Thread: SLS airbag pressure

The pressure will relate to the weight of the back of the vehicle. The volume of air will alter the right height.

Originally Posted by Slunnie

The pressure will relate to the weight of the back of the vehicle. The volume of air will alter the right height.

Correct, and I realise this. But there must be a ball park figure - e.g often ranges between 30 - 50psi. I'm not trying to raise it to the perfect ride height, just roughly.
Alternatively, I'm sure the airbags and lines have a maximum pressure, if I knew that I would know what to keep it under.

Just inflate until the ride height is where you want it, I am sure you will have a long way to go before any damage is done to the bags

70 psi is off road height empty!!

at least on mine it is.

Originally Posted by twr7cx

Correct, and I realise this. But there must be a ball park figure - e.g often ranges between 30 - 50psi. I'm not trying to raise it to the perfect ride height, just roughly.
Alternatively, I'm sure the airbags and lines have a maximum pressure, if I knew that I would know what to keep it under.

ok

I recalling mine being around 70 for normal ride height.

I would have thought that the airbag pressure would not change with height. It would only change with vehicle weight.

If the bags are at normal height at 70 psi, and you put more air into them, they will expand with the extra air BUT the internal pressure will remain the same. Hence will still be at 70 psi when raised.

The ONLY thing that is creating pressure in a partially inflated air bag is the weight of the vehicle i.e. heavier vehicle = higher pressure.

If the bag were to become fully inflated, only then will the internal pressure increase without the vehicle becoming heavier.

So if you put 70 psi in a heavy vehicle it may not even come off the bump stops. Like wise 70 psi in a very light vehicle may lift it to max height.

So as somebody mentioned earlier, the way to manually inflate the bags is to pump air into them until the vehicle is at the correct height.

Originally Posted by Freightdog

I would have thought that the airbag pressure would not change with height. It would only change with vehicle weight.

There is a direct proportion between the air bag pressure and the vehicles height. It differs on each vehicle and differs on vehicle weight, but it's still proportionate.

My vehicle is around 70psi for it's standard ride height with my modified suspension. At 90psi I am at offroad height. I measured these the other day. The vehicle weight has not changed, the pressure in the airbag has increased causing the airbag to expand and push the back of the vehicle higher.

Originally Posted by Freightdog

If the bags are at normal height at 70 psi, and you put more air into them, they will expand with the extra air BUT the internal pressure will remain the same. Hence will still be at 70 psi when raised.

The airbags work exactly like a tyre. If you put more air into a tyre, the pressure does not stay the same, it goes up. Likewise with the airbag, the pressure increases if more air is put it. Yes, the airbag does expand too, but the pressure inside increases. It will not stay at the same pressure.

The airbag does not expand to maximum size and then pressure goes up. It is a gradual expansion - pressure goes up, it expands a bit, pressure goes up more, it expands a bit more, etc.