Xray SCT Setup Help

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Old 01-24-2013, 12:00 PM
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Default Xray SCT Setup Help

I'm just getting back into racing after a 10 year lay-off. I decided to buy a used SCT to get started and I ended up buying an Xray 808 that had been converted to a ROAR legal SCT. The majority of the car is Xray with the exception of the CVDs, front steering knuckles, and rear uprights. Those parts are Losi. Those parts were used to help narrow up the car and give more clearance for the Xray arms inside the SCT wheels.

I bought this rather unusual conversion because of Xray's reputation for ruggedness, something a relative beginner in off-road could put to good use. I also liked the idea that the Xray needs very little in the way of hop-ups to be race worthy.

I've been going to the track during the week to practice, but I haven't started racing yet because I'm just not good enough yet to be anything but a rolling road hazzard. The track is a medium sized outdoor clay track. They race on the first and third Saturdays and do virtually no track prep between races. That means the track that I see for practice has a rough hard packed very dry surface with a lot of dust. Needless to say it's slicker than snot on a door knob!

I've gone through the truck and fixed or replaced quite a number of things to try and get it to handle a bit better on the slick track. That did make it a good bit better, but now I'm ready to set up the shocks and diffs. Since the truck is relatively unique there aren't any set-up sheets available to reference. Right now I've got the shocks set up with 35wt oil and a soft/medium progressive spring in the front and 30 wt with a soft/soft spring in the rear. The truck seems to have a ton of steering to the point that I have the endpoints reduced to 80%.

The diffs are currently set to 7-10-3. I have no idea if that's even close. I have been doing a good bit of reading on the Losi SCTE thread because I think that truck should be pretty close to what I have. There they reccomend 5-5-3 as an overall set-up, and 3-3-2 for a slick track.

The tires I'm using are Losi eclipse. Several guys at the track reccomended them for practice since they are supposed to hook up fairley well on the loose track and last quite a while.

My major problem is keeping the rear end under control. It's constantly breaking loose and sending me in some direction I don't want to go. I realize that a good part of that is in my trigger finger but I'm pretty sure I can do more to get the rear end hooked up a bit better.

Any comments or suggestions would be greatly appreciated.
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Old 01-24-2013, 12:34 PM
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5 in the center diff will be the biggest thing to keep the rear end in check. Maybe even go down to 3. I run 5/5/3 in my Mugen conversion.

Increasing rear toe will help add grip. Less rear camber will add grip.

More track time will certainly help too. Try turning your TH EPA down also. Make your goal running a pack without coming off the stand, drive as slow as you can to make that happen. Speed will come...
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Old 01-24-2013, 12:35 PM
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Good luck with your setup......
I think your best bet is to read up on the XB808 thread to get a basis on how the chassis wants to tune, then apply it to your SCT configuration. This thing of yours is very different from a SCTE. I would also not try to tune the car based on those practice tires. See what the fast guys are running on that track and start from there, otherwise, you will be too far off to even get close....
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Old 01-24-2013, 12:37 PM
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And download this and read it:

http://www.teamxray.com/teamxray/sho...p?file_id=4461

IMO, I wouldn't do anything to the front suspension. Leave it alone. Concentrate on making it oversteer less. You will get to the point that you want that steering lock for low speed corners. And if your controller has it, slow down the rate of the servo, and put the EPA back into it.
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Old 01-24-2013, 01:57 PM
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Billy, Skipper thanks for the help.

I'm going to start by changing the diffs to 5-5-3 and take a degree of camber out of the rear. I have read the Hudy setup manual several times, and I used the Xray 808e basic setup sheet just to check where things were set. Basically the truck is set up for medium conditions. The setup manual does give some reference to where things should be set up for bumpy low traction tracks. I'm going to make some of those changes one at a time to see how the truck reacts.

One other thing I have already done is change motors. I originally had a Tenshock 411 4600kv. It was way too much motor for me right now so I sold it and bought a HW 3656sd 4000kv. I ran it yesterday for the first time. It's a good bit milder and runs a lot cooler. It was coming off the track after a full pack at 110-115 running a 16 tooth pinion. I'm pretty sure it will take at least an 18 tooth pinion and that should calm down my low end punch quite a bit.
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Old 01-27-2013, 04:56 PM
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Ran my Xray SCT yesterday with the setup changes suggested. It was a big improvement!Ran the diffs at 5-5-3. I also removed the rear sway bar and increased the rear roll center. Along with the diff changes the rearend was planted much better.

I really didn't get a chance to run it very much because the track was really crowded. I spent a lot of time trying to stayout of the way of the nitro guys. I did notice that the truck turned much better and the rear end only broke loose a few times when I got too carried away with the throttle. I was also able to accelerate pretty hard down the straight without the truck turning sideways.

All in all I'm very happy with the way the truck handles now. I had no problem running clean laps except when I had to dodge someone else and I let the truck get out into the fluf. It may not be perfect,infact I'm sure it's not, but I believe i handles well enough on the slick track that now I can try to learn to drive it.
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