Infraction Another Limitless-to-Infraction Build

[suchtragedy]

Welp just finished my first ever 6s truck. I must say that compared to the 3-4s trucks this has a lot more going on from an engineering standpoint than I imagined. Anyways here's the summary of my limitless roller build turned Infraction.

Specs:
- Hexfly Hex6 160A esc (6s version, sad panda, but hey it was only $100 bucks)
- Hobbystar 4585 1580kv brushless motor
- PowerHobby "Booster" motor fans x 2 (30x30x10, 28k rpm)
- 3225SG 25KG servo (0.07 sec/60 degree operating speed, stupid fast, let's hope it holds up)
- 22/50 center diff/pinion
- 100k/500k/100k diff oil
- Spektrum 6100AT with AVC + DX5C radio
- 3D printed side skirts, front skirts, fender wells, dual motor fan mount, and power button mount

Build Summary:
Originally I was just going to build a Limitless for speed running after giving up on the Infraction coming back into stock any time soon. I found the the limitless on Amain and thought about getting it but then I decided it was a bad time to spend the money... but then I saw @fpvmiller 's limitless/infraction build thread and I managed to talk myself into it. After moving some numbers around I found a way to justify the purchase and ordered it and as soon as I did it was officially sold out, so I guess that means I got the last one they had, WHEW.

When I was picking out the electronics there was stuff I wanted to get but didn't/couldn't because it's either out of stock or it's going to take over a month to get here on a boat from china. Originally I wanted to get a Max6 but couldn't find one in stock in the states anywhere. I then found a Hexfly Hex6 8s edition esc for sale but as soon as I went to purchase it the site spit out a message that it was actually out of stock. I thought about holding out for a Firma 160 from Jenny's but didn't want to wait and see when might come in stock, and I wasn't in a position to spend the money to get a Max5 or Castle system. This is how I landed on the Hexfly Hex6 6s edition. I figured being my first 6s truck that I probably would be too scared to run 8s anyways, so the Hex6 fit the bill plus it gave me a 160A/1050A burst ESC and with only running 6s that gave me a little bit more wiggle room when it came to a motor.

So for motors I knew I didn't want to go with a stock 6s 2050kv arrma motor because it's just not "special" enough. TP motors are the kings of speed but too rich for my blood right now. I ended up going with a Hobbystar 4092 1730KV motor because I saw some threads of people running that in their Typhons and Kratons and whatnot but what I didn't realize is that it doesn't fit in the stock mounting location on the infraction/limitless and those who were running it in the infraction/limitless were turning the motor mount 180 degrees the other way to fit it. I didn't want to do that because I didn't want to lose 1 of the battery trays and I would also lose the stock esc location which I wanted to keep because it had mounting holes that fit the Hex6 already built into it and I wouldn't need to extend the motor wires. I returned the 4092 and after a little more research I ended up with the Hobbystar 4585 1580KV motor.

For servos I really wanted to get a JX Eco Boost ever since @jondilly1974 showed the speed of them on his Typ[Hoon] truck build but again the only ones I could find would be coming on a boat from china. I was going to with the good ol trusty 3225MG from Amazon but then stumbled upon the 3225SG which was coreless and rated for 0.07 sec/60 degree turning speed @ 7.4v. This put it on par with the speed for the JX Eco Boost and the Hex6 has a switchable BEC between 6.0/7.4v and being only 6 dollars more then the 3225MG (which is half the speed @ 6.0v) I decided to give it a try. I am hoping I don't regret it because it was not long after I got it that there was mention that they sucked and some members have had dead spots with them after a few runs. Oh well, GONNA ROLL THE DICE BABY.

The last bits of course was the Infraction body stuff which wasn't too hard to source on eBay except for the actual body itself. Jenny's was out of stock and all the other bodies out there didn't include the roll bar or the wing and I didn't want to have to buy them after the fact making the body close to $100 bucks once all said and done. Luckily I found a parts breaker pull body from justbashitrc.com for $65 bucks with the roll bar/wing, but the shipping said $97 dollars... yikes. I emailed them and got a reply right away and he was able to adjust the dimensions of the the inventory to what he knew it would fit in box wise and poof, shipping was now $20 bucks. SOLD.

