Kraton Project Aurora - Where the "RTR" means "Ready to Rebuild"! (Kraton 8s EXB RTR Complete Dougification)

[I_Am_Doug]

Welcome to what I have affectionately named Project Aurora. Why Aurora? I could offer some really existential or fancy reason but, I painted the body with this purple/green Tamiya pearl coat and it looked like an Aurora to me. Super deep. Here's a pic of Aurora around mid-build before one of my test runs:

As I am sure most of you have already learned the lesson that Ready to Run is just plain marketing. Sure, you can charge a couple packs and rip this thing but, after the first throttle pull, that part of your soul that loves RC will realize there is SO MUCH MORE potential for this platform. At that moment, your wallet makes your back pocket tingle and your wife starts to wonder why you stare at a truck so lovingly.

I'd like to break this thread up into several posts outlining each upgrade path I took as well and the success and pitfalls I found along the way. Aurora is almost fully complete however, I have a few minor touch-up points to contend with so, a final pretty post pic is coming soon. I hope you enjoy this thread as much as I did building this truck. It has been a dream of mine since I was a teenage boy too many moons ago to own and run a truly bad as$$ RC car. I think I succeeded, I hope you agree.

Alright, lets get to it.

I ordered a fresh new Kraton 8s EXB RTR from Horizon directly in December of 2023. It was a warm-ish winter here in the North East US so, I charged a few packs and decided to have a little test run in my back yard. As I started to get used to it, I got a little too giddy and ended my run early with this:

Giddy middle aged men, RC cars, and garden fence posts don't mix. Welcome to the gateway crash. Looks like I will need to brush up on my suspension skills. Lets talk suspension in the next post....

 

[I_Am_Doug]

Suspension: (and Steering)

I have learned I have a love hate relationship with suspension work. I love the results of a properly tuned and setup kit but, I really dislike the "fight to make it right".

My final suspension setup is as follows:

Stock Arms!!:
It is in my experience and my recommendation that you stay with the stock BLX/EXB front and rear suspension arms. Initially, I had noticed grass wrapping around my rear CVDs and thought that I needed mud flaps. This lead me to RPM arms and I thought these were the answer. I was completely wrong. Too much flex and too much work to install. Holes were too small for screws, the shocks didn't fit properly and the flex was atrocious for me. I ran them once, realized the error of my ways and went back to the stock. I mean, your milage may vary but, these could have been much better. Also, no droop screws. I really wanted to use m2c CVDs and droop screws are a requirement.

m2C 7mm Shock Kits - F/R:
As with EVERYTHING from m2c, these shocks are absolutely beautiful, strong and drop in fit perfect. I refilled both f/r with 50wt shock oil and kept the standard springs. I mean, look at this, its beautiful and burly:

m2c Outboard CVDs:
I am down with the thickness. See pic above.

Vitavon Steering Knuckles, front and rear:
Installing these was a breeze and I really do feel like they tighten up the feel of the truck and offer a bit more control. Also, the bearings seem high quality and the machining is top notch. Just WAY too expensive. I'd rather give my money to m2c for comparable parts.

Primal RC Steering Servo: (no pic)
I replaced the stock Spectrum servo with the generic version of Primal RCs steering servo off of Amazon. Its an orange/yellow one. Works well but, I think I will replace it with a Perfect Pass one soon. It still feels a bit sluggish.

Alright, now we’re bumpin and rollin. We need more umph to move this beast around. Let's talk about the powerplant and ESC in the next post...

 

[Tex Koder]

Looks wickedly awesome!

Keep up the great work

 

[RC Steve]

Aurora is Latin for "rising sun".

 

[I_Am_Doug]

Powerplant, ESCs and Gearing:

Alright, if you are still following along, thank you! I hope you are enjoying what I am posting. Now its time to upgrade the Vroom!

