Jump to content
Sign in to follow this  
DeeMiller

From gear diff to visco diff.

Recommended Posts

Acryl_diff1.jpg

Acryl_diff2.jpg

When I was locking my TT01  drifter's rear diff. I had an idea:

Why not using acrylic sealant to make a gear diff work like a ball diff by adding very viscous window sealant instead of diff grease?

I once noticed the sealant doesn't dry when sealed from air and it's very viscous.

I didn't use sillicone sealant because of the acetic acid involved which would damage the iron gears.

After the filling, a lot of resistance can be feld, great! it works!.....for now.

Now let's see how it keeps in a few weeks/months.

If it works, ordinary geardiffs can be made to visco locks...no more ball diffs needed![<:o)]

Time will tell...

Thought I share this with you.

 

Dee.

Share this post


Link to post
Share on other sites

It will not dry if the diff is properly sealed - any ideas how to properly make an air tight seal around the diff outputs?

One solution is to use differential oil, designed for 1/8th rallycross diffs. You will need to seal the diff to prevent the oil leaking out over time with silicone.  

The sensible solution is Tamiya Anti Wear grease http://tamiyaclub.com/CS/forums/thread/156748.aspx which is known to do the job properly and will not go hard.

Share this post


Link to post
Share on other sites

@Dee: Drifters have for years now used plenty of ways to make gear diffs limited slip using all sorts of viscous substances inside the diff: aw grease, bluetak (prestik), putty, clay, and so on.  All are more-or-less effective, and all are messy, because, as terry indicated, the Tamiya gear diffs are not designed to be sealed.

But the most popular is to use an "o-ring" cut from a piece of silicon fuel tubing on each of the three shafts for the 3 small gears to create friction: and you can "tune" the amount of slip by changing the thickness of the "o-ring" (ie changing the length of tubing you use). Its neat, adjustable and completely reversable.

For locked diffs, most TT01 drifters just fill the rear diff with hot glue. Its suprisingly easy to remove the glue if you need to reverse the mod. 

Share this post


Link to post
Share on other sites

As terry said with Tamiya AW grease or other very stiff oils/greases you get some kind of viscous operation of the diff, btw thats the recommended method from Tamiya on TT01D(rifter), since then I am using Tamiya AW grease on any geared diff, often preffer their viscous behaviour to some ball diffs. Here some older topics about it:

http://tamiyaclub.com/CS/forums/thread/196681.aspx

http://tamiyaclub.com/CS/forums/thread/189393.aspx

http://tamiyaclub.com/CS/forums/thread/171909.aspx

http://tamiyaclub.com/CS/forums/thread/168091.aspx

http://tamiyaclub.com/CS/forums/thread/152733.aspx

Cheers 

Cheers 

Share this post


Link to post
Share on other sites
For locked diffs, most TT01 drifters just fill the rear diff with hot glue. Its suprisingly easy to remove the glue if you need to reverse the mod. 

Yes, I've read that, a great clean solution indeed!

But for drifting, due to the low traction of the drift tires, the diff locks pretty quickly.

It will not dry if the diff is properly sealed - any ideas how to properly make an air tight seal around the diff outputs?

Again thx Terry! (You are nominated for the Tamiya Stars Oracle Star [:P]).

The acryl sealant dries very very slow and needs a proper and plenty air supply to dry at all so with greasing the diff's outputs with regular grease it would be enough to prevent the sealant to dry.

I've also prepared a diff with silicone sealant but it dries with very little amount of air supply so I don't expect it to be very usefull.

An advantage, on the other hand, is that, if stripped apart, it dries in 1-2 days and can easily be removed (I pre-greased the parts with sillicone oil to prevent sticking to the parts).

Thx guys for the other solutions as I would be surprised if I was the only one who would have discovered visco-diffs![A]

 

Dee.

 

Share this post


Link to post
Share on other sites

Forgot: I used a very viscous sealant, not only for drifting but also for off-road use (hé it's a WRC Subby after all!).

I think AW-grease is a bit too forgiving for that purpose.

For a proper off-road use, the diff should allow only very low amount of slip.

The acryl sealant has just the right viscosity to save the drive train from damage.

The sillicone sealant one has more slip and is more usefull for on-road driving (like AW-grease).

Let's see what happens to both of them in a few months...

 

Dee.

Share this post


Link to post
Share on other sites
Forgot: I used a very viscous sealant, not only for drifting but also for off-road use (hé it's a WRC Subby after all!).

I think AW-grease is a bit too forgiving for that purpose.

For a proper off-road use, the diff should allow only very low amount of slip.

You need to put more AW greae then. Especially for a light tourer it is more then enough, especially at higher rpms to give the gripping tire enough torque to propel the car when the other is in the air, if you use thicker one diff action will mainly only work on high grip surfaces and on the rest it will just act like a car with locked diffs. Where a thicker grease then AW would be usefull are crawlers or monster trucks with low speed but these anyway most people lock completely.

Cheers

Share this post


Link to post
Share on other sites

I used to pack the diffs with thick wheel bearing grease (from 1:1 cars)..... when you fully pack the diff it will work as a limited slip (probably not as "stiff" as your solution) but it will never harden, lubricates and does not leak because of the high viscosity.

 

Martin

Share this post


Link to post
Share on other sites
Forgot: I used a very viscous sealant, not only for drifting but also for off-road use (hé it's a WRC Subby after all!).

I think AW-grease is a bit too forgiving for that purpose.

For a proper off-road use, the diff should allow only very low amount of slip.

You need to put more AW greae then. Especially for a light tourer it is more then enough, especially at higher rpms to give the gripping tire enough torque to propel the car when the other is in the air

Yes, but my focus (not Focus) is pointed at drifting/off-road.

Good advice though!

 

Dee.

Share this post


Link to post
Share on other sites

To clear it up I meant above a touring car chassis, either if it is used as a drifter or offroader, if you put even stiffer "grease" at slippery conditions (off road or with drift tires) there will be almost no diff action, i.e. the car will behave as if it wouldn't have any so you could directly lock it instead if that is what you are looking for.

Cheers 

Share this post


Link to post
Share on other sites
For a proper off-road use, the diff should allow only very low amount of slip.

Actually all my off road cars have diffs which are quite free, my touring cars have stiffer diffs. Generally with tighter diffs you might have more forward traction, but you will have less grip when cornering. Using a really stiff diff means you might as well just lock it up which although good for crawlers is not good at all for off road at speed.

Share this post


Link to post
Share on other sites

Ok, thx![:D]

For that kind of money for the AW-grease, experimenting isn't quite usefull I suppose then.[:(]

I'll use the AW for it is indeed better for high speeds which I didn't think about.

Thx guys![;)]

 

Dee. 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×
×
  • Create New...