[ylee coyote]

Hows this for an Idea (PAT PENDING)

On the 9000 the front ar bar is coupled to the wishbone with a drop link

Idea
substitute one of the drop links with a suitale length and bore double acting pneumatic cylinder
control the ports with poppet valves and restrictors and you could ....
decouple it for max traction
in yaw shut both valves for max anti roll effect
on the straight ahead somewhere between the two
All you would need is a couple of accelorometers and a simple control circuit and roberts your mothers brother
even more simple is just have a poppet valve so you can switch it on and off (poverty spec )
If I can find one the right size might even try it @ anglesey...

 

[California Saab Tuner]

Very interesting idea ylee!

However you will need to make certain that the pneumatic valve can actuate with the force of several hundred pounds, and quite quickly!

Also you might combine it with an acitive pneumatic actuator at the rear set of wheels. In effect to steer them slightly, such that the car goes through the bend more controllably. It would allow you to setup for understeer, and then compensate when necessary by scooting the rear wheels slightly outward.

Put the two ideas together and you'd have some real fun! Though I think it would be even better if the actuators were electic so that you could control them electronically, and more quickly. But vacuum pneumatic ones (similar to a brake booster setup) might prove more cost effective for a do-it-yourself-er over the long run.

Just some more ideas.

Even simpler idea:

The anti-roll bar in the front is only usefull really when braking. When accellerating it may as well not be there.

So why not make one that worked like a bump stop? When braking it hits the bump stop and the anti-roll bar keeps things level, but when accellerating it went the opposite direction from the bump stop and it essentially wasn't there.

Basically the suspension can move downwards to grip the ground properly, but not upwards so as to prevent nose dive under hard braking.

Sound simple enough?

Might take some calibration, but it's simpler than pneumatic actuators, and if done properly could maybe even be nearly as effective for much less effort/money?

Dubbya~

 

[genuinesaab]

I tried it on my 79 99 racecar. Well sort of, It had airbags in the rear (no steel springs) It takes lots of air. My problem was speed. The air was too slow. Hydraulic, borrow from the P/S into an accumulator.. The cylinder life may not be as long as expected due to the shock loading. Sounds like a fun project...

The main reason I had air in the 99 was for the clutch sytem.. Push button.. Works great till you drive a regular car. (gearbox crunch sound) Need to do it to my Viggen.. We never got Sensonic in the USA. It was nice in traffic.

Those new Carbon NOS tanks would be great for Co2 or air at high pressure and rather light.

Nick Taliaferro

 

[ylee coyote]

Its simpler than this ..
the piston acts passively with no air pressure
it is effectivly an extendable rod that you can control the rate of extension or contraction when a force acts apon it to stretch or contract the rod
the control circuitry acts to direct the flow of air from the compressed piston cavity to a variety of flow resistances
(or vacuum to an extended piston cavity )

so instead of relying on the dodgy characteristics of a poly bush to transmit the force you have an infinitely variable, both in bump and rebound,rod

see what I mean...?

 

[grentarc]

sounds similar to the Landrover ACE system.. it uses 2 accelerometers , one in the ceiling and one in the floor, to tell when the car is starting to lean, then pimps hydraulic fluid into pistons to level the car out... works quite well, and allows smooth ride on rough surfaces, because the arb isnt solid

 

[Mark B]

Originally posted by Adrian W:
[qb]Even simpler idea:

The anti-roll bar in the front is only usefull really when braking.  When accellerating it may as well not be there.  
Dubbya~ [/qb][/b]

And I thought that an anti roll bar was to prevent roll (when cornering), not dive. Or am I missing something?

 

[mark e]

I'm with you, Mark- although I can see how the front ARB might help control any side to side pitching under braking.

 

[ylee coyote]

the debate is whether a front a/r bar works or not
Abbott for one advocate not having it which has some merit because it allows both front wheels to track bumps and undulations and so maximise traction..(on the straight) however alowing it to roll more (at the front ) which you might be able to offset by stiffening the rear where the need for independant movement and maximising traction is not as important
so in my system you could decouple it for the straight bits but "couple" it when it rolls so getting the best of both worlds...
or have I missed something ?

 

[California Saab Tuner]

You could also do completely away with the front roll bar, and then use what I would casually call "dive bars".

The idea being the same as an anti-roll bar, but instead of going from one front A-arm to the other, going from the rear suspension to the front.

Hopefully it would prevent excessive pitch under braking much in the same way normal anti-roll bars prevent excessive roll under hard cornering.

It would need to be a one way device to be effective. So it could not be used to control front end rise under accelleration without causing loss of traction. So your rear shocks and springs would need to be used to control that.

Still ... all of the above methods would require quite a bit of doing to setup properly.

The simplest solution is just to get a really hard rear suspension setup (springs, shocks, swaybar) and learn to deal with the oversteer by using the throttle. Much the same way many RWD cars have very hard front suspension, and simple power slide when they want to go neutral ...

... or we could go out and buy an AWD car.

But I wouldn't until one is available with more than just a Saab badge.

Dubbya~