Torsion bar ifs - How do I get more flex & droop?

Springs, shocks and all things between your chassis and diffs
mydmax
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Re: Torsion bar ifs - How do I get more flex & droop?

Unread post by mydmax » March 3rd, 2014, 7:47 pm

You may get more down but the total flex ie, full down to fully up may not improve. The shock can be longer but can that longer shock compress upward enough to allow the full up as designed?

jacnden
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Re: Torsion bar ifs - How do I get more flex & droop?

Unread post by jacnden » March 3rd, 2014, 7:58 pm

i think in that pic it is with the car jacked up and at full droop. i have less than 1/2 inch drop extra with the shocker off , so shockers wont help and i already have longer aftermarket ones
so you think that these arms or ball joint spacers wont give lift , just push things further down? if you look at my first post you wiil read just where things are at the moment

Timmo
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Re: Torsion bar ifs - How do I get more flex & droop?

Unread post by Timmo » March 3rd, 2014, 8:08 pm

mydmax wrote:You may get more down but the total flex ie, full down to fully up may not improve. The shock can be longer but can that longer shock compress upward enough to allow the full up as designed?
Exactly.

You are increasing the possible range of movement of the suspension by increasing down travel (up travel will remain the same) however it is only useful if you can find a shock that has a longer stroke yet a similar compressed length. That will be the tough ask.

jacnden - to answer your first post in the thread, those arms or ball joint mods won't help your CV angles at all, they'll make them worse at full droop by allowing more down travel.

The only thing to correct CV angles after a lift on an IFS front end is a diff drop, nothing else. Obviously you are limited as to how far you can drop it without some expensive mods.
Last edited by Timmo on March 3rd, 2014, 8:16 pm, edited 1 time in total.
Cheers,

Nathan

Peter Aawen
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Re: Torsion bar ifs - How do I get more flex & droop?

Unread post by Peter Aawen » March 3rd, 2014, 8:15 pm

No matter what the shape of the arm is, the critical thing is the distance between the pivot points on the inner/body end & the centre of the ball joints, which is effectively the radius of the arcs of travel - and no matter if the ball joints are above or below the arms themselves, or if they are spaced down (or up) an inch and a half or not, if that radius distance hasn't changed, ie if you haven't extended the length of the arms/radii, then you aren't going to get any change in the overall distance travelled by the suspension between its' uppermost point and its' lowermost point ie the total travel - but the variation may allow your static ride height to be different.

Similarly if the arms are the same length and the spindle that carries the wheel hub & swivel between the two are is the same length & you haven't moved the bump stops, you won't get any more down travel, regardless of which arm the torsion bar acts on or the bump stops act on; altho if you mod the arms or ball joints so that you get a higher static ride height without changing the torsion bar settings, you can get more 'accessible' down travel from the new static ride height within the original total range. But that's just because the vehicle is sitting higher in the total range to start with, so instead of having to wind the torsion bars up so that you have 2/3rds up travel and only 1/3rd down travel which is the increased the ride height (and reducing the amount of down travel left before you hit the bump stops) you can leave (or return) the torsion bars to the middle of the up/down travel so that instead of just having 1/3 down travel left (or if you like 2/6ths) you now have 1/2 down travel left (or if you like, 3/6ths!).

But it all comes back to the same thing - it doesn't matter what you do, unless you move the bump stops (illegal) &/or extend the length of the arms (needs engineering) you aren't going to increase the total travel range available to you on this sort of IFS suspension or if you like, you aren't able to increase the possible range of movement from the original designed limits. You can muck around with where the vehicle sits at static ride height, and there are some mods/changes/arms/shocks etc that can help vary where the vehicle static ride height sits within the total range so that you can get more of the down (or up) available to you, but the total travel overall or if you like the total possible range of movement is not going to change without making those other mods mentioned above/earlier!
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Timmo
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Re: Torsion bar ifs - How do I get more flex & droop?

Unread post by Timmo » March 3rd, 2014, 8:34 pm

Modding the upper arm or ball joint on that suspension setup will not alter static ride height whatsoever as it is determined by the torsion bar which acts on the lower arm. If he does not adjust the torsion bars, ride height does not change even with flipping the ball joints, all they do is space the upper arm further from the bumpstop resulting in a prospective increase in down travel. The shape of that aftermarket upper arm is to lower the balljoint to allow more down travel rather than just using a spacer on the existing arm. It will most likely be a tad longer also.

Spacing the stock upper arm away from the spindle with a spacer or a flip increases the distance between the stock upper arm and its down travel bumpstop therefore allowing further down travel providing the shock isn't the limiting factor.

Up travel remains the same limited by the bumpstop on the lower arm as it remains unchanged in its original position in relation to the lower arm. Down travel is increased by the thickness of the spacer or difference in balljoint location as it spaces the upper arm further from its down travel bumpstop. So if up travel is same same but down travel is increased, that is an increase in range of travel even if only minimal. There are plenty of Tritons/Challengers/Pajeros/Delicas running flipped ball joints. It gains about 25mm down travel without compromising up travel providing the shocks can cope. CV angles are obviously made worse.

