District track Tune? what to do?

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derbyfever
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District track Tune? what to do?

Post by derbyfever » Tue Jan 27, 2015 4:43 pm

Hello Folks, We are new to the Forum. what a great place to learn. Thanks to all that can help out.
I am in need of advice for the best tune on our car considering a unique track at our district race (pre run not allowed). This is our last year with cub scouts , so we really want the BIG trophy this year (like we didn't before..LOL) .. At least one of my 2 boys have won pack level going against (20-15 cars) every year for past 5 years. We must be doing something right I guess. Last year my eldest scout won 5th overall at districts, in 2013 my other son won a semifinal and then that was it. and previous in 2012 he won 3rd overall at districts. 2012 he was a2ndplzce semifinalist, and our first year in it my boy received a participation certificate. My older son liked the artistic design class, so we always made a sea creature themed.... so called "car". We combined the 2body design styles last year with a mini stingray mounted to the top of a low rider (it got the 5th at districts) and now my wifes favorite car to date. umm next to the octopus ,starfish and crab car.
So that's our history, but now its make or break..and our last year , so any good advice is welcomed to help on the final tune.. we have a cm of 11/16, extended wheel base, 2.5 neg .camber on rears, right side dfw and currently set dfw at 2.5 positive camber with 4-5 inch drift in six ft.. ( test align table incline is leveled at 2inch slope in 4 ft.) I have a huge discernment on using the 2.5 camber on the front.. its noisy and seems to bind.. we haven't made a true rail rider yet, and I am not sure it wins on this type of track.. Stan Pope seems to know quite a lot on alignment, I have yet to make his bias weights apparatus yet. We did check for year alignment with a forward and backward roll along the line and attaching an .80oz weight with tape and rear does not deviate from a constant 5/32 in along the line. car is notched 1/6 at dfw, District races for us are the 6th and 7th of January 2015. I will attempt to post some pictures of this track.. it is fairly long (40ft or so) a smooth and almost continuous slope and ramp and long flat.



<a href="http://s713.photobucket.com/user/roboja ... 1.jpg.html" target="_blank"><img src="http://i713.photobucket.com/albums/ww13 ... 41be61.jpg" border="0" alt=" photo disctrictpic3_zps4741be61.jpg"/></a>



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Re: District track Tune? what to do?

Post by derbyfever » Tue Jan 27, 2015 5:09 pm

Image

Image

Image

This is the track we race on at districts. It looks to be of some fancy material .. I forgot the name of the resin used. rumor has it that its some $50,000 worth of whatever material its made .. I dunno. it was donated years ago, I have yet to see pictures on this site like it. what is the pandolizlaoni(ha,ha) track ? is this one?



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Re: District track Tune? what to do?

Post by derbyfever » Tue Jan 27, 2015 5:17 pm

OUR DISTRICT RACES are on FEB 6th (not January) as incorrectly stated.. so we have a few more days to properly tune. thanks for any suggestions? what is the standard rail width for most tracks btw? Our district car rules require 13/32 clearance undercar, but after neg camber of rears itnow sits at 12/32 (exactly 3/8in.). 2.5 inch camber on front lifted the car higher than the rear.. will this ride ok with out risk of jumping track?



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Re: District track Tune? what to do?

Post by sporty » Tue Jan 27, 2015 6:55 pm

It sounds like youre bent axle for rail rider. The bend is st times coming in contact with the wheel bore. Or somewhere that wheel is hitting the wood.
but I'm thinking it might be a axle issue.
another option is the side/ edge of the wheel . Is it polished up and smooth and shiny. It rubs on the rail. And many rub graphite on that side edge of the wheel.

It also sounds like the drift may be to much.



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Re: District track Tune? what to do?

Post by ngyoung » Tue Jan 27, 2015 8:40 pm

I am thinking it is the fluting on the edge of the wheel that is making all the noise. That is typical for rail riders. If it is more of a "tick tick tick" it may be the mold line that is often present in the outer hub double step. There really isn't much you can do about that without screwing up the hub. You may also want to check if your axle head still has a remnant of the fins.



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Re: District track Tune? what to do?

Post by derbyfever » Tue Jan 27, 2015 8:51 pm

Thanks Sporty. Yes , its set up to rail ride. We had it a straight runner for pack level, as that track is side rail chute type.. It seems the 2.5 camber really snugs that front wheel tight to the rail on our test board. There is not much toe in visually and reference mark on axle is just about straight up and down. Just a very slight bit of adjustment was needed after insertion in reference to sharpie mark to get it drifting to 4.25-5 inches in6 ft. Board is 6ft. I installed axle with small gap to avoid bend. Body is dressed with polished resin epoxy. Hub polished.wheel inside rim polished and bores. Should I lessen the camber? That is the only bent axle. Rears are drilled @2.5.. I pay close attention to other winning cars at the districts. I haven't seen a front wheel with such an aggressive camber .it's got me concerned. Go on faith???



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Re: District track Tune? what to do?

Post by derbyfever » Tue Jan 27, 2015 8:55 pm

Thanks ngyoung, you may be right about the tread noise. Its just louder than last years car as flat wheel straight runner. The axle head is supper clean and polished to 14000 diamond paste. It wouldn't ride to the axke anyway with the positive camber shoving the wheel into car body , witch bogles my mind as how it can be faster. Ugg.



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Re: District track Tune? what to do?

Post by Stan Pope » Tue Jan 27, 2015 9:21 pm

The profile of your District track appears very like the 40' Freedom Track.

