[zookernator]

Hello friends!! Well, after doing the big 4 day trip to the west coast.. I’ve decided to go coils in the rear. The plan is either coil overs.. or standard coils.
Why: The rear is nice and soft, and also flexes sweet at the moment, BUT to stop axle wrap in the rear, and for the extra strength (im running lux diffs SOA, 35's, twin lockers) i put in hilux front springs into the Rear. These have proved to be nice and strong, BUT there bloody stiff!! I could put different springs in, but then i would need an anti wrap bar, and perhaps new hangers (again).. so if this is the case i may aswell go the extra step and go coils. As I said, the front is nice and soft (zook RUF and drop shackles).. and flexes really good, so its only the back im looking at changing for now.

The plan: At home I have a vitara rear housing (with control arms etc). Perhaps I could chop that up, and make up a custom vitara coil setup. Eg, using the vitara coils etc on the sierra housing, and making a 4 link set up with this. Just another option, which might be easier?? Or.. make a total custom set up, using.. well any type of coils!?!? I already have rancho 9000's witch are also already inboarded.. So, the next thing to work out.. 4 or 5 link?? Coil overs or standard coils? (would prefer normal).. should i use vitara coils, or another type? 3, 4 or 5 link?? Please.. help!!

[Gwagensteve]

Zookernator - this is my reply from Outers, which seems to be broken again. You'll notice there's lots of good advice on your outers thread about this job.

Quote:

Bear in mind get it up there that you've already got lots of things working against you

Very short wheelbase
High COG
Tall ride height.
The best link setup in the world can't change those things.

Also, the moment you lower the spring rate in the rear, the front will stop flexing until the rear fully flexes. That's going to suck.

At the moment, you have a soft front end and a stiff rear end. That's the preferable setup for stable and predictable climbing. what you are planning will reverse that, and it tends to unbalance the car.

With regard to vitara springs - bear in mind these are only designed for about 7-8" of travel maximum. Also consider that on a sierra chassis the springs have to go inboard of the rails, and that leads to very low roll stiffness, especially with a 4 link setup or an a frame. I'm going to almost guarantee that you'll need a rear swaybar to make the front work properly with that setup.

I'm coiling the back of my LWB at the moment. I'm using radius arms from the front of a range rover, upside down for clearance, vitara springs, a range rover panhard rod and OME N76 shocks. I'm deliberately using the radius arm design, even though I'm using a vitara rear diff with provision for an A frame because I WANT the roll stiffness the radius arms give me. I'm not trying to exceed maybe 10" of travel - well within the scope of rover arms and lifted vitara springs.

However, I'm also stretching my wheelbase to almost 100", and my car is low - I'm only running about 3" of compression travel a ride height, so my arms are quite flat and the angle change on them is small. That's going to be a challenge based on matching your front ride height and wheelbase.

With regard to coil overs - on a sierra they are going to be massive overkill, and quite hard to package - they'll come up through your floor in the rear, kinda killing interior room, and making for lots of hassle to close it all up - especially with a hardtop in Tassie, and that's before you play with valving, spring combinations etc. sure, on a comp car designed for huge hits and very high speed they might be great, but in a sierra I can't see the point.

Otherwise all the other stuff raised has been very sensible advice and many of the reasons that despite playing with sierras for 15 years, I'm only just starting to play with coils, and I'm cheating at that by using radius arms.

It's definitely going to be a body off job, and I'd be starting with a LWB so you can get the link lengths right and make the most of the advantages of coils.

IMHO the vitara setup is too short in the links, has excessive antisquat, and sits way too low to be useful for you. Also, it relies on the springs being outside the chassis to gain acceptable roll stiffness. Likewise Range Rover. Cars with rear A frames really have to run the springs outside the chassis to have any hope of being balanced, or else run heavy antisway bars to limit roll.

Just some thoughts.

PS I'd be building some upside down Caltrac traction bars run off the rear shackles first- these should allow you to de-rate your leaves enough to fix the ride. If that looks like too much work and too much experimentation, I don't think you're ready to coils. Not having a go, but there's lots of scope to stuff it up.

