? for guys running custom suspensions

[62fairlane]

for you guys running custom suspensions do you know what your geometery is? I am getting ready to lay mine out but I have no idea what range I should be shooting for on everything (roll centers and such) caster and camber will have plenty of adjustability in it so I am not too concerned about that one.

[TravisB]

for you guys running custom suspensions do you know what your geometery is? I am getting ready to lay mine out but I have no idea what range I should be shooting for on everything (roll centers and such) caster and camber will have plenty of adjustability in it so I am not too concerned about that one.


Do you have any software?????? I'm sure Dennis or someone will chime in here and let us know what is good and what isn't! I would like to find a decent software program to play with!

[62fairlane]

I am getting a copy of suspro3d later this week to use

[TravisB]

I am getting a copy of suspro3d later this week to use

Well then you should be able to put in all your measurements and ideas and test it????? Right??????? I'm not for sure but like you would like to know more!

[MarkM66]

Herb Adams "Chassis Engineering" book should help you get in the ballpark.

[TravisB]

Herb Adams "Chassis Engineering" book should help you get in the ballpark.

I have read that book several times it is very good :thumbsup:

[Musclerodz]

Having the software is one thing. Knowing how too interpret the info is another. If you already know how to read the info, then you should not have any problems. Otherwise I would contact someone who lives and breathes suspension analysis to help you out. That is what I did and was one of the smarter things I have done.

Mike

[62fairlane]

I got the herb adams and the staniforth book.....but they both just seem to describe what everythign does not what range of values a street car has. staniforth does talk a little about natural frequency of a luxo barge, sports car, built street sports car, mild track car, full track car...then then F1...

[race-rodz]

usually you will be working around variables or givens that will only permit a basis for the intial design, the idea with the software is to be able to run several simulations on minor changes, and what they will do to the over all picture. the whole layout is a bunch of compromises trying to get the best overall with taking every aspect into consideration.

my advise, input your givens, see where your at, then figure out a way to make it better. then when your all done.... let somebody who really really understands everything look it over.... btw..thanks dennis

[sinned]

Give me your numbers and plug them in, I use Wingeo3. Before spitting out a bunch of numbers it is pretty important to know what type of suspension you are going to be running F&R, intended purpose (realistically), and what type of car it is.

I PM'd a link to my proposed design analysis.

[62fairlane]

realistic goal is about 95% street use. I do live in the country so lots of twisties to drive on (that is just trying to get anywhere from my house) the 5% would be a once a year trip to a strip as a group outting type thing and there might be a 1.5mi track opening 25 mins form me....so maybe a little time there. I am having problems with my professor getting a stupid letter for the suspro3d discount so I think I might just lay the cash out for a full version of the performance trends software. I have been playing with the demo today (free 30 days) and think it migh tbe useful for the future. Well tomorrow my Sr Design group is getting together for a Bs session and working on the basics so I guess we will get a little laid out then.

[astroracer]

Go with the Performance Trends software. I used that for the Bad Ast project and I developed all of my suspension points on the 9 day demo. I have the SusProg3D software also and never really got anything useful out of it.
The PT software has a bunch of canned suspensions in it so you can use one of those as a jumping off point for your project. Figure out what your track width, tire and wheel sizes will be and use those to tweak the points.
Pay very close attention to the bumpsteer, antidive and roll center migration.
Your biggest obstacle is the steering gear. I used a Corvette rack as a starting point and let the program optimize the control arm points after I had all of the inner & outer tie rod & ball stud points laid in. These points need to be pretty close to actual as a lot of deviation will affect the whole package.
Mark

[Steve Chryssos]

I'm just curious how far from stock you will deviate? I.e. will you retain stock frame rails? Would you like to convert your steering to rack & pinion?

Stuff like that. I would love to see stock geometry compared.While not critical, it could be entertaining to see how much change is achieved.
/Steevo

[62fairlane]

we are cutting out the stock rails for 2x4 tubing. mainly this is because of some frame rot and ease of design. converting to r&p, all new points for everything. thinking of maybe L arms on the lowers though as that seems to be the trend in modern cars. Right now I am looking at using 1996 mustang spindles I have with a bracket bolted in place of the strut for the upper BJ (factory five does their cars like this as does griggs) so the only set points I really have are the lower BJ and steering points (planning on a mustang rack also but may change)

[Steve Chryssos]

Cool. This should be fun to watch. Keep us posted--lots of pix.

[Mean 69]

If you haven't yet bought the software, I'd recommend the Wingeo full car version, it is a darned nice program. I used the trial version of Performance Trends Suspension Analyzer, and also whittled up a rear suspension design with it, it too is a nice program. The Wingeo just seems to be a little more capable, nicer screen outputs, etc. Both use the same equations to calculate the various outputs, so the agreement in numbers should be the same. Either one is terrific, but to reiterate, getting the numbers out of the program is one thing, but understanding what they mena, and how it will affect the car is quite another. I'd highly recommend getting out to auto-x events or road race events to see what the folks are doing. Straying too far from typical setups can get you in deep water really quickly.

Most of all, have fun with it, it is tremendously educational to do this.
Mark