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Discussion Starter · #1 ·
For (today's) dream project ;) I'm thinking of an IFS with inboard coilovers, mainly for aesthetic reasons.

Can anyone point me in the right direction for reading/research material relating to the ins & outs of suspension (more specifically IFS/IRS).

Don't want anything overly technical, but something that explains why A-arms should be unequal length, why rose joints should be fitted with the 'eye' in a vertical plane, etc


I appreciate the spherical nature of the rose joint means movement won't necessarily be better one way or the other but my logic tells me there's more risk of the sphere part 'popping out' of the surrounding ring of mounted with eye vertically.
Or are the braking/acceleration forces greater than 'normal' up/down suspension travel thus better as per pic?

(have I just answered by own question?)

:tup:
 

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My name is Martin
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Have a play with this. It will help you understand the impact of the wishbone lengths etc to the camber etc.

EDIT - Pooop

Your file of 129.6 KB bytes exceeds the forum's limit of 97.7 KB for this filetype.

Si - Can we increase the limit pretty please?
 

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There are loads of suspension design books on the market, shop around on Amazon for example.
Everything has a reason for being a certain way. That pic you posted as an example....
The rose joints fitted that way are fine, but, it will limit travel,but, as the arms are long travel at the joint will translate into a lot of movement at the wheel.
Inboard coilover loacations are nice as you can easily change the ratio of the lever allowing for shorter shocks in a confined space. Trade off is heavy springs.

This is a huge subject so read all you can and make sure you understand it all.
 

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Bearing in mind that the rose joints used are high travel and not standard.Personally I'd never run it like that on the street, fine for a biliard ball track but potholes etc ..no way !

I know of 2 road cars set up like that , one of them broke within the first 500 miles of use.No idea how the other one is fairing but haven't seen it about after it's first year on the road.


Ross, the trade off IS heavy springs but also loss of space ( whne you've a big hole in the A arms that could be used ;) All depends what style of car you are trying to put together.

In my own experience the more complicated suspension can be a pain to get right , and a pain to live with on the street .I'd try something a little less complicated for my first attempt at suspension design.
 

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I remember that car well. It had top rocker arms, ie there was no pushrod or pullrod the shocks were worked directly off the top wishbone.
'Bones were tubing ,plated over for aesthetics. Too heavy looking imho.
 

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Discussion Starter · #7 · (Edited)
Never seen this Andy Robinson built MR2 based roadster but it's got it all going on at the front!

http://www.robinson-race-cars.co.uk/

Go to 'Customer Cars' then Sas Hunters.
Thats very much what I have in mind (mid engined), with IFS along the lines of a Sylva



Kapri, not thinking of using rose joint as know what a harsh ride they'll give (plus as my knowledge of setting up suspension is, er, minimal to say the least!)
This is all very theoretical at the moment, but interested in understanding the various principles, pro's & cons etc

For example, digging through a load of CC back issues found some pics of an Oakland winner with very suspect looking IFS geometry, & the editorial at the time
said as much. Fred Warren's 37 I think
 

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My name is Martin
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Thanks Si for lifting the attachment limit :tup:

This spreadsheet will help demonstrate the impact on the camber and roll centre upon cornering and normal suspension up and downy movement. Enter all the variables in the top left hand box.

Have fun with it :)
 

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Discussion Starter · #10 ·
Thanks Si for lifting the attachment limit :tup:

This spreadsheet will help demonstrate the impact on the camber and roll centre upon cornering and normal suspension up and downy movement. Enter all the variables in the top left hand box.

Have fun with it :)
Thanks! My head hurts already... :D
 

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i loved the c4 irs/ifs in my 56 f100 so much i put it in the nova, if you can find a set ( i bought the front and rear complete from a teacher in scotland for 500 quid!) it is easy to fit coilovers instead of the glass leafsprings and if you can ally weld then its easy to narrow the rear end halfshafts too, i narrowed the rear 6" so i didnt have to fit flat sided wheels i have 10" rims with 5" backspace, it is very lightweight as its all ally and polishes up good too, the earlier c4 (84-87) is better for rodding as 88 on they got wider and bigger brakes so you cant fit less than 17" rims , mine are 15" still and the brake discs are a third of the cost of 88 and later, i used a us company www.progressiveautomotive.com for info as they specialise in vette stuff (and others too) for rods and musclecars etc,i think my nova is nearly 300lbs lighter than stock due to a lighter front clip and rear end,
 
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