Steve.

PS it's just loaded on Outers, but I'll keep this here as not everyone on here reads outers, and especially the general tech page.

[kenn]

Zookernator, PM Joeblow he has already done coils on zooks and they work great. Not to say that Gwagonsteve is wrong, he brings up some good points..

PS looking at the stuff you build , I don't think you could stuff it up if you tried.

[zookernator]

Steve: Wow.. you hardly even bagged my idea out!! Wow, thanks mate!! haha, jokes. Thanks for the detailed advice.. i will definatly take it all on board.. it definatly makes sence!!

[zookernator]

kenn wrote:

Zookernator, PM Joeblow he has already done coils on zooks and they work great. Not to say that Gwagonsteve is wrong, he brings up some good points..

PS looking at the stuff you build , I don't think you could stuff it up if you tried.

I have already thought of PM'ing him.. but i remember reading a while back that his fla out atm with various things.. and i dont want to annoy him. But, if you are reading this Joe.. Please offer some advice?!?!?!? Thanks for the lovely comment/inspiration to Kenn,, bloody nice of ya! haha

[Taff]

Gwagensteve wrote:

Otherwise all the other stuff raised has been very sensible advice and many of the reasons that despite playing with sierras for 15 years, I'm only just starting to play with coils, and I'm cheating at that by using radius arms.

what are the reasons behind you coiling your ute? not happy with leaves anymore or just bored?

I ask as you seem to be
- Happy with your tried/tested/proven leaves
- Not chasing massive travel
- Ride cant be too bad in a lwb use with the right shocks, and you would be well used to it by now

[Gwagensteve]

I'm not really that happy with sierra rear leaves in a LWB. In SWB's they are fine because there's almost no room for anything much else, but in a LWB, there's more room to chase travel.

Cj's build has very long rear springs custom made, and they seem to be the business (currently unproven) but I wanted to try something different.

I've stretched the wheelbase 7", I should have no axle wrap, MUCH better ground clearance ( equal to a SPOA)

I've spent NO money on the back of my ute currently. It has totally flogged stock length shocks, and a collection of old OME springs and 2" bumpstop spacers.

On my last multi-day trip, I broke a leaf, collapsed a wheelbearing and destroyed the rear brakes. I fixed it temporarily.... then brocke a rear axle...It was time to spend some money, so it's time for Vitara rear full floater, discs, radius arms etc - try and fix everything in one hit, and yes, I'm a bit over leaves.

Steve.

[joeblow]

If you are going to consider going coils, the best bet is to go coils front and rear, that way you can balance out the package. A conversion of this nature is not to be taken lightly, and lots of time must be alocated to get it right.

Many people rave on about the benefits of going to coils being that of plenty wheel travel and better ride comfort. This is true, but the main benefit to me is the ability to TUNE ride height and spring rate, while still getting a nice ride. The key to getting it right will be knowing the wieght of the front and any potential load you may carry in the rear. Once those figures are known a good package can be designed around those parameters.

My vehicle for example uses standard aftermarket front Vit coils in the front, and aftermarket Vit rear coils in the rear. I have plenty of wheel trave, and they are by no means a very long coil. The front has a little too much travel, but this is realated to the current shock mount on the current diff and that diff is only a stop-gap until the new one goes in. I run an a-frame front, and a-frame rear. I also use a small Sierra lwb rear sway bar that was always in the design brief and was one of the first things to go in. Not only does the rear sway bar help with travel, but gives me very good handling on road. If a sway bar can be designed in, than my advice is do it! Relying too heavily on arms to provide roll stiffness may lead to excessive and early bush and mount failure. I use standard Vitara bonded bushes in my arms.

The design of you're coil placement will be determined by the chassis you are working with. Most of the time it is not possible to have the coils outside the chassis on the rear, but frett not, this is not a problem and most Jap vehicles run this setup. Pick the right coil rate, and this will not be a problem. Also, mounting a coil inboard will require less length for the same amount of travel as an outside coil, and give you more room to play with rates and still have adequate travel. My rear coils would be about 20% further in than my front ones....whoop de do.

