eDunerunner

[electro21]

Greetings,


I just started the conversion. I got it Friday, stripped it, and now it is at my local machine shop. He said it will be about 2 weeks before he can get started (2 driveshafts and a motor mount). As soon as he gets started and I get the DR back I'll start posting pics. I'm using the spur gear with drive cups from the XB-E, and placing them in the center of the chassis, so I can have 2 equal length driveshafts. Then the motor will more than likely be mounted at an angle since there won't be room to mount it directly next to the spur gear. I'm selling the engine w/ manifold and pipe, transmission (still attached to engine), radio, receiver, receiver box, center driveshafts, and center driveshaft coupling for $300. PM me if you are interested.

 

[mulepic]

What motor, esc, and batteries do you plan on running?

 

[electro21]

What motor, esc, and batteries do you plan on running?

I was thinking either castle xl2 w/ the 2028 or SkyRC's Toro 200A ESC with the Beast X528. Gens ace LIPO Battery 5000mAh 60-120C 14.8V (x2). I was going to start with a final drive ratio of 12.3 (41T spur, 10T pinion, 3.0 diff ratio) and then go to 13.67 (9T pinion) if the 12.3 is too much for the BL system.

 

[mulepic]

Will you be running 4s/10A or 8s/5A? Will you be running mod 1 gears?

 

[electro21]

I'll be running 8s and mod 1 gears. More than likely I'm going to order the motor this week, so the machine shop can take his measurements for the motor mount. I'm going to wait and order the ESC and batteries once the driveshafts and motor mount are in place. According to my initial calculations. I should be able to place the batteries in the back where the engine used to be. I'm having the machine shop trim off a little of the chassis on the left side (opposite the transmission) to provide just as much room as the right side. This way both batteries can be placed in the chassis without modification or getting in the way of the driveshafts. I actually enjoyed watching and reading your build. Part of my motivation to do mine came from yours.

 

[mulepic]

Let's take another look at your gearing. A mod 1 9t pinion only measures 11mm in diameter total. The 2028 uses a 8mm shaft. There will be very little material to handle the stress. I have shattered a 8t mod 1 pinion w/ a castle 1410. If you are going to use a pinion/spur combination maybe take a look at the 5ive or 1/5 cars w/ large metal spurs.

My 14sx400kv and your 8sx700kv will run about the same RPMs. So your ratio of 13:1 is pretty good. But these days I'm actually running much lower to get longer runtimes when I'm on the track. I'll try to get the ratio for you later today.

Your setup will be running at least twice the amps as mine. I'm run just under 75A I'm sure you'll be 150A or more. If you can keep the mechanical brake that would certainly help, and find an esc that has a setting that can control your startup power to minimize amps.

I'm excited to see how this turns out, it's more of the traditional e-conversion that could work out very well and more simply than mine.

 

[electro21]

I'm using the spur gear off of the XB-E. I was thinking that the motor driving a spur and pinion would be more efficient than using the standard DR transmission, since there are just less gears moving. I guess we'll find out soon enough. The mechanical brake is gone, and i was definitely considering about limiting startup power, or just not pegging the throttle. Kershaw Designs makes mod 1.5 gears, and they have a standard 8mm bore. The smallest he sells is an 8T, so with the 41T spur I can go as low as 15.375. With 7075rc's 48T spur, I can get down to an 18. I'll order the 10T pinion when I order the motor, so I can make sure they'll actually touch, when we design the motor mount. I'll be going back to the machine shop later this week, so I'll take a pic or two of the chassis and post where the cuts will be. He is making a more stable mount for the spur gear too, as well as cutting a hole in the chassis so the spur won't rub the chassis. I'm going to have a spur gear cover on the bottom of the chassis to protect from debris underneath. I'm going to run a receiver pack to power the steering along with a fail safe (receiver pack died in my custom 1/5th E-maxx, which hit a fence full speed and caused ~$300 in damage). Don't plan on repeating that incident. The only downside is that I'm at the mercy of the machine shop, and have to wait for him to make my stuff between the jobs that actually pay his bills. If you gear too low (down to the 18 FDR), will that cause a spike in amps, or put more stress on the motor or ESC?

 

[mulepic]

Just so we are on the same page, mod 1 and 1.5 are different pitch. Stick w/ mod 1.5 for sure. I just checked my fdr. The highest I run is 13.6:1 and the lowest is 18:1. I much prefer the 18:1 as everything runs much cooler; batteries, motor, and esc. I run a separate receiver/steering pack as well.