After running a few packs through the standard Spektrum Firma 150a included with the RTR and then stumbling upon Aldo Loyal (great channel btw @AldoLoyal ) I learned of the Hobbywing Max5 G2 800kva combo. I dove into some research and considered a few different set ups including a Castle kit but, I ultimately decided on the HW kit from reviews and the fact that it has a great programmer and data logging. Castle seems a bit weak on that, especially for the premium price charged. Now, I'm not knocking Castle, they look like some AMAZING motors/ESCs. I just think that brand may be better suited to speed runners and on road. The HW stuff seems built for bashers. (and my budget)

I mounted the Max5 G2 to the original servo/rcvr block with an m2c ESC mounting plate and the motor was added using an m2c motor mount and plate. Thats where the easy stopped.

I knew I was going to have clearance issues - thanks for the heads-up community! - so I did install the newer m2c steering bell crank and shaved the top mount where the upper suspension mount covers the steering assembly. The kit contains a replacement flat nut to use in place of the stock locknut. The pic shows where I ground down the end of the mount. The best way to judge this is to have the motor out but fit to slide in for testing. Put the front suspension pin bolt through to the mount, add the flat nut with a bit of loctite and tighten it down. With a dremel, start to round of the corner a bit. Slide the motor into place, check for clearance and repeat as necessary.

I also found that I had to reshape the side panel a bit to allow for the larger motor. Again, this was simply a dremel and some patience. I took the side panel off, traced a line of where I though it would work and ground away. I think it looks decent.

(Yes, thats a m2c chassis. No I didn't forget about it. We aren't at that part of the story yet. No spoilers. Hush.)

Ahem...where was I. Right... After all the pieces and parts where aligned, trimmed and installed, I took a nice pic.

*This is a pic after install and before I recolored all the red parts. Timelines are hard. See above. Also, the wiring under the center brace really irked me. I noticed it after I took the pic and had to take another one. I am sharing my OCD with you. If you are uncomfortable with this pic, here is a corrected version that should make you feel a bit better:

Ahh... feels good. I think the wire loom looks nice over black wires. Over the red ones, it looks like those candy sticks you get at the county fair.

**Oh, I also used QS8 connectors for the batts/ESC. If you are upgrading your ESC and want to run big amps, UPGRADE YOUR CONNECTORS! Undersized connectors can become the weakest and most damaging link in your setup. Overheated solder joint can cause wires to separate and things to melt. No one wants their hard work to smoke and burn.
In the above pic, I went with an initial gearing of 30p39s. This was not enough pizzaz for me so, I swapped to a 1:1 ratio of 39p39s. Still seeing how I like that but, I feel I will probably stick right there.

While I was mucking with the motor and ESC, I opened up the center diff and replaced the stock fluid with 20 mil.
IMPORTANT!!! - Heat the screws with a soldering iron BEFORE you try removing the center diff case screws. Medium Blue Loctite becomes pliable again at 500degF allowing for an easier removal. I only learned this fact after calling Horizon to complain about the incredible amounts loctite used. They graciously sent me a new center diff. They didnt have to but, none the less, they did and I appreciate it. Carried on with my quest, installed the new diff and the magic happened.

Speaking of diffs, I did the front and rear as well with 1m fluid in the front and 500k in the rear. Not sure how I feel about it yet but, its definitely better than stock. Those screws were not loctite'd in so, much easier to handle.

On a side note: Diff fluid (and shock oil) is gross. Have you've ever seen that scene in Star Wars where Anikan Skywalker (sp?) complains about sand? Yeah, replace sand with silicone.

At this point in the build I was where I wanted to be able to run it and see where any new issues would appear. I did that and in the next installment I will share why those runs were some parts "Worlds Okayest" and others mind-blowing-amazing. Spoiler alert...there is some more m2c shenanigans involved, I found out how staircases work with suspension and a wild new chassis appears. (Shhh. I know you already saw it.)

 

[I_Am_Doug]

She's a 'beaut Clark!!

A top down shot of Aurora before I took her for a test spin in the back yard.

Looks wickedly awesome!

Keep up the great work

Thanks a million Tex!