Suspension Set up

[MarkB]

Originally Posted by flyerncle

For self center to pass IVA set the mushroom hole in the middle to the front.
After IVA set the left with the hole at 11o'clock and the right one with hole at 1o'clock and this gives good feel to steering.

Far better to use centre machined mushroom and set the top wishbone in the correct position. All this over inflating tyres, toe out and offset mushroom is just a right old carry on as the car STILL understeers

[baz-r]

i find left foot jab on the brake and a lead right boot over comes the under steer and give a good amount of over steer
just wears the back tyres out a bit LOL

[baz-r]

all the light cars we had in for 4 wheel alignment (hillclimb and sprint) needed loads of camber on the front
softer springs and firm damping also improve things as do softer tyres and lower tyre pressure
its just a side effect of not having any force pushing the thing down
all made worse buy having no body roll to soak things up and a low more centered c of g

castor is only there to pull things stright and keep the thing going straight (what the offset mushroom should help)

if the start of a light turn feels unresponsive its could be too much toe out to twitchy and its mostlikly to be toeing in too much or the rear toe in reverse

if you ahve a problem later in the turn (half lock) it could be a problem with ackerman angle (not usualy ajustable) its basicly the angle of the tyre to its tyre path when driving in a circle as all tyres will have a diffrent radius of path so you could have toe in or out when the steering is turned
only way i can think of ajusting this on a roadster is to change the length of offset to the arm where the TRE mounts from the kpi line (note offset mushrooms have changed this length making its effective length longer) on or move the rack postion or change its rack length so the inner track rod pivots are a diffrent distence appart

rwd cars should toe in slightly fwd toe out at the front btw

also worth pointing out almost all production cars have positive camber to match the convex road serface (top out bottom in) not plum stright as you may think

im going to start with rear straight, front neg 1.5 deg camber and a tiny amount of toe in and the rest is trial and error with a thing like the roadster

also if you change the ride hight the hole lot will be out and you need to ajust it all

all just one big bag of worms realy

[David_17]

Sounds like you know what you're talking about What angle toe in would you reccommend as a starting point?

Also, any tips on setting the ride height?

Cheers

[MarkB]

The geometry is wrong to start with so get that right and adjusting for road and track use is made easier. It can be seen in ALL the pictures posted on the internet of the haynes cornering it goes into positive camber so the outside tyre is sliding.

[mark]

Originally Posted by MarkB

The geometry is wrong to start with so get that right and adjusting for road and track use is made easier. It can be seen in ALL the pictures posted on the internet of the haynes cornering it goes into positive camber so the outside tyre is sliding.

Wheres these fabricated uprights and new wishbones then?

You have me worried every time i drive my car that im going to understeer off into a ditch the ammount you go on about it!

Actually you dont as i go almost everywhere in tail out mode with my right pedal anyway

I am eagerly awaiting these new uprights etc though if they will improve the car

[baz-r]

sadly this is the problem when you use bits that where designed to fit a diffrent car with a diffrent suspension setup
why cortina uprights where used so much as it was simmular suspension
without having my chassis and suspension on one bit at the mo its hard to see where its all wrong but wheel camber should change as the steering angle is changed its to do with kpi
all the compounded factors of steering geomerty is a nighmare and i had to do weeks of the stuff at college

as for question on how to set things up as i said its a trial and error thing

and the comment on ride hight is to do with the nock on effect of changing ride hight as all the suspension arms and links have diffrent lenghts so when ride hight is changed it changes everything else so it should be set first

[baz-r]

Originally Posted by David_17

Sounds like you know what you're talking about What angle toe in would you reccommend as a starting point?

Also, any tips on setting the ride height?

Cheers

always set hight first! and only a small amount of toe but you would need garage equipment to do this (proper 4wheel stuff)
just set ride hight first set toe with string so its as close to zero as possible and camber gauges can be got but a sprit level or plub line would be fine for iva
once your driving feel and tyre fethering/would be a good tel tale or go get it on a four wheel aligner when your road worthy (thats what im doing)
road and track are also two diffrent kettles of fish when it comes to setup

[flyerncle]

I could be wrong but was the offset mushroom fitted to help with the built in anti dive built into the sierra suspension .