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Old 11-02-2011, 07:12 PM   #1
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Default Building an Associated B3 for top speed....how do I keep the front end down?

I am building an old rc10 b3 I have for speed runs. My goal is 80mph.

I've been using some 2.8" Losi "street" tires on chrome dish wheels for the rear and some worn out plain buggy rib tires in the front. They're pretty much slick. But I want to use some tires that are a but more appropriate for this project. Just dont know what. Ideas?

Right now I'm running a Hobbywing 60a / Ezrun Victory 5.5t 6000kv (the new blue one with the silver ends) geared 26/78 with a gensAce 5300 30c 2s lipo.

So far, I've hit ~50 mph. I know the esc/motor have plenty left. So I plan to gear it up.

I have a Zippy 5000 30c 3s that I plan to try but at this point, I can't seem to keep the front of the car down with the 2s lipos I'm running. I'm lucky to get to top speed without picking the front end up. I either have to let off or flip over backwards.

So I'm thing I need to make some sort of wing for the front. But I need some ideas on design and mounting locations.
I think I could possibly mount it somehow to the front shock tower using the extra holes.
I really dont wanna add weight to the front or at all. Also, the wing needs to create downforce without creating drag.

I realize that there are better, newer platforms that could easily hit 80mph but I like the idea of using a old buggy that was never meant to see real speeds.

I appreciate any feedback or ideas that you guys may have.

thanks
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Old 11-02-2011, 07:24 PM   #2
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...if you are running the buggy body, start by just making some lexan flaps (bent lexan) you can fasten to the body's nose area (w/ 2 sided tape).

Something w/ about a 1/2 inch base, and start with about a 1/4 inch kick, and go up from there as needed.

You'll find a little flap adds a LOT of front downforce at speed. (Positioning forward and back changes where that downforce hits too - and it another tool to play with)

your Car/Chassis angle will be a good tool to play with too..
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Old 11-02-2011, 07:34 PM   #3
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your Car/Chassis angle will be a good tool to play with too..
i did drop the front as low as possible to try to create some rake to the stance.

Hmmm. you got me thinkin that the buggy body really isnt that aerodynamic.

It looks cool though haha. Yea, I'm gonna grab some lexan to mess with.

What do you think as far as Tire choice?
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Old 11-02-2011, 07:34 PM   #4
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try a dirt oval late model body

http://www.mcallisterracing.com/index_files/Page364.htm

i think the 10 inch bodies will fit over the wheels
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Old 11-02-2011, 08:28 PM   #5
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Jconcepts makes a front spoiler for the B4 buggy that mounts to the front shock tower. It may fit the B3 as well. I'd also sugest trimming the rear wing down so it doesn't create as much downforce at speed that would cause the car to flip. Moving your electronics as far forward as possible and maybe a little weight up front wouldn't hurt either. With the power of the brushless motors your not going to have to worry too much about it hurting your top speed.

Really though I think you'd have an easier time getting the top speed out of somthing like a 10L 2wd pan car since they wont want to flip over at the push of the throttle since there more designed for it.
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Old 11-03-2011, 02:22 AM   #6
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I'm not using a rear spoiler at all. No need I dont think.
The Jconcepts spoiler wont fit. The b3 and b4 shock towers are quite different.

I have an old truck body that I'm gonna cut up today and see if I can come up with something.

As I said before, I know that there are plenty of other car that would be better suited for top speed runs. But, I wanna do it with a B3 haha.
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Old 11-03-2011, 03:21 AM   #7
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The lead will not slow you down... 10g on the nose would make a huge difference. I'd suggest trying it at least...
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Old 11-03-2011, 05:49 AM   #8
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The lead will not slow you down... 10g on the nose would make a huge difference. I'd suggest trying it at least...
Yea, I'm gonna try some weights....also, the 3s are way heavier thann the 2s I've been running. Might make the difference. I still wanna make a front spoiler.....I think it'll look cool.
Anybody have any ideas as to what gearing it'll take to get me to 80?
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Old 11-03-2011, 11:55 AM   #9
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Yea, I'm gonna try some weights....also, the 3s are way heavier thann the 2s I've been running. Might make the difference. I still wanna make a front spoiler.....I think it'll look cool.
Anybody have any ideas as to what gearing it'll take to get me to 80?

Easiest way to get that thing to hit 80mph, imho, is about a 100ft drop....give or take a few feet.
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