Foell.org

Broken, bent, lost, etc.

These are parts we’ve had to replace because we broke them or even just lost ’em somewhere…

• If you’re sticking with normal body clips get these Dubro Body Klip Retainers ($5). If you’re using the Pro-Line Extended Body Mount kit ($18) get an extra set of Pro-Line Body Mount Thumbwashers ($8).
• Extra angled body clips ($3) for the battery strap. The Slash only includes one and and you’re going to lose it.
• Shock Rod Ends ($4), or you could instead get the RPM Shock Shaft Guards ($12) which include RPM rod ends.
• Nerf Bars ($4) / RPM ($8)
• Rear Bearing Carriers ($3) / RPM ($9)
• Rear Suspension Arms ($10) / RPM ($12)
• XX-Long Shock Shaft ($3)
• Shock Diaphragms ($2)
• Shock Spring Retainers ($3)
• Steering blocks ($3) / RPM ($9)
• Driveshafts ($6)
• Diff Output Yokes ($4)
• Motor ($20)
• Extra Wheel Nuts ($3)
• TrackStar TS-900 SCT Steering Servo ($40)

The most disappointing thing about the Slash so far has definitely been the included Traxxas 2075 Servo. My son’s died within a week of taking the truck out of the box. Traxxas thankfully sent a replacement. The replacement ultimately died as well, several months later. We’re now both on TrackStar TS-900 servos, one of which also died shortly after installation. HobbyKing sent a replacement and we’ve been good since. If there’s one place you want to put some money, a quality servo would be a safe bet.

Things we haven’t yet broken after a year (knock on wood) but could probably stand to have extras of:

• Caster blocks ($4) / RPM ($10)
• Front Arms ($8) / RPM ($11)

Tuning Parts

Every Slash is ready-to-run out of the box, but these are the extras we like for Spec Slash racing.

• NitroRCX Shock Oil ($4/ea)
• JConcepts Shock Limiters ($6)
• Slash 4×4 Front Springs ($5)
• Extra Tires for racing (if you like to bash) front and rear ($50).
• XRAY X-Stiff Composite Servo Saver ($21)
• WTF “Blow Harder” 30mm Motor Fan ($14)
• MeatballRacing.com XL-5 Fan Mount ($10)
• TrackStar Vehicle Hauler Backpack ($17) – perfect size for hauling short course trucks to the track.
• “Shorty” battery pack ($40)
• Foam blocks to space out the shorty pack ($2)
• XT60plus with Insulating End Cap (Male & Female) (5set/bag) ($5)
• Bad Horsie Diff Locking Grease ($10) – if you go this route purchase an extra differential assembly so you can just swap it out rather than trying to clean the grease out of the one your truck came with.
• Traction Compound ($10) – check your local track to see what is legal/preferred.
• Electrical Tape ($4) – For high-grip carpet we put a strip of tape around the outside edge of the front tires to prevent traction rolling.

Radio Setup

For a radio, I use my old Spektrum DX3R Pro – but I have very few settings changed on it. Brake and Steering Rates are set to 100%. I have the steering endpoints cranked up to go as far as the TS-900 servo will let me (130%). I added 5% steering expo to deaden it a little in the middle.

My son likes his stock Traxxas TQ transmitter. One thing I noticed is that he would often overcorrect on his steering inputs. The current TQ radios don’t have any steering rate or endpoint adjustments. They also have a tiny steering wheel. I designed an adapter to put a standard foam touring car wheel/tire on his transmitter which is 62mm in diameter compared to the stock 48mm wheel.

He physically has to move the outside of the wheel further to achieve the same amount of steering input. He likes it and it seems to be helping smooth out the steering.

I acquired a bunch of nitro (foam) wheels to use for this purpose that I sell for $11. This is a fantastic upgrade for kids or anyone who prefers a larger wheel.

