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View Full Version : 4-link lengths/setups



blair
8th March 2010, 07:22 PM
Hey guys,

For all those out there with adjustable/modified 4-link setups,

-What works best for you i.e. which arms shorter/longer
-How MUCH shorter/longer did you find best??

I'm looking at getting a spare set of arms to cut and shut, and just looking for some first hand info!
Edit: obviously they will be getting a new set of superpro bushes through them aswel.


Discuss :)

pen15
8th March 2010, 07:49 PM
i have been told stock is the best though i have spoken to a bloke who does alignment setups on race cars and he said it is sorta pointless on changing the pitch of the pinion as all that you will get is vibrations from miss alignment

driftke70
9th March 2010, 04:16 AM
maybe when he did a cut and shut on his vs and didnt use a ruler.

measure each one individually.

worked
13th May 2010, 07:19 PM
i've dicked about a bit with rosejointed adjustable, wound too far for slip (nose down) you'll get bad vibrations
i've set up my current bus noseing up slightly and it's heaps grippier, can stick with higher powered cars while driftng a bit better, well i think so anyway, could be wrong

blair
13th May 2010, 07:31 PM
Really? damn. The sole reason I'm getting adjustable arms is to point the nose DOWN more.

Not for grip/squat/wheelbase/whatever, but purely to try and keep the nose from hitting the underbody so much!

I would of thought it would make less vibrations, as i will be returning the angle closer to neutral? because when you slam a car, the nose goes up?

Or have i got it all balls-ed up :(

ke70dave
14th May 2010, 12:35 AM
i have been told stock is the best though i have spoken to a bloke who does alignment setups on race cars and he said it is sorta pointless on changing the pitch of the pinion as all that you will get is vibrations from miss alignment

then why buy adjustables?:P

its a trial and error thing, and its determined by alot of different things than just the pinion angle

the squat/anti squat thing is a personal preference, weather you like it grippy not or as grippy. and things that influece these things are

-spring rate
-damper rate
-centre of gravity
-tyres
-tyre pressures
-angle of arms (this is where traction brackets come in)
-length of arms (this is where boxed in equal length arms come in)

and this is only in a straight line.

who knows how it works in corners.

you are just gonna have to experiment i think, there are a few "rules of thumb" (in reference to which way the pinion should be facing) i dont know them, but ive read them before.

i say just wind the pinion one way, and see what happends. and hopefully just make it so it doesnt hit anything as well!!

i always thought it was a good idea to put as little strain on the uni joints as possible, just makes sense to not have them flexing around because of your weird pinion angle, but who knows what effects that has on geometry etc.

worked
14th May 2010, 11:54 AM
nah blair you can nose it down a fair bit before it starts vibrating, but yeh dave has it take into account the stress you'll be placing on your uni joints by smashing it forward. i am only saying wha i found, there are so many other variables to it all like dave outlined, but when i experimented that was what i found.
nose down equals more 'watah tah tah tah'
nose up equals 'wataaaaaaaaaaaaah'

blair
14th May 2010, 01:40 PM
Ok coolio.

Will report back in here after a couple of experiments/dori sessions

Konakid
14th May 2010, 04:02 PM
Keen to hear the results as ive got bushed adj upper arms in the wagon, havent messed witrh them yet just left tham at stock length. Might try pointing the nose down for more grip.

worked
14th May 2010, 05:45 PM
i thought nose down was more slip???

Konakid
14th May 2010, 06:00 PM
If thats what you found then it must be. Ill try pointing it up sometime.

AJPS
14th May 2010, 07:00 PM
nose down more grip

blair
14th May 2010, 07:04 PM
mint. sounds like trying to solve my slapping problem will yield a win win situation! :)

H8CHIR6KU
14th May 2010, 10:08 PM
i found the best setup for me was with the diff nose pointing up. no vibration and heaps of grip. but yeah the diff is just missing the body of the car.

ke_70
14th May 2010, 11:34 PM
this topic is such a grey area. someone says point up for grip some say down for grip????

this is the only area that i have no idea what to do with??
90a bushed stock
rosejoint unequal
rosejoint equal

how im going to adjust it. i just have no idea???
would be good to get some solid info on this stuff

FAST EDDIE
15th May 2010, 02:58 AM
this topic is such a grey area. someone says point up for grip some say down for grip????

this is the only area that i have no idea what to do with??
90a bushed stock
rosejoint unequal
rosejoint equal



how im going to adjust it. i just have no idea???
would be good to get some solid info on this stuff
try it yourself and see how much difference it doesnt realy make!!

