Monday, January 24, 2011

A day at the races

I took a ride out of town to race a regional series race in Wisconsin. I was really there to race sedans, but they were saying they would have F1 as well as an extra class. I wound up with 3 classes to run, so I didn't do a ton of fooling with the car. I was also racing 8 minute heats since they combined F1 with 1/12..the class was more of a fun thing than anything else.

The point of all this is that I took the chance to run my Exotek with the 103 front end and tires, and my F103. At my home track, which remains fairly high traction most of the time, these cars produce almost identical lap times. The F103 is actually a fiberglass chassis car that started as a 15th anniversary. The fiberglass chassis seems to be hooked up in most situations however.

I ran the Exotek a few times, as I really like the car. I think since it's a bit longer than a standard F103, it is easier to drive most of the time. The track was still throwing off a lot of fuzz, and didn't have a ton of traction built up yet. It also was in a building that was about 100 years old, having a board floor vs. plywood. The floor was not in bad shape, but it was not perfectly smooth, so the pan cars chattered around a bit. The problem I was having was that the car would want to slide or wash out on 2 left hand turns. I wasn't sure if it was tweak or the floor. It also would sort of bind up if you used too much wheel input in the right hand sweeper at the end of the straight. It felt like it was either lifting a front wheel or rolling the chassis over too far. Kind of weird. This was probably from being too light on the side shock and center shock dampening. I was using CRC red side springs as well, which may have been too heavy. I changed dampening to 50 wt for both side and main shocks.

It got better and cut down on the chattering. It still wanted to slide a bit on the lefts. I also went to the medium gold front spring as well so the car let thr front end roll a bit more. Overall, the car wasn't bad, but it was a bit blah and not really fast.

I also ran the F103, which wound up being very good. This did surprise me a bit, but I have had a similar situation last year where the fiberglass chassis/long fiberglass upper deck was the hot ticket. It just seems that the extra flex seals the deal in lower traction. I actually used the same set of tires on the F103 as the Exotek. I actually did not change anything from my home track except to loosen the t bar a bit. One difference with the F103 is that it's fairly heavily dampened, so i could have possibly gone even higher on the Exotek car. The 103 car did slide a bit in the same corners as the Exotek, but it was better. In the main, the 103 ran about 3/4 of a lap off of the 1/12 17.5 open speedo car's time. I could also see he did have a h.p. advantage over the silvercan, so that actually was a pretty good result.

As far as the Exotek, what could I have done to get it working? I think a lighter side spring would have been better. Stiffer side to side dampening as well. I think it was skipping around as bit due to the floor. I would have wanted to go heavier dampening just to slow the roll in the sweeper and other corners as well. Maybe even o rings under the upper deck screws that attach to the servo mount. I wish I had more time, but I was running 3 classes, so I just put the car on the track that worked the best. That is the beauty part of a basic 103, you don't really even need all the optional parts. A motor mount, a shock, and a long upper deck and you should be good at most tracks.

Speaking of which, here's how the 103 upper decks play out-
Long carbon upper deck- definitely has most response/steering, but may be too stiff if there is not enough traction.

Long fiberglass upper deck - probably the best balance between chassis stiffness and steering response. Good for the majority of situations, even high bite.

Short fiberglass upper deck - steering feel is dead, not very good response. I think the front of the car flexes too much. Might be good for very low traction, or if you are trying to kill response.

Basically, the car steers more as it gets stiffer, but it also becomes more nervous. One way to reduce this is to run a o ring under the 2 screws that attach the upper deck to the servo mount. I do this a majority of the time, even with the fiberglass setup.

I did a back to back last year with all these parts.

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