Micro Racer's 1.9 Wraith Build

[micro racer]

Note to the mods: I am not sure if this is the right place for this thread, so please move it if needed.

Anyway...

Some of my other builds have begun to slow a bit as they near "completion ," or at least a building plateau, so I might as well start another . While browsing the forum for inspiration, a few Wraith ultra 4 builds caught my eye as well as the scale looks of the 1.9 Wraiths. So that is the direction I decided to go.

One of my pet-peeves is that everybody "knows" that the stock parts will "never" work on a higher powered build, an experiment that I will incorporate into my build; I bought all of the main chassis off of RPP's Salvage yard, so everything is a stock take-off (we'll see how long it lasts, but that's the point).

First, the bag-o-parts:



Pre-mounted RTR BFG's on the CRC Blackrock wheels. The wheels are actually pretty cool; I just wish that they were beadlocks...



Pre-assembled RTR take-off SCX10 axles:



Pre-assembled RTR take-off Wraith trans; this is from a Poison Spyder, so 48 pitch gears:



Cage in a bag, from a kit Wraith:



Cage out of the bag:



Original WB8 driveshafts, not HD:



Aaaaannd....

Roller! Almost... In this picture it is sans links, shocks, body, and electronics.



It is quite a bit farther along than the last picture, but the pictures haven't been uploaded to PB yet; I will have a continuation post in a little bit here...

[micro racer]

My continuation post was almost done, them my mom decided that 10:00 was too late for a high school senior to be going to bed.

So, it is currently saved on my computer while I type this from my phone.

I hope to have it posted before I go to school tomorrow morning though...

Besides that, please post any questions, comments, or suggestions you might have!

[micro racer]

Continuing with the interior:



Silver with a gunmetal floor:



I am starting with a Deadbolt body because I wanted a different look from everyone else's Wraith. Unfortunately, the way the body fit over the cage didn't come out properly (my error) and it doesn't sit quite the way I wanted it too. Oh well, new panels aren't that expensive...



After I painted it, I threw some electronics in to see what it could do. Stock 20/80 gearing, spare Castle 4600kv 4 pole motor, mamba max pro, LRP 2s 50c 4500mah shorty pack in the regular rear position, and a spare HS-645mg servo.

I can't post video yet, but here is a link to what happened...

About 5 minutes of running around my backyard track later, I broke a c-hub:



I replaced it with some Axial aluminum hubs, then this happened:











So, yeah. It has some power. While waiting for replacement aluminum knuckles and a new housing, I figured that I should order a slightly slower motor with the hope that I might break fewer parts by going slower.

I don't think this is the motor to do that....



To be honest, it is a tad slower, but it it still tries to do a backflip .

I need softer springs and/or dampening since I think that is one of the reasons for the hub breakages; almost all of the suspension is coming from the tire foam since the shocks are too stiff. Beef tubes may also help reinforce that area.

[DaddyJeep]

By the looks of things Beef Tubes are a requirement.

[micro racer]

Originally Posted by DaddyJeep

By the looks of things Beef Tubes are a requirement.

Probably, but I want to try a softer suspension first. I think that the springs or dampers are too stiff and a placing an unneeded load on the hubs and housing. But in all honesty, I would expect Beef Tubes in a few weeks.

While on the subject of suspension, I realized that I forgot to post what shocks I am using (for now). As this is supposed to be an "RTR-grade project," I chose some of the best RTR ahocks out there, Traxxas Slash rear Ultras.

Yeah, they aren't that great in the scheme of Powerstrokes, Pro-Specs, and other big bores, but they are they best $15 pair of shocks I know. Since the pair I bought is really designed for an E-Maxx, the stock springs were way too stiff. I dropped to Losi 2.5" silvers @ 3.4 lb/in, but those still seem too stiff. I will be ordering some Losi 2.5" reds @ 2.4 lb/in today...

[micro racer]

So, uh, I broke the chassis' frame rail.



Basically, the suspension has so much travel that the servo is over-steering at some points, even with proper EPA's at ride height. With about a inch and a half of straight travel, I figured that a CMS setup would cause some problems and here is the second (the first being trying to massage out at least some of the bumpsteer).

Since I replaced the stock c-hubs and knuckles with VP aluminum, the weak point moved to the axle housing itself. I gave it one try at a stock replacement and after that cracked (and later completely sheared due to overconfidence and boredom ) I ordered some steel Beef Tubes.