It all comes down to measurements.....and more measurements. And don't rush it. The following pics will give you some idea of the way I setup some vehicles, and by no means are they the 'perfect' setup, they are just a good compromise with the design parameters I had to work with.

2002 Hilux running 80 series diffs.




I'm using a 5 link rear, with the top arms 30% shorter than the bottoms for better pinion angle during suspension cycle.




Rear coil seats are made from alloy and then bolted to a new crossmember. This can all be made outside the vehicle and welded in place even with the body still on. JK Jeep rear coils are used for thier rate, length and diameter.




The new c/member in place with bolt on coil mounts.




Front mounts also showing the bolt on brace that ties into the original engine mount.


Standard front Toyota arms are use because this is what the engineer wants to see.


I have used Nissan GU 3.0 litre coils in the front for rate, size and length.


One of the two new crossmembers installed. NOTE: This has gone from a torsion bar rate of 500lb to a coil rate of 275lb's, so going apeshit on extra heavy crossmembers is not needed.


Put some time and effort into the design process and the outcome will be great. And no, you don't need super long coils or super long shocks. I'm sure there is lots of other stuff I may have missed, but as you can understand its a very complex subject.

[Gwagensteve]

That's some very clean work there Joe - nice.

Must say though, the inference that it's unsound to use radius arms to control roll stiffness because it leads to bushing failure is false. My Gwagen bushes are in excellent condition after 18 years and they are the only thing Mercedes intended to control roll stiffness. Vitara bushes weren't intended for controlling roll stiffness, and interestingly, calmini achieve much better than stock rear articulation with very stiff urethane, so bushing function on a vitara rear design isn't critical like it is in a radius arm design.

Likewise, I have a collection of Range rover radius arms (no sway bar on early rovers) in the shed and they all have bushes in excellent condition.

I may still require a sway bar to tube roll stiffness, but I doubt it, however, I can't see the point in going to more effort to build a suspension with inherently no roll stiffness and then having to add it later - I'd rather kill two birds with one stone.

Just my 2c.

Steve.

[zookernator]

woah.. thats some neat work!! So you have done a coil conversion to a zook.. how did you find the overall outcome? I realise that vitaras come out standard with coils.. but thats STANDARD.. not a custom joby on a sierra. Also, do you reccomend going 4 link? And if you were to do it again, would you use vit coils again? Thanks champ! Sounds like i have HEAPS of planning to do!

[joeblow]

Kenns LJ and Tabs Sierra are both getting coils using Vitara coils. For ease of instalation and legalities they will both have standard 3 link front. The rear however will be worked out depending on the room we have available. The following pics are from a Sierra LWB chassis I did using Hilux diffs and Jeep coils. The only reason for the Jeep coils was the weight this car was going to end up.

[kenn]

"Is he going to do coils again" He'd better my LJ's next in line for coils


Best i get up there and tile your bathroom, It'll be Saturday week Joe, as I'm being a camera gnome for Simon at the Engal WC this weekend.

[zookernator]

sweet.. makes heaps of sense. Thanks matey!! Love ya work

[bron5on]

There's a tassie guy on here who's brother is doing a coil setup. Did you see it? FCsomething. Has "Our shed" in the rigs section. Also saw lada coils in a sierra on hilux axels and 35s in 4wd custom a while back if it helps. Can't have too much information!

[zookernator]

yup yup.. thats Trent thats doing it to. Might have a look at his set up in the near future

[Dee]

are you stretching wheelbase?
4 link takes up alot of space. Where are you planning to put the tank?

hope 11evl doesnt mind...

