To much thought!!

Should throw some in the morris?

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Take it easy, & if it's easy take it twice!!

If you remove the rubber cone or the hydro unit it is going to totaly change the suspension setup, ie there will be none, just the air gear....

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If you want more inches, stroke it
Life's a garden.... Dig It!
http://www.ausmini.com/forums/viewtopic.php?t=20746

air bags, are like coilovers.. you need to do your home work to get a satisfactory result.
the larger the diameter of the bag or cylinder the more the stiffness of the ride... just like the diameter of the wire made to get your springs........(also the number of windings)
air bagging is in its infancy and is still just used for its bling factor more then anything. Don't expect to retain your handling with a universal air bag kit........ changing the ride height is all its good for.

I don't completely agree.....

Yes, this setup (cans) that I refer to is very similar to coilovers, and I do need to do more homework. Mainly how to fit into a mini, not on the equipment itself.

No, the diameter of the bag does not dictate the stiffness of the ride. Ride height and stiffness is controled within the cab to the drivers requirments.

No, airbags are not in there infancy they have been putting them in trucks and cars for many years now. Airbags are a very similar idea to hydraulic suspension which has also been used in cars for many years.

And, hydrolastic suspension is pretty much the same thing.

As far as handling, I think if set up properly you would be hard pressed picking the difference.

Have you tried to compress air lately.

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Take it easy, & if it's easy take it twice!!

It looks like you need to do a lot more homework. You need to look at the ratio of the suspension arms and how it effects leverage.

You may be able to control ride and stiffness but can you control the rate?


I know how much trouble I had 25 years ago when I was doing the all the trouble shooting on Airbags in trucks. Nothing has changed except the control valves are better (But the bags themselves still have a lot of disadvantages)


Name a car with hydraulic suspension?


Total bullshit. Hydrolastic suspension uses rubber as the spring, how is that the same thing?

You just don't get it do you?

Air compresses quite easily which is why it is inferior to rubber and steel as a suspension medium.

But compress' less the higher the PSI, comfort low PSI, performance High PSI.

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Take it easy, & if it's easy take it twice!!

Spring rate. You know how you make the coils thicker to make the suspension stiffer? Well that is spring rate.


Wrong! Citroen has hydropneumatic suspension. (notice the pneumatic bit, that is the spring!)

Hydrolastic is called Hydro/Lastic because that is what it is. Hydro (water) eLastic (rubber) You can't compress fluid but you can compress rubber. So it is a rubber spring with a water "piston" underneath.

But not on a mini. People do not add these suspensions to improve ride or handling, they do it to make the car bounce

The lower the psi the lower the car, the higher psi the higher the car. It does not change the spring rate.

I'm not going to win this one HaHaHa!!!

Your a hive of information, you've had a bit to do with this kind of thing before I suspect?

To tell the truth, I'm a bit of a mini purist. These crazy bits facinate me, although I don't think I could bring myself to hack a mini to bits.

It seems like to much hassle for very little gain putting them in a mini.

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Take it easy, & if it's easy take it twice!!

What you need to make is a hydraulic chamber to replace the Hi/Low cone. (kind of like your cylinders) You would be able to adjust the height on the run and with the right control box you could make it jump. You would keep the rubber spring and not have any fitment problems.
All you have to do is design it and make it!

It's always easier said than done!

Like I said to much hassle for benifit, but with something like that once manufactured would fit very easily, and without a need for modification.

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Take it easy, & if it's easy take it twice!!

**opens can**
I think you are thinking of bag assist suspension.... a coil spring with an air bag to assist.
if not and just a bag system then

you are wrong...

heres the calcs... so you can understand......
Assume that the airbag does not change its contact shape much.
Assume that the air in the bag does not heat up a shite load
Assume that the air bag is made of a homogeneous substance or that it is perfectly elastic like a spring......