Suspension Setup

This is where you can do the most tuning. I was able to cut to the chase by asking the track owner at MMR what the preferred setup was. His base recommended settings were:

Front:

• One Hole Piston (one of the extras included with the truck)
• Slash 4×4 Front Springs
• 50wt shock oil

Rear:

• Two hole piston (installed stock)
• Stock Rear Springs
• 45wt shock oil

To this setup I added one of the short JConcepts shock spacers to the inside of each shock. This lowers the truck by 3.25mm front and rear. I tried both 700cSt front / 550cSt rear and 600cSt front / 500cSt rear shock oil setups. My son had the softer 600/500 setup first and I noticed his truck was landing jumps much nicer – mine was too stiff. I switched over to 600cSt front / 500cSt rear shock oil and I’m pleased with where it’s at.

Results

Here is a setup sheet for carpet.

Spec Slash Indoor Carpet Setup Sheet

We’ve had good results with that setup, including a couple podiums.

The best part is, it is hard to not have fun racing these trucks. Even if we aren’t running at the front of the pack on a given race day, they’re still a blast to drive.

Even if you get all RPM replacement parts, everything in this list, including the base model 2wd Slash can be had for about $550. This covered us for a full year(!) of racing. Doing that with any other platform is impossible. The only thing I haven’t included is a battery charger – but you might have one already. If not take a look at these iSDT and iCharger options.

If you’ve got any Spec Slash setup tips you think we’ve missed, please share them in the comments!

The post Spec Slash Parts & Settings appeared first on Meatball Racing.

Paint

Paint wise I did a simple 2-color paint job – black for the top, and metallic red for the body. For the top I painted the inside with Spaz-Stix Black (any black will do).

To give the outside of the top some texture, I cut and removed the film from the hardtop (but not the windows) on the outside and sprayed it with some Dupont Armor bed-liner spray from Advanced Auto Parts.

For the red I first masked off the lights so they’ll be clear under the decals – in case I want to add a light kit later on. I used Tamiya PS-15 Metallic Red and I cut a scrap piece off of the front to experiment with backing colors. I tried five backing colors I had laying around: Silver, White, Orange, Gunmetal, and Black.

In the end I went with Tamiya PS-23 Gun Metal for my backing color as I liked the deeper red it created.

I also painted the locking rings from the Pro-Line Bead-Loc wheels at the same time. The next day I added a layer of clear coat to the locking rings to keep the paint from scratching off easily.

Mounting / Fitment

The wheelbase of this body is just right for the Slash at 325mm. And we adjusted the width of the Slash to make it look more plausible. So let’s mount it up.

Another great part about this body is that it almost exactly matches the 7-inch width of the Slash chassis. I took advantage of that and used velcro where the running board meet the chassis. I kept a small amount of lexan below the doors (instead of cutting it off).

I put a piece of electrical tape on the outside to make it flat black, and put velcro on the opposite side.

The body velcros nicely to the sides of the Slash 4×4 chassis tub.

For the body mounts I bought the Pro-Line Slash 4×4 Extended Body Mount set. But rather than cutting holes in the body, I used the set screw from the body mounts to fasten a magnet to the body posts using a 3D printed adapter.

Then I used some super-sticky extreme shipping tape to keep magnets in place on the inside of the body. I also like to use it to reinforce parts like fenders that might get bashed – to prevent the lexan from tearing.

The body stays on nicely even after taking a tumble. It’s easy to put on and take off, and without any visible body posts, it looks more scale.

The post Slash 4×4 Crawler (Part 4) Body appeared first on Meatball Racing.

But I made quick work of it by removing the gear reducer plate and enlarging the hole with a 17/32″ (13.5mm) drill bit.

Also the 550’s shaft is a bit long, so I cut off about 3-4mm from the end using a dremel and a 409 cut-off wheel.

The included pinion gear needed to be installed very close to the motor in order for it to engage smoothly. So I used the same cut-off wheel to extend the flat spot of the shaft almost up to the bearing.