With the extended flat, you should do best with less toe-in, and that calls for a slightly less aggressive CM. Why do you think that is true?

Since you have a sloped tuning board you can tape a wooden yardstick to it. With any toe=-in on the DFW, you can verify that the rear behind the DFW will travel approx. 1/8" off the rail. If it doesn't do so, then you may have to work on the rear alignment until it does so.

Just stacking additional weight on one side or the other of the rear of the car adds more stress on the rear suspension than I like ... that is why I use the "CLIP-ON" bias weights so that a total additional weight of 1/2 to 1 ounce shifts dominance from one side to the other. This is especially a problem for the wheel behind the DFW, which is apt to have 1/2 to 1 ounce less weight on it than the other! Even so, you can get a good idea of which rear wheel / axle is causing trouble and see the results when you adjust the loaded rear axle.

2.5 degrees bend is a bit heavy for the DFW, since you need way less to get 2 or 3" of drift ... about 1/2 degree will do that. You can get specific info based on your design at http://www.stanpope.net/driftcomp.htm 1.5 degree bend gives you 1/2 degree of toe-in and still enough positive camber to keep the outer edge of the wheel riding on the track!


Good racing!


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Re: District track Tune? what to do?

Post by sporty » Tue Jan 27, 2015 9:57 pm

That's drift number for 6 foot.

I was thinking those numbers were for four feet.

Sometimes I make the axle gap on the rail rider. I have a little more gap with the wheel to body.



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Re: District track Tune? what to do?

Post by derbyfever » Tue Jan 27, 2015 10:06 pm

Thank you for the tips Stan,
I would assume having the cm a little farther forward would give a delayed push into the flat .? And give stability. Our cm is 7/8 now. A few years ago, we ran a nice wedge car on that track and it had a cm of 1 inch and it did quite well . we ran a 5/8ths last year.and alignment was questionable(got lucky with bracket heats and still took home 5th overall. )Do you think a 7/8 cm is ideal for track type? We decided on a 3.5oz canopy tungsten this year. Last 2 winners used them. I'll attempt to make up the bias weight contraption to check rears for sure. But so far it tracks well against the yard stick. Is 2 inch slope in 4 ft to much for alignment board doing bias weight technique? Thanks .



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Re: District track Tune? what to do?

Post by Stan Pope » Tue Jan 27, 2015 11:57 pm

derbyfever wrote:Thank you for the tips Stan,
I would assume having the cm a little farther forward would give a delayed push into the flat .? And give stability. Our cm is 7/8 now. A few years ago, we ran a nice wedge car on that track and it had a cm of 1 inch and it did quite well . we ran a 5/8ths last year.and alignment was questionable(got lucky with bracket heats and still took home 5th overall. )Do you think a 7/8 cm is ideal for track type? We decided on a 3.5oz canopy tungsten this year. Last 2 winners used them. I'll attempt to make up the bias weight contraption to check rears for sure. But so far it tracks well against the yard stick. Is 2 inch slope in 4 ft to much for alignment board doing bias weight technique? Thanks .
Four feet is a bit long for convenience, but fine for accuracy. I work with a board about 30 inches long with good accuracy and the length is convenient. For that track length I suspect 3/4" to 7/8" will work best ... if you get the toe-in just right to match it! My intuition is that the track is excellent and only a small amount of toe-in will be needed to keep the DFW on the rail. Consider asking toe-in guidance of someone who has done well in the past on it but no longer has a scout racing.

In the past at our district races, the top few in each age group were running "rail guided." The rest of the trophies went to good "straight runners." Since our district races ran on the same track profile as most of the packs, and the pack races sorted out those who didn't "get the toe-in about right" the rail guided cars in the district race tended to dominate.


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Re: District track Tune? what to do?

Post by Speedster » Wed Jan 28, 2015 9:14 am

The track does appear to be a Piantedosi. The connector plate shown in the 1st photo is how the track sections are joined. The company was bought by Micro Wizard timers and the wood track is no longer made. They were very popular before the aluminum tracks took over. They are beautiful tracks. Our Pack had the good fortune to acquire one 2 years ago.



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Re: District track Tune? what to do?

Post by gpraceman » Wed Jan 28, 2015 10:11 am

Speedster wrote:The track does appear to be a Piantedosi. The connector plate shown in the 1st photo is how the track sections are joined. The company was bought by Micro Wizard timers and the wood track is no longer made. They were very popular before the aluminum tracks took over. They are beautiful tracks. Our Pack had the good fortune to acquire one 2 years ago.
It looks similar to the Piantedosi track, but the legs are different and no weights are used to hold the front legs down. It looks like a custom job.


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Re: District track Tune? what to do?

Post by pwrd by tungsten » Wed Jan 28, 2015 3:12 pm

A com of 7/8" sounds fine... Can you send your drift numbers for 4 feet? I would consider prepping a few extra wheels and axles fro the front and see which is the most quiet. The bend of the front axle is not that important and very fast cars have a wide variance on the axle bend...

I would keep COM in the 5/8 to 3/4" range. 7/8 is close enough. However I would not make it more than 7/8...


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Re: District track Tune? what to do?

Post by derbyfever » Thu Jan 29, 2015 2:35 pm

The bent axles are weird. So I filled existing front axle hole and moved it slightly back from the previous 5/8 from nose and drilled it at approx 1.5 degrees positive ( used jig with shim) I'll use a micro bent axle for tune.
Also rebuilding a proper tuning board. Our double layer MDF board has sagged during storage and isn't perfectly flat anymore. I'll post the drift numbers in a few days. Race is a week from tomorrow. Thanks.



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