My guess is it will just light up the front tires and go nowhere, unless you have a proper torque split I can't see it working. Should have massive on-power understeer too.

So what advantage are you hoping to gain with a centre diff:confused:

hi, I have tested it but only near home, not at track, it seems to work fine and the car turns very well and keeps on the turn under throttle much better (this is I was thinking to gain) with no loosening of the parts and no slipping of the diff.
And yes, I know I will lose power if front or rear train light up but I think this should be compensated adjusting the differential.
By other side I think that I lose the slipper function only if the car land with four wheel at same time, if not (the usual) the excess of rpm´s will "go out" through the train that its still in the air.

This its only an experiment, as I said Im bored and Im not really very very interested in offroad racing but if somebody wants to know what parts I used for it and how I will tell gladly.

sorry if you dont understand too well my poor english!
greetings!

No matter if it works or not, I still would like to know which parts you used !

Think about it a little more! 1/8 bugys use central diff and don't suffer from unloading on front wheels.

While turning every train keeps much planted and it's more neutral without the rear breaking out. It seems that can always turn as much as you want.

That's what you mean, isn't it Jordix? In other words: va de cojones. :D

Breaking through a one-way might be an issue though, you might loose a load of breaking effort on rough surfaces as the loading changes front to rear.

Don't they use oil filled or torsion diffs though? A normal ball diff has no limited slip effect at all.

here you got it:

associated parts

1766-B4/T4/GT ligthweight outdrives
6589-5/32" x 5/16" bearings
7677-differential rebuild kit for RC10GT

or you can order 7677 items separately
7666-diff rings
6575-thrust bolt and t-nut
6574-thrust balls
6582-thrust spring
6573-thrust washers

-I used duratrax spur gear (78T or 81T) but I think are the same that kimbrough spurs.
-For last yor will need eight 1/8" differential balls, associated or any other (these are 1/12 cars ball differential)

you must make some dremel work because the differential bearing dont fit the spur center hole (outer diameter of the bearing its smaller), I saw that standar 540 motor bearing do it but internal diameter its worst...

I made a plastic part (like a bushing) to fit the gap between bearing and spur internal hole, you must put special attention to make it well rounded because if not the spur will be eccentrix, (I have to test the resistance of this piece, I think will be better in metal material but its more difficult for me making it).

Now you can mount the diff. and tighten till the spring full compression, then loose 1/4 turn.

When you mount the diff. you have to do it with T-nut towards front center shaft and insert first rear shaft (I "touch" with dremel the rear upper deck inner edges a bit for easily outdrive insert through).

Now you will see that front outdrive bearings need a spacer to stay in its correct site of the bulkhead, its very easy to make a spacer for this, you need a 4.5mm spacer (from a brass ballpen jeje).

In the rear outdrive bearing I used 2 or 3 shim spacers (ASC2293)

It can be that spur touches the center bulkhead cap so you know: dremel work in the center bulkhead, only a bit...

Some pics (for sucolega AJAJAJA):

http://img91.imageshack.us/img91/9629/pic0004ml7.jpg
http://img518.imageshack.us/img518/5208/pic0003yq2.jpg
http://img20.imageshack.us/img20/2910/pic0002if3.jpg

The problem of the spur centering comes fron T-nut/front center shaft, with a shortest t-nut or shaft the spur wold be perfect in its place but...

A ball diff is a limited slip diff by definition. Oil used inside gear diff slow its operation making them to work tighter than they would without grease. In other words, ticker oil means more torque diference needed to make wheels turn at diferent speeds.

When you tigh a ball diff you are adjusting the diference in torque terms that is needed to make one wheel to turn faster than the other.

Ball diffs are better because their ability to change set up very easily and their much lower weight. However they can't take so much abuse as gear diffs do, and need more skills buiding and maintenance them.

"Sucolega" thanks the pics.

PS: Sioux speak better than us!

you can adjust the diff. action in a ball diff. like in a oil filled diff but more easily and quickly, its the same, but both have no slipping effect at all (I refer to a standar slipper clutch), diffs. slipps one wheel respect from the other not from the pulley or spur.

"hau" alberto

Nice work man!!
I wonder what it does on a off-road track.

BTW ever thought about a slipper on which you can adjust the amount of slip to the front and rear seperately. Solution to problems??

In fact something of that already exist. On XX4 you can find different slipper pads for front and rear.That makes them slip at different points, so there you have your idea. You can always play with that using different slipper pads or just wswapping between new and old pad to achieve the setting you want.

!!!!?

:wtf: What's the point of that?

I mean... both springs load on the same piece so... they share tension so it's the same than a single spring with different tension. Always the softer one will "unload" and the tension on the pads will be just the same. The only thing that will vary the friction will be the mu coeficient between disc and pad.

You need something a litte bit more complex to achieve an adjustable "bi-slipper" :p so both end can use its own tension.

Oh, sorry I should have mentioned that the middle-ring is attached to the spur.......

