1/8 buggy to 1/10 SCT conversion

[Sixtysixdeuce]

So I wasn't initially enamored with the 1/10 SCTs, but over time, I sorta got interested, then finally bought one in October (Associated Prolite 4x4). Seemed like a pretty tough truck at first, but what I've found to hold true with it and other 1/10 SCTs is that the hits have a cumulative effect, and ultimately you have a fairly large & heavy truck that has running gear only slightly stronger than a standard 1/10 scale vehicle. They hold up decent, but in the end there are only so many things you can upgrade, and when you punish them with 1/8 scale motors on 3S and 4S like I do, stuffs just gonna break.

So I started pondering upgrading many parts to 1/8 scale, but it would have been a rather costly and labor intensive endeavor. Solution? Just start with a 1/8 buggy, since the wheelbases are identical, and track width so close that only a ruler tells the truth. So I started watching auctions for 1/8 buggies to find a decent platform at a reasonable cost. After a couple of weeks, my vigilance paid off; a very clean Tamiya 801x roller with every possible upgrade that nobody seemed very interested in. I won the auction at $96 shipped!

Now, while I was wanting to do another Hobbywing or Tekin set-up, things have been a little tight with taking time off for the birth of my little boy, so I decided to take a look at Hobbyking offerings. Ended up going with a Turnigy Trackstar 120A WP ESC and 2100 KV sensorless motor for $99 shipped. So far, it seems like a pretty decent system for the money. I need to turn the punch up, but I didn't get the program card yet, as I thought I might be able to use one of my HW or Atomic cards. No such luck. Still, even on the default "low" setting, it's pretty quick on both 3S and 4S. Not quite as smooth down low as my Orion Vortex 2000 KV/HW WP8SC combo in the Prolite, but I don't spend much time going slow anyway.

Once again, I considered buying an RC Monster or RC Product Designs motor mount, but am just underwhelmed with the products in terms of beefiness. So back to the mill with a hunk of 7075-T6. I did opt for a more conventional design this time, just much thicker with the 3/8" billet. And as with my 801xT conversion, the battery tray is milled from solid polyethylene, and holds the packs vertically.

Just running one of my old Prolite bodies for now, but thinking JConcepts Illuzion would look good. Thoughts?

We'll see if the guys at the indoor track catch on (1/8 scale is technically not allowed), but in the mean time, I'll be tearin' it up with this!

[DMAT]

A little funny to me. The exact opposite has been made as kits. STRC did a 4 x 4 slash into 1/8 buggy.

[Sixtysixdeuce]

A little funny to me

I'd rather run it as an e-buggy, but like I said, 1/8 isn't really allowed on the indoor here. Making it a 1/10 SCT for all intents and purposes leaves me able to use it on that track, and without the parts breakages you see in the true 1/10 SCTs when you run them as hard as I do. 1/8 buggies are just tough as nails (even the cheap ones).

The exact opposite has been made as kits. STRC did a 4 x 4 slash into 1/8 buggy.

I've heard of people doing that, but it makes little sense to me. Weaker in every way than a real 1/8 buggy and too light to race in sanctioned events unless you add weight, which defeats the purpose of the conversion.

I'm overweight and slightly wide for a sanctioned 1/10 SCT class, but I don't have any interest in that class anyway. Just wanna be able to run a tough critter on the indoor track. That, and I was jonesing for a project.

[Kyoshojoe]

looks good,I did the opposite and converted a lazer zx from buggy to sct. race legal. I did it mainly cause I wanted a kyosho 4x4 sct. Ive seen conversion from 1/8 buggys to sct.I had a couple lazers and a ton of parts so purchasing another buggy wasn't cost effective. Ya the downscaling a 1/8 would be 100 times easier but I would have a heavy akward underpowered shelfwarmer. If your just building it for bashing and purpose built racing then its fine but compared to buying a racing 1/10 sct its always gonna come up short at the finish line if they even let you race. It will probably outweigh the competition by 1.5lbs. In order to make it race legal, not race look the other way, you will have to narrow your wheel width and then you will have to run on 2s and trying to push all that weight will become an issue, not to mention the narrower width will throw off handling and the extra mass going into the turn will force you to slow down. Im only listing my justifications for pouring 100s of hours into converting my 10th scale buggy rather than popping a sct body on a 8th scale buggy and adding bumpers. Just remember heavy means slow not durable. At our track the 1/8 scale buggys are what break most. too much mass in motion for the materials and a lack of endurance engineering. 6lbs will wear a suspension component much faster than 4.5Lbs remember that the components for the 1/10, 1/8 or whatever scale are the same materials just different engineering layout. I can throw my sons newbright 1/16th across the room and it will only be scratched, point being you just put a sct body on a buggy, not actually converting it to a sct. It will not be a beffier better 1/10th scale because it will be a 1/8 scale buggy with a sct body. Get the vehicle to meet the rules and then you will have something, untill then you are either cheating or bashing.

