Building a SS for 63 foot Nationals Track
- Thread starter KGL
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Depends how stable the car is with the 3" over 4 foot. Unstable inside 42' will still be unstable in the same 42' distance on the 63 foot track. I believe there are other factors to contend with on the 63 foot track other than steer. And adjusting most anything will effect steer. If you car is stable @ 3" in 4' I'd roll with it, IMO.
Something else to think about. As GX said, almost everything effects steer. The farther back the COG, the more steer you will need to keep the car stable. On a long track, too much steer could translate into unwanted friction. It may be desirable to have a less aggresive COG so less steer is needed for a stable car. Less steer should translate into less friction in the long flat section, but will also translate into less speed at the start. Somewhere there is the magic COG with the right amount of steer. I'm a relatively new racer in the NPWDRL, so I do not have the experience racing on a 63' track. I have not ever heard of one at all until now. For me, I have enough trouble setting up my car for a standard 42' track, so I am going with normal prep and a normal car configuration, regardless of the length of the track. There is just too many variables and I really have no way of testing any of them.
Good to see some more discussion coming out on this. I have no experience either, but my thoughts were the same. If you change COM for stable flat section then you would trade for lower top speed at the bottom of the ramp. I was thinking to go with the same aggressive COM for 42' and try to walk the line on the stable side for steer. Hedging the bet that the rolling friction on DFW wont cancel out the extra speed too much if steer is correct. I am also scared of the other cars blowing me around on the flats after watching the May race where I had too little steer./images/boards/smilies/wink.gif
My car has a 5" wheel base. Body just has weight pockets, no extra material removed to lighten the body. GEE fenders. 12 weight cubes are behind the rear axle, the rest are placed centered in front of the rear axles. I don't know how to measure COM / COG. I only have a tuning board and no access to a track.
Thanks,
Sam
Thanks,
Sam
KGL said:
Do you by chance have access to any scales? If you do you can figure COM by using this calculator. Have fun... play around with it. The tool will help you visualize what moving weight around will do to COM, both side-to-side and fore and aft. Input can be either in grams or ounces, your choice.
- Nov 24, 2011
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Yeah - you're right. On a regular track, I try to have the least steer possible and still be stable.
What I was trying to say is that if you move the COG forward, you need less steer, but moving the COG forward could translate into less speed. So the question that I have is would the weight being moved forward which should sacrifice some speed be nullified by less steer equating to less friction because the car is inherently more stable? Not ever having seen a 63' track, I'm just setting my car up the way it normally would be, right or wrong. I have a hard enough time with that...
What I was trying to say is that if you move the COG forward, you need less steer, but moving the COG forward could translate into less speed. So the question that I have is would the weight being moved forward which should sacrifice some speed be nullified by less steer equating to less friction because the car is inherently more stable? Not ever having seen a 63' track, I'm just setting my car up the way it normally would be, right or wrong. I have a hard enough time with that...
- Nov 24, 2011
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B_Regal Racing said:
It would depend on the amount of movement and steer involved. I know it's cliché but every car is different.
I'm learning that. There have been a number of times now I have built two seemingly identical cars and for the life of me, I can not get them to turn in the same times. I found Minoins Racing to be amazing at the last race to be able to build 5 cars within 2 thousanths of each other. I need to the experience to have that consisentcy, but that is another topic.
IMHO, the only way to get the steer right is using an 8' test board and a timed track.
Start at any point, say 12", then time the car at least 2 - 3 times.
Move the point up or down by 2" increments, time again, until you find that sweet point.
The steer seems to never be the same from car to car. Maybe close, but not exact.
Also changes a lot with different classes.
Start at any point, say 12", then time the car at least 2 - 3 times.
Move the point up or down by 2" increments, time again, until you find that sweet point.
The steer seems to never be the same from car to car. Maybe close, but not exact.
Also changes a lot with different classes.
I think the awesome thing about this race is the fact that 99.999% have never raced on a 63ft. Or have the ability to. I have had thoughts on COM and steer but in the end I'm going with my normal prep and tune, I hope I'm not missing the boat with it. Time will tell.
I think COM may be a major player on this long track and believe it should go the same way as the track, unlike the 42 foot track.
There's that thinking head again...
My hunch is that whatever the fastest setup is at 42' is going to be the fastest at 63'. I only say that because it appears to me that the car slows at the same rate per foot of track as soon as it's off the hill assuming it's not wobbling. It takes the most efficient chassis to win at 42 or 63 IMHO.
There were a few in stable cars that won heats and were wiggling while a stable car nearly caught up at the finish. Having the longer flat you may see more lead changes in the flat. That was mostly middle if the pack cars though. The fastest were almost all running smooth the whole way through.
bracketracer said:
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