The radius of the suspension travel hasn't changed, but the length of the arc has.
Cheers,

Nathan

jacnden
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Re: Torsion bar ifs - How do I get more flex & droop?

Unread post by jacnden » March 6th, 2014, 12:27 pm

well i have browsed hundreds of sites and i think timmo is right. if the torsion bar attaches to the upper control arm you can get lift from a spacer or a ball joint flip or a calmini ontrol arm. if the tosion bar attaches to the lower control arm then thes thing dont acheive any lift.
i did find a few interesting things , 60 mm droop was considered ok and 90 mm normal for most isuzu IFS suspension. mine is 70mm. i think i will wind back the torsion bars a little and see what happens.

jacnden
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Re: Torsion bar ifs - How do I get more flex & droop?

Unread post by jacnden » December 5th, 2014, 9:38 am

I got a lot of helpful advice from everyone on this post and as I am always tinkering, I have another question.

it seems the length of control arms dictates the total travel on ifs suspension. if I put 1 inch wheel spacers on would they make any noticeable differrance to suspension travel? or would you need much more to have an effect?
not really concerned at the moment about whether wheel spacers are good or not, just the theory of adding an inch either side effecting suspension travel
what do you think?

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Re: Torsion bar ifs - How do I get more flex & droop?

Unread post by Timmo » December 5th, 2014, 11:52 am

It'll make no difference at all mate. Just widen your track.

The only way to increase the range of travel on IFS is to alter the point at which the arms contact the upper/lower bump stops (by either modified arms, ball joint flip/spacer or removal/modification of bumpstops) or lengthening the arms to increase the radius as mentioned already.
Cheers,

Nathan

jacnden
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Re: Torsion bar ifs - How do I get more flex & droop?

Unread post by jacnden » December 5th, 2014, 1:09 pm

so a wheel spacer doesn't give you the same effect as longer arms?

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Re: Torsion bar ifs - How do I get more flex & droop?

Unread post by Peter Aawen » December 5th, 2014, 2:41 pm

Hey Timmo (& jacnden) a ball-joint flip or spacer won't increase the total range of travel available either cos it doesn't increase the radius of movement the arm can travel thru... In fact, on many IFS vehicles while the extra height between the outer end pivot points (ie the upper & lower ball joints) that ball joint flips or spacers provide can allow a variation on where within the existing range of travel the vehicle will sit at static ride height, ie effectively 'lifting' where the vehicle sits within the existing range of travel, it can, by pushing the arms further apart & therefore forcing one or both arms closer to any bump stops or existing limiting devices, actually reduce the total range of travel available. :(

Jacden, I guess that 'technically' you could say you might get fractions of an inch of increased travel at the outer side of the wheel thru fitting a wheel spacer (yeah, the outside of the wheel will be travelling at the end of a very marginally longer 'radius' altho the pivot points & arm lengths haven't actually changed) the gain provided by useably sized spacers is simply not enough to warrant it!! So practically, as has been said before, unless you do something to significantly change the radius of travel &/or the limits on that travel imposed by the physical components, ie lengthen the arms &/or move the bumpstops, then you aren't easily going to get any more total travel out of your IFS....

Think of it sorta like swinging a Yoyo around your head on its string to hit something that's some way away from you & out of reach from where you are currently standing - fitting a bigger Yoyo to the same string isn't really going to make a 'real' benefit to the reach that you'd get & increase your chances of hitting whatever; altho it does add 1/2 the increase in Yoyo dia to the total length of the radius of swing, so unless it's a big increase in Yoyo dia (or a bloody big wheel spacer!!) there's no real point! The only effective way to reach further is to either fit a longer string to the Yoyo (longer arms); or if you can, move closer to whatever you want to hit (move the inner pivot point). And if you hafta stand at a fixed point behind a gap in a wall (ie like the relationship between the chassis end inner pivot points of your suspension arms & the bump stops/upper & lower movement limiting devices) so that the Yoyo can only swing in whatever limited arc is allowed by swinging it thru the gap in the wall - it's fairly clear that unless you change where you stand (ie vary the inner end pivot point) or fit a longer string (fit a longer arm) then your Yoyo has a fixed arc of swing just like IFS has a a fixed range of total travel! ;)

As for the spacer idea, all that's even before considering the adverse effects that fitting wheel spacers can have on steering geometry, wheel alignment, ride & handling, etc, as well as the potential for extra wear & stresses on front end bushes & bearings.... :(
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Re: Torsion bar ifs - How do I get more flex & droop?

Unread post by jacnden » December 5th, 2014, 3:20 pm

thanks guys
its very quiet at work this afternoon , that's why I start thinking things to play with on the car
I like the yoyo analogy :)

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Re: Torsion bar ifs - How do I get more flex & droop?

