Kraton 8s Park Basher Build

[Cr3pitus]

Time to start a log of my new K8s!

My goal with this amazing beast is to turn bike parks into a giant rc playground. I live in WA so while there are about 3 RC tracks within 100 miles of me there's a bike park every 100 feet. The k8s is a great platform to turn these bike parks into a giant 5th scale bash track.

Obviously we don't know much about what will be available for these and when but as I make changes I'll post them here. I will probably do an m2c chassis when it's available just for peace of mind. Other than that too early to tell.

First packs in today resulted in first "mod" - swapping out the stock rx for my r304sb so I can go back to my futaba 4pv. The dx2e active it comes with is approximately 20 million times better than the stx2 and there's nothing wrong with it besides the cheap feeling wheel. My problem is with the AVC, so since I'm not going to run the AVC I might as well use my favorite radio.

The AVC, even at like 10% gain, moves the wheels around too much in the air and can make you crash even on like a 3 ft high jump. It does work really well for smashing at speed on the ground, but the car is so dang stable inherently that for me there's no need for the avc it just feels like a handicap.

We will see what's next!

 

[Mongoose]

Dude, I love your dog lol.

 

[Cr3pitus]

Dude, I love your dog lol.

Haha hes such an awesome weirdo. Anytime I take the k8s out he still just goes and sits by it and you can tell he thinks whatever he's doing is really important.

 

[Mongoose]

Hahahaha! He looks like his thought right after the pic was taken was “ok, now that we got THAT out of the way, sheesh...” then he rolls his eyes and turns back around to concentrate back on the Kraton ???
What’s his name?

 

[Cr3pitus]

Hahahaha! He looks like his thought right after the pic was taken was “ok, now that we got THAT out of the way, sheesh...” then he rolls his eyes and turns back around to concentrate back on the Kraton ???
What’s his name?

Flynn, named after Kevin Flynn from Tron haha.

 

[Cr3pitus]

First real run today. Was awesome. Definitely could use more wheelspin in the air like we all know. Had a few medium crashes and tumbles from bad timing but everything held up like it was nbd. Lost the capture nut from the back of the front left upper A arm, but didn't notice until cleaning at home, nothing came loose luckily. Here are some pics of the bashes; it handles really well and can even navigate my local 8th scale track with ease, only really having to slow down in the 2 tights low speed corners. Everything else I could approach just like the Talion does. The triples were actually even easier to pop than on the Talion, despite being undergeared.

 

[Cr3pitus]

Made a couple changes tonight that I'm excited to try out this weekend.

All bearings replaced with rubber sealed.

Tuned the diffs with 600k/2.5mil/500/ f/c/r. Putting action through the diffs by hand makes it feel subjectively clear to me that the "500k" in the f/r diffs stock is a very liberal viscosity rating. I run 200k center in my Talion and the stock f/r on my k8s though filled appropriately felt way more like my Talion center diff than they do now.

I also committed a wee bit of heresy and put on a Traxxas branded e Revo 24t pinion to hold me over until the safe-d5 pinions come out. The e Revo pinion though not as mega tough as the better brand pinions, had a decent hardness grub screw (at least in that I didn't strip it out like I do on other cheap pinions) and it has a really nice width that matches up to the wide spur in these things nicely. I went 24t because I don't normally go WoT for more than a brief moment, but I do want the wheelspin potential in the air.

Here's a pic of the pinion lining up nicely. Excited to try it out.

 

[Cr3pitus]

Alright things are starting to shape up. Got the m2c chassis installed with the 9mm braces. Probably could have just used the 6mm but figured I'd just go with what it comes with and see how the stiffness affects driving characteristics before making any changes.

Have settled on max punch with 0 additional advance timing. 7.5 was imo a negligible gain for a noticeable run time loss.

I have diffs at 200k/20mil/100k which feels good.

Carbon fiber tubes over the braces.

Need to do some runs but so far I'm still thinking of holding off on a motor/esc swap. The added weight of the chassis is not a big deal considering I run relatively light 5000mah packs.

 

[Cr3pitus]

M2C chassis the cleanest it will ever be, moments before inaugural bmx bash. Some doucher drove by and started yelling at me to get off the track and actually honked a handheld airhorn at me lmao. I started walking towards him and he peeled out and drove off. Dork.
On stock electronics I noticed no negative impact in performance from the small increase in weight. Actually it felt a teency weency more grippy from the heavier chassis. When you land anything over 5 feet high to flat and bottom out to the chassis you can definitely tell it is impacting the ground harder. It was kinda slush snowing today around 30deg but had no issues with the plastics. Good times!

 

[jondilly1974]

M2C chassis the cleanest it will ever be, moments before inaugural bmx bash. Some doucher drove by and started yelling at me to get off the track and actually honked a handheld airhorn at me lmao. I started walking towards him and he peeled out and drove off. Dork.
On stock electronics I noticed no negative impact in performance from the small increase in weight. Actually it felt a teency weency more grippy from the heavier chassis. When you land anything over 5 feet high to flat and bottom out to the chassis you can definitely tell it is impacting the ground harder. It was kinda slush snowing today around 30deg but had no issues with the plastics. Good times!View attachment 60268

Glad you stood your ground. Freaking air horn ??????‍??‍

 

[Cr3pitus]

Glad you stood your ground. Freaking air horn ??????‍??‍

Like how much of a crotchety taint are you to carry that around just so you can blow it at people on the street out of crankiness lmao?

