4-link for my corona

[keiichi]

just heard about 4-links today. all i know is that they are to do with your diff and they make your wheels spin easier. dont really know though. could someone plz tell me how it works, why you want one and where i can get one or how to make one (im pretty handy with the fabricatings bro).
thanx

[keiichi]

alright sweet thanx. so do you replace the arms that go from the bottom of the diff to the car or are all replaced? are they adjustable?

[breno]

Yeah, they do come adjustable, and also rose-jointed seems to be very populer with these. Mabye if you just wanted a cheap upgrade you could replace the bushes in the standard ones,
They range from price from $100 to $1000.

[Javal]

Or.... you could just buy traction brackets.

ROB-AE86: you are correct in saying that the tailshaft goes down when you lower a car, and therin lies the problem. because the tailshaft goes down, the whole diff is on a lean towards the front of the car. as such, power does not go directly to the ground in the way in which it's supposed to.

When the diff is on a lean, peak force is no longer placed where it should be, i.e. on the contact patch between tyre and road, it is placed just after the contact patch. because of this you are correct in saying that it wil bog down easier, although i havent had a direct before-after experience in one car.

What traction brackets do is change that angle back to normal. they are mounted to your upper trailing arms (don't remeber on which end, it's been a while since i helped swap diffs, but im pretty sure they mount onto the diff and bolt onto the arms) and return the peak point of force back to where it was at standard (optimal).

Yr 11 physics y0!

These will probably be cheaper than adjustable trailing arms.

Javal.

[ae86 slide]

if your car is going to be a bit of an all rounder than yeah look into one of the options posted above (traction brackets, new bushes) but if it will be just for drifting and it will be staying NA, i really recomend a four link.
it lets you adjust how the diff sits, by shortening the top arms and lengthening the bottom ones it points the front of the housing down which will make your car more tail happy, adjust it the opposite and it will grip like crazy.
also make sure you get a set that have rose link ends, ive heard some nasty shit about the ball joint ones.

free ajps plug AJPS (http://www.ajps.com.au/corolla.html)

there called trailing arms on his site by tune adgent for 595,
the ones in the pic are actually my T3 set that are in my car now.

[keiichi]

somethings not quite right here. what javal sais is that the diff leans forward (ie. the front of the diff goes down yes?) so it bogs down (what i understand by bogging down is that you lose power and just slow down). but ae86slide is saying that when the diff is at that same angle it makes it more tail happy (ie it rips it up easier yes?). so from what i have gathered by the idea that you shorten the uppers and lengthen the lowers (which is making it the same as lowering the car) is that i should leave my car the way it is so that it rips it up easier cause its NA.

[RobertoX]

i will be putting 4 link im my new ae71

thanks for the plug man!

[keiichi]

so is there anyone who can safely tell me its worth the money?

[RobertoX]

your car will be worth $5000 then

[crazy86]

Forgrt the bit about the diff "bogging down", go by what AE86 slide said. when you lower a car with a stock 4 link, then because the top arms are shorter, the pinion angle points to the ground. When you get an adjustable 4 link, you can either bring the pinion angle up level, or point it down furthur, or even point it up toward the car, for some reason http://www.ae86drivingclub.com.au/dcimages/7/5/4/536981.jpg .

when you level the pinion angle, it returns the static suspension geometry to where it should be, and improves traction. The same thing can be said for traction brackets, but traction brackets are not as adjustable. PS, traction brackets go on the BOTTOM diff mount, to level the lower links, not the top link as stated above.

The best thing, is to change the stock unequal 4 link system for an equal length adjustable 4 link rear end, where all 4 trailing arms are the same length, so that as the diff travels through its suspension limits, the geometry changes as little as possible. This requires a bit of surgery on the car though, and it will most likely become a 2 seater because of this, so if you are going to this extent then you may as well also go for a watts link on the rear of the diff instead of the panhard rod, giving a completely adjustable roll centre etc.

[Javal]

1) When you get an adjustable 4 link, you can either bring the pinion angle up level, or point it down furthur, or even point it up toward the car, for some reason http://www.ae86drivingclub.com.au/dcimages/7/5/4/536981.jpg .


2) PS, traction brackets go on the BOTTOM diff mount, to level the lower links, not the top link as stated above.


