My First E-Dune Runner

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Here it is:

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Thanks, I wasn't sure that was coming across in the picture. The bumper is also notched so the bridge recessing into it. The bridge sits flush w/ the rest of the bumper.
 
Today I made a wheel nut. I was always nervous at the track that I'd loose a wheel nut and my day would be over b/c I didn't have an extra (like I do w/ my other cars). With the tap I bought I made a hardy aluminum wheel nut. It's about twice as thick as the stock one. That'll allow for more threadlock to be used ;)

Next I need to tear in the diffs. The car doesn't rotate well at all, so I'm going to put some lighter oil in the diffs.
 
Starting to figure this thing out

I took the DR to the track today and got through two sets of batteries, i.e. 50mins of runtime, with no broken parts. The rpm bumper is worth every penny! I cartwheeled the DR several times and in that past something would have broken; the bumper took all the impact w/ ease. Aside from the bumper, I also made the suspension arm tabs/braces for the rear arms as well. I'm starting to feel like I'm getting ahead of the weak points and can start to count on the reliability of the DR. I also changed to a 2s lipo for the steering: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=20422 It may look a bit on the small side but it gives about 40mins of usage. It's a good battery and you can charge it in under 10mins. Also, I"m still running the turnigy servo. It's been a good value. My Savox was returned and I've not received any info one when I'll it back. I'm probably done w/ Savox.

I've not mentioned the belt drive for a bit b/c I wanted to get significant runtime on it. I'm happy to remote I've had no issues w/ it and the belt is staying together. It's a keeper.

I'm going to give 14s a try. After about 20mins of runtime on 12s the cells get to about 3.7v each and the punch goes away. Also the cells start to stress out and voltages fluctuate too much. With 14s I'm going to turn down my throttle endpoint by 20% in hopes to keep the punch throughout the full runtime and increase the runtime to >30mins.
 
Shout out to hobbyking. I returned two of those lipos and they refunded me even though their warranty statement says 'forget about it'. But they don't refund shipping..oh well.

Then I scored a handful of 5A packs for a great price. I'm going to wire them up in parallel to make 10A packs. I'm hoping it gets me over 30 mins of runtime.

I'll still consider 14s as well, but I'm running out of space for batteries :) I'd like to gear down if I do run 14s. I just need to figure out if I have the right pulleys and belts to do it.
 
Making the mods to support 14s, 10A i.e. 11k watts :) This didn't require the mill but I did have to get out the sewing machine!

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RCDAD said:
You could punch a bunch of holes in that L-channel. :D
Click to expand...
Sure thing; take out a few grams to go faster in my soon to be 40lbs car ;) I think the shocks are going to be the next upgrade to handle the weight. To be honest that just crossed my mind. Yikes, I hope this thing stays together.
 
I took the DR out for a little test run. I installed a 9500 rpm clutch spring b/c I read (and have read long ago) that brushless motors are most efficient at 75% of the max rmp. Well it didn't make much difference over the 8k spring. But the car and belt drive stayed together for another 30 mins of running.

The next major mod is going to be the 14s fitment. The ESC and batteries are going to have to be situated differently. The goal is to keep the wires as short as possible and fit the batteries.
 
I managed to just about complete the 14s conversion. I was a soldering fool, I tell ya. You can see from the pictures I had to rotate the esc up to get more room for the batteries. This increases the airflow to the esc and motor. There are additional batteries in the back which will help w/ the balance of the buggy too. This is the set up w/ 14s 10A, there are 28 5000mah cells in there. I need to weigh it but I don't think I actually gained that much more weight. I also switched to velcro straps b/c I needed to accommodate varying sizes between 8A and 10A packs. The straps will also quicken battery removal which now requires me to take off the roll cage. I need to come up w/ a quick disconnect for the cage. The other item is the brake linkage needs to be relocated by 180 degrees and run between the packs. Any and all ideas are welcomed.

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I agree but they don't make 10A 6S packs or at least ones I can afford. Also This might be one of just a few e-1/5 that are getting 30+ mins or runtime on a single charge.

Maybe a long term project would be to relocate the servo tower and get all the packs to lay flat in the chassis. It sure would look better.
 
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Since the drivetrain is progressing nicely I took a break from it to do some tuning. I first started on the rear shocks. They desperately needed new oil.

I couldn't get the top cap off so I emptied the shocks from the bottom and mud soup came out. I cleaned them out and loaded them w/ 40w losi oil. I realized how difficult it was to get the air out from the bottom cartridge. I needed to get the top off so I could get the air out. So I milled some flats on the tube to put a wrench on it. I took .050" off two sides and it worked like a charm:

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When I was putting the bottom cartridge back in I noticed the rubber o-ring would not go in nicely. It would get pinched. So I milled a better bevel for it to slide in. This worked great too:

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The shocks work better now but I noticed they have too much pack. After a track session I'll probably open up some of the holes in the pistons for less pack and get the rear-end to react quicker. It's much too slow and bucks the car around.

I'll do the same mods to the front shocks.
 
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