My build: "Kraut-cast X"

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Orlando, FL
Arrma RC's
  1. Kraton 6s
  2. Nero
  3. Outcast 6s
  4. Outcast 4s
Hi All,

I just finished building what I'm going to call the "Kraut-cast X". I started with a really beat-down Kraton roller that I purchased pretty cheap. I thought I might want to convert it to Outcast in the future, so I also acquired some of the parts necessary from Ebay chop shop. Seller "luimdave35" is awesome. I just wish he were about 30 minutes closer to me so I could save all the shipping charges.

First things I notices on the Kraton donor was that the rear shock tower was twisted up, and one front axle shaft. Also all the bearings and diffs were making gritty sounds, so I decided to go ahead and order the Fast Eddy sealed rubber bearing kit. With the level of apparent abuse to this truck, I'll say those are small things to replace, but Arrma axles are not cheap. Parts cost and availability is my primary concern with choosing Arrma over another brand.

I proceeded to tear apart every screw from the Kraton. I washed every bit of dirt and grease from every crevice. I decided to spray-paint the bottom of the chassis which was 98% silver when I got it from so many scrapes. Putting everything back together, I decided I definitely wanted the taller plastic side guards from the Outcast, and the mud guards behind the front wheels to keep junk out of the electronics tray. I also realized that the taller side guards will allow me to velcro on the stock body, as I did on my Revo, so no more fiddling with those pesky body pins all the time!

For electronics, I chose the Castle Mamba Monster X ESC (with Castle Cap Pack installed), and Castle 2200KV Mamba motor. I'm a big fan of Castle electronics, and I love how much program ability you get with the PC connection. I really only want to run the maximum power, 6s, of course. I'm trying to build a 6s truck that can take punishment and stay intact through at least 2 sets of batteries in a day. I set my ESC to 50% punch, 10% drag brake, 50% brake, 6.0v BEC, and set the throttle curve more flat at the low rage, and ramping upward, that seems to keep the take-off under control. One of my major complaints with my previous Nero is that it punches way too hard, and has no way to adjust these settings like the Castle ESC. It's a big plus when running 6s.

I'm topping it off with Savox 1256tg servo soon, but I had a 1231sg for now, which does not quite fit because it's too tall. The stock plastic servo mount flexes Waaayyyyy too much. I'll be doing the aluminum standoff mod as soon as the show up from China. Because of this flex and taller servo, my steering was crap on my first run.

For tires, I love the Outcast "Backflip" tires, and ordered a set of those. They have excellent grip for grass and dirt, and the tread won't wear off if I use them on pavement a little (rare for me). I always loved the Proline Badlands on my E-revo, so these are similar, but appropriate scale for the Kraton.

I see the RPM bumper just released, so I'm going that way over the massive, cumbersome T-bone for the front, and trying to decide whether I should do the Outcast wheelie bar, or T-bone rear bumper to protect me from excessive wheelies and cartwheels. I already see some carnage of the wheelie bar. I'm hoping RPM will soon release a rear bumper, which they have alluded to more parts for Arrma being released soon.

Diff fluids: 50K-100K-50K Traxxas fluid. I like wheelies, so I wanted the center more or less locked, but not so locked it might break something. The 50K rear is pretty good, it tends to drift out in the loose stuff, and the 50K front may be too stiff, but I'll have to determine when I correct the servo and mount issues affecting the steering right now.

Shock fluids - I put 60wt in the rear, and roughly 70wt in the front (mix 60 and 80). I like the dampening effect, but I may need some heavier springs. Currently pre-load on the stock springs is almost as far as the collars will go. It's almost neutral now, drop it and it slowly rebounds to horizontal arms.

My first run was pretty successful. I'm running the Robinson Racing hardened pinion 15T. I ran through a pair of 3S 5500mah 35c batteries. I did a few cartwheels and a back-flip without breaking anything. The batteries felt a little warm at the end, but the motor was not too hot to the touch. I didn't temp gun it, I should have. I think it could handle a couple more teeth on the pinion, but it's pretty darn fast as it is, especially considering the ESC is toned down a bit. The backflip tires just bite hard and make it wheelie. I still have to exercise some throttle control to keep it down. It's wheelies on demand, as my throttle curve jumps up at the top of the throttle range. Punch too hard at fast speed, and it will flip backwards.

I think some suspension tuning is still necessary, but I like the truggy style handling far better than the Nero's bulky top-heavy, bouncy handling. I noticed that it really handles bumps well with the current setup. Most cars seem to rebound hard from the rear, say if you hit a sidewalk edge or root, and push the nose down hard, causing possible crash. With this setup, the nose sits down and just absorbs it and keeps running. Center of gravity is low. I didn't hit any jumps really, just breaking it in.