Besides adding a few steel threads to screw the hubs to, the tubes gave the axle a nice connected feeling from side to side and a solid weight-y feel overall. It was such a difference that even though I haven't had any issues with axle housings on neither my dad's nor my SCX10, I might get these just for the solidness.

Test fitting:



The stock replacement; it first cracked on the front half hub "tab" and across both halves between the link mount (same side as the hub), then the end of both halves came all the way off:



Obligatory flex shot; it has more articulation, but this is as far as it goes on its own before lifting a rear tire.



Other stuff: I put a Heyok light switch in and have two LED's installed in the middle bumper lights. I know that I need more, but I just wanted to get it able to dork around the backyard first.

Also, the suspension is still too stiff even with the Losi 2.4 reds. I ordered some 1.4-ish Losi golds to try instead. If that doesn't help, then the shocks are too stiff, not necessarily the springs (trying to isolate the problem).

[R/C Bashist]

Any more pictures with the body on? This is the first Wraith I've seen with a Deadbolt body, so I'd like to see more of it.

[micro racer]

I didn't quite cut the body right, so it doesn't fit like it should, but I can get some pictures up later today or tomorrow.

Any specific shots or angles you are looking for, RC Bashist?

[micro racer]

Here are some pictures with the Deadbolt body on. Sorry about some of the lighting and blur; I had to take these on the run. Also, ignore the Cali lift in the first picture. I finally have soft enough springs that at least half of the truck will sag...













In the next picture you can see the extra gap between the edge of the body and the cage work. The body is supposed to sit more tight and lower against the cage, but I didn't cut out the dashboard area right so I couldn't get it pushed down enough when marking body screw holes.



If it wasn't clear from the pictures, I now have Losi 2.75" gold 1.4 lb/in springs all around. These are just about the right spring rate, I could go lighter still but I will keep these for a while, but the suspension is still too stiff over jumps for my liking. I will put some three hole pistons (up from two hole) and 25 wt. oil (same as current) in the shocks next weekend and will see how that works.

[Jeepfixer1]

Looks killer, love the carnage of all the axle parts. Thanks for letting us know how the shock tuning is going and what's working for you . I'm sure that info will help some people save time and money trying to find what works for their rig!

[micro racer]

Originally Posted by Jeepfixer1

Looks killer, love the carnage of all the axle parts. Thanks for letting us know how the shock tuning is going and what's working for you . I'm sure that info will help some people save time and money trying to find what works for their rig!

This has definitely been an interesting experiment/project! The shocks have been a little bit frustrating because I bought two pairs of each rate (for both the front and back; currently on my third rate besides what came with the shocks) and that adds up costs. However, the build/learning process is part of the fun, so... Anyhow, it is pretty close to handling how I want, but I went to my local indoor track this last weekend for some stock buggy racing instead of rebuilding my shocks with different pistons.

For the experimental part of this project, I have confirmed most of my skepticism over the "needed/required" parts for a high power build. Besides the front hubs and then axle housings and a slowly licorice-ing front driveshaft, I haven't had to upgrade nearly as much as some people would say is a necessity. **NOTE:** I put the chassis breakage up to an over-extending suspension setup on my part.

Another note on the all-important suspension setup: I will be internally limiting the front shocks for less downtravel, since the last 5mm or so is at such an angle that the bumpsteer goes crazy.

[micro racer]

I don't have any pictures today, but there are still a few things to report on.

First, I haven't broken anything!! The beef tubes seem to be holding well, as I haven't sheared another axle housing . A wheel or two has a bit of wobble, and the front driveshaft is a bit licorice-y, but I haven't "broken" anything (yet).

Next, I have got the suspension into a range of proper function, but it STILL needs a little work. I have three hole pistons and 25 wt. oil all around, but the dampening is still a bit stiff; I have narrowed the problem down to dampening, because the suspension is very slow to drop back down after being compressed in the air. I am going to try 20 wt. oil and hope that that is light enough, because I don't know if the oil goes any lighter in weight. (Quick check: Associated oil goes all the way to 10 wt.)

