autopaul

anyone know where i can find free suspension software, that i can download and use to figure out the best mounting points and link lengths for my cusotm irs project?

im trying to use the fc hubs and lsd diff, to make a custom irs unit for my ist gen and im at the point where i have all the components and have started finding good mounting points on the hubs themselves, but i need to start figuring the mathematical portion of the project to make it look good on paper before i start spending loads of money and time making this thing,


sooo im looking to find out if i can get some suspension tuning software so i can make this project work, so if anyone knows where i can download a complete program free, or the names of some good products they have used, (thats not too complicated) please pm or tell me about them. thanks, and

any tips would be great, like if theres a good way to figure this out on paper, with ratios and compases, or something haha thatd be good too.

thanks

Paul

DamonB

I don't know of any free ones.

The only way to do it for free is to build simple scale models from sticks or paper etc. so you can easily change pickup points and measure the differences.

saxyman990

Unfortunately, I only know of one or two free ones and they are close to useless. You're better off crunching the numbers by hand, or building your own spreadsheet to help you out. Some relatively cheap programs are available for download (here's one example: http://www.rahul.net/dennisp/suspension/), but they are not all-inclusive programs. They are mainly setup to help you with springs and wheel rates, not geometrical design.

As far as complete suspension design programs, ADAMS is close to the best you can get. I use this program quite frequently. Unfortunately, it is extremely expensive. So if you're not serious about it, I would not suggest investing in it. An alternative would be SusProg3D. It's a very well designed program that has pretty much everything you would need. And it's relatively affordable (can be had for a couple hundred bucks). Any 3D CAD program can also be used to simulate car suspensions, they're just a little more cumbersome to operate (I use Solidworks fairly regularly).

Damon nailed it on the head though. If you're on a short budget, the best method to use is a pencil and paper, with the help of a scale model or two.

-Rob

DamonB

If you change your mind and want to spend money check out William Mitchell's stuff.

http://www.mitchellsoftware.com/products.htm

autopaul

awsome thanks guys

ok i can crunch numbers, whats the best way, like with a compas laying out a view from the rear, or what, all i have at the moment is the wheelbase, to the exact mm, measurements from the hub that i plan to use as mounting/pivot points, and imagination,

i can draft stuff, out, but i need a writeup on how other people have done this or at least a quick how to, if any of you guys have done it...

thanks guys, i knew this was the right place to ask,

Paul

autopaul

comon theres gotta be someone like me who is cheap, and doesnt want to take lots of time and money to buy and figure out fancy suspension software, and if not, can somebody tell me something cost effective that will work for my needs, ??

thanks again guys

Paul

GTRay

ok, i know this suggestion may not be the most popular but if you ever want a run down on the major points to look for when building a completely custom suspension all you have to do is check out Spike TV on the weekends. my favorite show for suspension fab is Extreme 4x4. right now they are working on a pretty badass double triangulated 4-link in a back halved old school Toyota FJ. It's all a matter of scale. Trucks also just wrapped up a nissan mini truck where they build a custom triangulated 4-link on air bags.

Ray

GTRay

as for your needs, build yourself some scale models. it's the only way you're going to figure it out. $25 in balsa wood, cardboard, paper and glue will get you pleanty of materials to build some models to figure out how things will work.

i would recomend using pieces other than the FC IRS hubs. The FC uses a swing-arm style IRS and the links are positioned to use that style. I would look for a car with unequal upper and lower control arms and copy that outlay.

it's not an easy project but it's not the most difficult one either.

Ray

TrentO

I forget which suspension book it is in, but one of them had the idea of using string to mock up the suspension. You build a scale template of your suspension upright, with pins placed where the ball joints go. You do the same for your proposed suspension mounts on the chassis. You take string and go from the chassis mounts to the ball joint positions on the hub carrier. You tie the string to the proposed length of your suspension arms and you have a functional simulator. You can use this to check camber gain under roll, etc. Low tech, but functional. The book suggested a scale of 1' to 2" when building the model, so it fits on a table top, but is still large enough you can pull measurements off.

I'd have to agree with GTRay, the FC suspension is a bad source for uprights. You'd be much better off going FD.

-Trent

2a+RoN

We use Susprog at the shop, I think it goes for about $300. It's pretty simple, but the coolest thing is that you can email the guy who wrote the program and he'll get back to you ASAP, plus he'll even update the software so you can download the latest version for free.

Eggie

Sounds like "Tune to Win".