Thread: Caster question caster was out -2.7

Originally Posted by ROVERNIT

I didn't say it wasn't going to be engineered what's the point of engineering a vehicle not complete, the moment I get the caster arms bush sorted its the next step, so please stop harping me about engineering I've been there before with moded performance cars

I didn't say I wasn't going to do it, there is really nothing out of the ordinary that cant be engineered, Slunnies was, and the only difference between his and mine is I have a cranked watts linkage and no one has proven to me there illegal yet and if so I'll remove it and eat humble pie and I bet his even sits higher then mine with his street tyres which are 34's I believe

Christ sakes you all comment on the thing yet you have never seen it or driven it and sorry most of you speculate on how it drives as you have never driven a 4 inch lifted disco 2, I only run 32's will have it engineered with 34-35 if legal

how many guys have cargo draws from what I've been told they need to be engineered too no one has them engineered I bet

as said before there are heap of 3 inch lifted fenders and Disco running 34 35 that are higher then my disco how many of them are engineered probably zero how about the RR which was out yesterday again monstered over mine he had an axe on the bonnet now that's not legal, are they engineered I bet you there not, and even if they are engineered are they legal

I have passed a many RBT hell I even tested the arc in a park on a bush rocks right next to cops and they didn't care luckily maybe they where having lunch

Come on let it go, and give me break, are bush the go or arms I didn't go for bush as they have the stigma that the reduce arc if they don't it is a cheaper option isnt it

Less whinging, more paying attention

You NEED to know what the castor is exactly, not "bloke not no, me sure not"

If its -2.7 as an actual figure, you require +6 degrees of correction, which is not possible with bushes, as they offer you 3 degrees max, leaving the arms as the only VIABLE without getting out the grinder and MIG

If it drives so freaking good now, why are you bothering to correct the castor at all??

[QUOTE=ROVERNIT;661256]

Originally Posted by Slunnie

On Simex's I sit 7" over standard combined and 6" over the D2's max spec ride height and it's fine considering its on Simex. QUOTE]

what do you reckon my one sits at over standard

The shadow across the sun? What does it measure?

ALSO, Cranked arms OR offset bushes, WILL have the same effect on pinion/tailshaft angle

Ok...

Breaking it down...

You want to run bigger rubber, you want lots of articulation and you want it legal....

Bigger rubber needs clearance.
You cut the guards out and lift the suspension, this gives static clearance.
Dynamic clearance (inside of guards, suspension components etc..) hasnt improved because the tyre (now larger) can still stuff into the guard the same as a stocker under load.

Fix, Lengthen bump stops to reduce up travel and prevent fowling of tyres on suspension components.

This makes the upper (compressed) portion of the shock redundant, as the bump stop prevents its use.

So fit longer closed length shocks, this removes the wasted portion of travel and enables a longer shock enabling longer down travel.

Now you calculate the open length of the shock, this is your MAXIMUM down travel and requires that other components in your setup comply with THIS factor...

Coil free length MUST be no less than this length at full droop or springs will click free or dislocate.

A work around is to retain the tops and bottoms of the coils OR dislocation cones... Your call, theres LOTS of arguments for both, its your personal choice here.

You have modified the clearances on the watts link so thats not an issue.

You now need to look at the ACE system...

It has ample scope for the lift you have, but needs clearance checks and centering again, using different links to centre the rams to their correct position.

Careful attention to the clearance at full compression and full extension MUST be taken, so start measuring!! And testing on an articulation ramp etc...

There should be no need to cut and relocate shock mounts with your setup at all.... You only have 14" shocks, although probably a 'little' too long (12 would have been perfect) its no biggie... and sortable by coil changes...

So, you fit longer and SOFTER coils with a longer free length, that will stop dislocation at FULL droop, but careful of COIL BIND at full compression (again Bumpstops play a part)

The softer you go the easier it will flex offroad, ACE will help control it onroad, but quick stages will risk bottoming out and work your shocks damn hard... (Be warned!)

So assuming thats all done......

Now turn your attention to drive ability...

Caster will be way out (it is!) so fit some (legal) 3 degree bushes, bringing it back and improving centering and reducing tramlining.

Now check how offset the front axle is.. You *may* need to fit an adjustable panhard rod IF its excessive.

NOTE: Bump steer will be induced more and more if the panhard rod is not PARALLEL to the ground... The more angled the more pronounced the bump steer will be.

If this is an issue you need to get a professional to LOWER the chassis mounts for the panhard rod.

Now, I know your aware so we'll just gloss over...

You need longer, ADR approved (small tag on the hose) brake lines, and longer ABS lines (which you've done)

You've also increased you C.O.G which needs to be countered...

So increase track by max legal with a wheel change (NOT SPACERS)... This helps offset the altitude increase.

So now you need some Flares to cover the tyres...!

Increased tyre width will need steering stop changes, so do that...

Now, you have 2 driveshafts trying to KILL themselves!
Custom shafts, with FULL lube points and DC joints for both front and rear shafts will be needed.... Not later, NOW.....

So that fixes *most* issues...

IMPORTANT: DO NOT TRY TO DO IT ON THE CHEAP>>> ITS GOING TO COST, BE PREPARED TO ACCEPT THAT AND SPEND THE MONEY ACCORDINGLY.

Now your brakes will need upgrading for larger tyres...
Better pads, slotted rotors is often enough for up to 35s with engineers blessing, but a set of 4 pot upgraded fronts doesnt hurt.

