Adjustable 4 link / pan hard / traction bracket

jondee86

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Jul 14, 2007
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so the ideal off the shelf setup for grip is to use traction brackets, arms with poly bushes,
rubber bush on pass side top drilled out
You need to define what you mean by "grip" ? Are you looking for straight-line drive off
the starting line as in drag racing ? Or are you wanting a car that sticks to the road during
cornering and keep the wheels in contact with the ground over bumps and rough surfaces ?

For drag racing you need the rear axle to be held as rigidly as possible against rotation
(rod ends), and controlled by short stroke double adjustable shocks with soft springs.

For handling in the twisties, you will want a reasonable amount of suspension travel, not
too stiff springs, and quality "Euro style" shocks such as Bilstein or Koni valved to suit.
Rubber bushes are good, as are adjustable sway bars for tuning the handling.

Poly bushes and rod ends are good for increasing noise and reducing traction. Add some
rock hard springs and shocks with heaps of compression damping, and BINGO you is
a hardcore drifter who can slide his car because now you has NO traction !! :hardogay::hardogay::hardogay:

Cheers... jondee86
 

Anastasios

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Oct 7, 2006
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the group a AE86s used chassis side bush with diff side rod end?

ive ordered the half bushed kit from grp4, is that a mistake?
 

Pat

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Nov 29, 2006
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probably not. it depends on a lot more than the choice of one componant in the setup. That being said, the grp4 setup has been treid and tsted by varying companies over the years and works well. it certainly helps with the binding issue, although it may still pay to drill out the drivers side (???) bush for extra squishyness depending on how soft a setup you have.
 

Anastasios

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Oct 7, 2006
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They probably were not allowed to cut up the chassis to use equal length 4 link like group N ae86, so I guess using bushed links on chassis side is better compared to rose joints?
 

Jimmee1990

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Apr 15, 2012
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Mount Dandenong
That's correct, in Group A you aren't allowed to change any of the suspension pick up points. In testing they were faster with half bushed half heim jointed rear arms than they were with plain bushes so while it isn't the ideal setup it isn't as bad as everyone makes out.
 

Anastasios

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Oct 7, 2006
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Yep that was my reasoning to purchasing the half bushed kit, if i do go equal length one day i will use rose joints.
 

jondee86

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Jul 14, 2007
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New Zealand
the group a AE86s used chassis side bush with diff side rod end?
ive ordered the half bushed kit from grp4, is that a mistake?
Suspension bushings rate like this...
Soft = OEM rubber, absorb noise and vibration
Firm = TRD hard rubber, as above but with less movement
Hard = Poly bushings, don't absorb much, but fit OEM links
Rod ends = don't absorb anything, no unwanted movement

Wear characteristics...
Rubber = never wears out, no maintenance, laughs at impact
Poly = needs to be lubricated, wears, flogs out under impact
Rod ends = get loose and flog out under impact

What you use comes down to how you plan to use your car, how much noise you
can put up with, and how much maintenance you are prepared to do. The problem of
"binding" is covered above, but you can consider it this way... if your car has stiff
suspension, is driven primarily of smooth surfaces and sits flat under hard cornering,
then binding is not going to bother you. Poly bushes or rod end will be fine.

But if you have long travel rally type suspension with lots of body roll, and drive on
roads with bumps and hollows, then you really need soft bushings to avoid transferring
excessive loads into the mounting brackets. Poly bushings are not totally rigid, but
they don't have much give. I see that the GRP4 kit is listed as a Tarmac Rally item,
and as such I would expect the cars using them to undergo regular inspections for
cracking, as well as bushing replacement.

The GRP4 stuff appears to be well thought out and made, so when you get the kit
installed on your car, post up your impressions :)

Cheers... jondee86
 

Jimmee1990

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Apr 15, 2012
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Mount Dandenong
Under hard use, rubber bushes wear out far faster for me than urethane? If your having issues with pick up points stretching/tearing using softer bushes is a bit of a band-aid solution. Why not stitch weld the brackets to the body and enjoy more consistent suspension movement and fix the issue properly?

Another issue I have is if your car sits flat enough during cornering that binding is no longer an problem, you have almost zero suspension movement and I really doubt the car would grip well at all. Some weight transfer is good.
 

jondee86

New Member
Jul 14, 2007
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New Zealand
Under hard use, rubber bushes wear out far faster for me than urethane?
Interesting... what kind driving are we talking about ? Gravel rally ? Tarmac rally ?

I have looked at links and shocks and generally speaking the rubber bushings will
be in good nick, and the poly bushes will have oval holes in them. For sure, I don't
know the history of them, or how hard they have been used, but I'd guess road use
and a bit of track.

The TRD bushes I have now are full rubber, and somewhere I have seen a picture
of moulded rubber bushes with "channels" in them to make them more flexible. This
would be the equivalent of drilling them. Strengthening mounting brackets to stop
them moving under load with poly bushes or rod ends, simply makes the binding
problem worse. Anyone who is having a serious binding problem should definitely
be looking at equal length trailing arms, or perhaps a three-link rear end.

Cheers... jondee86
 

Jimmee1990

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Apr 15, 2012
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Mount Dandenong
This is daily road use, with the occasional hill climb and circuit day. If you run the car at a sensible height it's also far less of an issue with the arm angles and binding. I am looking at an equal length three link rear with a roll centre adjustable panhard rod however as I'm still chasing more traction.
 

jondee86

New Member
Jul 14, 2007
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New Zealand
This is daily road use, with the occasional hill climb and circuit day.
I have an AE86 that was a daily driver for 20 years, and in the first five years of its
life it did street sprints, sealed hillclimbs and club circuit days. It is still on the original
factory rubber bushes and there is no sign of wear or softening. Mind you, it only has
86,000 km on the clock.

If you run the car at a sensible height it's also far less of an issue with the arm angles and binding.
Exactly right, and the pinion angle stays within a better range. This car mentioned above
was fitted with a Koni suspension kit (Koni lowering springs and Koni yellow shocks) which
dropped the car about 40mm. Oh, and traction was never a problem with stock power :)

What springs and shocks are you running ?

Cheers... jondee86
 

Jimmee1990

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Apr 15, 2012
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Mount Dandenong
I'm running Shockworks coilovers, and it's more of a balance issue as I've changed a lot with the front end geometry and have a massive amount of front grip now when compared to the rear.
 

Anastasios

Member
Oct 7, 2006
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Sydney
Guys what is the best way to install?

set all arms to stock length

install traction brackets

install top arms

adjust lower arms to suit traction bracket?
 

Bluesprinter

Member
Aug 25, 2008
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Sydney
^ yup pretty much

you can measure pinion angel first then install and make sure its the same angel after if your really paranoid
 

Anastasios

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Oct 7, 2006
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Sydney
Ended up needing to give the original brackets a couple of whacks with a sledge to allow the smaller tube spacer to fit