Finally, I have a new servo! I am testing a Tower Pro MG958 (I think that is the number) for my manager to see how it holds up. So far so good, but I know it is a cheap, China brand so.... It has a nice amount of torque and is faster than the Hitec 645mg that I started with. This truck seems to eat steering parts, so I'll see how this goes.

That's all for now! I want to get this truck out on the trails and take some pictures!


Quick little story: I was trailing a few weeks ago with my dad when we came up to a three or four foot drop off on the trail. Basically, there is a ledge that drops a foot or so to a very tight, truck-sized landing, then drops straight down another two or three feet. Dad ended up driving backwards down the face while slowly winching himself down, but I thought that I could gap it and stick the landing.

I really should have paid attention to a little farther down the trail...

I punched the throttle, the wraith flew off the first ledge perfectly, aired over the second ledge like I hoped, landed flat on the trail, then ran over a rock on the right side as I was trying to slow it down and began to roll. And roll. And roll. And kickflip. And roll some more.

In the end, it had rolled/flew/flipped its way down about a hundred feet of trail, dropping about 40 feet in elevation. It stopped when it hit and was caught by a piece of a shopping cart left on the trail.

Fortunately, nothing broke, but the plastic servo horn was completely stripped. You know how a stripped horn feels gritty? Well, this was so completely stripped that it felt like it was on bearings!

Takeaway: Yay, nothing broke! Also, an aluminum servo horn is necessary...

[micro racer]

So, I am not too sure what happened here... This is the stock plastic housing with a VP lockout; it looks like the lockout was twisting forward (toe in) and pulled the tab off the main part of the axle. The other half bends in slightly which would seem to confirm this theory. I replaced the broken housing half with a new one and will see if that lasts. If the axle fails again, then I guess I need beef tubes for the rear.



This, on the other hand, I very much know how it happened... BMX jumps and un-sleeved all-thread.



Funnily enough, the axle managed to stay aligned with the chassis so that the CMS was still steering almost straight. I only noticed the bend when I had stopped driving, happened to look straight down on the truck, and went "that looks a bit off..."



When I was not lobbing the truck off of random trail jumps, I fabbed up some deck panels for the rear of the chassis. The panels are simply plasti-welded to some tabs bolted to the shock mounts. Unfortunately, the panel on the right popped apart while tumbling down a hill. Fortunately, neither the panel nor the truck were damaged, and I should be able to just glue the panel back onto the tab, albeit with more reinforcement.



In the ongoing war against bouncy suspension, I decided to pick up a set of these RPM two-stage pistons. I can hear that the tires are still taking up most of the drop, even with the 3 hole pistons and 25 wt. I figured that this is probably a good time too throw in some upgrades, since the shocks will be apart anyway. Actually, I am basically building new shocks, now that I think about it.

I bought Traxxas TiN shafts and a rebuild kit for all the seals. I also have a set of STRC shock bodies coming in silver. I already have blue STRC caps so I thought that the silver might look a bit like Kings, but I know that it won't be anywhere near scale-accurate. In the hopes of transferring more force to the shocks instead of dissipating in the tires, I am also going to order a set of CI Deuces Wild (I don't quite know which foam would fit the Pro-line 1.9 KR2's, so any help would be, well, helpful. I'll ask in "Wheels and Tires" as well). The more I drive this rig, the more I like it to go fast. Most of its crawling performance can be sacrificed for some high speed stability.



I have also put on a Hot Racing clamping servo horn. It bends in an unnatural way while "clamping;" the splines physically twist into the output shaft, instead of clamping straight down on the splines. It works, but I don't like it. An Axial horn should soothe my OCD...

[micro racer]

I have another interesting one here:





These are the stock stub axles. I assume that I managed to get a rock between the c-hub and knuckle to catch the drive cup. As the first picture shows, the metal seemed to flake, but stayed together until I knocked it off in the bench. There is actually another, smaller chip off the other side of the stub, but this was a better picture.

The rig still drives fine; I noticed this a few runs ago and have put a few packs through since. I guess that I will have to XR mod this to use VP's scale knuckles and hubs, since they have some large gussets that should protect from this type of damage. Oh darn, guess I need to buy more parts...

In the mean time, I ended up buying the 1.9 Deuces Wild for the TSL XLs, but I don't have tires yet; I should be picking up the KR2s tomorrow. That just leaves wheels and then I will be set for rolling stock. I really want to keep something like the CRC 6 spokes I have on it now, but I can't find anything quite like them as a beadlock. The closest I have seen are the Gearhead BTR TTs, but they are silver and I want black. Please let me know if anybody makes something like the CRCs in black aluminum!