Unread post by Timmo » December 5th, 2014, 4:51 pm

No need to address me Peter, I'm well aware of how an IFS front end works. I have one myself and have tested it with a ball joint flip (just to satisfy curiousity) to prove what effect it has.

We have been down this path in this thread already. Fact is, moving the balljoint from above to below the upper control arm on an IFS vehicle where the torsion bar acts on the lower arm (as it does on jacnden's rig) will increase the range of travel, as long as the shock has the ability to extend further without bottoming out. It will increase downtravel by increasing the distance between the upper arm and the down travel bumpstop. The uptravel will remain exactly the same as it is limited by the lower arm acting on the uptravel bumpstop, which hasn't changed.
You said it yourself in your last post;
"unless you do something to significantly change the radius of travel &/or the limits on that travel imposed by the physical components, ie lengthen the arms &/or move the bumpstops"

While you won't be moving the bumpstops as such, doing a ball joint flip increases the distance between the upper arm and it's bumpstop to achieve the same end result. More downtravel. This has been proven. It is has the same effect as moving the bumpstops by increasing the gap between the components (the upper & lower arms) that act on them.

What you have said below is not true mate;
"pushing the arms further apart & therefore forcing one or both arms closer to any bump stops or existing limiting devices, actually reduce the total range of travel available."

Pushing the arms further apart actually increases the gap between the arms and the bumpstops, increasing the range of movement. The downtravel bumpstop acts on the underside of the upper arm and the up travel bumpstop acts on the top of the lower arm. If you increase the gap between the arms, you increase the range of travel....simple.

The only time a ball joint flip has any affect on static ride height is if the torsion bar acts on the upper arm where you are flipping the ball joint (ie. Hilux). If the torsion bar settings remain the same, then the upper control arm stays in the same position and the hub is moved down whatever the distance gained from the spacer/flip. Even then, you have still increased the range of travel as the lower control arm is pushed down, increasing the gap between the lower arm and it's uptravel bumpstop. If the torsion bar acts on the lower arm as it does on my rig, ride height is governed by the force applied to the lower arm from the torsion bar. The upper arm has no bearing on ride height whatsoever, it is just there to support the hub assembly.

A wheel spacer is going to give zero increase/decrease in anything except for wheel track. The length of the arc travelled does not change in any way, shape or form through the range of travel by fitting a spacer, no matter how thick it is. It could be 200mm and still make no difference. The centre of the hub will still have the same range of movement from full compression to full droop when measured centre to centre. Not taking camber into account, the axle/hub will be near enough to parallel with the ground, a spacer will only move the wheel out further from the hub face. No increase in anything. The length of the arc of travel remains the same, it is just moved further outward from the vehicle. If you want to increase travel by increasing the radius, the radius needs to be increased in length between the ball joint and the control arm pivots at the chassis.
Cheers,

Nathan

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Re: Torsion bar ifs - How do I get more flex & droop?

Unread post by Timmo » December 5th, 2014, 6:20 pm

jacnden - easy way to test it out mate. Jack your rig up and back one torsion bar right off and disconnect the shock. Now jack up the suspension until it is at full compression on the uptravel bump stop. Take a measurement from the ground to the centre of the hub. Now remove the jack from the suspension and allow it to relax to full droop on the downtravel bump stop. Take another measurement from the ground to the centre of your hub. Subtract that measurement from the first and that is your total travel from full droop to full compression.

Now, flip the balljoint on that side and take those same measurements again. I think you'll find that your compression measurement will be the same but your droop measurement will be less. When subtracted from the compression measurement, the overall available range from full droop to full compression should be larger. Rather than take the words of people on the internet as gospel, prove it yourself and let us know your results. Shouldn't take more than an hour to do and you'll be able to form your own, educated opinion.
Cheers,

Nathan

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Re: Torsion bar ifs - How do I get more flex & droop?

Unread post by Dree Mon » December 6th, 2014, 7:55 am

it's to easy to agree with Timmo, if you jack the car up supporting it from the chassis just enough to get the wheel off then do a ball joint flip, to get the wheel back on you'll need to jack the car up a bit more. = more droop.

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Re: Torsion bar ifs - How do I get more flex & droop?

Unread post by Peter Aawen » December 6th, 2014, 9:47 am

Sorry Dree, but no - all that means is that the wheel is now mounted lower down in the already existing total range of travel so that the vehicle body will sit a tad higher - I'm sorry for anyone who thinks otherwise, but unless you have a vehicle that doesn't need to comply with the (so far) immutable laws of physics, mathematics, & basic geometry like everyone else's, then unless you do things like moving the chassis end pivot points, or appreciably lengthening the swinging arms, or cutting/removing bump stops, then you are simply not going to get any MORE total travel out of your IFS than is achievable within the parameters of OE design & construction. And if you do have a vehicle that doesn't hafta comply with those laws, I'm pretty sure that there will be scientists & engineers beating a path to your door very soon! :sillywink:
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