Brushless Baja Build

[Ninetiesbeard]

Okay, what with lockdown boredom setting in i thought id post a little thread about my hpi baja build. Its an ongoing project that gets worked on a lot more than ran, and has been through many transformations and iterations. Originally it was supposed to be a cheap 1/5th scale for me to experiment with, having only used and ran 1/8th and under for many years before. I managed to find a good cheap one on ebay, and the feller dropped it off the next week for me. It was big, heavy and pretty loud. 

 

 

Here it is next to a traxxas nitro sport that i had at the time. Youll have to excuse the odd photo formatting, these are all stolen from my instagram. It had an integy type 2 cage with custom acrylic panels, area rc hex extensions, integy shocks, and an irc chassis. This coupled with a kingmotor 30.5 engine made for a good cheap baja build, it didnt really have anything wrong with it, but i started throwing parts at it from my want to modify things.

 

Here i added some hostile nightmare copies, and a vrc bigbore rear exit exhaust. About 10x as loud, and about twice as much power.

 

 

Next i found a good cheap sx5 cage, again from ebay. Coupled with some spiky wheel nuts, it looked great i thought. Shame whoever painted it had used the wrong paint, and it was flaking. I did try to remove the paint with brake fluid as i had seen done before, but ended up weakening the panels. The cage sits in my loft, externally painted satin black, probably never to be used again as ive misplaced the mounting brackets.

 

Then a few more upgrades like an air filter, velocity stack, a side mount exhaust and a zenoah G320 for a bit more power. This combo was really powerful and shrieked like a banshee on full throttle. Properly loud, way too loud for residential parks where i usually bash. Shocked nobody called the police to be honest, dont know how guys get away running the 40+cc unsilenced but thats none of my business😁

 

Then we fire up the parts cannon once again, with some fancy steering rods, silverback wheels and beadlocks, gh roof scoop, turtle transmission case, scorpion shorty kit, uber bumpers and more. This was by far the most fun id had with this buggy at this point. The shortness makes it so much more nimble and playful, almost needing less power to do the same thing. I think its the weight lost from the conversion doing that.

 

 

Hostile hubs, and turtle shock braces added. At this point its looking more like a show vehicle than a runner, which is awful. Really need to use it more.

 

It did look great though.

 

Managed to get a proline body to fit that a friend gave me, and also source some spiky wing pegs that i like.

 

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And then took it apart again to add more parts. I think its buying stuff from ebay "because i might need it" at some point if its cheap enough. Really need to turn off those saved searches. ALX godzilla dogbones added, along with a turtle clutch case and some other stuff.

 

Chopped the photo pretty badly, but you get the idea. This was about when i figured out the layshaft was bent, as the robinson steel spur and hostile pinion would not mesh correctly for the whole 360 degrees of rotation. There was a high spot. Both of those gears are wayy too hard to file, so back to the drawing board with the 19/55 combo. This engine really needed that too. Sidenote, those red arrow beadlocks are beautiful, glad i found those.

 

Work on the big car subsided for a long time to make room for this beast. Cant have too many projects going at the same time due to my ADHD, makes it difficult to concentrate on even one, lol. This savage ate a lot of my time, its not finished yet either but out of all of my rc cars, i think its the closest to being called "done".

 

Then i decided to convert the baja to brushless. It gained a full set of rpm arms and an irc backplate (with a nice crack) during this time. I havent made as much progress as id like to at this point, it probably sat exactly as it was in that photo until today, six months+ later...

 

These are from today. I managed to nail the technique for chemically de-anodising parts which i had managed to score in odd colours. I think there were 5-6 different tints on this before i got busy with the oven cleaner. Yikes. Looks great now though, I added integy front hubs (wanted GH but too rare) And a fullforce rc front shock tower; Which is probably the nicest quality part on the whole build. The integy shocks also got stripped and look a lot better for it, i didnt do a 100% job of that but its good enough. Ive got a max5 esc, and a surpass motor waiting to go in this buggy, but i am having doubts about power. Because ive added so much weight in the rear end by bomb-proofing it, i think itll need more power. Im still going to run what ive got, and see how it goes. Maybe i need to get an MGM combo for it, but my wallet currently doesnt run that deep, lol. I bought a speed passion baja brushless conversion mount, but it doesnt fit the motor. It goes up to a maximum of 50mm diameter, and the surpass is 56. The length also needs shimming to work. I will make a small spacer for the mount, and some cross braces of my own to make it work, but first ill be stripping the ghastly orange anodizing off of it and giving it a bit of a polish. Hopefully then i can fit the motor, sort the gearing, get the mechanical brake sorted out and buy some batteries. I did buy some tooling and a large piece of aluminium sheet stock to CNC machine my own mount, but the cad and everything will take wayy too long with me being just a beginner. Nothing to say i cant revisit at a later date.

 

Anywho, thats all folks, for now. Im now waiting for my shift pattern to change again, and when it does ill be stripping more parts, and working out if the mount i want to make will work. Would be handy if i had access to serious machinery, but for now its all hand work. Hope you enjoyed the post, i will update when i have more photos/news.