Anyways just a few small touches here and there to make it special like braided wire mesh that I added after seeing it on a different build thread here on the forums. The 3D printed parts I made out of nylon so they'll be strong yet pliable and hold up. The designs were existing already minus the side skirts which I modified an existing model to be printed in 2 pieces since my printer has a small print bed, and the fan mount I just threw together real quick but I might end up looking for a legit heat sink or modifying that design further if the cooling isn't optimal/sufficient. Last but not least I polished it off with some parody fake branding stickers I found on eBay.

Final Thoughts:
The build took about a month to complete because of all the shipping times, returns, and just zero inventory out there making some stuff a little tricky to find. I finally got to run it yesterday in a huge empty parking lot at the high school near my house and dude this thing has got Charlie Sheen tiger blood in it I swear. On 4s the car is very snappy and I feel is almost liek the perfect amount of power for this motor/gearing set up to do some hooning. On 6s it becomes super pissed off and kills tires like nobody's business and after 3 packs my rears were pretty much needing to be replaced already haha. I have some GRPs sitting on the shelf ready to go in the meantime and have ordered some silver hoons that will come in hopefully by end of the month as soon as it gets here from china. After 3 sets of packs almost all back to back with not many breaks the esc/motor were warm but not too hot. I forgot my IR thermometer so I'll hit them with that next time I'm running just to be sure.

Anyways that's all for now. For speed runs I will convert back to the 34T spool and experiment with gearing and probably go back to the limitless body. The DX5C I picked apparently doesn't have the best range so I am going to be looking at modifying it to get more range out of it somehow, probably with a booster. For now I am going to just try and get comfortable driving this thing before attempting a speed run. I also have a bag of capacitors laying around and may attempt to make my own cap pack, we'll see.

Thanks to all on this forum. Without this abundance of knowledge there's no way I would have known where to start with this thing

 

[fpvmiller]

Congrats man! Enjoy the hard work ?

 

[jondilly1974]

That’s a dope af rig bro. Take some vids ??

 

[BustedBudget]

Awesome build man, and great write up. An interesting read ?

Sounds like a blast to drive! And if your anything like me, the build is just as exciting!

Just finished my "build" today (basically just converted my 3S Senton to a 4S Kraton with 6S power...but kept the Senton body) and came on here to do a write up...spotted this and it looked cool...glad I took the time to read through. Very cool build. Now mine seems a lot less exciting though ??

Enjoy!

 

[Turbobrick]

Nice sweet build Dude, Enjoy!!!

 

[Porschetech🇬🇪]

Nice write up and vehicle ?

 

[suchtragedy]

Thanks guys, it is definitely going to keep me busy. I just hope I can keep spare tire inventory going without going broke.

Also forgot to mention that I have O rings in each of the drive cups to take out the dogbone slop and I had to also drill out the stock mounting holes slightly bigger because for some reason the holes on the 4585 were a tad bit narrower than the stock holes on the mount and the screws would try to cross thread if I forced them. Is that something common or is that a new to you all? Also, they don't make any unmounted tire replacements do they? I would totally remount new tread myself if they did. GRPs will work but I like the more meat of the hoons just not the hoon price.

Future plans are adding the the spektrum battery monitoring cable, PPS or hot racing aluminum diff mount, and maybe other improved braces and such once my wallet isn't as thin. Also probably more 3D print designs of some kind which I will share to the community if I think it's worthy enough.

That’s a dope af rig bro. Take some vids ??

Lol I need to rig up a phone mount or something on my transmitter and get my GoPro back from a friend for the truck view but I'll try.

 

[fpvmiller]

This might only be me but after putting in some wrench time between my pps mounts and the v4 mounts I find (for me) that I can do my adjustments just as fast on the v4 mount than I can on the pps mount.

 

[Jimbobjr]

the different mounting holes in the 4585 is the same issue I had with my 4585 rocket motor. I believe they are the same.

killer build, love the 3d printed fan mount and other custom bits.

 

[suchtragedy]

This might only be me but after putting in some wrench time between my pps mounts and the v4 mounts I find (for me) that I can do my adjustments just as fast on the v4 mount than I can on the pps mount.

