My 5lb 1/8 E-Buggy (Kyosho DBX8e) - RC-Monster Forums

jsr · **My 5lb 1/8 E-Buggy (Kyosho DBX8e) -** 01.24.2010, 11:00 PM

One of my favorite vehicles since I got it was my Kyosho DBX. I converted to brushless and loved its performance, especially considering I could use 1/10-scale electronics and it could still keep up with 1/8 buggies. For a while now, I kept staring at it thinking "it's only 20mm or so shorter in wheelbase than a 1/8 buggy...I could make this a full 1/8 buggy ultralight". So I drew up a new chassis in CAD, but never made it due to lack of interest and it being too costly to make a one-off. Then I thought, I'll just pick up a 1/8 chassis and drill the living hell out of it to make things fit. That idea took a whole 6+ months to finally complete, which is the end results I have today (after a good 4+ hours in my garage...ay, I'm tired!).

So here's my Kyosho DBX8e extended 27mm in wheelbase for a total wheelbase of 327mm (same as a pretty long 1/8 buggy). It weighs in the realm of 5lbs with everything (I'll weigh it at a scale hopefully soon). I run a HW EZRun 60A ESC (external UBEC) with a Medusa 3300kV motor on 3s (2s for small tracks and testing). Currently it's geared for about 40mph on 3s (perfect at Revelations). It's never gotten hot on me except for the one time 3 of my 4 wheel bearings seized up. The donor chassis a Hot Bodies D8 4mm 7075 chassis.
It's been very durable, even at 40mph...had some horrid crashes and do fine as long as I don't hit the wheel dead on when I nose dive down...which will sometimes break an arm. The only other thing I've broken is a rear bulkhead because of 2-days straight of landing directly on the wing (yes, I'm a bad driver).
Finally, I got my DBXe to what I wanted it to be. Can't wait to get some time to hit up Rev for some on-track testing.

In the pics, I tried to show the wheelbase and the stock chassis next to the extended one.

01.25.2010, 05:14 PM

Nice. I thought about something similar with a Hyper 10SC truck

thzero · 01.25.2010, 05:44 PM

Cool... :)

Um, btw, a Hyper 10 SC has a longer wheelbase than most 1/8th scale buggies.

Quote:

Originally Posted by (:DK

Nice. I thought about something similar with a Hyper 10SC truck

magman · 01.25.2010, 05:54 PM

Cool..I love homemade projects like this one..well done

jsr · 01.26.2010, 01:37 AM

Thanks guys. My favorite thing about this setup is that it's so light I can use 1/10 electronics which have thus far been more reliable and cost considerably less than 1/8 brushless setups without any loss in speed or power.
A 4x4 SC would definitely be a nice base for a 1/8 buggy conversion too...the same principle and advantages as the DBX8e...same size as a 1/8 buggy with half the weight.

01.26.2010, 02:48 PM

Quote:

Originally Posted by jsr

Thanks guys. My favorite thing about this setup is that it's so light I can use 1/10 electronics which have thus far been more reliable and cost considerably less than 1/8 brushless setups without any loss in speed or power.
A 4x4 SC would definitely be a nice base for a 1/8 buggy conversion too...the same principle and advantages as the DBX8e...same size as a 1/8 buggy with half the weight.

Yep that was excatly what i thought. but the wheelbase is just "short" enough for a 1/8 buggy

nativepaul · 05:06 PM

That's seriously impressive, I tried to do a similar thing but from the other side here, taking a standard 1/8th buggy and doing all I could to lighten it but while I shaved a couple of pounds off, it only came down to 6lb 7.4oz,

after seeing yours with its 3mm turnbuckles and anorexic arms I'm thinking I started from the wrong place, although it has given me ideas on how I can improve mine, thinner turnbuckles on the steering and rear upper links would be easy enough. What servo are you using? I have a 66g/2.3oz Ace 1015 standard size servo in there at the moment, I have a Hitec 5245MG digital mini servo at 32g/1.2oz that I could put in but I am unsure as to whether a mini servo is up to the job. After that it's either start whittling on my arms or switch to a 1/10th set up, I have a 1509/1.5d 4500kv and 2s 5000mAh packs I could use but I think with 2s its going to pull huge amps to get good speed and I wouldn't be able to downgrade to my from a MMM to the MM.

scarletboa · 07:32 PM

Quote:

