XRAY - Model racing cars

So I had my first race with my newly built EC this weekend. I started it with JB's starter setup, other than the diffs were 7 5 5. I got to the track nice and early to give it a test. The first thing I noticed was the 48t spur was way to much for me. The EC was not even like driving and Xray with this setup. The turnin was incredible, it jumped much much better, but was really really twitchy. With the V-spec I was all over the place, just way to much low end, so the first change was going back to the 46t, and changing the diff fluid, which was prolly good since the diffs should have been fully broke in. I also put the shim under the knuckle to try to call down the steering.

Out to the track again, and I just could not keep the backend from being loose. Back to the pits to put on the 38t bevel gear and change the front diff fluid. This helped a little, but not the change I was looking for. I was really suprised at how much preload I was having to run to keep the dogbones level. 15 in the rear and 11 in the front. The shocks seemed to have loosened up a bit by this time and I was able to go down to 13 rear and 9 front, which still seems like alot. The shocks seemed to be real stiff, just slow action up and down which I did not think would be good with the track already starting to get rutted, so I decided to make a big change. I went with light blue springs front and rear and 50 wt front and 35 weight rear.

I went out on the track and things were going much better, but I was still getting just a bit out of shape at different parts of the track so I put on the +2 hubs on the front. I definately lost some steering, but made a real nice difference on the stability. So this is the setup I used the rest of the day. The track got extremely blow out. Ruts everywhere and really loose. Everyone was fighting for traction. I still felt that I was looser than most in the rear, but maybe it was my driving.

I almost feel like there is something wrong with my shocks. My daughter buggy have 60f 50r with the same springs, and her rebound is quicker than mine with 50f 35r. Like I said before, they did loosen up during the day. They have been apart 3 times now, they are put together correctly, the run smoothly with no oil in them, I dont have the nut too tight, just tight enough so they spin a bit. The arms all seem to be real nice and free, with no binding. The only thing I could possibly think of is that since I started with the the dark blue springs which were used, I put the new springs on my daughters XB8, so when I switched back to the light blues they were the ones off her buggy that have 12-13 gallons on them. Not sure if that matters much or not.

One a side note, I am not trying to tell anyone there setup is wrong here. I am not the greatest driver and still new buggy since coming over from MT's, but my kids have been racing XB8 for over a year now. There is kinda a running joke at my local track that I never break the Xrays. 3 Xray buggies now, around 20 gallons, and never a broken part. They were all joking with me about the track conditions and long main that maybe this was the day I would break something. Once again I had the last laugh again

shocks will perform better with 4x holes

Dogbones level?!

Try lowering it with the light blue springs to where the arms are level, ride height is a very sensitive change as you are moving 85% of the cars weight up and down... The lower you make it, the more stablility you will gain, especially in the rear... I can't drive my car with the back end that high, it makes it real edgie.
I wouldn't suggest changing the front end to calm down the back end, the more steering you can get out of it, the faster you will go, keep the 38t crown gear and 7k in the front diff, try going to 3k in the center to calm it down, and when the track gets really rutted up, go up in dampening.

I saw that you are running Branhams setup, but what is your shock setup, which pistons and everything are you running?

Turanden,

You sound like you have exactly same situation I had when I first ran the car. There are two things you should do.
1) Sand the out drive as per recommended by tech tip
2) You may have an earlier batch of shock bodies with the area where the 2 silicon o ring sits being too small and it made the 2 o rings squeezing too tightly onto the shock shaft. Try to get a replacement set of the latest shock body.

Your problems will be solved and the car will be awesome to drive. I found I like the diff 553 very much and very forgiving to drive. I also like 775 but its a little more aggresive.

Let me know if you still have problem after addressing the two points above.

He won't have the early batch of shock bodies, as RC America didn't receive kits with this problem.

Ok, second race day now with the EC. Wow, I found my main problem. The light blue springs I was using was off my daughters XB8, which jumped like crap btw. Since I originally used the dark blues on mine, I just put the new ones on her buggy. Mine still didnt handle well, and especially did not jump well, nose down one time, up the next. I decided to take off her shock springs (the new ones) after driving her buggy for 2 laps. That thing jumped like it has never jumped before!!!! Once I got them on my buggy it was night and day. Jumped so much higher, farther, and the biggest difference was flat. The track went from damp and sticky, to dust and slick, to blue groove. Once it went blue groove my buggy finally looked like all the fast guys. I have never drove so well. Extremely happy with the way things went with the lone exception of once it went dusty the back end was soooo hard to control unless I was just babying it around the corners. Also did not have enough steering, but I dont have the aluminum steering blocks and the +2 hubs up front is not helping.

Here is my setup that I used today:

xform/index.php?act=view&ID=260&setup=xb8ec

Since I am now using the the 1.3x4 pistons with the light blue springs 50f 40r would I need to change fluids if I try to go back to the dark blues to see how it works?

Another question to go with the one above. When I was coming onto the long front straight I was noticing that the rear was riding quite low and the front arms were extended as far as they would go. Is this the best for rear grip? I was noticing the front was a bit squirrely, but at least the rear was not. I could stay on power just had to do a little more steering. I am thinking if I switch over to a heavier spring I may correct this, but most likely at the cost of rear traction.

I will ask the above question again. I currently run the 1.3x4 with 50f and 45r. If I switch back to the dark blues to give them another try would it be best to also go up in fluid a bit.

On a side note. I know I ask alot of questions, but on race day I usually dont have a lot of time to experiment since I am getting my daughters xb8 running along with my sons truggy. If I can have the best setup when I get there and then only have to make a couple quick adjustments, that is best. Things like changing the diff fluids is almost completely out. The last 2 races have been the exception as I have been alone and I have learned more about the setup of this car as I have in the last year.

I would go with

1.3 x4
50fr/60rr
antisquat 4°
shortest wheelbase

shock shims 4mm fr/ 10 mm rr
front lower as rear

Thanks guys, now I have some things to try.