Diff oils - Need help, plz look!

[Dafni]

Hey guys, I need your help to clear up some confusion here!

First of all, how do I choose a diff oil weight for my application? In my buggy I tested some combos, but somehow it does the opposite of what I was expecting. For what should I look for? I need suggestions for front, rear and center, because I'm still only beginning to understand these things.

And second: What would be a good oil weight to start on my center diff in the revo (ofna ultra diff) and front or rear (stock gears)

Another thing: I have several different brands of diff oil, and I recently got some UE bottles. They were in the same containers as some oil I got from a german distributor. (probably the same producer) But the labels on them are totally off. The weight numbers correspond in no way. I mean, the viscositiy of a liquid is a well defined number, and it can be measured. So why on earth would companies invent their own scale?

Thanks for reading. If someone could elaborate on this a bit, I would be most gratefull. What oil weight will have what effect on driving characteristics?

DAF

[coolhandcountry]

I run a 10 k oil in my center diff daniel. That seems to work will. I used ue oil to. I am not sure on the stock diffs you have for they only have the 4 spyder gears in them I think. That would require the thicker oil for the same effect as the 6 spyder diffs.

Could you explain on the difference between the other two companys. Like is it thinner or thicker. And what have you tried with results you got.

[Dafni]

I meant I have these bottles from a german company, look exactly the same as the UEs, but the labels are different. And the weight value seems to be one order of magnitude higher on the UEs, for the same viscosity, apparently.

I tried different combos in my buggy. Haven't tested the revo with center diff yet.

[Mike.L]

i would choose and try out the best one that would work ...or yes get advise

[coolhandcountry]

With big tires I find that the stiffer oil is needed. I have the 10k and wondering about trying a little thicker. but it seems to do well.

[squeeforever]

daniel, is the center diff a 6 or 8 spyder? like coolhand said, the more spyders, the lighter the fluid you need. i have seen a BUNCH of people that run 30k in the front of the revos with 10k in the rear.

[Dafni]

Okay, nobody wants to give a lil' explanation....

So I bring it on bit by bit, to see if anybody can help me: At the moment my buggy runs fine, basically, but it has a massive understeer under hard acceleration. What would you change, diff-oil-wise, to prevent this?
(it has pretty light oil in f&r, and heavy oil in the center)

If anybody could give a short explanation on what oil does what to your handling, I would be gratefull.

Squee, the ofna ultra diff has 6 spyders, as you would say.

DAF

[coolhandcountry]

I would change to a lighter oil in the center diff. The reason is this. The lighter oil would allow more diffing action in turn would pull the front end around. With the thick oil it is push more with the back wheels because that is where the weight is at on hard acceleration.

[RC-Monster Mike]

Here is a bsaic breakdown for you, Daf:
Front diff - heavy oil = harder pull out of corners, more push going into the corners. In general, you want the front oil a bit heavier than the back.

Rear diff - Heavy oil = more push everywhere, along with the tendency to "hang out" the rear on hard acceleration-generally, this is the lightest oil of the three diffs

Center diff - Heavy oil = less steering and more traction-OK for a blue groove track. Lighter oil allows the power transfer to "diff" better, which results in more stability on hard acceleration, less tendency to "hang out" the rear, and better steering into and out of a corner(particularly with electric power-a nitro setup will allow individual brake adjustment and the ability to tune braking-generally almost all rear brakes and very little front brake bias works).

Personally, I like very light oil in the rear(1000 or 3000 weight in 1/8 buggy)and equal weight oil in the front and center (5k for 1/8 buggy). This is for my particular track, which gets a bit loose and loamy. For a monster truck, heavier oil is almost certainly required (bigger tires = more "diff acting" force). In an electric Revo, I would start with 30k in the center, 7k in the front and 3k in the rear. Then, adjust accordingly for track conditions. This my personal preference. I prefer stability over traction(especially on a monster truck where traction is usually not an issue). I also like a lot of steering. :)

[Dafni]

Thank you Mike! Exactly what I was looking for! Nice explanation, thanks for taking the time. I will print it out an pin it to my bedroom wall :)

[Trick440]

Heavy oil in the front? I gotta disagree with that.

Lighter in the front.

If you have heavy oil in the front. Yes you will pull out of the corners easilier, but coming into them with both wheels having more of a tendency to spin your gonna break loose of traction and not get as sharp of a turn. You don't want to 'hang out' your front end on turns.

Heavier oil in the rear so you do get more of a posi traction rear end that you can power slide around corners.
In general the oil in the rear should be heavier than the oil in front.

center diffs I have no clue.

I don't know RCs very well but I know about off road vehicles. Unless I'm missing something here.

[coolhandcountry]

When applying the brake you have more weight on the front you have more traction to get around the corner. You do no hang out the frontend. You push it and the rest follows.