BirdmanMD

true story

#Rotor

Well I know for a fact, My Ackerman's angle intersect 15mm behind the rear axle and I need to have a steering rack, 10mm shorter, But I'll have to lie if I where to say I can feel it while driving....... So yes, suspension perfection is mainly theoretical, but that does not mean one should not strive to attain perfection....

eboostjr

insane , props on your project!!!

krustindumm

What program did you use for designing the suspension (susprog3d?)?

Ackerman is tricky to set up. Some claim that + ackerman is the way to go, some say -, I'd probably stick with zero (or whatever the spindles end up being if using some from a donor car). Then it all goes out the window once you start working it dynamically, because you can't really predict what your toe change due to body roll will be at any & every steering angle, Especially once you start changing ride hight (or if your steering rack is the wrong width ).

Have you ever heard of using a infared temp gun to set up your suspension? I've heard of it being used by circle track guys. The theory goes that you measure the temp across the tread surface, and change (mostly directly, sometimes indirectly) camber until the tread is an even temperature across the width. Thats when you know the tire is being used most efficiently. Not sure how well the trick works, but one of my friends just picked up a temp gun and I plan on borrowing it to find out.

#Rotor

I use AutoCAD for all my designing....


http://www.imaging1.com/razir.html

this should work like a charm..... for setting up....

#Rotor

kind of what it's going to look like...



this is just with a sheet of lexan in it.... works like a charm

ososlohatch

thats so gangster

krustindumm

uh, yeah, and $12,000. Cool though. I was a firefighter for 5 years and I used their thermal imaging cameras during truck inspections. THye were about the same price, they were greyscale, but fireproof.

Autocad works great for designing the structure. Susprog3d does an analysis of the dynamic range of the suspension. It does not let you design the control arms or anything like that, just where the pivot points of the control arms should be.

here's a random screen shot for a better idea of what I'm talking about.


Another suspension dimension you don't see very often was mentioned in SCC a year or so ago. The tech editor (Dave Coleman) reffered to it as the "Dave Spot", and it was defined as the point where the spindle axis intersects the ground. The important bit was the difference between that point and the center of the contact patch. That would be caused by spindle offset and by caster. Most spindles I've seen have little or no offset, but the 240sx does, and he claims that is one reason for they're popularity in drifting. It adds stability when at the limit of traction, which would be even more helpful in a short wheelbase car.

#Rotor

you mean king-Pin-Inclination, being such that the front wheel will rotate around a point, smack in the middle of the contact, patch...

ill have to have a look at that proggy, looks sweet.....



here is a little vid of the windshield's first outing on the car.....
http://www.youtube.com/watch?v=mCtRADxIm0U

krustindumm

no, king pin inclination is different, but if you used the line used for king pin inclination (so a line through the balljoints on a normal car) normally the spindle/axle is located dead center on that line, if the axle is moved forward or backwards from that line you can use it to create an effect like caster, without camber change while turning.