A quick aside – something I found out later is that the pin that holds in the reduction gear… it worked its way loose and into the vent holes of the Titan 550 within the first hour of running – ruining a brand new motor

So I bought a new Titan 550 (and performed all of the aforementioned modifications) and put the gear reducer back together but added a piece of silicone tape to keep that shaft from wiggling loose again. Silicone tape is the same stuff powder coaters use to mask metals – it will withstand high temperatures. Anything that can stand reasonably high temps should do.

The gear reducer doesn’t include mounting screws as they’ll vary by installation. For it to fit the Brushed 4×4 Slash I needed two 4x25mm tapered head screws to fasten the motor plate, gear reducer, and motor all together in a stack.

The endbell of the Titan 550 barely cleared the driveshaft cover. If it didn’t I was prepared to remove it and cut some plastic, but I had about 1mm to spare.

To make sure the power would keep all the wheels moving at once, I purchased a $2 egg of Silly Putty – the cheapest part in this whole build. I removed the grease from inside the diffs using Simple Green and re-assembled them, adding Silly Putty in layers. They feel extremely locked, but hopefully will provide just enough give to relieve stress from the rest of the drivetrain. They’ll likely loosen up as the gears slowly push the putty out of the way – then I’ll add more putty

For traction I found some old-stock Pro-Line Trencher SC M3 (soft) tires – the ones that have some tread on the sidewall. I’m sure Pro-Line removed the tread from the sidewall because track racers found it contributing to traction roll at high speeds. But I wanted the soft rubber and extra tread for climbing.

I mounted them up to a set of Pro-Line Bead-Loc wheels that were made for the front of a Slash 2wd. That offset keeps them from rubbing the front shocks at full steering lock. I like these wheels because they can use any Pro-Line short course tire with the bead lock system which requires no glueing – so I can change tires easily later.

For the tire foams, I used open-cell soft HPI 103335 Short Course foams. I kept the included closed-cell Pro-Line foams to maybe run in the rear if they need more stiffness.

To complete the power package, I needed a speed controller that has a drag brake. This is helpful when you need to stop on a steep incline or decline without your rig coasting down the hill like a runaway tractor-trailer. The HobbyWing WP1080 “Crawler” ESC is popular among locals and it’s available for less than $50. It’s a waterproof 80A ESC with tons of features for both crawlers and brushed racers.

I mounted it up front to add a little nose weight. I’m excited about it – it’s the first ESC I’ve purchased that I didn’t have to rewire the battery connector on. The future is now!

The post Slash 4×4 Crawler (Part 3) Powertrain & Tires appeared first on Meatball Racing.

One of the bandit arms is modified. To get the bandit arms to fit in the Slash 4×4 front caster blocks (6832) and retain full suspension travel, I had to cut and trim some things. If you’ve got the aluminum 6832X caster blocks you may not need to trim as much – as always, your mileage may vary.

I trimmed off much of the bridging near the wheel side of the suspension arm using a cut-off wheel, leaving just a small amount. I also used a sanding drum to remove some material from the top of the forward arm link so it wouldn’t rub inside the caster block.

Removing the forward arm link material allowed the suspension to droop much further without binding. You can see here how it dips below the caster block support:

I used a Dremel and two attachments to make these changes: a 409 Cut-Off wheel and a 430 Sanding Drum.

Axles

I planned on switching to Bandit axles, but it turns out the cross pins on the Bandit universal joints are smaller diameter than what comes on a Slash. RC Driver explains and shows it very nicely here:

This would mean also switching to Bandit diff output yokes and stub axles – the latter of which I wasn’t sure was going to fit in the Slash 4×4 bearing carriers. Not to worry – there’s a cheaper and easier solution: cut the stock Slash 4×4 telescoping driveshafts.

I cut 20mm from both halves, using a pipe cutter worked nice and kept a clean edge.