3) so if you are going to this extent then you may as well also go for a watts link on the rear of the diff instead of the panhard rod, giving a completely adjustable roll centre etc.[/b]

1: up towards the car? haha, in theory

2: yes i realised this after getting under my mates car yesterday, edited as such.

3: Mmmmm, watts link... would be nice but who can be bothered? (bar race teams yo)

Javal.

[keiichi]

oh damn. what the hell is a whatts link? so much to know http://www.ae86drivingclub.com.au/forums/emoticons/tongue.gif i looked under my car today and the diff looked to be perfectly level. so whats with that?

[Javal]

Ok, time to crack out MS Paint....

http://www.ae86drivingclub.com.au/dcimages/4/8/4/3/117385.jpg

As you can imagine, lengthening or shortening the length of the upper and lower trailing arms (if you get an adjustable setup) will adjust the way the diff tilts (on all it's 3 axis, mind you, so measure them all against eachother). Traction brackets do the same, however they only effectively adjust the length of the lower trailing arms, and only adjust the tilt of the diff one one axis (forward / rearward roll, the one you want to adjust). The advantage of this is that you can have traction brackets in use with standard trailing arms. Disadvantage is that the adjustments are not as fine.

Also, supposing the rear end in your corona is the same as mine (i have an older model, xt130 bro) then you have a 5 link setup. 2 upper, 2 lower, 1 panhard rod. 5 links from rear end to body. but we're only worried about 4 of those 5 links at the moment.

EDIT: a watts link is like having 2 panhard rods. the panhard rod prevents the rear end from moving laterally, and goes from the mount on the body on one side of the car, to the mount on the diff on the other side. a watts link is pretty much 2 panhard rods, each mounting to the body at one end (one at each side) and then mount toward the centre of the rear axle. Sort of like a really wide V, but they don't meet in the middle(i think). advantage is it much more predictable and adjustable. (or this is how it was explained to me)

[keiichi]

well what happens when the diff goes up and down when you got the watts link. wont the links just be pulling and pushing againsy eachother?

with the traction brackets do you need to remove the old mounts and weld on the new mounts?

[RobertoX]

you normally just bolt them on the lower trailing arm mounts

[keiichi]

btw cool diagram javal.

[Billzilla]

Best that you guys a lot of research as to how suspension works.
Almost no-one in this thread has any idea what goes on. http://www.ae86drivingclub.com.au/forums/emoticons/sad.gif

[LAZY]

Bill, why do you say that?

[RobertoX]

Here is a watts link, should be pretty obvious how it works. Fitting one to your sprinter would be pretty fabrication intensive. Would include making the link, mounting it to the diff and then getting suitable mounting points on the chassis.

the advantages are that roll centre remains more consistent (doesnt wander side to side or up and down as much as with a panhard rod). Also adjustable rear roll centre height can be built in if its for a racecar (like in a v8 supercar)

and then there is also a mumford that I think bill knows about http://www.ae86drivingclub.com.au/forums/emoticons/wink.gif

http://www.teamvenomracing.com/images/slib/cobra/WattsLink-TA.JPG

The "traction brackets" change how much of the acceleration forces generated are transfered through the trailing arm links (as opposed to the springs/dampers). The ones you can buy for your sprinter will make the car pitch rearward less (squat).

The replaceable trailing arms are for setting your diff pinion angle which AFAIK effects tramp. Also the allignment of the rear wheels.

I wouldn't claim to really understand suspension that well but I think Bill is right (it is a fairly complicated subject though)

[keiichi]

ok ok....

[RobertoX]

keeecheee:

err you do know who billzilla is dont you???


me thinks editing what you just said would be wise

[Micknofx]

God damn I'm very very far from being an expert on anything with my car but I know enough (and have reads billzilla's site enough) to cringe at that last effort keiichi

[ae86 slide]

kechieeee, mate your digging yourself a hole here,
and you have it all wrong,
i can tell you for a fact that pointing the front of the diff upwards will make it grip, and angeling it down will make it slippery,
i have a four link in my car, and use my car to drift, if i had the settings wrong i would just be going for quick lap times around QR,
by the sound of it you should worry about it later once you have had a bit of track time/driving time and understand what will make your car handle better.

[keiichi]

sorry i take back all that lame crap i said, was late and brain not working, dont want to cause trouble.