 

[jondilly1974]

Like how much of a crotchety taint are you to carry that around just so you can blow it at people on the street out of crankiness lmao?

As I get older, I have to actively fight my grumpy old man syndrome. The struggle is real. ???

 

[Cr3pitus]

Is it overdramatic to say this setup has changed my life and is the best upgrade I've ever done? Good God it's so refreshing to be able to charge to full and discharge to storage for the whole family's 15-20 packs in a safe and time efficient manner. We usually are rushing to get in a big family run between rainfall and this makes that so much better. Love being able to use an unused pack as the power source and discharge it into used packs to bring everything to storage so easily.

 

[Cr3pitus]

Some more iterative upgrades today, mostly in preparation while I decide what motor I'll eventually do. Also because my stock esc died. I'm leaning towards the leopard 58113 v2 1050kv, but not going to do it until the weather's better / warmer since I can push the stock one pretty good in these temps.

Tossed in the leopard bl5 200a esc (hw max5) with the m2c plate, the hobbystar 6192 70kg servo (cheap so might as well try), the 25t safe-d5 pinion and stuck my futaba temp sensor on the can. The temp sensor is pretty sensitive and I have it set to display on the radio at all times with an alarm set for uneasy temps.

Soldering ec5 connectors onto these 8 gauge esc leads is the biggest pain in the ass I've ever experienced related to soldering leads! I'm kinda ocd about my soldering because of all the drones I've built and I'm still super unhappy with the result. The ec5 was just clearly not made for wires this big. I'm either going to buy the progressive RC ec5 tool I saw online somewhere to make it easier to tap them in with oversized wire without breaking the connector, or I'm going to swap to xt 150. I should have just swapped the packs to xt150 and left the esc xt150. Supper irritated that I didn't tbh...

I'm going to do the first temp test with no heatsink or fan to really get a read on what max temp without any cooling is. In my ideal world I'd never run fans. Probably get away with it for now but won't in the summer. Will report in with temps when I can, as well as servo test results from the iCharger.

 

[bicketybam]

What happened to the stock ESC?

 

[Cr3pitus]

What happened to the stock ESC?

Not entirely sure - if you try to turn it on like normal it just won't turn on. If you spam the power button like 5 times in quick succession it will turn on and go through regular startup tones indicating all clear. Then it completely shuts off anywhere from 10-30 seconds later, whether you're driving or just sitting there watching it.
Sent my warranty request to horizon on Saturday, no response yet.

Happened out of the blue, the last time I drove it was really really light driving while I was just hanging with the fam at a playground. Not even any jumps there.

 

[Cr3pitus]

Alright over geared temp test 1 complete. Finally found a 15 minute break in the rain.

53f ambient temp, stock motor, stock wheels/tires, max5 (leopard variant), 25t pinion, 5000mah packs, added weight from m2c chassis - full run on the packs to lvc with as much motor heat generating activities as possible (basically constant acceleration to wot, and braking around in light but wet grass).

The futaba telemetry temperature sensor registered 136 after about 2 minutes. From there temps went up steadily to 160 at the 5 minute mark and 163F by the time I hit lvc at about 11 minutes. This was with no heatsink or fan on the motor.

I'd call those acceptable temps for no fan or heatsink. I prefer my motors around 140, warm enough for good running but not too warm. I also try to create setups where a failed motor fan will not force you to stop. I expect when I place the motor fan back on the temps will drop quite a bit with the bec running at 7.4v. The batteries were warmer than on 24t though - so I would say with these motor temps and battery temps, Arrma picked 25t as the max factory pinion size for a reason. I don't expect these temps to be sustainable in the summer.

I will do the same run next weekend with the heatsink and fan and compare. Ultimately I'll probably replace the motor anyway with something bigger ?

 

[Buckwhea7]

Time to start a log of my new K8s!

My goal with this amazing beast is to turn bike parks into a giant rc playground. I live in WA so while there are about 3 RC tracks within 100 miles of me there's a bike park every 100 feet. The k8s is a great platform to turn these bike parks into a giant 5th scale bash track.

Obviously we don't know much about what will be available for these and when but as I make changes I'll post them here. I will probably do an m2c chassis when it's available just for peace of mind. Other than that too early to tell.

First packs in today resulted in first "mod" - swapping out the stock rx for my r304sb so I can go back to my futaba 4pv. The dx2e active it comes with is approximately 20 million times better than the stx2 and there's nothing wrong with it besides the cheap feeling wheel. My problem is with the AVC, so since I'm not going to run the AVC I might as well use my favorite radio.

The AVC, even at like 10% gain, moves the wheels around too much in the air and can make you crash even on like a 3 ft high jump. It does work really well for smashing at speed on the ground, but the car is so dang stable inherently that for me there's no need for the avc it just feels like a handicap.

We will see what's next!
View attachment 56511View attachment 56512View attachment 56513

What’s up mate!. Was wondering if you could link me to a site that has the 70kg hobby star servo for the K8S. I’ve searched the internet and can’t seem to find it anywhere. Bizarre. Anyway, thanks for any help!

 

[Jimbobjr]

Rcjuice has them.
https://www.rcjuice.com/servos/serv...-brutal-torque-large-scale-digital-servo.html

 

[Buckwhea7]

Rcjuice has them.
https://www.rcjuice.com/servos/serv...-brutal-torque-large-scale-digital-servo.html

Thanks!. Appreciate that! Unfortunately they’re sold out. Strange that I can’t seem to find them anywhere else with a google search. Oh well, I’ll wait till they get more in stock.