Here you can see before & after:

Turnbuckles

For the camber links, I used Bandit turnbuckles (2443), two sets for front and rear. You’ll also want to buy some extra hardware to mount them as the screws for the Brushed Slash 4×4’s non-adjustable, plastic camber links are different. A bag of 3x15mm button-head screws (2579) should cover you, or you can pick some up at the hardware store.

The steering turnbuckles are thinner than the suspension camber links – 3mm instead of 4mm. Also the rod ends are specific to the Slash steering bell crank and steering blocks. So I opted to retain the stock rod ends and install them on a shorter (3x45mm) turnbuckle. I reinstalled them into the forward most hole on the steering blocks for maximum turning angle.

I used a turnbuckle from TLR that I found at my local track, but any 3mm x 45-48mm turnbuckle will do. These ones are from popular models, so there’s a good chance your local hobby shop will have one:

• Team Associated 3x45mm Turnbuckles (4404)
• Team Associated 3x48mm Turnbuckles (91723)
• Arrma 3x48mm Turnbuckles (330013)

Keeping the front wheels/tires from rubbing the shocks at full lock was tricky. Crawlers need maximum steering angle for tight turns and I didn’t want to lose even one degree – especially considering the Slash wasn’t built with crawling in mind.

Using Pro-Trac wheels like on the Ultimate RC Chimera-B were not going to work with the short Bandit arms. They rubbed on the suspension and limited steering angle. Luckily I have a 2wd Slash on hand to facilitate some testing. The next level of wheel offset was the 4×4/2wd rear wheels. These also rubbed the shocks at full lock. Switching the wheel hex to the wider 2wd Slash front wheel hex (3654) helped, but it was still touching the shock (barely). In the end I used 4×4 Slash wheel hexes with 2wd Slash front wheels on all for corners.

The result is 254mm of overall width with tires on. Close enough to the 249mm I was going for to call it good.

The post Slash 4×4 Crawler (Part 2) Width appeared first on Meatball Racing.

To start this hair-brained experiment I started with two main ingredients:

1. Brushed Slash 4×4 (high center of gravity chassis)
2. Pro-Line Jeep Rubicon Unlimited Body

I understand that the thought of an independent suspension Jeep Wrangler gives many people an uneasy feeling. Somehow, it’s just wrong. But this is a thought experiment, and if you need help suspending disbelief, this does in fact exist in the real world.

I’m enamored by the Slash (both 2wd and 4×4) – it is the best selling RC platform in the world. With excellent parts compatibility between other Traxxas models, why not see if it’s possible? That’s what this hobby is all about anyway, making something custom from your own ideas.

I also love Jeeps. The Pro-Line Wrangler Rubicon Unlimited body, while made for the TRX-4, should be a perfect fit for this build. It just happens that the long wheelbase configuration of the TRX-4, at 324mm is exactly the same as the Slash 4×4

But could the Slash 4×4 be narrowed enough to look convincing? And could it still maintain good suspension articulation? Let’s try to remove some width and find out! Stay tuned for the rest of this build series.

The post Slash 4×4 Crawler (Part 1) Introduction appeared first on Meatball Racing.

At the front end is a Renogy 100 watt portable solar panel and a MPPT controller. This model is more expensive (at $275) than the normal $1-per-watt deals you can get on just panels. But it folds nicely, comes in a carrying case, and includes a waterproof controller and all necessary wiring.

The panel turns sunlight into power, and the MPPT controller decides how much power goes to the battery. It has several settings for different 12-volt battery chemistries (Lithium Polymer, Lead Acid, AGM, etc.).

For my “energy sink” battery, I went with a tried-and-true Interstate group 27 deep cycle battery that I got from Costco for about $100. It’s got 160 minutes of reserve capacity, so figure about 67Ah at 12v. Pro-tip: the deep cycle batteries aren’t available at Costco in the winter here. You gotta get them in the spring when Minnesotans are bringing out their boats.

