scojo
Green Lumber
Posts: 14
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Post by scojo on Jan 27, 2010 8:59:29 GMT -6
How much steer should I be looking for (how many inches over a four foot run)? Does the slope of the run factor in (i.e. more steer for a steeper slope)?
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Post by cycrunner on Jan 28, 2010 1:27:14 GMT -6
Steer is, in my experience, depended upon, for one thing, the C.G. of the car. If you have a very aggressive C.G., that is closer to the rear axel then you probably will need more steer. With my latest Pro Mod car I managed to get a C.G. of 0.5" in front of the rear axel. I started with a drift of 6" over my 6 1/2 foot tuning board and ended up at 12" to get my fastest times on my 39' test track. If you don't have a test track then it is a crap shoot! I have found that with a C.G. of around .7" then a drift of around 6 to 9 inches works pretty well on my tuning board. Hope that helps.
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Post by shovelhead on Jan 28, 2010 3:22:54 GMT -6
Guys, My son and I have just finished our first PWD car for our cub scout pack race this Sat. night. The car seems to be pretty fast, or hopefully competitive anyway. My question is; The CG of our car is at about 1 1/8" in front of axle. On my tuning board - 4' piece of glass from bar top marked with sharpie - we get right at 2in. of drift in just under 4 ft. Does this sound about right? We were at the Derby Monkey Garage yesterday. We were getting about 2.5" to 3" drift on his tuning board. And we ran 2.253 sec, 2.257 sec and 2.255 sec on his test track. I don't remember the length of his track. But after gluing axles the car seems to have lost some of its drift. Will losing 1/2" to 3/4" drift make a huge difference?
Hope this makes sense.
Thanks, Scotty
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psycaz
Addicted to Speed
Posts: 86
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Post by psycaz on Jan 28, 2010 6:09:34 GMT -6
Scotty,
It depends a lot on the car itself and the track if losing that steer will make a difference. Not the answer you are looking for, but it is the truth. Some cars take more steer, some less.
Any chance of going back to the Garage with another car and running both down the track? That second car will help you get a better feel for what will really happen. That second car will change the track harmonics and simulate race conditions better.
I think you should be ok.
Always amazing and irritating when the simple task of gluing an axle in changes a car.
Drives me nuts. Same thing when I am playing with weight placement using paper tape. Car ALWAYS changes when I finally glue it in. Most times for the better, sometimes worse.
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Post by shovelhead on Jan 28, 2010 8:37:41 GMT -6
I would love to be able to go back and run on the test track, but I just can't swing it. We have an old school slide from a school playground. The kind with the slick sheet metal. That's as close as I have to a track. When I run it down this, it is very smooth. Probably doesn't mean anything, but makes me feel better. We get to do a test run Friday night at the track we'll be racing on. I don't know if this is normal, but everybody gets one pass on track. That's all. I think I will video tape it and watch it Friday night before the race. Maybe I can tell if it is doing something goofy.
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