Build questions.

[autoxvw]

Most of the build on the car is covered in the instructions but I do have a few things that I may have overlooked. When it comes to the diffs, what side of the car does the outdrive with the screw and thrust go? Does is matter? What should the belt deflection be on the front and rear belts? What other pistons (losi, AE, Kyosho etc) work in the shocks? And lastly, when doing the shock blader mod, do you cut the whole thing out so you just have a o ring or do you just make a hole in the center? Thanks in advance!
chris

[Chrislong]

The direction of the diff doesn't matter, as long as you have locked them with the grub screw they should never loosen.

Belt deflection? Whats that? Just set them as per manual, I find the front on the Lipo car is too tight so slacken it by one notch.

Other pistons? No need & I don't know the answer. But im sure somebody else will confirm what will/won't fit.

If you cut the bladder, then remove just the baggy centre, not the O-ring outer. I haven't done this and can't see any benefit, the shocks built as per manual are amazing. Im sure somebody will describe the benefits of doing it for me and you.

[autoxvw]

thanks for such a fast responce. What I mean by belt deflection is the tension basically. I remember in my cougar 2 instruction book it showed you how to set the tension on the belt but I did not see any way to measure the slop in the sx belts in the instruction.

Thanks for clearing up my other questions for the most part

[MattW]

For belt tension, i run 1 setting looser than central - if you assume that the mark straight up is centre.

Pistons - Losi and AE don't fit, not sure about any others.

[Rich D]

For Worksop ...........

Are you guys running the front one way with the std layshaft ? ( Chris and Matt )

Can i assume that a "locked" one way layshaft works exactly the same as the std layshaft as supplied with the kit ?

Have both of you guys took the 3mm or so off the top of the front yokes and fitted the ball joints flush minus any washers ?

Thanks muchly

[Oliv996]

Originally Posted by Rich D

Have both of you guys took the 3mm or so off the top of the front yokes and fitted the ball joints flush minus any washers ?

Smart question, sure I would also like to have the answer

[Chrislong]

Hey Rich,
Yes I am running a oneway layshaft without the pin. If you were to fit the pin then it is effectively the stock layshaft = locked.

The front yokes, I think you mean the castor blocks? Im never sure what to call them either but Matt White corrected me a few weeks ago, but yes - I cut mine down flush and then drill the hole right through so then the balljoint will go in and sit flush.

If you read the setup sheets and the team guys run 0mm, this is actually the castor blocks cut. The stock blocks have 3mm moulded onto them and this is too much camber change, even with the inside ballstud mounted with 0mm washers.

Chris

[Lee]

Cutting out the bladders will give less initial pack?

Its probaly more noticable outdoor where tracks are more "natural"

[Chrislong]

Cheers Lee,
But the theory (in my own mind) is that the bladder holds a volume of air which is taken up when the shaft plunges. So with no bladder there is no volume to compensate, and the shock pressurises more at plunge and so isn't so linear in damping when it gets to full plunge.... I think this is what I don't like about AE shocks and why I can't build two the same without having a few attempts at it.

This is in my own mind though, and so aware it is likely to be wrong.

[jimmy]

With no volume to compensate the shaft wouldn't budge at all - the air is still there but is allowed to mix with the oil.

[Lee]

With a bladder in though you are actually reducing the volume of the shock as well.

Does the shock use a bit of foam above the bladder as a compensator? If so leaving this out will reduce pack slightly but then the next step is cutting out the centre. I agree with what you say Chris, the bladder ensures there is an equal amount of oil/air in each shock, but i think as the piston moves the higher pressure is a bove the piston on compression and this in theory is pushing on the diaphragm as there is a lower volume of fluid above the piston and i think this is where the feel of more pack comes from, if that makes sense

[Chris Doughty]

has anyone ever thought of drilling a hole in the cap while using the bladder so the bladder does not hold air? the air in the bladder can escape to the outside world (and get back in again)?

NOTE: - its just a theory, I have never seen a proper Cat SX shock

[Lee]

I thought about suggesting that chris but i didnt want people to drill a hole and have to buy new shock caps if it becomes "the norm" to run bladderless.

[Wraggy]

Originally Posted by Lee

I thought about suggesting that chris but i didnt want people to drill a hole and have to buy new shock caps if it becomes "the norm" to run bladderless.

you could always run a thread through it and then use it as a blead screw like the Yok ones ??

[Chris Doughty]

Originally Posted by Wraggy

you could always run a thread through it and then use it as a blead screw like the Yok ones ??

that would be pretty cool, then you could 'set' the amount of air in the bladder and then seal it, so you could adjust the rebound or suck just by loosening the screw, compressing or extending the shock and then tightening the screw up again, this could be done 'on the fly' almost!

[Lee]

but also very confusing to the less technically minded, at the end of the day though these are race cars and knowledge is power

[frogger]

When you cut the bladders you are effectively building the shock with no air in it at all right? As it's possible to bleed the shock through the little bleeding hole before tightening completely. That is how mine was done anyway.

The way I understand it is that pack comes from the oil rushing through the holes and by the sides in the piston very quickly. This agitates the molecules which rub against one another and causes friction and resistence, effectively stiffening up the oil. Thinner oil and smaller holes create better pack.

So that would mean on fast compression pack occurs in the lower part of the shock as the oil is rushing down through the holes. Having a bladder in the top will effectively lessen pack because there will be less pressure in the upper part of the shock as the air compresses inside the bladder (until the air compresses fully that is). By cutting the bladder out and building your shock with no air you should in theory get better pack for landing jumps while being to able to use softer oil for better small bump absorbtion.

[Chrislong]

There are bleed holes in the shock caps, and when the cap is tightened the hole is sealed- this is why the O ring of the bladder has to be left in even if the centre cut. So in effect it does what you say, but the hole is not covered from the outside, to adjust the rebound you would have to remove the shock, loosen the cap, set the piston position to suck in or blow out air, then tighten the cap.

Whether the air is in the oil, or in the bladder, the air will compress. But with the air in the oil its hard to balance the amount of air, and with that air going through the piston then it leads to unbalance. When that air is in the bladder I personally can make shocks balance on first attempt.

I could be wrong ofcause, im only theorising in my mind. This thread is really interesting.

[Lee]

Frogger, there has to be air in the shock in order for it to work, the piston will be locked "packed" if there is no air in there

I am also of the opposite theory in that there will be more pressure further up the stroke i think that shaft speed will be at its highest in the first part of the shaft movement, as the oil, piston holes and the spring should all slow down the shaft speed if they are doing their job correctly, i cant see an advantage to having a bladder other than making the shock easy to build.

[Chris Doughty]

let me explain my adjustable bladder idea.

in the cap, there is a screw that can be opened to let air 'into' the bladders air pocket.

you build the shock as normal with the bladder.

you can run it without the screw so that you have pure (as pure as possible) oil for the piston to move in, and the volume compensation has no pressure against the compensation, so in theory you will have no suck or no rebound.

have the screw done up with the shaft is fully extended to have the some air trapped in the bladder and provide resistance to volume compensation so will provide some rebound to the piston/shaft

have the screw done up with the shaft full pushed in will provide a bit of a vacuum in the air part of the bladder and this will provide some suck for the shaft.

this should be easily adjustable while the shocks are on the car??