Originally Posted by nativepaul

That's seriously impressive, I tried to do a similar thing but from the other side here, taking a standard 1/8th buggy and doing all I could to lighten it but while I shaved a couple of pounds off, it only came down to 6lb 7.4oz,

after seeing yours with its 3mm turnbuckles and anorexic arms I'm thinking I started from the wrong place, although it has given me ideas on how I can improve mine, thinner turnbuckles on the steering and rear upper links would be easy enough. What servo are you using? I have a 66g/2.3oz Ace 1015 standard size servo in there at the moment, I have a Hitec 5245MG digital mini servo at 32g/1.2oz that I could put in but I am unsure as to whether a mini servo is up to the job. After that it's either start whittling on my arms or switch to a 1/10th set up, I have a 1509/1.5d 4500kv and 2s 5000mAh packs I could use but I think with 2s its going to pull huge amps to get good speed and I wouldn't be able to downgrade to my from a MMM to the MM.

you could switch to plastic body shocks to lighten it some more. you would be surprised how much less some plastic body shocks can weigh compared to alloy. also, switching the battery's wires to 12awg and shortening them as much as possible while still keeping a little slack will help.

magman · 01.26.2010, 03:22 PM

What are you going to use for a body?

magman · 03:28 PM

I actually made my own chassis for my crt.5 and it is close to 1/8 length.

I am considering adding the wheel adapters to run 1/8 wheels with this. The nose dives you spoke of in your first post is exactly why I have the front bumper. The plastic on this tuck is not all that strong...I have broken 3 front arms so far.

jsr · 01.26.2010, 10:34 PM

I'm looking for a new body currently. I'd like a VE8 body, so if anyone has a stock body for sale, I'd be interested. For now, I'm going to run the stock body modified to fit.

Magman - I'd really like to make my own and a rough design drawn up, but one-off cost would be too much and I don't have my own machining facility or equipment. All the modifications I did to the D8 chassis was with a hand-drill and dremel in my garage. I have some scars from that. You'll be amazed how dramatic the handling difference is switching to 1/8 buggy wheels/tires. The plastic's not bad on the DBX. If I hit directly on the front, everything's fine. It's when I land a bit off directly on the wheel. If I were to design and make a new extended chassis, I have several things in mind that would strengthen a couple of the weaker spots and likely not break any more arms (or make it more of a rarity).

nativepaul - that's some beautiful use of CF. I know someone who can make me a CF chassis, but I question the overall durability of a CF chassis considering my poor driving skills. While the turnbuckles, arms, and driveshafts look thin, they're not that weak. The arms break at the hinge pin, but that's because there's no support behind them. They don't break anywhere else. And no problems with the turnbuckles or driveshafts. Because it's lighter weight, there's less force in a crash, so smaller components aren't necessarily a bad thing...it just has to be matched to the application.
For a servo, I use the stock Kyosho digital servo and it does fine. It has enough torque to turn the wheels easily. It's not the fastest responding, but it does the job for now.

I may ask my friend what the cost would be for a CF chassis just to see if it's lower cost than a one-off 7075T6 chassis I had planned. The D8 chassis is a proof-of-concept. Can't wait to test it at the track.

jsr · 01.27.2010, 10:37 PM

I got it on a scale today...

5lbs 2oz!!! in ready to run form (3s 3000mAh battery...this actually runs for quite a while because it consumes so little current).

I'm really pleased with the weight.

Overdriven · 01.27.2010, 11:36 PM

Thats a very cool project, nicely done. But you'd be suprised what you can do with basic tools and some time. With a hacksaw, a file, dremel, and a drill you could make your own chassis. Thats all I needed to extend my Revo to baja 5T size. Either way, enjoy the tinkering!

jsr · 01.28.2010, 12:54 AM

Yeah, I did that with my hand drill and dremel. It turned out pretty well, but I really want to make a CNC'd chassis. I had a CAD drawing done up, but the cost for a single chassis was too high. I also have someone that can make me a CF one, but again, it will probably cost too much.
While I think a 5lb 1/8 buggy is a great idea, most people probably won't do it because it doesn't fall within ROAR rules (it's too light) so you wouldn't be able to run in ROAR events or at club level races that are sticklers to ROAR rules.
But I think the lower initial and running cost in both batteries and electronics due to the considerably lower weight is great.