Direct Drive to Diff E Revo Build

[lincpimp]

Originally Posted by sikeston34m

I'm uploading Video's to Youtube right now. I'll post vids in a few minutes. You're gonna think this belongs on "beat your truck" or something. LOL

The Diffs held up great through the first run, and ummmmm well.........15 minutes into this run, the rear pinion bearings went out. The gears sounded like they were munching on balls.

I'm not sure what to do at this point. The 10/43 gears won't and don't hold up to this kind of power. The spiral cut loads the pinion bearing like a thrust bearing. Even the Ceramic Nitride bearings can't take it.

I might go with the 13/43 straight cut gears and try again. They will tend to side load the bearing instead of loading it like the spiral cut gears are doing. This custom Wye Wind starts better and makes more torque, so I think I still have a shot at it even with the 3.3:1 ratio.

Somebody show me a Diff that can stand it and I can make the power to shove through it. LOL

Sounds like it is time for a needle rooler bearing, not sure if you could find one that is the correct length to replace both of the stock bearings. You would need to have the diff cases machined to remove the two raised portinos that hold the std bearings in place. I vaugely remember that a needle bearing will hold up better than a ball bearing will, in a situation where there is alot of side loading. Sounds like the races are just getting hammered and falling apart.

I have a feeling that the hpi baja diff will be able to handle your outrunner, but it may not fit in the revo very well!

[sikeston34m]

A Needle Type Thrust bearing would be ideal! Problem is, I don't think anyone makes them in this size.

I just charged the Batteries back up. 15 minutes of running like this on 6S used 2182mah according to my MRC Superbrain 989. This setup would run HARD for over 30 minutes before it hit the cutout.

Dang Dang. What to do? LOL

I'll have to check that diff out Linc.

What kind of diffs do those 1/5th scale Firehammer's have in them?

[sikeston34m]

Check this out!

[JERRY2KONE]

The raw power of that thing is absolutely awsome. Can you imagine a race with like 10 or 15 vehicles with that same amount of power all barreling around the race track together? That was pretty cool Sikes. Thanks for sharing that with all of us. I hope that you can find the right Diffs to handle that thing. Overall it seemed to run very well, so we know that you had it hooked up pretty well. Great job.

[lincpimp]

Very Nice!!!!

Traxxas really needs to come out with a wheely bar for the revo, something like the setup for the maxx trucks. Looks like your custom wind works very well. Good luck with the diffs, maybe somebody makes a really heavy duty bearing?

[othello]

Nice display of raw power. Congratulation on your outrunner setup (especialy for custom winding your 4130). It would be interesting to log some data with an eagletree: with the rpm sensor you could immediately tell what kv your custom wound motor now has. You really should get one

I wonder what would happen at startup with a jazz 55-10-32 or a MGM 9032 on 10s1p A123 with your factory wound 4130/20 (305kv). Determining the right KV of your outrunner in combination with the right voltage to eliminate cogging at startup with the right esc seems to be the most challenging/interesting part. Your setup seems to do well with a very small hicup when starting up from a near stand still.

BTW: i had the same bearing problems (spiral cut pinion/diff) with my Neu 1512/2Y on 10s1p A123 in my buggy. I changed the bearing quite often. I thought it was due to the fact that the buggy already was 10 years old when i converted it to brushless.

[sikeston34m]

Originally Posted by othello

Nice display of raw power. Congratulation on your outrunner setup (especialy for custom winding your 4130). It would be interesting to log some data with an eagletree: with the rpm sensor you could immediately tell what kv your custom wound motor now has. You really should get one

I wonder what would happen at startup with a jazz 55-10-32 or a MGM 9032 on 10s1p A123 with your factory wound 4130/20 (305kv). Determining the right KV of your outrunner in combination with the right voltage to eliminate cogging at startup with the right esc seems to be the most challenging/interesting part. Your setup seems to do well with a very small hicup when starting up from a near stand still.

BTW: i had the same bearing problems (spiral cut pinion/diff) with my Neu 1512/2Y on 10s1p A123 in my buggy. I changed the bearing quite often. I thought it was due to the fact that the buggy already was 10 years old when i converted it to brushless.

Aaah, so I'm not the only one. LOL

I've never tried a Jazz ESC, they look really good though. The MGM is said to work well with outrunners.

Yes it is an interesting challenge. Now for the diff challenge.