I am at th epoint of designing the wishbones. wanted to know what design is better? The standard equal length arm and angle (for rear). Or the formula one type that has one arm connected to the back of the seat area. i beleive this transmits the acceleration forces to the chassis better but do you compromise on stability? Hope it make sense
Rescued attachment wishbones.JPG

not sure, where do you want to fit the rear end of it? If you allready have the chassis, you better stick to the original plan.

When you fit a standard engine, with less then 200 hp, i guess the forces are not that big. F1 uses engines with more than 800Hp, so there is a diffrent

it also affects your choice of joint, as bushes wont like bending in two plains if you see what i mean. You would maybe need rose joints for the F1 style setup.

Alain,
I suspect your drawing derives from early GP cars eg lotus 18 (!) & the well kmown jag IRS. The long bar going forwards is more of a drag link & on the jag IRS its forward pivot should be in line with the bottom link inboard pivots to give correct goemetry - JAG relied on squashing rubber to sort out the gemoetric errors in the design. If your inboard hinge is not parallel with the outboard hinge you'll get bump steer. If the hinges don't point straight forwards the brakes will make the back end move up & down.
See what others say & decide, I'm sticking with good ol' parallel Aframes!
Cheers
Bob C

hello alan i cant say which is better but look into the mounting position of rose joints very care fully as if they are side loaded like mine they can only take about 15% of there ratting
is wish i knew that before i finshed my irs back end
look at diggers thread on it
the wcm seem like a good way to mounted them
good luck dave

The fact that you're asking for directions, hints that you may not have the knowledge to pull off what you're aiming for. I would suggest sticking to The Book, and if it's not a Book chassis, then aim to make the rear end as per The Book.