blair
15th May 2010, 09:14 AM
this topic is such a grey area. someone says point up for grip some say down for grip????

this is the only area that i have no idea what to do with??
90a bushed stock
rosejoint unequal
rosejoint equal

how im going to adjust it. i just have no idea???
would be good to get some solid info on this stuff

It took me over 6months to finally make this exact descision man.
I'm going with 90A bushed arms built from scratch, using the stock ones for measurements.
This is purely because my car gets streeted, alot.
they're going to be a bit thicker than stock so that the threaded section is about the stock thickness :)

blair
17th August 2010, 10:35 PM
OKAY. after almost 6 months of rooting around, i'm back to square one.

Anyone looked at / used these?

http://www.nahux.com/NPOWER/PICS/SUSPENSION/KTA120.JPG
"KTA120 - H/duty adjustable lower trailing arm kit (on-car)" by Whiteline.

Not quite sure what bushes they have... cant seem to find much info on them hmmm

Dylan
22nd August 2010, 08:39 PM
These look to have poly bushes ,might be a better option for street driven cars. How bad are the noise/vibrations caused by rosejoints on 4links for those that have them?

keiichi
24th August 2010, 09:30 PM
those n-power things look kinda pointless imo, why not just get urethane bushings. or get rose links. you wont achieve anything really from moving the links around a few cm.

keiichi
24th August 2010, 09:32 PM
These look to have poly bushes ,might be a better option for street driven cars. How bad are the noise/vibrations caused by rosejoints on 4links for those that have them?

unequal length rose links make alot of noise n stuff because they bind i.e. push and pull on your seems when the diff yaws during cornering.

Dylan
24th August 2010, 09:52 PM
Ah understood, so equal length is the go then

assassin10000
29th August 2010, 10:16 AM
Equal length is nice, but a good trade-off if you don't have time/skills/money to do equal length is to use heim/rose joints on one side and a bushing on the other. Like the old battleversion and Cusco Jr link, 4-link replacement arms. Having the bushing on one side (urethane/stiffer than stock) and solid joint on the other allows for a very stable/predictable movement without the problems of binding, vibration, and noise you normally see with both sides being solid on an unequal length setup. The vibration and noise will still be present even with equal length if it's present in the rear diff (ie wont change), it will just have less chance of binding.

I've had solid/solid and solid/bushing setup on my car back to back trying things out and there is a definite difference between how the rear end articulates between the two. If running stock/unequal length I'll probably NEVER go back to solid/solid.


Pinion angle on our cars does NOT gain any traction on our cars, or at least the gains will be so minimal we shouldn't be able to tell (afaik). With a 4-link (or link style susp) the forces on the arms stay pretty much the same and transfer directly to the chassis. That's only something you worry about with leaf springs, slicks and drag racing. If you want more traction run traction brackets.

Andrew

blair
30th August 2010, 07:22 PM
those n-power things look kinda pointless imo, why not just get urethane bushings. or get rose links. you wont achieve anything really from moving the links around a few cm.

I have Urethane bushings already man :)

And i dont want the adjustability to gain/reduce traction, I want it to try stop the diff nose slapping the underbody so i can go lowerrrr!

but, if the whiteline ones arent urethane (they look fairly rubber-ish and cheaaap) then i dont wan't to backstep!


:(

slydar
30th August 2010, 07:51 PM
theyre definately poly bushed.

keiichi
30th August 2010, 08:17 PM
I have Urethane bushings already man :)

And i dont want the adjustability to gain/reduce traction, I want it to try stop the diff nose slapping the underbody so i can go lowerrrr!

but, if the whiteline ones arent urethane (they look fairly rubber-ish and cheaaap) then i dont wan't to backstep!


:(

ah yep, but i think if you go lower the diff nose points down no? either way, you are right to change it, i didnt think of that. you should go equal length setup with rose joints. thats what im going to do eventually, i want to go lower but im starting to get a huge reduction in anti-squat already - though its already low enough, scrapes rails :P
however, adjustable polybushed links coupled with some traction brackets should do the trick eh without the binding and noise you get from rose.
you could also get traction brackets with the hole drilled directly below the original so when its remounted it pulls the bottom forward and then remount the upper link further up the rail pushing the top back - centering the diff, increasing anti-squat even more, without pulling the whole diff forward and having to get adjustable polybushed arms.