“Apocalypse” Speed Build

[Nut-torious]

Like many others, I love speed. I love building. I love tweaking. This is a “parts” build from the ground up, meaning there was no donor vehicle. I started with (basically) every ARRMA upgrade Scorched RC offers. You will also see ARRMA, HoBao, GPM, RamJam, Ghost RC, BSR, TLR, M2C, Castle, Onyx, Perfect Pass, Sky RC, Futaba. You get the point. Just something I’m playing around with in-between meetings. I’ll post a complete build list (down to the hardware and grease I use), but wanted to share some pics as it comes together.

Psalm 19-11. If you know you know!

 

[Nut-torious]

If you haven’t had the opportunity to get your hands on one of these… it beautiful.

 

[Nut-torious]

It’s intentional…

 

[Doom!]

Nice bits and pieces ya got there!

 

[Tunedfrog]

Woot Woot, eyegasm.

 

[Nut-torious]

All those shock bits together!

They are ARRMA “upgraded” shocks however I opted to go with 7075 lower bits. They are by ADU Racing if anyone is interested.

*Note - I did order an extra pair to have in my tool box but turns out two of the shock ends were tapped differently than the other four. This made one of the pivot balls backwards and both ended at an angle when the end and lower spring retainer were screwed together. Buyer beware if esthetic things like that bother you too. Ha.

This was a milestone (for me at least). I put way too much focus on what shocks to use for this build. GPM has 5mm vs 4mm shafts, as do other aftermarket options. Why does that make a difference when Scorched RC was running with turnbuckles instead of shocks? If I use aftermarket shocks what are the spring weights? Can’t find the spring weights. If I change the spring weight what weight shock oil do I use? Wait, what brand shock oil and o-ring grease do I use? Bladder or Emulsion? Loop back to “why does it matter???” And why can’t I find the color combination I’m looking for. Way too far down a rabbit hole. Balls.

I digress. If you are still reading, I went with the TLR oil and grease. Why? Because as you know, ARRMA doesn’t have its own branded oil or grease and doesn’t recommend a specific brand. BUT for those of you that this matters too (well aware most use whatever they use) TLR/Losi is a sister brand to ARRMA both owned by Horizon Hobby. Assuming that is why there is a TLR tuned ARRMA Typhoon 6S and the CNC’d ARRMA shock pistons and seal guides are labeled TLR so I went with it.

Parts list:
AR330491 Shock Cap Aluminum Black 6S (x2)
AR330208 Shock Bladder
AR715008 Nylon Nut M2.5
ARA330728 Machined Shock Piston, Tapered 8x1.2mm Hole (x2) **Note - tapered side down
AR709051 Washer 3.4x10x0.5mm
ARA330598 Shock Shaft 4x48mm
ARA330596 Shock Shaft 4x43mm
ARA330597 Aluminum Shock Body 16x41mm
ARA330595 Aluminum Shock Body 16x36mm
AR330514 Aluminum Shock Collar Black (x2)
AR716010 O-Ring 19x1mm
ARA330599 Shock Springs 40mm 6.6N/mm
ARA330631 Shock Springs 35mm 6.6N/mm
ARA711003 X-Ring 4x7.5mm
ARA330729 Machined Shock Seal Guide Set (x2)
ARA330513 Shock Cap Lower Aluminum Black 6S (x2)
AR6S216 ADU Racing ADU 7075-T6 Aluminum shock rod end and spring cup set for ALL ARRMA 6S (x2) **Note - Purchased though the RCModel store on eBay
TLR5278 Silicon Diff Fluid 2000CS 30ml **Note - one tube is enough for all four shocks
TLR77002 Shock O-Ring Grease 8cc

 

[Ledzoix]

Thanks for all your hard work building and posting it! Really curious for the end result.

 

[Nut-torious]

It’s been a minute but wanted to post an update. After I assembled the shocks one had a leak. A leak?!? Whatever. That’s why I ordered extra TLR 2000 wt silicon oil. So I rebuilt it. Used a bit more TLR green grease on the x-rings. Bada boom. With many many “squishes” problem solved. I ended up rebuilding all four shocks because they should ALL have the same amount of grease and squish sound, right?

