Kinematic Data & Modelling of FD Suspension

[TwistedHumour]

Hello to all!  Its been quite a long time since I’ve posted here but as I have a few FD related questions I thought it would be a good time to drop back in.

I’m going to be completing an investigation into the dynamic suspension characteristics of my FD which I will be starting in a few weeks.  I’ll also be looking at loads transmitted from the engine to contact patch through acceleration, and loads from the road back through the vehicle under braking.  

My main goal is to make a fully functioning kinematic model which can then be used to analyse how camber and toe change through ride height and roll, and to try and find optimum suspension settings.  The results of this will be down to the accuracy of my measurements and the information I can obtain.

I’m currently studying motorsport engineering & design, and whilst this isn’t an assignment or thesis it is of major interest and something I’d like to work on through my summer and continued spare time.

At the moment I’m trying to get a hold of as much technical data as I can for a bit of a background research and I’m just seeing what information is currently available.  I’ve found a few sites with generic sort of stuff but no real detailed technical data.

The things I’m looking for are at the moment are:

Powertrain & suspension pickup points with XYZ co-ordinates
Component dimensions or CAD models â€" doesn’t have to be to a high level of accuracy as I’ll be looking at individual items in more detail later
Any detailed technical data that may be of use
Any research data or papers that have details on the FD

Ideally I’d like to get my car to Uni to make use of equipment on site. More likely I will need to invest in a flatbed over summer and borrow some measuring equipment and record all the points I need at home.  I’m expecting this to be a bit of an ongoing project that will hopefully prove useful in the end

If anyone knows of any resources or if anyone has their own data that they are willing to share please let me know.

Thanks in advance
Chris

[turbotoaster]

Hello to all!  Its been quite a long time since I’ve posted here but as I have a few FD related questions I thought it would be a good time to drop back in.

I’m going to be completing an investigation into the dynamic suspension characteristics of my FD which I will be starting in a few weeks.  I’ll also be looking at loads transmitted from the engine to contact patch through acceleration, and loads from the road back through the vehicle under braking.  

My main goal is to make a fully functioning kinematic model which can then be used to analyse how camber and toe change through ride height and roll, and to try and find optimum suspension settings.  The results of this will be down to the accuracy of my measurements and the information I can obtain.

I’m currently studying motorsport engineering & design, and whilst this isn’t an assignment or thesis it is of major interest and something I’d like to work on through my summer and continued spare time.

At the moment I’m trying to get a hold of as much technical data as I can for a bit of a background research and I’m just seeing what information is currently available.  I’ve found a few sites with generic sort of stuff but no real detailed technical data.

The things I’m looking for are at the moment are:

Powertrain & suspension pickup points with XYZ co-ordinates
Component dimensions or CAD models – doesn’t have to be to a high level of accuracy as I’ll be looking at individual items in more detail later
Any detailed technical data that may be of use
Any research data or papers that have details on the FD

Ideally I’d like to get my car to Uni to make use of equipment on site. More likely I will need to invest in a flatbed over summer and borrow some measuring equipment and record all the points I need at home.  I’m expecting this to be a bit of an ongoing project that will hopefully prove useful in the end

If anyone knows of any resources or if anyone has their own data that they are willing to share please let me know.

Thanks in advance
Chris

best person to speak to is jon at atomicrex, his guy called ben there has taken all the measurements and showed me some software he created to show bump, camber, toe changes etc, i would say he would be the best person to ask for more information.

of course alot of your information depends on a few things, overall weight, tyre grip, suspension setup, aero, brake setup.

for example the stock fd comes with 16x8 wheels all round with 225 street tyres, firm but not hard suspension

my car is having 18x10 front with 285 track tyres and 18x12 rear with 335 track tyres, harder suspension, will have standard brakes and hopefully we can get the car to weight 9xxkg.

this means ill be able to brake later and harder than a stock car, but then will have less mass to transfer to the front wheels under braking

[TwistedHumour]

Thanks for that.

I\'ve previously bought some stuff from Jon but thought I\'d avoid asking any companies that make their living from those matters. I can understand that they wouldn\'t want to share their hard work, especially if that work gives them an edge

I don\'t need any information on aero, suspension  or brake setup.  The models main job is to look at how the contact patch changes in relation to the other parameters.  At this stage the springs and dampers wont be looked at.  However, it will be added later, and is something I can easily measure.

The limitations of the movement of the system will be dictated (mainly) by the contact points of the system.  There will be an amount of compliance in the system from bushes etc but again this isn\'t something I\'ll be adding to the first model.

The basic model needs to be right, to a good degree of accuracy, before I can begin looking at weight transfer and other more complicated details.  In an ideal world, I\'d be able to match the predicted data against some real data from a data acquisition system, but at the moment I need to be realistic.  I\'ve already asked if I can borrow a £20k PI system but my request was declined (no surprise :p)

With regards to weight, I will be looking at sprung and unsprung mass to carry out a few calculations but I seem to remember finding a thread somewhere with a breakdown of the weight of all stock parts.  That\'ll save a bit of work!

Thanks again
Chris

[turbotoaster]

http://www.rx7club.com/showthread.php?t=723617

try this thread, its a long one but there is alot of information on there, for example camber changes between different rates of bump etc

[shaunwil]

What kit have you got access to at uni ? Do they have any CMM measuring and CAD design available ? You could model it based of point information if you have phyiscal parts to measure.

Howard is a huge wealth of information on rx7club.

Shaun

[TwistedHumour]

Thanks for all that.  I\'ve read some of Howards threads before and found his stuff is always very useful.

I have access to CMMs at out chassis lab, but it either involves me taking the whole car there and doing it on the flat bed, or taking it apart and doing it piece by piece - not such a bad idea as in four weeks I\'m off til September!