Outer Limits 4x4 Board

I have fitted new suspension to the front of my hiluxs and had ( turboshop.com.au ) fit the coil over mounts and bump stops, the towers were lengthed by approximately 2 inch to the old setup to bring the truck height down have less compression and more extentsion in the suspension travel.... but it ended up huge.

My questions,

Should i change the coils to softer ones to allow the suspension to compress more, i currently have about 6 inch upward travel, or look at dual rates for the front?
I have a set of lifted spindles which will retain the same height but level the lower control arms out and better the steering, i currently have extended spindles which increase the seperation at ball joint end by 3 inches, lifted spindles will bring this back to standard.

Im finding it hard to find info so any help would be great as i cant leave it the way it is.

Definately go dual rate.
What exactly is your concern, did you have a planned suspension travel based on ride height that you were aiming for or are you just wanting to reduce some of the down travel to keep spindle angles at a safe limit.
Looks like a great set-up so far.




brooksy

my main aim is to get both control arms more horizontal. i thought by making the coilover hoop taller it would have lowered the ride height and leveled the arms but this hasnt happened.

I am beginning to think that maybe your coil layout may not be suited to the cycle of the arms you have. At a quick glance your upper coilover mount needs to be in 2" per side as your upper frame looks to be close to coil. Just guessing the cycle of the set-up obviously. Pretty hard to workout without knowing pivot point lengths & actually having better visual on set-up.
Is this a purchased kit or home grown (just wanting to confirm from first post whether fitting details are supplied or guestimated) ?




brooksy

hi, it is a manufactured kit.

The more i think about it, all i really wont to know is what you think about the angle of the arms, to me they look to steep? should the tie rod arm running parallel with the control arms, does it effect bump steer?

So is the pic with it at ride height & weight on it, if it is it is NOT good. Need a better pic sitting at ride height.What length are the coilovers & are they what is recommended. Spring rate could be way off too.



brooksy

At those angles you will be looking at grenading your CV's/DOJ's in no time unless you have lowered your front diff. It's not all about the suspension angles.

One thing you will find is VERY erratic steering due to the variations in track with suspension travel causing severe bucking of direction.

Weigh each front corner, work out where you want you "neutral" point to be in your suspension travel, do the maths to work out the suspension travel limitations (safe working angles for the DOJ/CV), try to work out your lb.in spring requirements, then backtrack to work out overall free length of springs. Any half competent suspension shop should be able to do the maths for you if you supply them with:

Max suspension stroke, or max allowable coilover stroke(taking into account CV/DOJ limits)
"neutral" height
leverage ratio (a frame inboard mount to suspension link attachment, and to kingpin or center of tread on tyre)
each corner weight

For a 1.8:1 leverage ratio and a guess of the weight of the corners I would be starting with about a 360lb.in spring as a best guess. Free length of the coils will be the major engineering matths.

Don't laugh, but I went through this whole exercise getting a 2.5" lift in the Kia (no one made them here, only 1.4" lifts) and ended up with about 320lb.in springs. Given the additional weight of the Hilux front end my guess at a starting point. shouldn't be far off.

there is no front diff or CV shafts so there is no drama there, the springs are 380pound which were originally for a cast 350 and T400 set up, im running a 1uz auto which is about 100kg lighter.

As for susupension travel i have Uni ball upper and lower joints with 12in coil overs, the limit straps pull the down travel up about 15mm short of full extention, and the hydro bump stops limit upward travel. there is alot more potential in the suspension travel but im limited buy inner guards as i didnt want to cut them out completely to fit larger towers. In total it is possible to get 18in of suspension cycle out of this kit but i have it limited to about 15.

Today i moved the engine back 60 mm to put more of the weight behind the front cross member, this bought the complete front height down about an inch and flatened out the lower control arm considerably. Now the bonnet height is bellow chest height ( im 6'1 ish ).

I have decided im going to leave it how it is until the truck is finished, still need to add front bar lights, fuel tank and radiator and remove the rear tub and fit the fiberglass sides so it is to hard to estimate a weight. A friend suggested having it put on the shock dyno at extreme motor sports, has anyone had this done?


NICK

I would wait until you have evrything on the truck. Personally I think 380lbs is too heavy sprung. I would be starting at 300. I remember a suspension guy coming over to Bartso's a couple years ago with various coils & he started with 350lbs & I remember talking to DGR about what weights we should be looking at. 350lbs coils were about 100lbs too heavy for our application but were probably only about 20-30lbs too much for faster application. This was also using a 2 stage set-up.




brooksy

I would be concerned about the suspension ever getting extended that far. In a corner if the suspension unloads it will tuck under and roll the vehicle.

I would start by removing the springs and setting the fully compressed height, from there you need to see what amount of suspension can be used safely which will dictate the shock travel. This would involve roll-centre calculations and a lot of controlled testing. At present that setup scares me.