Happy with the shocks, I started to assemble them to the Scorched Speedrun Rocker Arm kit. The solution is brilliant. Instead of heavier springs and maths to figure out different oil weight to prevent bottoming out, the rocker arm kit allows you to use the factory spring and oil weight. It also allows full 5mm of wheel travel where before 5mm of wheel travel would mean 2.5mm of damper travel, now it can be 5mm (per Scorched). The design and manufacturing is, well, beautiful. Almost to the point that I will be sad getting them scratched or even dirty for that matter.

I did ran into a little snafu assembling. Welcome to my most recent rabbit hole! The kit comes with RC4WD M3/M4 Long (31mm) PLASTIC turnbuckle ends. These are required for the rocker arms to counter the shocks and pivot the rocker arm. I didn’t want plastic. I wanted aluminum. Red anodized aluminum to be specific. A quick search and hey! RC4WD makes a long (31mm) red anodized aluminum turnbuckle end. But wait, why is it not for sale on their website? Just these plastic ones. Well turns out they were discontinued in 2021. RC4WD confirmed they have no plans to produce again. Balls.

So I ordered some medium length red aluminum M3/M4 rod ends off of Amazon. Items received. Started to assemble. Shock attached to rocker arm, check. Turnbuckle attached to the rocker… er, not check. The lip on the pivot ball installed as too thick. What?!? Nice. So I searched and (I believe) found the LAST set for sale on RCbitz.com. Ordered. Currently waiting for delivery…

Parts List:
-Scorched Speedrun Rocker Arm Kit
-RC4WD M3 / M4 Long Straight Aluminum Rod Ends RED Z-S1673
-ZRRC Adjustable Sway Bar Links for Arrma 6S RED (purchased on Amazon)
-RamJam Arrma Limitless V2 Titanium Lower Hinge Pin Set
-RamJam Arrma Limitless V2 Titanium Front Upper Hinge Pin Set

 

[Nut-torious]

Rear end is "almost" done. Who can tell me what I'm missing/waiting on?

As you see in the background, (finally) sourced all of the 10.9 and 12.9 hardware in zinc. I had to use four separate suppliers when it came to see of the specialty lengths we see in our hobby. Check.

Thank you 1up Racing for the micro tuning M3 and M4 suspension shims. Then Ram Jam outer titanium hinge pins sick out 0.5mm of the Scorched RC Speed Run Rocker Arm Kit. Item to note, the 1mm nylon washers used on the inner and outer hinge pins needed to be sanded. I used 800 grit and sanded each one from 1.2mm to 0.96mm. This allowed for a bit more free movement, with zero side to side play. The goal having the arms and hubs to fall under their own weight.

Another item to note, yes, those are the composite ends on the rear camber links. Why? Well I asked AI. Why did I ask AI? It's kinda the field I'm in. I was working on a project training a new AI model so I decided (for entertainment purposes) to have an AI debate on composite vs 7075 aluminum. One side of the argument, at 200+ mph composite absorbs micro vibrations. It also doesn't permanently deform so your camber/steering settings stay true. While the chassis needs to be 100% ridged as possible the suspension needs separate considerations. On the other side, at 200+ mph everything needs to be locked in (no play) and ridged to withstand the downforce at those speeds. Conflicting, but both logical thoughts. So I'm trying both. Not shown, I'm using the GPM 7075 steering and camber links (in silver). While the ends are composite, RamJam titanium pivot balls and turnbuckles complete the links.

Finally, what's missing... Give up? Pivot balls! In my search, you can't find metal pivot balls for the upgraded ARRMA aluminum shock caps using the M4 RamJam (or Scorched RC) shock standoffs. For these to work, you need a pivot ball that measures 4.5x6.8x4.5mm. The easiest way to get them is to order the whole standoff kit from Perfect Pass. Not interested. I just need the balls. Messaged Perfect Pass. They do not sell the balls separately. I did find out that RamJam will be offering these pivot balls THIS FALL. I'm okay with that. I missed the Speedrun and Drag race in Decatur, IL this weekend and will be traveling during the Horizon Hobby RC event in Monticello, IL August 29th. So I have plenty of time to build and fine tune everything for 2027 events.

Any questions, please reach out!