So you've done all this, and now the weak points are the drive shafts and CVs and diff hemispheres..

Get some Maxi Shafts, a HD CV and front shaft upgrade and replace the centres with a locker of one type or another... That strengthens the 3rd members...

Whilst your at it, change the Gearing to 4.11's for the larger rubber.

Get hold of a truspeed speedo correction unit, and rectify the now out speedo (engineering requirement). On TD5 Manuals this often looses the cruise control, at this stage no-one has been able to solve this, but its being worked on by a programmer I know in the UK...

Your nearly there by now if you've done ALL of this....

Now measure your headlights from the ground on the largest rubber you'll run... If the headlights exceed max allowed height your going to HAVE to lower the vehicle.... I cant see it being a problem with a 4" lift on a AU spec D2 though.

DONT FORGET, regardless of how big the engineer says is OK the maximum legal tyre sizes are dictated by the state authority in your state...

In Victoria for instance, that D2 running 37's which is "engineered and legal" is actually NOT LEGAL...

Maximum engineered tyre size in VICTORIA is 33"... UNLESS originally fitted with larger by the factory.

Vehicles in Vic, previously engineered with 34"+ are being recalled at random and having the 35's removed from approval....

By this point, all going well, its ready for engineering approval.

So good luck with your mission, but in the mean time... DONT DRIVE IT....

And also remember, on a moral point - that your machine, like all of ours, represents us as a group to the general public (you know, the sheep the media get to turn against 4wdrivers)

Keeping it tidy and not over the top, plus being able to prove its legally done and safe helps our cause... And covers your butt if something goes wrong!!!!

Originally Posted by rovercare

Less whinging, more paying attention

You NEED to know what the castor is exactly, not "bloke not no, me sure not"

If its -2.7 as an actual figure, you require +6 degrees of correction, which is not possible with bushes, as they offer you 3 degrees max, leaving the arms as the only VIABLE without getting out the grinder and MIG

If it drives so freaking good now, why are you bothering to correct the castor at all??

LMAO!!! Subtle...

But yes, have you tried an emergency stop on a cambered road?
I'm betting its not nice...

And self centering of the wheels would be greatly reduced, something that will become MORE pronounced with larger tyres and/or increased offset rims

Originally Posted by tombraider

LMAO!!! Subtle...

But yes, have you tried an emergency stop on a cambered road?
I'm betting its not nice...

And self centering of the wheels would be greatly reduced, something that will become MORE pronounced with larger tyres and/or increased offset rims

You asking myself or ROVERNIT, I know the effects of losing castor, I wouldn't lift anything now without correction, I use to drive mine (RR Classic) with around 5" bumpstop clearance, all set up to use it, the last thing I did was machine the swivels.......well **** me, how much of a pig was it before hand........6 years ago I learnt that lesson

I was asking ROVENIT why as a pizz take, with -2.7 its WON't drive like standard, you know that

Originally Posted by ROVERNIT

you would know better then any one when comes to the D2 lets pretend for moment that money isn't an issue would you go the arms from QT or the bush

It has no increment of a vibrations, it drives straight, it doesn't wonder any more then it did standard hight which I believe its the tyres it is overly bouncy though

if there is a small chance that the bush will cause variations then forget it I rather go the arms if there engine able

with out all this nonsense do you think my truck will be engineered In your opinion?????

now the thing has Springs, shocks, front lower shock mounts, spring retainers, wats linkage, and the x member spacer, I also have shims to correct the rear spring seat angle havent put that in yet though

If money were no issue then I'd rotate the knuckles if the pinion is pointing at the tranfer output. I wouldn't have a problem with doing that, and it's been done plenty of times before on other vehicles - but not the D2. I would get a very very good high level 4WD modification specialist to do this though, someone like Dobinson Engineering, perhaps Macquarie4x4 or OPW if he will. If the pinion angle is wrong, which I doubt it will be anything wild, then if money were no problem - QT radius arms, but it seems they will give no more than what the Superpro bushes will give and there is perhaps no reason to spend or engineer things unnesessarily when you can get the same end result. The QT will no doubt pass engineering. With Castor, its not a setting where you need it to be dead accurate like a wheel alignment for example. The more you have, the more the steering should self centre, track etc. If it drives straight and doesn't wonder, then is it a problem? If its the initial return to centre, then perhaps a RTC steering damper may help with the problem???

Ah... I understand. The chance of the bushes causing vibrations is exactly the same as the radius arms causing vibrations because at the end of the day they are just rotating the whole diff housing to regain castor angle, but a by product is increasing the pinion angle.

The bouncyness will be in the shocks.

I would expect that you'll be able to engineer it under DOTARS NCOP. Keeping in mind that max total lift is 6", which I interpret as being from the highest factory tolerance, so your lift will also determine your max tyre size in that repect. Under the old RTA guidelines, I'm not sure, as long as you can show the lift over max spec is no greater than 1/3 metal to metal suspension travel and then whatever tyres you decide to fit.

Originally Posted by rovercare

You asking myself or ROVERNIT, I know the effects of losing castor, I wouldn't lift anything now without correction, I use to drive mine (RR Classic) with around 5" bumpstop clearance, all set up to use it, the last thing I did was machine the swivels.......well **** me, how much of a pig was it before hand........6 years ago I learnt that lesson

I was asking ROVENIT why as a pizz take, with -2.7 its WON't drive like standard, you know that

Rovercare, sorry, wasnt asking you...

Was directed (poorly) to RoverNIT.... I know for a fact that it wont be nice.