Can you post a link to the 8t pinion and 48t spur?

 

[electro21]

Yeah I know they are different, and I thought it was mod 1 that i was gonna be using, but when you mentioned that there wouldn't be much material left to handle the stress, I looked up the part again, b/c i remember their being plenty of material on the pinion.

Pinion

Spur

What capacity are your packs and how much runtime are you getting w/ the 13.6 and the 18? Have you ran your DR on 8s?

 

[Guest]

I'm look'n forward to following you build.

 

[electro21]

Thanks. Does anyone have any experience with the SkyRC 1/5th scale ESC and motor?

 

[mulepic]

Yeah I know they are different, and I thought it was mod 1 that i was gonna be using, but when you mentioned that there wouldn't be much material left to handle the stress, I looked up the part again, b/c i remember their being plenty of material on the pinion.Pinion

Spur

What capacity are your packs and how much runtime are you getting w/ the 13.6 and the 18? Have you ran your DR on 8s?

It doesn't say but I'm almost positive that 7075 spur is mod 1 (isn't that what the X series redcats use). But you have me thinking so I'm looking around for mod 1.5 spurs. I think the 5ive is 1.5 mod, but still checking.

I've never run on 8s b/c I bulk charge my packs at 50V so 12s is my min. On 14s/10A packs w/ 13.6 I can get 28mins of runtime. I just installed my belt drive again which will put me at 18:1 and I'm hoping to get over 30 mins so I can race this weekend at the Nitro Challenge.

 

[mulepic]

Thanks. Does anyone have any experience with the SkyRC 1/5th scale ESC and motor?

I don't have experience w/ it but this reminded me of something. Take a look at what the e-bike guys do. They add extra (hi end) capacitors. I did the same to my heli esc and it makes a big difference. The rubycon caps (from digikey) are just a few $$ each but adding a couple to the esc help it and the batteries to stay cool.

 

[electro21]

It doesn't say but I'm almost positive that 7075 spur is mod 1 (isn't that what the X series redcats use).

I honestly never saw it in writing one way or the other. I just assumed that since it's an electric version of their 1/5th scale gasser buggy, that it was mod 1.5. If it's not...

I've never run on 8s b/c I bulk charge my packs at 50V so 12s is my min. On 14s/10A packs w/ 13.6 I can get 28mins of runtime. I just installed my belt drive again which will put me at 18:1 and I'm hoping to get over 30 mins so I can race this weekend at the Nitro Challenge.

That's good runtime. I plan on racing mine at my local track, but like you, I doubt my run is actually scored b/c it's electric. I'm still working with the racers and the track owner, to figure out exactly how much runtime I'll need, so I'll know how many batteries to purchase.

Good luck at the race!!! The fate of the eDunerunner race class is in your hands, lol

I don't have experience w/ it but this reminded me of something. Take a look at what the e-bike guys do. They add extra (hi end) capacitors. I did the same to my heli esc and it makes a big difference. The rubycon caps (from digikey) are just a few $$ each but adding a couple to the esc help it and the batteries to stay cool.

I had planned on running Castle's CapPack

 

[electro21]

Minor Update

Dropped off some more parts to the machine shop and decided to take a few pics while I was there so you can hopefully kinda see how the layout will look.

The black marker on the chassis is where the cut will be made so both batteries will be facing the same direction and not in the way of anything. The 2S packs in the photos are their just as a prop. The batteries I'll probably be using will be 5000 4S 60c packs, these batts, and I think they use 8 gauge wire to the batts. I couldn't find the info, but I'll keep looking. I did run across an XB-E forum where one owner mentioned using mod 1.5 pinion gears, so now I'm really assuming the spur gear is mod 1.5. I'm waiting for SkyRC to send me the invoice for their Toro 200A ESC, Beast x528 motor, programming card, and shipping charge. I should be getting it sometime tonight. As soon as I do, I can order the parts.

 

[Guest]

It's going to be nice!

 

[electro21]

Thanks. They should be able to get started on my parts by the end of next week...I sure hope so.

 

[Guest]

The waiting is the worst....

 

[electro21]

Greetings All,

It has been a while...working in between jobs, the machine shop finished in June, so it took him 16 months to finish and I'm just getting finished with it today.

 

[electro21]

A test day at the track

[ame=http://www.youtube.com/watch?v=9X3DT_XNe1A]Project Griffin[/ame]