vindaloo

On our cars we have springs and anti-roll bars to provide suspension and body control around corners. However, we only have four shock absorbers, not six to damp down excess spoinginess.

It seems to me that it would be better to have six. One on each wheel and one as an anti-roll-shock-absorber at each end. In theory this would be less of a compromise.

Maybe I've got too much time on my hands if I sit down and think this stuff up.... :-)

Vindaloo.

Apple

why not ten - as you say plus one on each side for going round corners?

then change all suspension bushes to springs & dampers...

and what would you use as anchor points for the front & back ones (ideally the road but might defeat the performance side of things )



yup, too much time on your hands...

vindaloo

Apple,

I was wondering whether there would be a response. After all, it's been three days and you're the first to respond (even if it is a p*ss take).

The idea for 6 shocks is that we have 6 springs, including the ARBs. With only four shocks to cater for bumps and cornering. The question is: How much of a compromise is made by having 4 shocks?

Only way I can think to do it would be to link top-left suspension to bottom-right suspension (and vice-versa). That's pretty impractical in a road car where one wants a drivetrain at one end and a boot for luggage at the other end.

Vindaloo.

ex-webby

What you're describing (i think) is a roll damper. Some forumla racers have these (including - I believe - F1).

Apple - not all ideas are stupid

I don't know of any road cars that have them (although there are bound to be some).

They are an incredibly powerful method of tuning handling, but only as a finishing touch once you've reached the point where you really need it. So not really necessary for our cars are there are so many compromises already.

Out of interest, how would you consider benefiting from them? (could be an interesting topic to discuss).

Apple. You can't use a damper instead of a spring as the car would sit down on the dump stops and pretty much stay there. The dampers are primarily for "damping" the springs.

Cheers

Simon

vindaloo

Simon,

Hopefully the improvement would be in improved body control during cornering transitions or steering adjustments. Steady state cornering wouldn't cause the suspension angles to change much (!?).

It was a question that arose from an idle-moment wondering but it furrowed my brow, so I thought I'd ask the question. I did think that it could be done on any car if hydraulics were used but that put me in mind of the BL (Rover) Metro.... so that train of thought became kind-of uncool.

Vindaloo.

Apple

Lars

OK now you have started.
Why not a anti roll bar from front to rear, to prevent dive and lift.

Citroen made a Xantia some years ago with no roll and no dive/lift. I have never tried it.

ex-webby

hehe

I wondered how long it would be before someone asked this.

I don't know the definitive answers as it's not something I've ever been asked to test / develop but..

If you think of the actual reasons for roll bars (in terms of performance) you are more likely to come up with the answer...

1) Control the roll of the body whilst not increasing the spring rates, why? ...
2) Keep the contact patch flatter on the road
3) tune the "roll couple distribution" (the difference between roll resistance of the front and back).

So, whilst having an "anti-pitch bar" would control the pitch of the body, it isn't as necessary, as the contact patch is not altered significantly in pitch (as it is in roll). Also, there would be no benefit (for a normal car) to alter the difference in pitch resistance between left and right.

Cheers

Simon

cliff_vtr

but the ARB is connected basically between a set of wheels rather than between a wheel and the chassis. Surely the current dampers will provide dampening for the ARB.

example right wheel goes up, ARB tries to push left wheel up to stop roll, therefore right wheel compress spring and damper and left wheel expands spring and damper

Cliff

ex-webby

Hi Cliff

The main difference is that the strut does not ONLY damp roll, it also damps pitch and general bump / rebound of the suspension.

A roll damper ONLY damps roll.

Cheers

Simon

ex-webby

To over simplify it...

the springs and bars effect the theoretical steady state of the chassis (once the car has settled into the corner) and the dampers affect the transitional states (when the body of car is moving around on the suspension).

So a roll damper is used to affect the transitional states more directly than the roll bars do.

Cheers

Simon

vindaloo

Lars,

Well not so much a front-back damper, but an intelligent suspension would help, allowing just enough dive for maximum effect braking and resisting lift and squat when WOT.

I think the Xantia Active does all of the above, in the thread (or tries to).

My latest thought is this.....
Cut a massively stiff ARB in two and stuff what is effectively a very tight viscous coupling and a sprung "clutch plate" type arrangement in the middle. Note, not a clutch but springs as in like in a normal, non-paddle type clutch. The "clutch plate" springs provide the additional spring effect of the ARB, whilst friction within the viscous fluid provides the damping.


Vindaloo.