kpi camber caster & toe

[breezeblock]

i am going to build my own front uprights and wishbones what is the optimum kpi camber caster & toe that i should use it is going to be a double wishbone set up along kinda cortina lines

[bugs]

????

[R59]

Originally Posted by breezeblock

i am going to build my own front uprights and wishbones what is the optimum kpi camber caster & toe that i should use it is going to be a double wishbone set up along kinda cortina lines

Will it handle like a Cortina then?

Hope not...

[johnny yuma]

measure up the"kinda cortina"specs,then build something with ample adjustment available to camber and caster so you can experiment. The kpi should be such that the center of your tyre contact patch on the road is not very far outside a line down thru the centre of your two outer ball joints.Dont forget to get the Ackerman angle right if you are fabricating the steering as well...read a few books, there's some tricky geometry in there that took big car manufacturers years to explore.

[breezeblock]

The only one i cant make adjustable is the kpi the cortina has a kpi 7-8 I was recomended to use no less than 5 This gives a scrub radius of 50mm the position of the top and bottom ball joints on the cortina uprights gave me 100mm and the steering was very heavy The size of the brake disc prevents me from getting the kpi line right on the centreline of the wheel

[Goran Malmberg]

Originally Posted by breezeblock

The only one i cant make adjustable is the kpi the cortina has a kpi 7-8 I was recomended to use no less than 5 This gives a scrub radius of 50mm the position of the top and bottom ball joints on the cortina uprights gave me 100mm and the steering was very heavy The size of the brake disc prevents me from getting the kpi line right on the centreline of the wheel

This is one very complex question where the solution is limited by practical and economical factors. As you point out yourself, the disc is setting a limit for scrub. Well, you have to use a more positive offset wheel to get the spindle and brake equipment inside the wheel. You say you are going to fabricate your own spindles and A-arms, then this operation is possible to relize. You may even be able to use less that 5 dgr spindle to kpi angle with reasonable scrub.
KPI creates steering lift, either way the wheel is turned, and it also creates positive camber on the outer wheel during turns, which we do not want. Some drivers prefer a small amount scrub for steering feel.
If you are fabricating your own spindles, you may take a close look at where to possition the steering arm in order to get a good bumpsteer.
Also the Ackermann angle has to be thought of.

Goran Malmberg

[breezeblock]

what would be the consequences if i used 0 kpi

[ubrben]

Originally Posted by breezeblock

what would be the consequences if i used 0 kpi

You'd get no positive camber with steer, this would generally be a good thing. Problem is I'd be surprised if you could achieve zero KPI without an excessive scrub radius. I would suggest that the advantages of zero KPI would then be lost to excessive steering weight and kickback.

Ben