4-Tec conversion
 

Ok, so I decided to actually convert this turd. After fooling with it a bit I got all of the belts to run smoothly and it actually feels good when rolling. Maybe not as bad as I thought...

So I took an old rcm revo mount and modded it to fit the chassis. Had to drill 1 hole in the chassis, but it is a bit scratched so I really do not care. The previous owner had already cut down the upper deck and side mounts, so I cleaned them up a bit and put it back together. By the looks of it I will have enough room to run a 6s 2100 maxamps lipo. I can cut and mod it a bit more to get addl clearance for the lipo.

Here are a few pics, lighting was weird, so some of the pics are dark.

http://i206.photobucket.com/albums/b...p/DSCF3113.jpg
http://i206.photobucket.com/albums/b...p/DSCF3114.jpg
http://i206.photobucket.com/albums/b...p/DSCF3115.jpg
http://i206.photobucket.com/albums/b...p/DSCF3116.jpg
http://i206.photobucket.com/albums/b...p/DSCF3117.jpg
http://i206.photobucket.com/albums/b...p/DSCF3118.jpg

Looks good...it should really go

Tried a few other lipos, even the big 4500 30c 6s! The pair of 2170 3s packs should handle a decent load, as I run them in my 1/8 buggy.

http://i206.photobucket.com/albums/b...p/DSCF3119.jpg
http://i206.photobucket.com/albums/b...p/DSCF3120.jpg
http://i206.photobucket.com/albums/b...p/DSCF3121.jpg
http://i206.photobucket.com/albums/b...p/DSCF3122.jpg

Thanks, I ran the numbers on the calc, here are the 5s results:

Differential Ratio: 1
Transmission Ratio: 1.7
Other Ratio: 1
Spur Tooth Count: 41
Pinion Tooth Count: 20
Total Voltage: 18.5
Motor KV: 1638
Tire Diameter (inches): 2.5
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor coil Ω: 0
Spur/Pinion Ratio: 2.05 : 1
Total Ratio: 3.485 : 1
Tire Circumference (inches): 7.85 inches (199.49 mm)
Total Motor Speed: 30303 RPM
Vehicle Speed: 64.67 mph (103.88 km/h)

I will see how this works with the maxamps 2100 cells wired up as 5s. They are not bad cells, but I do not know if they can push out 750 watts...

I may swap the bk9920 out for a quark 125b and run 6s with the fp 2170 lipos. Here is the setup on 6s:

Differential Ratio: 1
Transmission Ratio: 1.7
Other Ratio: 1
Spur Tooth Count: 41
Pinion Tooth Count: 20
Total Voltage: 22.2
Motor KV: 1638
Tire Diameter (inches): 2.5
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor coil Ω: 0
Spur/Pinion Ratio: 2.05 : 1
Total Ratio: 3.485 : 1
Tire Circumference (inches): 7.85 inches (199.49 mm)
Total Motor Speed: 36363.6 RPM
Vehicle Speed: 77.61 mph (124.66 km/h)

And I can push the gearing up to a 25t pinion:

Differential Ratio: 1
Transmission Ratio: 1.7
Other Ratio: 1
Spur Tooth Count: 41
Pinion Tooth Count: 25
Total Voltage: 22.2
Motor KV: 1638
Tire Diameter (inches): 2.5
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor coil Ω: 0
Spur/Pinion Ratio: 1.64 : 1
Total Ratio: 2.788 : 1
Tire Circumference (inches): 7.85 inches (199.49 mm)
Total Motor Speed: 36363.6 RPM
Vehicle Speed: 97.01 mph (155.83 km/h)

Not sure what kind of battery setup I will need to get that kind of speed. I doubt the 15l will handle it either.

I do have an aveox 2000kv motor, 1512 size. I am sure that it with a decent 90+ amp capable per cell 6s pack will do 100mph. I will have to whip up a 3200 30c 6s lipo, and use a MMM. This will be down the road, if the platform can even handle 80+mph.

Differential Ratio: 1
Transmission Ratio: 1.7
Other Ratio: 1
Spur Tooth Count: 41
Pinion Tooth Count: 25
Total Voltage: 22.2
Motor KV: 2000
Tire Diameter (inches): 2.5
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor coil Ω: 0
Spur/Pinion Ratio: 1.64 : 1
Total Ratio: 2.788 : 1
Tire Circumference (inches): 7.85 inches (199.49 mm)
Total Motor Speed: 44400 RPM
Vehicle Speed: 118.44 mph (190.26 km/h)

OK... This might be a dumb question, but dont they already make 1/10 touring cars that are designed for electric? Why go thru the effort of doing a converion for one. Of course I guess if you have and and have nothing better to do.

Seems kinda like converting a Tmaxx to me.



No offense meant, just wondering.

Im assuming your talking about the Traxxas 4-Tec electric. They dont adapt very well to brushless, where as the nitro has been proven to handle 70mph+.

Nice work Lincpimp:yes:

Very true Jeff. I only have this as i bought it in a lot of other stuff, and have been unable to sell it. The electric version is crap too. Worst tc next to something duratrash...

Thanks, I am sure that a tc4 would be a better platform ,but this is something different. I have a feeling that it will handle a crash better than an electric tc... Kinda heavy with the al chassis and thich plastic bits!

Looks good pimp. You need to pm me back!! :lol:

Linc, looks good so far. The way you have your batteries was the method I initially wanted to do, but some people don't have nearly the lipo choices that you do! :wink:

I'm sure you'll be done far before I am because I still have to special order the "SE" Medusa motor (still undecided if I want a 50mm or 60mm motor), the ESC (MM and BEC), and fabricate the parts I need.

I do have a few lipos hanging around...:oh:

I hoe to finish it by the end of the week, or at least get it rolling... If it performs well up to 65 or so I will go all out... I also need to get my top speed tamiya back out and prep it for 100+mph runs... Time for some ceramic bearings...:tongue:

Good luck on your build Brian, what speed do you want to get out of it?

I'm not looking for anything crazy, just around 50-60. Just for around the house or maybe a vacant parking lot.

Ok, the 50mm motor will be plenty for that... But you might as well get the 60mm, right:lol:

Yeah, that's what I was thinking. Being belt driven, there's a fair bit of drag just from the drivetrain. And if I decide to go faster, the extra torque will pull a taller gearing easier.

Besides, I did some more work tonight and I really have to get a 60mm motor now...

Why, did you add a bunch of weight? I agree with you on the drag issue. I cannot imagine that any belt car could be smoother than a shaft driven one... Maybe I have not experienced a pro level belt car yet. The tamiya 4wd tc that I had setup for speed runs was so smooth you it felt like it did not have diffs in it. It would barely slow down during off power coasting...

No weight (well, a little), but I need the extra length for wire clearance...