Middle ring = piece wich the screws are attached? In that case I don't understand its design. Why is it asymetric? 2nd Newton law says that in spite middle ring is attached to the spur the tension on both sides will be the same.

Because if it wasn't how would you get it both sides of the spur and still one piece? :confused:

G

An exploded view.
Maybe this will clear things up?

Good design :o But... I don't have things clear enough. My brain is out of order for today, we'll see tomorrow

arrgh, Im going crazy but I think its the same thing as in the first drawing....

It is the the same drawing only streched-out
I can understand its difficult to understand how it works.........
Just remove one side of the slipper and see if the other side will still work.

hi, after yesterday testing and have no problem with the car after four batteries the car seems to have a very good
corner entering, very agressive but it loses steering under throtle (mid-out corner), the track was very slippery
and wet so the grip wasn´t good, nevertheless I used bow tie rear and hole shot front and the car had a
great traction, very good.
the test I made against a friend with a losi xxx-4, my friend is much better pilot than I but my car works very well
,traction, corner entering and no rear slip was the key for racing with him almost at the same time.

The car lost some front traction passing through the dubbies we have at the begining of the main straight
because of the light up of the front train, no matter, I speeded up equal or better than xxx-4 and brake better so in the straight I eat him and in some corners too.

first battery the differential finished a bit hot, I could hear the diff working hard at the beginning
of the main straigth but no loosening happend and the diff was ok at the end.
I tighten it a bit for the second batt and all was ok, I think I will need to tight it a bit more if we have more grip
another day (is the usual)

Havnt read everything in this thread, but what ive heard the B44 slipper is difrent to the BJ4 (adjust nut outside centerbulk). Centershaft have other dimension to...

CAN the B44 center tranny be fitted in the BJ4 WE, if i ex buy,front center,rear center, and everything else that has to do with the B44 slipper, will it fit or?

From what i have heard no.

The b44 slipper means the shaft lengths are different and they dont use MIP cvds where they enter the gear boxes.

This is only what i have been told i have not tried to myself.

Lee

Hmm, nice to hear if some one realy can tell, maybe even if the B44´s last pice of the shaft tht enters the gear oxes can be fitted in the BJ4WE..propably not, but would be nice to let this thougt away =)

Thomas, the outdrives will not fit, the gearbox of the NTC3 (BJ4WE) has the outdrive support bearing closer spaced.

However...

There are ways to make them fit, and of course all of the other parts as well if you really want to use the B44 slipper. I have a race coming up this weekend where I hope to put my little "B44 slipper in Bj4WE" to the test. I will have feedback on it next week.

Some of the main challenges with the project are these:

* The whole slipper assembly sits higher in the B44 (to allow larger spurs)
* The motor sits higher as well in the B44 (not a prob in it self except that you move up the C/G even further).
* Outdrives are longer (support bearings are wider spaced), and the gearboxes themselves are very different so it is not possible to bolt on B44 boxes either to allow the wider spacing of the bearings
* B44 and Bj4WE top decks, even though they look very similar around the slipper assembly, is not compatible, screw holes are offset
* Slipper assembly top holder blocks are then of course also very different even though they look very similar

If someone else is working on this, please share your solutions and ideas.

Regards,
Roy

Thank you Roy for this, il be waiting for your upate.

Reg

Thomas P

BJ4WE Slipper Conversion
 

Hi guys,

As promised I have put together a .pdf guide that hopefully will help at least some of you guys out.

I tried to attach it to the post, but it was unfortunately too big (260KB). However, It can be downloaded here.

Please let me know what you think.

Take care.


//Roy

Looking rel good Roy, i will order the parts in a few weeks, no rush for me. Cant wait to test it in my S4

/Thomas

Just priced that parts list.

might as well just buy a B44 :woot:

barely 100 dollar without the concept parts...aint so expensive at all...and way lower then a 319 dollar car :)

Well worth the money if you ask me :thumbsup: And by the way, did I ever mention it was going to be cheap? :D:D

And what, have the B44 snap in half on the first hard landing and then have to spend another 100 for replacement parts? :thumbsup:

Nice job DaHomie!
Congratulations for your work and especially for the quality of your pdf...
Do you authorize me to put it on petitrc forum in order to share it with french drivers? (with your copyright of course :thumbsup:)
Regards.

Of course you can, please PM me a link to the post on Petit when you have it up there.

//Roy

very nice !!! Thanks for your work !!!!

Apologies for the resurrection of this old thread, but I've just found it while researching what to do about the slipper in my BJ4WE.

I'm weighing up either doing this mod, or fitting a B44 slipper and centre shaft mod, mentioned in another thread, and the PDF instructions are available online, I found them with Google.

What are the handling differences likely to be between the two? What kind of surfaces does each favour? It's possible I would build one BJ4WE for each surface type.

Jordix hasn't been here in a while, and I believe he sold his BJ4WE.