[Kyoshojoe]

Crash damage has nothing to do with durability but rather has everything to do with driving. hit the wall at 40 mph at 45 degrees with only front wheel contact and you will be buying parts in whatever scale. chances are the heavier car will require more repairs. An object in motion tends to stay in motion unless acted upon by an equal and opposite force. more mass in motion means more stress on weak points when it has to suddenly stop due to an unmovable force like a wall. The law also applies to handling because in order to turn your car. the tires must apply the equal and opposite force necessary to put the car on a new vector thus a heavier car will require more contact friction and power. Its a common misconception to think bigger is stronger, or 4s is faster. Ive seen plenty of 1/1 4 banger v-tech powered cars smoke 302 v8s like they were a blunt in a rap video. Power to weight ratio is the golden rule for speed. Sorry if i sound condesending but it urkes me to see people post assumptions based on limited mechanical experience. From what Ive seen of Associated's engineering practice, is to design weak points into strategic locations in order to protect more costly and critical components. like a sacraficial zinc on an outboard motor. you can beat the hell out of traxxas cars because the components flex and give which helps deflect the kinetic energy built up in the car. So to say most 1/10 scts are weaker than all 1/8 buggys or that more weight will improve handling, or more voltage will make my car faster is unsupported by fact or testing. Its great that you had fun with the project, and im sure its a great car but I dont think it will pass for a sct, the 17mm 1/8scale buggy wheels are a dead giveaway and will be the biggest hurdle to overcome if you try and convert to sct wheels because of the negative offset. Hey, if they dont care at your track then its all moot and your good to go.

[Sixtysixdeuce]

Sorry if i[SIC] sound condesending[SIC] but it urkes[SIC] me to see people post assumptions based on limited mechanical experience.

Well, yes, you are being both condescending and presumptuous. I don't think someone with 20 years in 1:1 automobile repair, an equal amount of time fabricating everything from model railroad accessories to functional firearms, and who has done considerable study of mechanical engineering, chemistry, physics and metallurgy is a person you should accuse of having "limited mechanical experience". I know how to perform the calculations that ascertain energy, force and momentum, as well as how those forces act on various materials & parts based calculations incorpating vector and leverage, and factor in the elastic properties of real (as opposed to theoretical) collisions (elastic vs. inelastic). Kind of a moot point, though, as all one has to do is look at the difference between 1:10 SCT and 1:8 buggy parts to see that the 1:8 parts are a lot more than 20% stronger:



So next time, please save yourself the effort expended on such a loquacious post that is not only insulting, but also erroneous in more ways than I care to summarize at this hour (such as your mashing together and butchering Newton's 1st & 3rd laws, with a splash of Kaiser Permanente commercial verbiage)

[Kyoshojoe]

using strength of material calculations to total cross-sectional shear plane of both sets of arms from what I can see is nominally the same and if both are made out of the same material then they both will fail at approximately the same load. but the heavier car will exert a greater load on the part. Sorry I was not trying to be condesending, I was outlining basic facts of mechanics, and I presume nothing. I am not putting your project down in any way. It looks good and I bet it is a hoot to drive, but It by no means is a 1/10 scale sct yet. How many different sct trucks have you tested? how many 1/8 scale buggys have you run. that was what I was refering to about limited mechanical experience. not a personal dig at you, rather it was a generalization about people spouting statistics without supporting facts is all. for all I know you could be President of GM research and development. I stated facts and just because something looks beefier doesnt make it so. You have to find its weak point and that is all that matters. How many suspension arm fractures happpen in the middle of the arm? Its always at the hingepins. same with caster blocks and all moving parts. the weak point is usually where the part pivots. This is not about ego or who knows more, It is about the cons of scaling down a vehicle and debunking the idea that bigger is stronger. Talk is interpreted, Math is fact

[Kyoshojoe]

I was paraphrasing not qouting Newton. I was too lazy to google it. Just remember "winning an argument on the internet is like winninig the special olympics, your still retarded" I am sorry that I offended you but I think that you are being extremely biased in your analysis of the durability of 1/10 scale vs 1/8 scale vehicles is all, I could be totally wrong and spouting nonsense but you posted in a public forum and should take criticizm without taking it personally.

