Outer Limits 4x4 Board

tryin to design a 5 link front end for my hilux, wat do think of the position of links in the pic, both arms are parallel. bottom arm chassis mount will need to be in-boarded slightly and the upper one out-boarded slightly so the both run straight. will mount to diff in same position as the leaf spring perches. where the diff is sitting now is bout 1-2" lower then ride height.
cheers
steve

I think the top arm is too short to give enough flexibilty for the type of 4wheeling that you're aiming at. Other than that, it looks like the geometry would work well from an engineering stand point.

beebee wrote:I think the top arm is too short to give enough flexibilty for the type of 4wheeling that you're aiming at. Other than that, it looks like the geometry would work well from an engineering stand point.

yeah was thinkin the same thing bout that top arm.
this is the other idea i had, i think the geometry would work better but the links would hit rocks an shit more then i would like. altough there is nothin to actually hook onto a rock. i think this is similar to the way calbah do there 5 link kits.

That wouldn't be too bad on the rocks actually. Links act as sliders well. I think that you may struggle however to get a bent link engineered.

you said you were looking at one link being inboarded, ond one out boarded, would you still need to have the bent link in there, if you had them offset enough, you could have both straight links

These are parralel links-



These are converging links-



Ignore the bend in the link and picture a straight link from the lower mount to the housing.

is it best to have parallel links?

does the answer to that question apply to the rear suspension too?

and which link should be longer top or bottom?

MaccA

I'm no suspension engineer, but it looks like you would get massive axle rotation (in the wrong directions) during bump and droop. Would something around equal length arms be closer to the mark if you want to prevent or engineer the axle rotation? I also didn't think you could weld the chassis flanges if you want it engineered.

ozy1 wrote:you said you were looking at one link being inboarded, ond one out boarded, would you still need to have the bent link in there, if you had them offset enough, you could have both straight links

no, the links sit one on top of the other, the reason the mounts would be inboarded/outboarded is because of the shape of the chassis rails angles out where the links meet the rails, so therefore the chassis is wider where the back mount goes.

RUFF wrote:These are parralel links-



These are converging links-



Ignore the bend in the link and picture a straight link from the lower mount to the housing.

yeah i see what ya meen there tony, would it work with converging links or would it cause too much axle rotation?

what about running the link to the standard spring mount and using the same mounting system as the rear of a nissan patrol, this would allow you to inboard and run longer flatter upper links.

would only work on the uppers but.


NICK

yeah i know what you are sayin there nick, putting the upper link mount up on the inside of the chassis rail, i was just a little worried about exhaust clearance etc up there.

this was another idea i had, i know it looks like a giant rock anchor, but i dont think it would hang much lower than an extended shackle, or using the bent link. it would allow the links to sit a lot flatter and they can be paralell and equal length. of cause the mount would need to be very strong and have a lot of bracing up the sides of the chassis rail.

just throwing ideas around, all suggestions are very helpfull, im not a suspension engineer either

true, but i think you could run the exhaust over the top of it, depending what type of motor you run.

i think i would be concerned with the engine mounts, i guess it comes down to how much verticle seperation you run and the distance on your bump stops. Also moving your axle forward will help.


NICK

post the pic with on drawing on it.


NICK

yeah i will definetly look into it a bit more, bump stops will be about 2-2.5" longer than standard and diff forward bout 4"

Can you bring the mounts inboard or outboard and raise them up to chassis level?

This may have stability implications with the angle they sit at????

blank

also have a pic from above

i think i would be looking at something more along the lines of this.

yeah that looks good, so the upper link would be on the inside of the chassis rail?. one question, do the two arms have to be parallel?
cheers
steve

just thinking about it, if you run the lowers on the outside of the chassis rail/under it, i think the tyres will rub them on full lock.

looking at that pic you could fit a 60s P/steer box where the pitman arm runs forward and move the axle forward far enough that it would sit ruffly under where the box is now. run a bundera/80s style steering. make sense?

doing this would also allow alot longer links and you may even be able to triangulate them to a 4 link setup.



NICK

yeah, i had thought of running them outside the chassis and using an 80 series front diff to get the tyres out further.

this thing needs to be fully engineered so i cant go too crazy with mods.

altough i think it will work with the lower links under the chassis, slightly inboarded and the upper links up inside the rails, just have to make the exhaust fit.

I would have thought that you'd get bump steer with a 4 link setup.

Slunnie wrote:I would have thought that you'd get bump steer with a 4 link setup.

yes you would, thats why i am staying away from the 4 link

killalux wrote:yeah that looks good, so the upper link would be on the inside of the chassis rail?. one question, do the two arms have to be parallel?
cheers
steve

Keeping them parallel is worthless if the uppers and lowers are of a significantly different length. It's all about the pinion angle/castor angle change throughout the arc of travel. In the front, the more constant this is, the better the handling. The easiest method is to keep them equal in length and paralell. The other option it to draw out the position and angle of the diff as it follows the suspension travel and see how it acts - you can find a compromise with different length links and being non parallel it's just more difficult. Although the travel that the axle experiences on road is probably only a couple of inches so maybe you can get away with a few things........

killalux wrote:this was another idea i had, i know it looks like a giant rock anchor, but i dont think it would hang much lower than an extended shackle, or using the bent link. it would allow the links to sit a lot flatter and they can be paralell and equal length. of cause the mount would need to be very strong and have a lot of bracing up the sides of the chassis rail.

just throwing ideas around, all suggestions are very helpfull, im not a suspension engineer either

i am thinkin i will go with this design, what would be the minimum vertical seperation of the links be?thinking bout 4-5"

running the links as close to equal length as possible is a very good idea for a front end. the engineer will like the idea of constant castor, and it also gives you some flexibility with adjusting your ride height.
if you are going to drive this on the road a lot, i wouldn't run the links parallel. unless the link angle is quite steep you will have very little anti dive, and unless the panhard and drag link geometry is spot on, this will translate into a fair bit of self steer under brakes. try and make one of the chassis mounts adjustable so you can play with it, but something like 15-20% convergance will make it handle a fair bit better in most cases. your minimum vertical seperation depends on what sort of bushes/rod ends you plan on using, and how much beef you want to build into everything. if you are using a poly or rubber type bushing shoot for around 250mm, but that will probably be pretty hard to achieve, try to stick to atound 200mm though. if you are going to use a solid type joint (heim, bollocks, etc) 150mm or maybe even a touch less will get you out of trouble as long as everything is strong.

I dont wana sound like a killjoy .. but of your asking these kinda question's at this point .. do you realy feel comfortable about doing this level of mod ??

I am looking at this as if I were doin it to my lux ..
If someone else designs it I would probarbly be able to follow a drawing weel enough to build it .. but for a street driven rig I would want to be sure that the design was good to begin with ..

love_mud wrote:I dont wana sound like a killjoy .. but of your asking these kinda question's at this point .. do you realy feel comfortable about doing this level of mod ??

I am looking at this as if I were doin it to my lux ..
If someone else designs it I would probarbly be able to follow a drawing weel enough to build it .. but for a street driven rig I would want to be sure that the design was good to begin with ..

this is mainly just throwing ideas around at the moment, i think i will end up just goin a 3 link set up mainly to keep road maners acceptable, and it has been done before and i have seen it work.