[zookernator]

thanks for the advise everyone!! Now, Does everyone think i should bother doing it? It seems like 4 link is the way to go, BUT to be able to do that might not be achievable due to the SWB factor. Eg: Fuel tank, not being able to have long enough arms etc. What are everyones thoughts? I did I quick measure before, and by making custom mounts/cross members etc, the longest I could have my lower arms are approx 1000mm, and the upper arms approx 700mm. I’ve been told I should keep these arms close together in length, and they should be kept parallel to each other. I have also been told the opposite!?!?! Where the diff sits now, it all misses the tank while articulating. The rear diff is moved back 1” from standard, and im running a vitara tank. 11evl said on outers he has done a 5 link coil rear on his swb, and loves it. So really all im left to ponder is “should I do it, and would it be achievable?” Please help me decide!!

[joeblow]

Zookernator, if its just a coil rear you are going to do than i would not bother, as at the end of the day it won't be very balanced, contrary to what people may say. Though, if you are willing to go coils at all corners the results can be, if done with alot of thought and effort, very rewarding.

You say you have lengths of 1000mm bottom and 700mm tops. These are great measurements if the arms are kept between horizontal and 20°. And yes, if you can keep the top and bottom arms as parallel to each other as possible that will help with input-output pinion cycling during straight travel. The angle of the arms will also determine how much it interferes with things like the tank. If done right the tank will not be an issue. And yes, while it would be nice to stretch the wheelbase this is NOT necessary, and comes down to the limitations you have to work with. Niether of the 2 zooks I am about to do will have a wheel base stretch, and they are both shorties. You can do 4 link with no panhard, or 5 link with panhard. Both will be determined by space limitations. Tab and Kenns vehicles will both be triangulated rears with no panhard.


The best advice I can offer is either keep it ALL leaves, or do ALL coils, don't waste you're time mixing the 2 systems.

Take a week off and come up to my workshop to see the projects on hand.............I will supply accomodation!

[steve]

zookernator wrote:

Does everyone think i should bother doing it?

I've had a couple rumbos so i thought i better give some tech advice

It looks like you have some good flex with what you have, so my question would be why go to a massive effort to get a different setup?

If you do coils i think you should do the same setup front and rear, don't do coils rear and leaf spring front, i think joe blow said that already. I think you need to have the same front and rear so they are equal.

If you want stupid flex do 4 link or A frame. 3 link i think would be great for more stable realiable front ends, as they have on Patrols and Cruisers, but 3 links won't give you flex.


Sounds like you have seen all the stuff i have seen about lengths and measurements, a lot of experts have fights with eachother on the forums and there';s threads with experts abusing eachother about what is right and wrong. So i got the impression that if people that know what they are talking about argue with each other about what is right, then it's must be a bit of a weird science about what is right.

When i set my front and rear A frame up i made and re-made the A frames 3 times trying to get it right as i had no one to help that knew how to do it. I have settled for what i have at the moment even though it is not 100% correct, but in research i found that people juggle with antisquat a lot. And some people don't beleive in antisquat and just say "just weld it and go"..

What i did take note of in research is, try to build in a lot of adjustment, so your 1m lower arms may be a good length, but try to build in some adjustment to you upper arms, in length and height. So if you find when you're doing a hillclimb and you're bogging down and not getting anywhere, or you're biting in and bouncing like crazy, you will be able to change the height of your upper arms and change the antsquat.

hrrm, gees.. more drinkies

[zookernator]

once again, awesome feedback fellas, thanks heaps!! Joe.. hehe i will hold you to that!! When suits you?? Flights are bloody cheap to melbourne these days!!

Steve: That makes heaps of sense what your saying.. i'm not looking at doing the conversion just to get that "coil flex".. its more for comfort, and reliability. Plus, i get bored very easy, and when theres rum in the fridge, and a shed full off tools.. things must be modified!! haha

[joeblow]

just give me a week or 2 notice. plenty of room in the house!

[steak_knife]

joeblow wrote:

just give me a week or 2 notice. plenty of room in the house!

If I come down, can I stay in ya shed??

[zookernator]

Hello everyone again Just wondering a couple of things.. what would be the pro's and con's on using all of the coil components off a GQ into the rear of my zook? (bundera housing).