Thanks for reading, stay safe all.

NB.

[Ninetiesbeard]

Todays work consisted of more de-anodizing of aluminium components, fitting of previously ordered parts and a test fit of the motor mount. I have lost a brace for the chassis/engine so im debating on making one or trying to order one. Its only small, but i had to work some aluminium today which has left me not wanting to do that again for a while, lol. I had to file the locating lugs off of the turtle clutch case to use it with this motor mount system, as it locates on a flat face. Its a bit sacrilegious, but doesnt affect its functionality if i went back to petrol. The rear chassis plate is bent i think, nothing seems to want to line up easily. It can be forced in, which i think i will when im ready to final fix it. The aluminium round stock i ordered for the motor mount cross braces didnt turn up before i left work  yesterday which means i have to wait until next time i am off in 8 days. Rats. Otherwise the buggy is starting to take on a nice form, ill drop a few photos here below.

 

[Ninetiesbeard]

So today i set about making the mounting plate adapter to join the surpass motor to the speed passion mount. I used some random aluminium stock i had, which i believe to be quite old and a pretty nice alloy. I had to do all of the work by hand as i dont have a lathe, so it took around 6 hours to complete. I used some old stock 4BA fasteners to fix the mount to the plate, and then some metric bolts to fix that plate to the motor. It was an interesting experience, the motor is a very tight fit on the chassis. Next i need to either buy or make that left engine mount to continue with the build. I also need to bore out the shaft to pinion adapter which came with the kit; im pretty worried about that. It must be concentric, otherwise it wont survive 36000 rpm from that motor.

 

[Ninetiesbeard]

An update;

Made the drive adapter sleeve thing, it fits pretty well. Made the motor mount cross braces and they work as well. The whole assembly is very rigid now and im not worried at all about anything failing or falling apart. I havent threadlocked anything yet, i need to check it works first. Plus the only thread locker i have is very strong. The motor is final fitted, with approximately 1mm of clearance behind, the TP motor in the mail *should* be the same size, if it isnt then ill have to work that out. I got some bonehead rc carbon engine mounts which are super sweet, i think ill get some more carbon parts from him. The drivetrain had an issue where it seemed to be binding on things, after taking a look i noticed whenever i torque the brake mount down it bends something and binds everything up. I just added some m5 washers and the whole problem is fixed. This is close to finished now, just need to get the back slicks in the mail, get a body which will probably be a grafil evo, and make sure the gens ace lipos ive got will work properly. The brakes need doing, the esc needs mounting, and i also need to figure out how to fix the batteries down. Thanks for reading, heres some photos;

 

[Tug]

Is that the original clutch housing from the gas engine?

[Ninetiesbeard]

On 16/05/2020 at 07:26, Tug said:

Is that the original clutch housing from the gas engine?

Wow sorry mate didnt see this. Yes, its the turtle v2 one. It bolted up to this kit with a little bit of filing to the back side, just removal of the locating lugs.

[Ninetiesbeard]

So ive done a lot of work since i last added to this thread. ive added a hostile plastic spur as its a bit harder than stock, and also added a full set of brp slicks. The bodyshell (grafil evo) is in the mail and my TP motor is on back order. Ive been through and threadlocked a bunch of bolts but not all of them so that still needs to be done. I also need to figure out a way of holding the batteries down and also the manual braking system. I have tested the car on 8s, and it seems to be a lot faster than i thought. Maybe that is because of the size of it, or maybe i just got used to the petrol baja. I also changed the connectors to xt90s, for fear of botching the soldering of ec5s on the batteries. As these gens ace packs come with xt90s and are readily available, it would be silly not to go xt. Heres some photos;

 

[Ninetiesbeard]

Okay a few more things have happened. I have tested the rig twice so far, second being the first offroad test. I got about 5 minutes in before i could hear some sort of suspect clicking sound so i stopped there and went back home, luckily its a 5 minute walk. I think the grub screw on the motor-pinion adaptor has come loose but havent investigated yet. The battery tray was made, and took around 11 hours to complete. Its heavy, i think ill do something from carbon fibre in future. It does however work, and its very quick indeed. Perhaps not as much top end as i thought, but the new motor (if i ever get it) should cure that being slightly higher kv. Overall im pretty impressed, now i need to get a full pack run with it to see how long they last, i estimate about 15 minutes from what ive seen so far. Then i need to get the slicks back on for some speed testing. I ordered some 0 degree big bearing rear hubs and some Skf bearings so once those are fitted i can do a bit more onroad testing. Anywho heres some pictures

[Acidsnow]

Very nice work Ninetiesbeard, can't beat shed brewed bits! 

[Ninetiesbeard]

10 hours ago, Acidsnow said:

Very nice work Ninetiesbeard, can't beat shed brewed bits! 

Hack saw, files and squares!

[Fruitbat]

Nice build , I’m converting my baja to a brushless system soon .

[Brumboy]

Enjoyed reading, I’m planning on building a brushless baja soon, thanks for sharing