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Air bag suspension chat


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Thanks for replies.

That is a good steer in the right direction. Looks like I need to get in touch with those guys you linked.

I'm definitely attracted towards a "kit" for simplicity reasons. I've dropped quite a bundle on this car so it won't be straight away...but it's next on the to do list, as the 64's just look soooo much better dumped out low to the ground.

 

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On 2/8/2017 at 19:33, Rookie said:

Which is great when you can adjust the spring rate, but seeings as this is "airbag chat" and an airbags spring rate is dependant on pressure, which also happens to be dependant on height, then you realise that slammed = low spring rate, hence the question to other airbag users...

Hey man. Hope you are all good etc.

Realise this is an old question but cant see a reply to ya comment (and i know nothing about bags but are curious)

 id have thought pressure within the bags was dictated by bag diameter, vehicle weight and that height would be irrelevant (assuming not at bag travel limits or using helper springs)

 

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Pressure = force ÷ area

So

Force = pressure x area

So the bigger the diameter...the more force for the same pressure.

If you think of force as spring rate...then the more pressure the more/stiffer the "spring rate" becomes...and the higher the car will sit.

 

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Hey mate.

Does Your math contradict  your lower paragraph.

The surface area within the bags does not change...?

Just like holding up anything with your arms- your body does not extert more force on an item to hold it 1cm or 1m off the ground.. why would the bags need more pressure to exert more force upward?

Edited to make it sound less like im arguing. 

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5 minutes ago, flyingbrick said:

Hey mate.

Your math contradicts your lower paragraph.

The surface area within the bags does not change...?

Just like holding up anything with your arms- your body does not extert more force on an item to hold it 1cm or 1m off the ground.. why would the bags need more pressure to exert more force upward?

Correct. Once a certain value is achieved its volume in the bag that really lifts the car....but also the pressure has an effect as area is constant...so let's put some numbers into the equation and see how it changes.

P=F/A

Therefore 

F=P.A

So let's simply it and just use 100psi and 80inch2 for area. Then;

F=100psi x 80inch2

F= 800lb of force.

 

Lets do it again with 50psi and the same area of 80inch2

F= PA

F=50psi x 80inch2

F= 400lb force

 

So you see the force is a direct relationship with how much pressure is in the bag. And just like a jack lifting a car...as the bag fills it expands and exerts lift...but only once the force is larger than the dead weight of the car.

 

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1 hour ago, Kimjon said:

Correct. Once a certain value is achieved its volume in the bag that really lifts the car....but also the pressure has an effect as area is constant...so let's put some numbers into the equation and see how it changes.

P=F/A

Therefore 

F=P.A

So let's simply it and just use 100psi and 80inch2 for area. Then;

F=100psi x 80inch2

F= 800lb of force.

 

Lets do it again with 50psi and the same area of 80inch2

F= PA

F=50psi x 80inch2

F= 400lb force

 

So you see the force is a direct relationship with how much pressure is in the bag. And just like a jack lifting a car...as the bag fills it expands and exerts lift...but only once the force is larger than the dead weight of the car.

 

Hey man.

 

Thanks for that. Conclusion: rookies wrong

Happens to all of us sometimes.

Except spence 

Oh and david.

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10 hours ago, flyingbrick said:

Hey man.

 

Thanks for that. Conclusion: rookies wrong

Happens to all of us sometimes.

Except spence 

Oh and david.

We were both right...but I think we were talking past each other and just missing each others points. :)

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I’m wrong all the time.

I think rookie was right in some sense, he’s saying it seems the purpose of bags is to roll around with your car slammed. But when you have low pressure to get the car low you do get less spring rate which seems like it is exactly what you don’t want, he was asking a question.

In practice though you never really roll at max slam dragging the chassis with 15psi in the bags unless you are like 22 still and trying to be awesome. Even then a low spring rate when slammed actually works quite well on the road, especially with good bump stops and shocks. IRL it’s never really a problem because you roll a couple inches above max slam and by then you might have say 50psi in the bags and shit is all good, driving on a cloud etc. 

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Yeah and the weight of the car. Crown wagon weighed nothing in the arse and needed like 20psi, and maybe 50 in the front at cruise height. My numbers were just for argument sake. It had no shocks and man you could feel the difference in spring rate with pressure front to rear, rode best loaded up with cunts so you could run more air.

It’s fact you get less spring rate with less pressure which intuitively is the reverse of what you want (for slam, it’s great for load carrying you can add more spring). In practice shit is gravy. Run the biggest bag you can fit for more volume and better ride when low.

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Gtfo nathan. Lol commodore hahahaha

 

Pretty certain you can buy everything you need to convert an impala as a bolt in type deal and is adequate for nz compliance 

Yes as above give Simon @ airride a call. GC. He does  bulk shipments every so often so if you arent in a hurry if he doesn't have what you need in stock then it would probably be cheaper to wait for that.

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7 hours ago, nzed said:

Gtfo nathan. Lol commodore hahahaha

 

Pretty certain you can buy everything you need to convert an impala as a bolt in type deal and is adequate for nz compliance 

Yes as above give Simon @ airride a call. GC. He does  bulk shipments every so often so if you arent in a hurry if he doesn't have what you need in stock then it would probably be cheaper to wait for that.

And oi! Lay off the poor old VN Commodore...they say there's an arse for every seat:-)

love that car. It's got an LT1 and a 6 speed manual...hauls arse! Though I do understand only drug dealers, scout masters and glue sniffers own VN's...well at least that's what my mates have said in the past...

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