Also, my shock bodies finally came in! Now I can do my front shocks with the TiN shafts and RPM pistons.

Another thing I don't have a picture of: I finally sleeved my links! Instead of the usual 5347 Revo ends, I used 5525 Jato ends for a longer shank to thread into. The ends of the rod towards the flat actually have better clearance than the Revo ends as well; they have about 3 degrees more movement before they rub the skid, compared to the Revo ends on links with the same eye-to-eye length. Disclaimer: I did have to file/sand the skid a mm or so to slot the offset balls into the skid, but the whole suspension cycles much more smoothly.

That's all for now! I hope to have the front shocks built by my next post so I can report how the new suspension setup is working.

[micro racer]

Well, I haven't built the shocks yet, but it has only been a day... I did, however, pick up the Proline KR2s from the hobby shop.







If you don't have eagle eyes (I don't), then the second and third pictures are very difficult to read. The warning reads "Serious fun may result from: -Extreme speed and loose terrain, -A heavy trigger finger."

Anyway, I thought I would just post a quick update with something funny...

[micro racer]

Just a quick update here:

I built the front shocks and they are amazing! It's a wonder what decent suspension will do for a vehicle's handling...



TIRES!! More specifically, TIRES!! with some proper foams. I only need a set of wheels and these will be good to go...



Besides the new shocks and tires, I also finally took the time to sleeve all of the suspension links. No more noodle all-thread for me! While I had the links apart, I replaced the regular Traxxas rod ends with some fancy, blue RPM rod ends, too. They totally weren't necessary, the regular Jato ends were just fine, but I thought that the bright blue would add some bling for fun.

[Natedog]

Great thread, love the start basic approach and 1.9 Wraiths are how they should have been built. Keep the updates coming.

EDIT: BTW turning your steering servo mount 90* so that the arm is down and swings side to side like the arms on the knuckles do will help a LOT.

[Big Foot]

Man this thread is simply awesome! I use a bl motor too, not as powerful as yours I think, mine is a 1870 kv@11v, but I've already broken all my traxxas shafts, bended links and all that kind of stuff! And, last, but not least, I'm on a budget too ;) so yes, I know the struggle! Subscribed!

[micro racer]

Thanks for the compliments guys!

Natedog, I totally agree with you about 1.9 Wraiths; they look way better than 2.2/AR60 Wraiths. Unfortunately, the Vanquish CMS bracket mounts the servo laying down, but I haven't found a clean enough standing setup (like Wertymade plate or such) for me to change over. With my current suspension travel, however, I have mostly fixed the bumpsteer problem. If only the Wraith cage was stiffer. I am losing torque at lock because the CMS is twisting the whole cage... I am running STRC Slash rear shock bodies up front limited with the shorter length of the front shafts. Originally, I limited the stock rear bodies/rear shafts with some fuel line, but the tube would have interfered with the valve action of the new RPM pistons.

On that subject, I'm not totally sold on the RPM style of valve; it seems to be finicky in bench tests and possibly unreliable while running. I am considering switching to the MIP flapper valve style, instead of the mechanical slide valve. Overall though, the lighter 20 wt. oil and more flowing pistons seem to have settled the truck down a lot. A rear swaybar, at minimum, is going to be the next upgrade. With such soft dampening, the chassis rolls almost all the way to full bump on the outside, unless the truck has already rolled over. I should do a sway bar either way, but I want to see how much the stiffer foams in the KR2s help; I just need wheels.

We're probably pushing similar power, Bigfoot, though I'm only on 2s with the Tekin 3300kv! I think the key to the survival of my drivetrain is that my slipper is not tightened all the way. It is set to slip only in severe binds.

[Big Foot]

Originally Posted by micro racer

Thanks for the compliments guys!

We're probably pushing similar power, Bigfoot, though I'm only on 2s with the Tekin 3300kv! I think the key to the survival of my drivetrain is that my slipper is not tightened all the way. It is set to slip only in severe binds.

And that's why, perhaps, I'm destroying all that stuff: I'm using a 32p gmade transmission, wich is, guess what, without slipper