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...

Don't we all.... Don't we all....

I am looking forward to some updates in your thread!

why do you want to know when he gets his extra length linc?

I guess that I am just a whore for knowledge...

definately a whore for something:lol:

This forum cracks me up:lol:

You got that right, I always get paid, no matter what!

This forum has its moments... At least the frequency of "which neu motor for my revo" threads has dropped...

That's what the newb forum is for! Besides, with the ERBE out, people pretty much know what works.

dont say that too loud. and now that the BEER is out, everyone is gonna think there a brushless pro

Actually, among higher lever TCs, belt driven ones are typically smoother. This is because of the more efficient transfer of power from the motor to wheels, i.e. cars with drive shaft would have to convert sideways rotation direction of the motor/shaft to forward direction.

The sideways rotation also affects steering in a well balanced car, which is not the case on belt-driven cars.

Because of this and the increase in belt durability, more and more companies are converting their pro level TC to belt. For example, the TC5 is belt driven where as previous generations were shaft driven.

Also, the fastest RC is based on the belt driven MI3

Anyway, shaft is good too, especially for bashing, drifting, driving on asphalt/outdoors since the drive train is mostly (except for spur and pinion) enclosed.

Nice build so far, I want to see how fast you can push that thing.

Good info flipmac, I plan to beat this turd like a red headed stepchild...

Lol, goodluck :party:

That thingy from Nic Case isn't a car anymore IMO. It's more like a rocketship or something like that...

So I finished it up, well, at least V1...

Current config is a feigao 15l with a bk9920. Using a maxamps 2100 20c? 5s lipo. Gearing is 20/41, and it should get me close to 65mph.

All I can say is this setup is not smooth starting at all... The bk startup is terrible... I remember this combo being much better in my 2wd emaxx. Maybe I have better standards now that I mainly run castle escs...

If it was not raining I would have some more info. But I will wait for it to dry up first.

This is also the crappiest selection of equipment that I have put together in a while! Feigao motor, bk esc and a crapamps lipo:lol:

http://i206.photobucket.com/albums/b...p/DSCF3136.jpg
http://i206.photobucket.com/albums/b...p/DSCF3137.jpg
http://i206.photobucket.com/albums/b...p/DSCF3138.jpg

To bad one of your 1521 wouldn't fit...that would be real fun

I will have to take a pic of it in there just for you...

I don't think those poor belts would handle it! Not to mention the diffs, axles, tires, etc...

Thanks!

Probably not, but oh what fun it would be, even for a short time

You got that right, it will almost wheely with the 15l in it...

Lincpimp, did you make those batteries trays yourself? If yes, from which material have you made those battery trays? Because I still don't know from which material I should make mine for my LST...

I use kydex, about 3mm thick. It is a plastic that is easy to fold with a heat gun and when it cools it is very strong. I made the tray in my lst out of it, and have made at least 6 other trays with great success. Plus it is lighter than al, and it can be made to protect the lipo well, by making the sides thesame height as the lipo, on all 4 sides. Have a look in my lst thread for a better example of a full 4 side one.

Man that is digging through the bottom of the box of old crap you gave up on. Airtonics fm reciever, unclamped feigao, old BK, no name bec, unwrapped 2100 maxamps !! sweeet ! That things going to be serious springtime fun, Da bucket ghetto hoochie mobile

You got it JJ! Getting back to fun brushless. I best that I do not have 400 bucks in the whole deal...

I ran it around for a while yesterday, dodging puddles. I did not have the rrom to get it up to speed, and the tires that are on it suck... I will say it drifts like crazy, and can take a beating...

I need to go to the local mall on a sunday morning early to run it in the larger open blacktop parking lot.

I did get about 20+mins of playing on it and the temps were great, and the lipo looks to be good for around 25-30mins... I may be able to gear it up a bit and try some 70+ mph speed runs. Need to dig up my foam tires for that...

So I have gone thru 2 sets of tires... They were old, but man can this bad boy destroy tires! And I have only put about 5 packs thru it!

So I geared it down a bit, to an 18t pinion, with the 20t it was wheelying at speed a bit much... The poor maxamps 2100 5s is having trouble keeping up, so I purchased some neu 2500 30c cells to make packs out of. That should allow me to push the gearing up and try some speed runs.

I need some new foam tires for it, my old ones off my other tc are all different diameters from drifting!!!

The 15l and 9920 are doing just fine, temps are just fine. Driveability is good too. Even geared for 65 it is doing just fine, and throttle control is great.

linc, how much tension do you have on the long belt? If you push down with a finger on the top, how much does it "sag"? I'm trying to set mine so tension is good but not too tight to reduce unnecessary drag.

I have tons of sag on that belt. I can easily get it on and off by hand too. Not sure how you set the tension, I guess by altering the height of the front transfer shaft...

I need new belts, but I intend to wear these out first!

Wow, I thought mine was loose with ~1/2" of sag! There's no way I can get it off without removing the end plate from a pulley.

Yeah, you adjust tension by shimming under the 4 screws holding down the front transfer shaft. Not very effective though because by the time you get the long belt right, the front is too tight. I'd rather see a simple spring-loaded idler riding on a bearing.