I call it a sink, and I drew it to look like one in the illustration because I like to think of the stored energy like water in a sink. Energy in the sink can be emptied to charge another battery, it can be refilled by the solar panel, and it can be refilled from another battery. I’ll show you how…

Regenerative charging

My favorite part about this setup is with the right charger, I can do regenerative discharging. I did my research and found a couple of chargers that can do fast discharging by reversing power flow and putting energy back into the input – the energy sink. The two chargers I’ve found that will work are the Turnigy Reactor and most Junsi iCharger models. I went with the iCharger X6 because it’s extremely portable and packs a powerful 30-amp punch.

Why do I want to do regenerative discharging? When I go racing I usually bring two batteries for every vehicle we’re going to race. I’ll use one during practice and charge the other for qualifying and racing. At the end of the day, usually a 5-8 minute practice, qualifying session, or race isn’t even close to getting the battery to its most stable resting (storage) voltage – 3.8v per cell.

A quick way I had been discharging was to use a AOKoda Cellmeter 8 to bring their voltage down to 3.8v per cell. It works incredibly fast because I can draw up to 150 watts of power by running three 50 watt incandescent bulbs. The power turns quickly into heat and light.

But why not recapture that energy instead? Regenerative charging allows you to put that energy back into an energy sink battery just as quickly.

X6 regenerative discharging setup

The X6 has 4 “input source profiles” that you can use to tell it whether it’s being powered from a normal power supply or a battery. You can give it parameters for how much power these sources can deliver and whether or not they are regenerative.

To set up the input sources, first get to the system menu by pushing and holding the nav wheel down from the home screen. Then you can go to the “Input & Power Limit” section.

You then select one of the four available profiles you want to edit.

This is my setup when connected to the deep cycle battery. My Costco/Interstate battery has a reserve capacity of 160 minutes (at 25 amps). I set the max current to 20A so even if there’s no solar power input, I should get over 3 hours of charge time at 20 amps – but I’m never charging at that rate anyway.

Check the regenerative enable box to get those options. Here you need to know what the fully charged voltage you want to stop at and what the max charge rate is. This will vary whether you’re using lead acid, LiPo, LiFE and how many cells it has. Maybe you want to use something like my 6S lawn mower battery as the energy sink. Regardless of what you use, you need to know the max charge rate and voltage.

Based on my 67Ah deep cycle battery, charging it at 10 amps is a 0.15C charge, or 15% of its capacity. That’s between the recommended 10-30% of capacity rates. Best to be conservative here.

Discharge vs. Storage Programs

Once regenerative charging is enabled on the input source, we need to also enable it on the discharge setting for your charging profile(s).

Why Discharge and not Storage? Because storage is a smart mode that will either charge or discharge cells based on whether or not they’re above or below your target voltage of 3.8v. As long as all of your cells are above 3.8v, you can use discharge mode and set the discharge voltage to 3.8v instead of the default 3.5v. The charger can still do some balancing of the cells on the way down to the target voltage – enable it in the “Advanced” section of this screen.

There are several safety measures built in to make sure you don’t send power back to something that can’t accept it. The iCharger will warn you here with a yellow exclamation.

Once you’ve enabled Regenerative Mode, when you go to run the program, Discharge will have “REG IN” in red next to it.

One last safety feature – when you select discharge it will give you another confirmation on whether or not you want to do a regenerative or normal discharge.

Now you’re taking energy out of your RC battery and putting it back into the source energy sink! In the lower left you’ll see RE in yellow & red with the voltage and current. No wasted energy to light or heat – just put it back where it came from

Wireless Charging in Action

Here’s my setup at the track. On a sunny day I’ve seen the MPPT controller send out 6.0 amps to the battery. At 14v that’s about 85 watts. Not bad. Without taking away any battery charge from the energy sink, I can charge a 2S battery at 10A, and my 6S lawn mower battery at 3A.

Do you have any other green charging ideas? Let us know about setups you’ve built or seen in the comments.

The post Solar Charging Setup appeared first on Meatball Racing.