- Serpent SRX2 RM - Jared Kirkwood - Batavia RC Raceway - 27.10.2013 -


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I started with Ryan's (a fellow team member) setup from the week before and progressed to this during the day. He had finished 2nd last weekend on this same layout and his car was working very well for him so rather go back to the stock setup I choose his as the base. The track this weekend had a bit less grip than what Ryan and I seen it the week before. Some of my changes are perhaps to address the slicker conditions, and then the others are simply difference in driving style.

Shock positions

I'm liking the shocks laid down a bit more from the stock setup. I found the car a bit hard to drive with the shocks stood up and inconsistent for me. Bringing the top of the shocks in one hole all around I felt like it put the car a bit more into the track. I tried the #1 hole on the rear tower and that seemed to be too much but with perhaps a harder rear spring that would had been good as well.

Shock Pistons & Rebound

With the conical pistons my car felt like it packed up a bit better for the large jumps. I think next time I would try a 1.5x2 piston in the rear for a bit more pack on that layout. The 1.5x1+1.6x1 was Ryan's idea from last week and it really seemed to make the car better for me as well, especially on this layout that has a demanding and large jump rhythm section that requires the car to settle fast to get the timing right. Since there seems to be a bit more blow by on the pistons than what I've been use too I built the rear shock with a touch of rebound.

Front Caster

I think my driving suits more caster in the front. I didn't feel very comfortable with the 25 degrees (too twitchy) so I went back to the 27 deg as I originally had on the car the week before. The 27 deg seems to work better for me. I haven't tried 30 yet.

Rear pivot and anti-squat

I tried several different roll centers with 2deg. I went really low and wide at one point but found that i would need to make other changes to make that work. I pretty much concluded the stock setup was the most balanced with the front roll centers in the testing I did. I did end up going to 1.5 squat which I liked, but it wasn't any faster, nor slower.

Rear Limited droop

This is something Ryan and I both played with the week before and I took it a bit further yesterday. The car felt much more stable at speed, at the end of the straight and into the downhill turn. When I limited it, my lap times improved and finally got into the 24 sec lap range. I could just drive the car further into the turns.

Weight

IMO big bore shocks in 1/10th scale just require weight to work properly. I've tested a light car several times and it just seems every time I go below 1560 with other kits I have issues with consistency. I tried this car at ~1510, and ~1540 but the car still just didn't seem fully connected. At 1580 the car was really starting to work the track better. I'll probably replace the weight over the servo with an aluminum front pivot and try that.

Overall Impressions

The setup was very balanced for how I drive a car around the track. Laptimes was very close to those set by JP's and Ryan's times the week before. I felt I could drive it the same every lap and put it on the track where I wanted. My friend said he thought it was lacking a little weight transfer to the front entering the turn but that's due to the limited rear shocks more than anything. The mid corner attitude of the car looked good with a level roll front to rear.

If I could say anything needs to be improved at this point it's the forward grip of setup. The track had developed a polished groove in a few spots and everyone was struggling in those sections however with a little more fine tuning it will be there.


Source:

J. Kirkwood