Pictures of brake upgrades

[Error404]

I think we posted at the same time mate as i didn't see your either

Andy the roll sentre is pretty compliated to work out on a mcpherson strut...
i saw a diagram i while back explaining it i'll try and dig it out

[stiglet]

Thats the ticket. Draw a perpendicular line from the strut top (strictly speaking the steering axis) then a line from the wishbone. Then where they intersect, join with the contact patch centre and the halfway mark on the car is the roll centre.

Infact you don't actually need to work out the roll centre as such. Where the lines from the top of the strut and the wishbone meet, thats the instantaneous roll centre. That has a factor in camber change, which is the main thing i'm trying to change. The further towards the wheel it is, the more camber you gain.


Anyway, "holy thread hijack, Batman!"

[Error404]

No we just need a mod to rename it, delete Ant's post and we can carry on discussing suspension witchcraft

IIRC the roll centre with a Mcpherson is noamlly about 1/3 the distance between the arm pivot and the ground

[stiglet]

One thing worth mentioning, the reason Audi designed it like that is to keep the understeer nice and progressive. With these extenders, you loose that and loss of grip (whether its oversteer or understeer depending on what ARBs you are using) will be much snappier.

[Error404]

you really need to tune the difference between front and rear roll centre to get it nice and balanced.... i wonder if you can work out an ideal for a given ride height?
I'm sure I saw a bit of software to calculate these things.... you bang in weight distribution, spring rate, ride height etc etc etc and it works it all out for you.

[Rusty]

Start a new thread, copy and paste sticky. Simple.

[stiglet]

you really need to tune the difference between front and rear roll centre to get it nice and balanced.... i wonder if you can work out an ideal for a given ride height?
I'm sure I saw a bit of software to calculate these things.... you bang in weight distribution, spring rate, ride height etc etc etc and it works it all out for you.

You can do, with ARB's.

The roll centre height also has a similiar effect to ARB's in that raising the roll centre has a similiar effect to using a stiffer ARB, and the opposite for the opposite. So if the front RC is too high, then you can stiffen the rear using a Whiteline or something.

If the roll centre is too high, you can get jacking which is bad. And also excessive track change. The whole thing is a balancing act!

[anton]

lol there already is another thread about this! i posted it a few posts back. Alex has a picture of his car at the ring that shows the camber issues well, will be the same for everyone, regardless of lowering or not (unless you have stiffer springs at stock ride height) the issue is that the point at which the angle of the wishbone bushes to the ball joint hits vertical, the ball joint starts moving in, this will become a problem before this tho as propper camber compensation requires it to always move out. i'm not too bothered about getting more roll stiffness (from the higher roll center) its more of a bonus, i just really really really dont want positive camber on the front wheels at the limit lol.

neway....so these front A8 pics......back on topic you hijackers!!

no i'm fine with this becoming the new extenders thread just as long as i get one picture

Ant