Bored and cheap, and wanna go offroad!

[valk]

decided i wanted a toy to play with between race days.. sure, my tc will work on the street, but speed weekend demonstrated how delicate it can be.. pancars no good, nitro car.. WAY too expensive.

so, no one wanted my ntc3's big lot.. cant say i blame them nor am i particularly upset. $200 in for three complete cars, one of which had pretty much all the expensive hopups and im sure if i cared, i could part the cars out but thats entirely too much work.
I wanted a toy, something i could play with on the street and not care too terribly much about. I also wanted something i could take off the road, maybe run on the cor track on practice days, without spending any more money on the hobby this year.

nitro isn't particularly appreciated by all the rich new homeowners on my street, so I converted one of the cars to electric for $20. low cost, low precision and very minimal time investment. a couple hours to cut out the motor mount, make some lipo blocks and a lipo top holder.





the more time consuming part was probably modifying the two speed to use standard gears. this isn't required for the car to work, but the stock gears were too small to get the right ratio with the pinions that were available. also, the motor tucks really tight to the center bulkhead. One day, if i like the car and it performs ok, i might spend more time to make a proper center bulkhead/motor mount, and pick up a tc3/4 spur adapter and input shaft.



first impressions? it moves!. actually better than expected.. Ive had a few hicups with the servo and rear camber links being aluminum, but the gear mesh hasn't had a single problem, and im surprised the offroad i've done with it hasn't killed the 64p test gear. not a single stone.
unfortunately, the 8 turn motor is a little too hot for soft rally tires on the street ha. not even a minute and the pins were worn down to tiny nubs. that' my bad though.
I haven't been very careful with it ha. its met the curb in drifts, rolled off the sidewalk and hit some poles. pretty glad its a nitro convert as im sure many touring cars would have broken some stuff by now.

ah well. ghetto project, im sure i could "Just buy an offroad" but spent enough this year. if any more money leaves my wallet, its for the 1/1 car =)

[Muddy Mudskipper]

very cool to finally see it. The battery hold down does look like a foot. I can't wait to see it in action on some trails.

[valk]

The foot shape wasnt planned, just worked out that way when i figured out how hard the alu chassis was to drill through. Ha.

[gotnitro]

you do no aluminum is a soft metal.lol sounds like you need new drill bits. but looks like it will blow up good

[valk]

7075 is pretty hard without the right bits but i didnt have proper metal bits your right. I had more ellegent plans but this got it working =)

[valk]

so it is no surprise that round 1 was somewhat less successful than i had hoped, but i knew going in that it wouldn't last so no delusions of grand success. first shot out i tried to take the double which was pretty stupid not knowing how to fly a car. bounced off the peak of the second jump and dislodged my motor mesh.
no biggie. fixed and went back out. car got around the track quite well otherwise, was able to handle the infield jumps and handled well around the bumpy track. bumps unfortunately, murdered all my acrylic battery holders and i had to resort to fiber tape to hold the pack in place for the rest of the run. with the battery held in this way, i was able to get a little ballzier on the main jumps and it could clear them, but i still pussed out and just did a little bunny hop down the front straight on each jump ha.

so, having had the day at the track, I'm starting work on the more comprehensive conversion. I want to point out that all aspects of the car itself survived the offroad expose and worked without incident. the parts that failed were the ones i made, quickly lol. enough for the street, but definitely not enough for extended bumpy abuse.

this weekend i built a new motor mount/dif casing to carry a central dif. right now I'm just using a ball dif but i can paste it up with very thick grease to limit the dif action. discovered this while taking one of the difs included in my team magic car. he used a grease so thick it was almost a putty which limited the dif action.
ill experiment with the dif composition later, but for now this allows me to use standard touring car 6 hole spur gears in the balldif. i can remove the balls if its too much and just use slipper pads if need be.

This new motor mount is made out of cutting board plastic. very cheap at industrial and easy to machine. the plastic itself was either cut on a table saw with veneer blade, bandsaw with a much more aggressive than veneer blade, and high speed router with a flush cut bearing bit.
I made the three sections out of mdf to assure compatibility with the motor, differential and bearing set and test fit in car. was just a simple matter of tracing it onto the plastic using the high speed router and drillpress.







still have to make a battery retainer out of this plastic. the hope is that it will be as rigid as the acrylic without shattering on impacts.

[weekend camper]

thats a cool addition.

[Aravan]

Looking good!

[valk]

cut some battery strips today and got everything bolted securely to the chassis. one of the battery blocks doubles as a servo mount, as moving the servo to the other side, and it being so close to the main shaft prevented the use of a second actual servo mount.

took it out for a burn and it all works! the center dif is actually pretty awesome for a touring car. the car has so much on power steering its kind of rediculous on the slower corners and its very stable at high speed with the steering. you can slow down and start turning and hold the throttle through the whole corner, car just keeps turning.
I actually kind of miss the full time 4wd as i cant get the car to drift on the road now lol. just has too much traction and pushes like a sob when the boost kicks in.

swapped out my 7.5 brushless setup as my brushed esc doesnt have a reverse function, which ill need on the cor track.

i did run into a small issue with the dif though. setting gearmesh with the fully enclosed housing is a real pain, having the remove the whole casing and take the back plate off. i might revis it with a new backplate with either holes to access the motor mount screws, or a removable back cover to access them. its pretty hard to set the mesh with the backplate off as the dif will move a little when its all assembled and installed on the chassis. going down to 48p will help here, or i can try 32p even if the ratios line up.
long story short, ripping around the street full throttle, i mangled a spur pretty good. has some chunks missing and something ive never seen, the difballs pushed themselves out to the next set of holes outward lol. that must have been a massive fail inside to cause that. of course, i didnt assemble the dif with any due care. just wanted to see if the thing worked.

[Tom]

long story short, ripping around the street full throttle, i mangled a spur pretty good. has some chunks missing and something ive never seen, the difballs pushed themselves out to the next set of holes outward lol. that must have been a massive fail inside to cause that. of course, i didnt assemble the dif with any due care. just wanted to see if the thing worked.

Diff was too loose and was slipping.

[valk]

all things considered, tonight went pretty well for the rally car.

i was in a pretty big rush to get it all back together and have dinner before ripping out there so i missed a few things that i had to run off the stand to fix. first of all, lost the cotter pin for the front diff input shaft and it was just freewheeling in the housing. cut a body clip to make a replacement and got back on the track.
had issues with the motor moving due to the wrong washer use. sorted that and raced it in the main.
ill have to address the servo saver backing out as it will loosten with bumps and then i have no steering.

nothing broken though. next week im sure there will be other mods to help it out. ill also have to mess with the center dif. put some putty in it or somthing very viscous to slow the dif action down. letting off the throttle causes the car to oversteer quite a lot, but on the throttle it tracks straight and true and doesnt get upset too much by the terrain.