1520 + 6s = diff killer
 

So I let the plastic centre diff be killed:whip: I was just to lazy to change it before it died:whip: Did a good job too, melted the gears into the cup. I had to cut the cup to get the gears out.

I had the nova diff cups here waiting for the event. From my understanding thicker oils work the gears harder. So I made another diff using only the outdrives from the old one, nova cup, new inners and 120k wt oil. Took it for a bash out the front of my house and loved it:party: The wheelies were long and low. Worked the drivetrain hard. Then unexpectadly the car flipped on it's lid. Didn't think much of it first time round but it quickly became apparent the centre diff was locked within 1 battery pack:diablo:

Before you say anythng - Yes it was shimmed properly, I double checked myself on that knowing what would happen if I didn't. When I took it out again the screws in the cup on weren't tight. They were all the way in but not nipped up (yes, I used locktite) and the diff spooled one way but not the other. The internal gears showed some wear but I thought I could get more use out of them.

I put an extra shim in and re-assembled it. I also cut some slots in the screws so I can crank on them a bit more (I hate hex keys for stuff like this). I haven't used it yet but I think I need to rebuild it (again:no:) cause it is still very notchy one way. I'm thinkng to just flip the internal gears so it spools nicely on acceleration.

If problems persist I might have to stick with lighter oils. Or would an ofna spider fit in an rc8t?

Damn... I have noticed the temps in the ofna spider i'm using spike up pretty quickly during the runs... I normally see numbers around 150° to the higher 160s...
the diffs seem to be working really hard while transferring all that power from the cc1520...

It's been some time since my last update... Ive been using some Novak pinion for a little while now and I must say, I impressed... they have performed nicely... :yipi:
the cogs only have a polished effect on them... nothing unexpected... So I guess I'll be keeping them... I finally got some vids of the truck with the 1520 powering it... see the below link...

| flm maxx | carbon fiber | ofna spider | cc 1520 1Y 1600kv l 1 ----- | flm maxx | carbon fiber | ofna spider | cc 1520 1Y 1600kv l 2

Alien

i use a 6 spider ofna diff in my savage.. i thought it was the only diff that would survive the power!!! i have used 100k, 150k and 300k oil.. but im currently using 500k in the centre diff now...

edit...

alien... your truck is performing nicely on 5s with the 1520... how much does your truck weigh and what gearing are you running with the cetnre diff???

THanks

Yep, it's a fatty, but it shore moves well... it weighs approximately 11 1/2 lbs and it's geared 52/17 (mid 40s)

Alien

Currently im weighing around 15lbs (elephant of a savage) and i was geared 12/47 and only run 6s... but i think i am going to up my pinion to a 14 or so as my temps are pretty cool at the moment...

Thanks for the info... You have some big gearing, but your truck is 3-4lbs lighter....

hmmm... from the temps and the performance of the motor so far, it appears to be slightly under geared actually... i ran it on 51/18 for a while and it was insane...
wasn't easy keeping the front on the ground off the line... when i did get them down, the truck was really quick...

Alien

On 6s running roughly 13/48 and badlands, i was supposedly geared for 50-53mph or so... but i was clocked at 43mph (speed gun)...

I am definitely going to gear to around 58-60mph which should give me an actual top speed of around 50mph or so... I wil ljust monitor my temps closely....

Interesting... Ive been thinking about asking the local police to give me some help with their radar guns, but i haven't gotten around to it yet... it definitely would be cool to see the actual speed of my truck...

Alien

what i personally have noticed is that your actual speed is usually 8-10mph less that your hypothetical top speed... Seems to be the same senses for buggys and truggys etc that we have compared to at our meets.

8-10mph??? :surprised:... that's quite a bit considering the scale of the car... hmmm... I'll do the radar test with a couple pinons and make some comparisons with the calculator...

The 1520 Is a very nice motor. I am installing an 8ight CD with Nova-RC Cup. Panda what kind of Diff did you use with the Nova Cup? I thought these would be near bullet-proof...

It was all associated gear. The nova cup doesn't have a mark on it. It was just the pressure trying to separate the spur and cup, it loosened the screws and affected the shimming. I need to really crank on the screws. That's why I cut slots in the screws, I am too afraid of stipping the hex.

I like that mod... I have stripped so many when trying to remove them for maintenance..

I am running a 1520 on 6s in my muggy, currently Im running 20mm hexes with losi super bolt on tires. I keep hearing that on a low KV motor I should be running a higher tooth pinion. I am running 14t pinion on a 48t spur. Should I bump up the pinion a tooth or two? I dont want to overdraw current form the batteries and make things hot. But I also dont want to put too much load on the batteries and burn up the esc. Batteries are turnigy 4000mah 6s 30-40c rating (no worries I have some 35c batteries on the way)

Gear for the intended use of the truck... and check the temps to be sure you are with operating limits...


Ok... some sort of update... earlier tonight I decided to mount a 20t pinion on the 1520 to see how well this thing would do with the additional load...
Well, to be honest... i was not surprised to see the 1520 handle its business with no effort... It was so quick going down the street.... I had a hard time
holding in the smiles when I blasted up and the parking lot... Rolling wheelies are even easier now since the wheels spin up so quickly... Needless to say,
i am still having a lot of fun with this truck..

This motor is AWESOME!!!!!!... I am still running it on 5s...

Here are the numbers:

Differential Ratio: 4.3
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 52
Pinion Tooth Count: 20
Total Voltage: 18.5
Motor KV: 1600
Tire Diameter (inches): 5.65
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor Coil Resistance: 0
Spur/Pinion Ratio: 2.6 : 1
Total Ratio: 11.18 : 1
Tire Circumference (inches): 17.75 inches (450.85 mm)
Rollout: 1.59:1
Total Motor Speed: 29600 RPM
Vehicle Speed: 44.5 mph (71.49 km/h) (21v-50.52 mph (81.15 km/h)
Effective KV Value: 1600

Alien