I am mostly just wanting the piece that replaces the 2 post plastic upright portion and keep the rest of it the way it is, about 20 bucks for just that part. I would only need to go to a different mount entirely if going bigger motor and need the additional adjustment for clearance.

 

[fpvmiller]

I like this piece. But it's all up to you in the end

I have it installed on my kraton6s.

https://hot-racing.com/?partnumber=ANN38C01;c=1444

 

[suchtragedy]

I like this piece. But it's all up to you in the end

I have it installed on my kraton6s.

https://hot-racing.com/?partnumber=ANN38C01;c=1444

I was going to skip that piece since it's not as integral as the main mount and the other upright that bolt to the chassis. What's the benefit? More stability which translates to less bearings wear?

 

[fpvmiller]

I was going to skip that piece since it's not as integral as the main mount and the other upright that bolt to the chassis. What's the benefit? More stability which translates to less bearings wear?

On my kraton6s it has the provisions for the roll cage pins. In past races I used to have issues with plastic bearing retainers (like in the center diff) losing tolerance due to heat. So my habit is just as much aluminum around bearings (especially wheel and diffs) to help with tolerances. Bashing I wouldn't think adds much of a benefit.

 

[suchtragedy]

On my kraton6s it has the provisions for the roll cage pins. In past races I used to have issues with plastic bearing retainers (like in the center diff) losing tolerance due to heat. So my habit is just as much aluminum around bearings (especially wheel and diffs) to help with tolerances. Bashing I wouldn't think adds much of a benefit.

Hmmm maybe I'll design a set of pieces I can print instead ?. It's hard for me to not just buy the best everything I can right away but I get your point and will consider it, but yeah no racing or anything for me here. I don't even know anyone else in the area that's into ground RC haha. There's a lot of old timer plane guys that have a club but that's it. The nearest hobby shop and track is 1.5 hours away ?

 

[fpvmiller]

I miss old steilacoom park

 

[suchtragedy]

I miss old steilacoom park

I miss being social in person with friends hahaha

 

[suchtragedy]

Had good luck today with GRP S7 slicks. In a parking lot on a 70°F day through two sets of packs on both 4s and 6s (same as my first runs on stock hoons). After 2 back to back runs of hard drifting the GRP S7 slicks had very little wear and barely noticeable tire debris in the chassis. After measuring the rears were only 1.2mm smaller in diameter and fronts only 0.8mm smaller in diameter. I will say that this compound does stick better once heated up so 4s was no longer easy to drift but 6s was still really good.

New GRP S7 slicks vs. used rear S7 slicks after 2 packs comparison:

I also had a chance to check temps after each set of packs. On 4s the motor was only 94°F and esc was only 89°F and after 6s the motor was 119.6 and motor was 109.5°F. All temps taken right away after full non-stop pack runs with all fans off. With motor fans on the 119°F motor temp was down to 105°F.

I am really happy with this motor on 6s with the 22/50 center diff setup. Next time I need to bring the GPS to get a baseline speed run, but my guess is on 6s I was hitting at or near 60mph with this gearing.

 

[fpvmiller]

Does hobbyheroes sell the grp tires by the pair?

My infraction is down because my tires are done ?

 

[suchtragedy]

Does hobbyheroes sell the grp tires by the pair?

My infraction is down because my tires are done ?

Aye sir, free shipping on orders over 39 bucks too ?

https://www.hobbyheroes.com/collections/grp-tyres

 

[suchtragedy]

Update 6/13/20:

I gambled and ordered the K8S heatsink and happy to say its a near perfect fit for the 4585 motor, only needs a tiny bit of stretch to fit. But FYI if anyone is going to use this on their infraction/limitless with a 4585 motor you will probably have to grind a few fins on whatever side you face towards the bottom in order to not bottom out before your mesh is set when using the stock V4 motor mount. I grinded off like 3mm to make clearances but it was super easy and quick.

The K8S heatsink has mounting holes for a 50mm fan which I don't have nor want to use. I designed and printed an adapter plate to be able to mount 2x30mm fans and it works out really nice. With the heatsink mounted sideways the air jets out of the heatsink directly onto the left (driver) side lipo battery.