Does anyone know if the rorty IRS can be changed to fit the +442 chassis. If so is how would i go about getting this info ?
quote:
Originally posted by ashtal
Does anyone know if the rorty IRS can be changed to fit the +442 chassis.
: wich part I have to widen, central part or wishbones?
seeing how the rorty plans are for standard sierra track.
i have left the centre part alone and just extended the width spanning members,
and also centalised the vertical tubes on the very rear part...i think..lol
this means your chassis sides are 2 inches closer to the rear hubs than a book width chassis.
hope all that made sense
[Edited on 29/9/06 by meany]
quote:
Originally posted by meany
i have left the centre part alone and just extended the width spanning members,[Edited on 29/9/06 by meany]
Hey macintosh, what's that car in your avatar?
quote:
Originally posted by kb58
Hey macintosh, what's that car in your avatar?
So no exact mesurements then ! 
quote:
Originally posted by kb58
quote:
Originally posted by meany
i have left the centre part alone and just extended the width spanning members,[Edited on 29/9/06 by meany]
Doing so will lower the roll-center, which may or may not be an issue.
Gents
I have a spread sheet that details how the roll centres change as you play with the set up of Rorties design if you e mail me on
d_n_malcolm@yahoo.co.uk I will send it to those interested
YHM
Macintosh, you don't have to widen any part of Rorty's suspension, the bit that changes is where the sides of the chassis are.
Rorty's plans are for a standard Sierra width rear track, if you are building a +4" chassis, the outer rails of the chassis will be 2"
closer to the wheels each side, than with a "book" chassis.
Check the plans, the extra width is in the area where you sit.
Glad this has come back to the top, I might have missed it otherwise.
I'm going to use the +442 plans but havnt decided between De Dion or IRS yet. As I understand what has been said here the alterations for IRS to
the back of the +442 would be the same as those to a book chassis. The extra width just means the body sides are closer to the wheels but there is no
other real difference?
As regards roll centre etc, where can I find out what effect it all has, & how to change it & use it to advantage?
I have Staniforth's Competition Car Suspension book but find it a bit heavy going.
Oooo, that was the very book I was going to recommend, since it's not too, uh, heavy...
Ah, shown myself up there then havnt I!
I've been through the book but I aint much the wiser. He tells you how to work out where the roll centre is but he doesnt really tell you very
well what the effects of the roll centre are, & why it's better to have it higher or lower in whatever circumstances you happen to have. The
book pretty much assumes you are dealing with a single seater, I know the principles are the same but it doesnt help. I work on single seaters every
day but they usually have John Deere or Massy Ferguson along the bonnet so it aint much help 
The problem with me is I learn best "hands on" & also that I dont just do what I'm told, I like to know & understand WHY I have
to do it.
I haven't seen it explained better than Staniforth does anywhere.
Cheers
Fred W B
Try this Excel sheet. It is based on the Staniforth calcs. It assumes that your chassis is plenty strong. Sorry but a book chassis is not strong
enough.
http://www.ncs-stl.com/Files/ChassisCalcsPublic.xls
AW
I've looked in the index of Staniforth's book & roll centre is only listed on 3 out of the 230 odd pages so it isnt excactly written
through the book like a stick of rock. To be fair I dont really find it heavy going, it just seems like it when you cant find what you want. I'm
not saying the book isnt any good, he knows his stuff & it will have been a great help to many people.
I've just started reading the Costin & Phipps chassis book at the moment & found a better explanation of it there.
Thanks for the help anyway folks & sorry for jacking the thead.
The calc's are David Goulds,and really helpfull. I put them into exel a few years ago, but there are if I remember two printing errors in there.