Pros: Its seems like it would make life heaps easier, as most of it would be weld on jobs (rather then fabbing up all new mounts everywhere). The spring mounts etc would all suit the GQ coils, and i know where there is a set of bloody soft GQ springs that might go good in the zook!! Also, the GQ panhard rod and control arms would also suit the rest of it. Also, theres heaps of GQ parts available (funny that hey!!)

Cons: More than likely they may need beefing up a bit, but even if only used some of the GQ mounts, and any others i could fab up?

I am going to go coils in the rear to begin with, and over my next lot of holidays i'll look at doing the front, but at the moment its only the rear that needs work. So please.. help me out!!

[Ridge]

zookernator wrote:

Hello everyone again Just wondering a couple of things.. what would be the pro's and con's on using all of the coil components off a GQ into the rear of my zook? (bundera housing).

Pros: Its seems like it would make life heaps easier, as most of it would be weld on jobs (rather then fabbing up all new mounts everywhere).

definately right using as much of the stock gear as possible. it is what i am trying to do with my zook ute

zookernator wrote:

The spring mounts etc would all suit the GQ coils, and i know where there is a set of bloody soft GQ springs that might go good in the zook!! Also, the GQ panhard rod and control arms would also suit the rest of it. Also, theres heaps of GQ parts available (funny that hey!!)

why not use vit coils and try to modify the mounts slightly? The rear coils i have from a swb soft top vit fit perfectly the front mounts of a bundy diff. i only have to cut a small section away from the rear mounts for them to fit. im not sure but the bundy coil mounts on the diff could be similar to the gq, i can take a few pics and measurements if you want?

[zookernator]

Thanks Ridge.. unfortunatly i choppped off the bundy coil mounts when i put the housing in.. their probably in japan melted by now So either way, i have to put new coil mounts onto the housing.. which is why i thought i would stick with GQ. What vehicle are you using for the donor parts??

[Ridge]

i have gotten all my parts from 3 different cars. got the bundy diffs from a wreck along with chassis mounts for the control arms, and all the steering bits, air lockers too .
my coils i got from a wanted ad i placed and my motor came from another sierra.

still heaps to do before its in one piece

[zookernator]

uh huh.. sweet. So your planning on running bundy mounts (inc on the housing, and on the chassis), but on vitara coils.. is that right??

[Ridge]

yes but i dont have bundy chassis mounts. i have an idea on how i will make mounts if i cant find something i can use instead. here are a few pics to compare to the gq mounts

a rear coil on the rear mount,


the rear diff mount measures 82mm across at the widest section and 75mm long. the front coils are a tight fit in the rear, the rear coils can fit well if a small section is ground off the big bulge in the pic, 1 or 2mm.



the front diff mount has a 78mm internal diameter. both the front and rear vit coils fit well in this. a front vit coil is used below


i don't think that even the softest gq coil(2T+) will be good in a sierra. you might want to look at this link on vit/180sx coils http://www.outerlimits4x4.com/PHP_Modul ... -asc-0.php

[zookernator]

Thanks for the pics, and the link matey!! Those 180 coils sound the goods.. and even better, i have a vitara rear housing at home i can use the spring mounts as "donors" for the bundy housing!! By the wright up on that OL link, vit mounts, 180 coils on a budy housing should work well. Although, i have alot of weight in the back of my sierra (drawers, fairly heavy duty swing away spare wheel carrier, custom rear bar, full size spare). So.. the 180 coils might actually be to soft?? Maybe?? hmmm.. thoughts please?!?!?

[Ridge]

No worries mate. Im really not sure at all you could always try with the 180s and see how they go.
They will not be too expensive too buy a set to try them, i got my coils for $40.
HD lifted vit coils should be good too. In the next two weeks i start holidays so should have my rear diff stripped and ready for experimentation
here is a good link i found the other day on setting up everything
http://www.outerlimits4x4.com/ftopic89201-0-asc-0.php
What are you going to do with the front if you are going 4 or 5 link in the back?