[Kyoshojoe]

lol, Heres a thought. How about a new thread about determining the veracity of our stance on this little debate. I will defer that a part made identically but only difference being scale it would be mechanically weaker to load bearing but as far as cumulative effects such as wear and stress failure, the parts would be identical, as those effects are regulated by material composition not part geometry. I say the longer arm in your post is weaker if materials are the same,the moment exerted at the hingepin is going to be greater and thus be subject to a greater force. Think of it this way, your swing-arm is basically a lever with is fulcrum at the hingepin and in the case of your example the arms look to have about the same amount of material around the hingepin so I would say load bearing would also be the same. the longer arm has to support a greater load. From what I can see the larger parts are actually structurally equal or deficient but not superior in every case. some of the parts i'm not sure which is which.

[Sixtysixdeuce]

some of the parts i'm not sure which is which.

If you can't tell 1/10 parts from 1/8, I don't think you have any business lecturing us on the durability of either.

[Blacktiger355]

I have a Mugen MBX5 I converted to an SCT. Runs very well and is a pure tank as far as durability.

[Kyoshojoe]

As I stated before. I apologize for ofending and was not intending this hijack this thread and make it a knowledge pissing contest. I tried to post respectfully while presenting a differing opinion that I back up with specific examples. You have responded by throwing cheap insults at me

If you can't tell 1/10 parts from 1/8, I don't think you have any business lecturing us on the durability of either.

I was trying to make the point that the parts are very close in size and that from the view I have there is no difference in beefy it looks only marginally larger in some cases.
I cannont appologize enough for you taking offense to my post. Please refrain from insults and prove your points with evidence such as strenght testing. Also make sure the comparison is marginally similar. comparing strength of an alloy hub to a cheap rtr plastic one is just stupid. I presented you with a rebuttal supported by specifics and facts while you respond with a dig at my credibility. I actually have 25plus years working professionally on 1/1 vehicles doing fabrication and coustomization. since I was born I have had a screwdriver in my hand and I rarely take the easy road. you mounted a body on a car and call it a conversion yet it doesnt meet any of the criteria the rest of us use when refering to a sct.

I have a Mugen MBX5 I converted to an SCT. Runs very well and is a pure tank as far as durability.

Thank for your response. I was hoping peeps would chime in. I have a rustler that is a tank as far as durability. Tank is also how I would describe its handling. How about your mugen. Its a top notch car. How does it handle compared to a true sct. Id like to see how you converted the wheels as thats the big hurdle when converting. As a side note I use ROAR rules as a guideline when talking about sct parameters and one of the rules expressly prohibits dish wheels. the fact that just bolting on sc wheels will not work due to wrong offsets andwheel hex size makes the conversion near imposible to make a legal sct. I will be strarting another thread to debate this issue as this is not the proper thread for it.

I have my sct conversion posted in the kyosho forum where I stretched a 4x4 buggy and made it legal. I bet it would win in a head on with your Tamiya toy. but i really probably only have to worry about getting rear ended exept When I lap it. ya its fast nimble and can turn on a dime.

[Sixtysixdeuce]

I have a Mugen MBX5 I converted to an SCT.

Electric, I presume? Did you retain buggy wheels? I have seen quite a few people go to 1/8 SCT wheels, but it looks a little disproportionate, IMO.

[Blacktiger355]

Currently it still has standard 1/8 scale buggy rims/tires. Butt here is what most people use that try to stay roar legal.

http://www.amain.com/product_info.php/cPath/1_26_2353_1253/products_id/208711/n/DE-Racing-Trinidad-SC-Front-Rear-17mm-SC-Wheels-Yellow-2-SC8


Parts used for the conversion were:
-Mbx6 eco motor mount.
-Associated RC8 battery/ESC tray and radio box.
-RPM Losi SCTE bumpers.
-Traxxas Slash front bumper mount.
-Losi SCTE body mounts.

I was able to get everything to fit without drilling any holes in the chassis as well.

This was taken before the SCTE body mounts were mounted.


And with an HPI Blitz body.

[Sixtysixdeuce]

Well, the program card for the Turnigy ESC showed up today, and the verdict is in. While turning it up improved performance, it is still lacking, so I swapped in a Hobbywing SC8WP. Made a world of difference, and the truck is plenty quick for tighter tracks on only 3S now (pretty low top speed on 2S, though still decent punch). On 4S, it's an animal. No complaints on the Turnigy Trackstar 2100 KV motor, but I'll never buy another of their ESCs. I didn't have real high expectations, but I could find no reviews on this particular ESC, so I figured I'd give it a shot on the chance it turned out to be one of those low cost gems like the HW stuff.

In summary, the Turnigy trackstar 120A WP ESC is:

-Excessively coggy
-Lacking punch
-Unable to crank out the top speed that the HW can
-Large
-Not very tunable, even with the program card.

So Turnigy motors & batteries get the green light from me, but not their speed controllers.