F=PA
force (load placed on wheel) is proportional to either area (A) or pressure (P)
force is always the same.... it is static... unless you change the weight over the wheel. Area is also static... unless you can change the dynamics of the bag/cylinder in dimension... so hymm.... that means that pressure is the same too then.....
consider:
if you lift your car with a bottle jack, does it get harder to push the handle the higher you lift it? (only bottle jacks as the load does not change through lever arms like a trolley jack)

so to lower your car you don't actually drop the pressure in the bag, but the volume of air in the bag.
If you change A (the diameter of the bag) but the force is the same then P must change.... a bigger bag, less pressure.

Area of the bag is calculated by (pi radius squared) so if you double the diameter of the bag you actually reduce the pressure by.... a quarter.
pressure is proportional to volume, when using the ideal gas equation (PV=nrT) where n,r,T are constants in this situation.

Volume change can only occour when the there is a change in airbag/cylinder extension or retraction as the area does not change. If you can't work out volume of a cylinder, then I would have lost you at calcs.

this change in pressure as the volume changes can be described by the spring formula

An air bag acts like a spring.... and the formula for a spring is.....
F=kX
F is force...... k is spring constant... and X is distance travelled, which is the change in volume.
by substuting f in both equations

PA=kX
so if you hit a bump.. then X changes... and seeing as k is a constant, A is constant then p must change....
so now you get an increase in pressure in the bag.... so what does the bag do? trys to equalise this pressure... by changing x to the origional value.

so a larger air bag will have a higher A value, because we know that the bigger the area the less the volume (X) needs to change to get an increase in pressure.

the bigger the bag, the stiffer the ride, the smaller the bag the softer the ride.

but you can fully extend your airbag/cylinder to increase the pressure. Adding the load force from the wheel and the force exerted from the limit of travel add to give you the higher pressure. Then you can create hardness or softness... but you have no movement (no more extension) because of the extreme extension.. your wheel will lift off the ground when cornering which aint a good idea....

I know its all over the place, it is late, but you can try to prove me otherwise. I am open to learnin new things and this is my interprutation of me educations.

trucks use it... because the load changes.....
range rover, and other manufacturers use it because they incorperate springs in the system. Find me a car producer that relies on just air bags alone.

Just like springs, you can change all this.... with springs they change the diameter of the wire, the number of coils.... to do this to an air bag means a change in diameter and perhaps the material that the air bag is made out of.


like people say.. if you had enough money and time, anything is possible.

do f1 cars have air bags for suspension? ( i really don't know the answer)

**closes can o worms**

farking took ages to write that....
thought you would argue a little more on this one......
oh well

[quote="manofaus. . . . . . .Just like springs, you can change all this.... with springs they change the diameter of the wire, the number of coils.... to do this to an air bag means a change in diameter and perhaps the material that the air bag is made out of.


like people say.. if you had enough money and time, anything is possible.

do f1 cars have air bags for suspension? ( i really don't know the answer)

**closes can o worms**[/quote]

Give a man some credit where it's due, that is pretty killer when you start working out monents around a suspension system.

FYI F1 requires Sprung suspension, you will find that air wouldn't be used due to weight and less precision than whet they are currently using.

thir's not much argument when you speak to anyone who's used airbags that their the most comfortable ride out there

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-doing a Degree in Mechanical Engineering,
and a few conversions:
13B Extend in a 1600
4EFTE in a mini ute (all slowly)

Ok guys i cant hold this in any longer... All i need is 4 batteries to power it all up...
And the rams just straight replace the cones or hi-los

The hydraulic Rams, for the front and rear


The adapters for the rams to the rubber cones



The pumps


The dumps/switching gear and connection lines

_________________
If you want more inches, stroke it
Life's a garden.... Dig It!
http://www.ausmini.com/forums/viewtopic.php?t=20746

What the !!!!!

Where the hell did you find that one gordo? That's a bloody ripper. I had just about given up when I saw that freaking essay that manofaus wrote me, also a champion effort!!

Manofaus, you must be an engineer? I'm surprised you got it all out properly that time of the evening. I would have argued a bit more but I got a headacre reading it, and It was time to have breakfast.

But now..... I think all our questions have been answered thanks to gordo. And I don't have to butcher a mini.

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Take it easy, & if it's easy take it twice!!