i just came to a so so solution with multiple changes.

Changing shock oil to 40/30 helped a bit,
the shoks were in the middle hole on the arm and very angled on the shock tower (closer to car center)
More rear negative camber also helped.
Moreover, i have the werks adjustable clutch and set it for the softest setting, the clutch engaged as early as possible, there is loads of power on my c5 bb and no need to rev high on the start
Than i turned the throtle expo to 60% and the main thing that did most impact was to learn how to pull the throtle, you have to be very gentle all the way to the top.

And one more thing that has a lot of impact is tires, you have to choose proper tires for the surface, to have high grip and the car will be more stable in general.

4? rear toe will welp quite a it too.

add 1 oz of weight ( tire ballance weights ) to the rear.

maybe go up a tooth on the clutch bell as well.

Like they said, as far as suspension setup goes, going up on the rear toe-in is the best thing you can do to stop fishtailing when the car is pointed straight and accelerated hard. More negative camber might hurt on the straight but .5 isn't going to do much for you in the turns.

Antisquat can be tricky depending on the track surface. Going up on it might hurt you for what you are trying to do. It really sounds like you just have too much power for the track surface. Going lower on your center diff oil will transfer more power to the front tires under acceleration which will keep the rear from breaking loose. A tire with great sidebite like the Proline Crimefighter should help increase overall traction in both the front and rear.

Speed Metal your setup is very much different from the standard setup that is with the TQ version. By the way you can also download it on this site.

My suggestion is to change your setup completely to the standard setup for American or European track and then make your adjustments so they adapt to your style and track.

I also suggest using Xray oil and springs, this gives you the possibility to compare. You can then read the team drivers setup and look for their changes comparing a setup on a loose, medium and high grip track.

Team driver Yannick A. let the WC final with the standard springs and clutches – which proofs the quality and speed.

Regards
Peter

I run 335 on a very loose, hard packed, technical, tight track. I was having the same fishtailing problem you had when I was running 357, and 555. I only have an O.S. RG so it's not a too much power issue .

I agree with nitroracer, I think going down in center diff oil will help. It helped my car. 7k,10k, and 5k seems way high to me, but I am new to the hobby. Maybe your track is open and flowing where mine isn't. I know my car with 553 had bad intial turn in, but I could power out of the corner faster.

A local Xray team driver said that he adds like 1oz weight to the back of his car. He actually puts it below the universal rear driveshaft somehow. He claims that the Xray has a slight weight bias to the front of the car and that's why you see more fishtailing problems. The weight front bias also contributes to the Xray's superior steering.

My setup: xform/index.php?act=view&ID=256&setup=xb8tq

would the new proline high downforce rear wing help in this situation?

I have never played with altering pistons before. How do you make two extra 1.3 piston holes?

yes special size drillbit of 1.25 mm or so
to compensate plastic burs
and mark + carefully make the holes