2017-02-05 11.45.43.jpg
Very Nice! Looks like a brand new truck. BTW, I also purchased stuff from Lumidave35 and he ships very fast! Nice seller... I'll be buying more from him as the need arises. Great write up!!!
Poseidon 1515 2200kv motor on the way! I couldn't pass up a deal, so we'll see if it's better than the Castle with new ceramic bearings. Both designed by Neu.


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Poseidon 1515 2200kv motor on the way! I couldn't pass up a deal, so we'll see if it's better than the Castle with new ceramic bearings. Both designed by Neu.
I run this in my outcast and it is a bad ass motor. Run it with a 17 tooth pinion and with a 50 degree day wasn't even warm to touch on 5s
I tried the Poseidon p1515 motor and decided to go back to the Castle. The Mamba seems to have more raw power and torque. The Poseidon seems smoother, but got really hot on the exact same setup. I might step down a tooth to 14t pinion, and I ordered a PowerHobby heatsink/fan to install on the Castle motor, it's still running over 160F.

I also found that the rear shock tower bent on what seemed to be a small impact. I found a carbon fiber clone on Ebay from Germany and ordered one. I also ordered a few other dress-up items. I need to win that RPM kit!
Back for an update:

Carbon Fiber shock tower is holding up nicely.

I was having a LOT of trouble with overheating. The ESC would go into thermal shutdown (240F!!!) before I could drain a full set of 6s battery. I mainly run on grass, which is quite thick here in FL. I tried the Nero 2000KV motor to try and bring the load down, but it also got very hot, even with a fan and heatsink on it. After logging data on the MMX a few times, I decided my gearing was just too high for my conditions. I was pulling spikes over 180 amps, and I believe that was overheating the ESC, which is rated up to 150A. After dropping to 12T pinion, and also installing a Wild Turbo Fan on the ESC, my temps get up to 195F and hold steady through a full battery run of roughly 15 minutes. With no fan on the motor, it's hitting nearly 200F, but waiting on another WTF for my motor heatsink.

Next step will be to try the Nero 2000kv motor again on 12T pinion. I felt it had more torque, and the Castle 2200kv just doesn't have the same punch that it had on the 15T pinion. I even turned back up the settings that I had turned down trying to avoid the heat issues with the ESC.

Upgraded to Tekno yellow truggy springs front and rear. I really like them, still deciding whether I may go down a step to green in the rear, it's still a bit stiff in the rear, causing the rear to spring up and nose down or even front-flip over small bumps, like the edge of a concrete sidewalk. I think softer spring rebound in the rear will help this. It does float nicely over big rolling jumps now, big improvement over stock springs.
I finally found the setup I like: MMX with the WTF fan, Nero motor with a heatsink/fan, 13T pinion, Backflip tires; works great on 6s power.

I tried the Nero motor again, with 13T pinion. The motor temps stay cool, unless it's 95 degrees outside on hot pavement and I'm pounding the throttle. ESC temp varies with conditions, but trying to keep it under 200F on the logs. 12T with the 2000KV is definitely safe, I stepped up to 13T and it has the pop I like now.

A couple of other factors that were adding to my lack of fun "pop" or wheelies were that the center diff cup had separated where the metal piece was joined to the plastic piece, leaking out all the 100K fluid. I replaced that with HR aluminum diff cup, and it's holding up nicely. Second, I had my TX throttle sensitivity way down, so boosted that back up. I'm running the Traxxas TQi system with Bluetooth, I like the way it's super easy to modify all the TX settings quickly with the app, and may add the sensors for voltage and temp later. It also allows you to set a learner mode for the kids when they all want to try.

I switched to the Tekno green springs in the rear, slightly softer. I was getting a lot of tail kick-up over things like speed bumps in the parking lots. Now with the Yellow front / Green rear, I'm able to go pretty fast over a speed bump without the tail kicking up too hard and pushing the nose down. I'm probably going to experiment with shock oil weights, because it still kicks a little more than I want. I'm thinking slightly heavier in the rear to slow down the action. My experiment control will be a certain speed bump, I want to be able to hit it at pretty high speed and launch evenly.

I think this setup is a good baseline, but if you don't like wheelies, I'd recommend thinner center diff oil than 100K. Now I have the tightly sealed HR diff cup, it really likes to wheelie. I also have the throttle curves on my MMX set up for my wheelie-on-demand style, I'm sure I could smooth it out a bit there.

I'm happy to say the only things that have broken from abuse so far are: Rear shock tower (original was bending frequently), One rear arm, and the center diff cup issue. Now that I have a stable setup I like, time for more abuse!
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