myfirstl322
Well-Known Member
Yes probably but I'd hazard an educated guess they drive perfectly ok on springs....on tarmacAdam.
stuu
Well-Known Member
Quick question regarding the hatred of coils. Are they any good off road with air? I don't mean pottering round a field. I mean proper off roading. Of the 2 I always thought it would be more sensible to have coils?
Mine sits level stu. And I'm fat bastard
Both of mine have both sat lopsided on springs let them settle both mine have been on spring years prior to me having them
Mainly road use and a little exploring now and then and towing the drift car 150miles to the track eas is more upto the job for me then coils.
Ways I feel it's more suitable
The fact it self levels
The adjustable ride height like the way it lowers at higher speeds takes less wear and tear on the props and probs helps gain .5 of a mpg haha
They are a nicer ride on air
And if you do ground the motor out on the highest setting it will actually try raising itself more.
Itl take away the light steering feel when towing.
The only way I can see coils being a preference is they're care free until a coil breaks
And in an al out off roader since soft high lift springs are desired where as the eas puts more air in the bags = harder ride.
My 1st dse was on coils I didn't care I wanted it and got it but then after being in an air sprung one I wanted mine on air.
Then this one came on coils and eas is going to suit what I do more with mine.
Wazzajnr
Well-Known Member
Point of order, more air in the bags does not equal harder ride, just higher ride.
Joss155
Well-Known Member
I guess my though was for towing and axle articulation when off road as that's where I want it to be at its best
Depends how extreme you want the articulation to be. If you're going silly articulation then you have to use springs but you'll probably need specialised props too. Arnott Gen III air-springs give a greater range, so much so you'll have to look at the dampers and the height sensor arms. For me when off-roading the biggest issue was the clearance under the diff. Only way I can think round that is oversize tyres but then the speedo goes out and on full lock you start hitting wheel-arch liners. At this stage you'd probably be better off getting a Defender and giving it the full treatment.
Probably. If the viscous or aircon is having to work hard then the increased resistance will probably cause the ECU to pick the revs up a tad.
stuu
Well-Known Member
You are correct.
Wazzajnr
Well-Known Member
Pressure is force over area, therefore, unless the mass of the body and chassis changes, the pressure will remain more or less constant. If anything, on high, the ride should be softer due to a larger volume of air and more airbag sidewall available to flex.
As i said, try driving over speed humps in high mode. Ride is considerably harsher. Make sure your teeth are secure if you try it. The ride is not controlled by bags flexing it is controlled by compressing the air in the bags, the bags are there to retain air. The more pressure in the bags the harder they are to compress.
Wazzajnr
Well-Known Member
I know it isn't controlled by the bags flexing, I was just pointing out that at high setting, there is more sidewall available so (very slightly) more flexing rubber.
And, yes, if there's more pressure in the bags, of course they are harder to compress, however, it is the downward force of the range rover that creates that pressure, so unless the weight changes as it rises, the pressure will stay the same. Simple schoolboy physics.
Imagine a piston in a pneumatic cylinder with a cross sectional area of 1" squared. Now fill retracted cylinder with air at 30psi and the force exerted will be 30 pounds. Now, allow the cylinder to open to halfway through its stroke and top back up to 30psi (bear in mind the pressure will have dropped as it extended) and what is the force exerted? Yep, you guessed it, 30 pounds. No matter where that cylinder is, at 30psi, the force will be 30 pounds.
Now substitute the cylinder for an airbag, the result will be the same. The cross sectional area might change ever so slightly with an airbag but the difference will be negligible. Fact is, it's still supporting around 500kg per corner with virtually the same CSA so the pressure is the same unless the laws of physics changed last night whilst I was asleep!
Look i am not going to argue, drive over a speed hump at 30mph in standard setting then drive over the same speed bump in high setting. Find out for yourself.
Wazzajnr
Well-Known Member
No disrespect wammers, but quite clearly you are arguing basic physics with me. Harshness at high settings could be caused by all manner of things such as different geometry, shocks stiffer at that ride height due to not operating in that area. The simple fact is that unless, either the weight or the CSA changes, the pressure is the same.......... Period.
It really is a bit irrelevant really to the question originally posted but physics don't lie. Clue is in the name. Pounds per square inch. Kg force per square centimetre etc etc.
That makes sense, I think. Pressure times Volume is a constant (NkT where N and k are constants and T is Temperature which for ease we'll say is constant by the time it has reached equilibrium with the surroundings). So, if the volume increases the pressure must do too otherwise the pressure would drop considerably. That's an ideal gas. There will be some force required to get the bag to extend against friction and so forth. So, the pressure increases until the bag extends to equalise the pressure (and therefore you have a heating and cooling cycle in the gas in the bag too).
Have a look at the Arnott Industries website. https://www.arnotteurope.com/produc...and-rover-range-rover-p38a-left-or-right.html
They claim "The specially-designed piston gives your Range Rover suspension a lower spring rate for off-road driving and a higher spring rate in highway mode." Presumably this is the way the air compresses inside the air-spring during a bump. I wonder how much of a difference the shape of the end-cap insert actually makes to the spring rate?
Review on RR.net adds some clarity:
http://www.rangerovers.net/rrupgrades/suspension/arnottgen3.html
In the Gen 3 rear spring, the narrower top zone reduces the spring rate of about 145 lb/in in high mode, greatly softening the ride. In standard mode, the bellows are near the bottom of this zone and yield a spring rate of about 155 lb/in. The fatter bottom section gives a spring rate of 225 lb/in in low or highway mode.
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Wazzajnr
Well-Known Member
The heating effect will be there but very minimal. Much more heat will be generated bumping over undulations in the road etc. This eventually will make the car rise slightly to keep the pressure constant, the valves will then open to drop it back to the correct ride height.
Fact is, if you put a pressure gauge on a bag and set to any position, the pressure will be almost constant, certainly within a couple of percent.
jamesmartin
Well-Known Member
how about tyres then when you raise the pressure from 10 psi to 30 the car rises and yet vehicle weight is the same,its different to hydraulics as air is compressible
Does the area in contact with the ground not change as the car is inflated?
Pressure = force / area so area must = force / pressure. Force is constant (mass times acceleration = gravity) so for a smaller contact area the pressure would have to increase.
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jamesmartin
Well-Known Member
it does the wheel doesnt
