Air Shock/Springs

CairoManx · Post by **CairoManx** » Sun Dec 23, 2007 5:54 am

I was looking at the air spring kits on the Airkewld website and saw that most of their kits use the large air bag type springs but I saw that they also sell a standard front suspension air ride kit that appears to use Monroe air shocks. They remove all the upper and lower torsion leaves and use DOM tubing with bolts and washers in each end as through rods to hold the trailing arms in. They say by using the through rods instead of the torsion bars, wheel travel is increased to in excess of 12". I'm guessing that that's after they also remove the stock snubbers. They say the reason they use the air shocks is, "Ease and availability", and "they do a quality job of it". They say if the shock is mounted in the stock location, you need to run 160-185 psi. If you move the lower shock mount out 1.5", you can lower the pressure to 130-150psi. I think on a glass buggy, it would probably be even lower than that. I went to my local part store and got a copy of the page out of the Monroe catalog that has the lengths and travel of their air shocks. They range from 4.5" to 12" of travel but most are around 8". I think they go for about $70 a pair. I understand air suspensions can give a better ride than coil spring. I have no idea how reliable an air shock/spring would be in a dune buggy and the airkewld kits are meant to lower a bug, not raise it, but it seems to me that you might be able to create a pretty good extended travel suspension with the right parts, inexpensively. http://airkewld.com/parts/proddetail.php?prod=ARK- 4001F http://www.monroe.com/catalog_lookup/misc_app_docs/ShockAbsorberDimensionChart.pdf http://www.monroe.com/catalog_lookup/misc_app_docs/ShockAbsorberMountingStyleSheet.pdf

manxdavid · Post by **manxdavid** » Sun Dec 23, 2007 5:22 pm

If it counts for anything, Bruce used airbags off an old Chevy truck [sic] to suspend the rear of his old monocoque 'Quattro'.

fubar · Post by **fubar** » Sun Dec 23, 2007 7:34 pm

I have seen people use fox shocks with no torsions or coil over springs (front only) relying on nytrogen pressure for spring with good results. Down side is they will overheat quicker without a spring and the dampning is not so good with frothy oil. And they are not a cheap date even without coilovers.

CairoManx · Post by **CairoManx** » Sun Dec 23, 2007 8:07 pm

fubar wrote:I have seen people use fox shocks with no torsions or coil over springs (front only) relying on nytrogen pressure for spring with good results. Down side is they will overheat quicker without a spring and the dampning is not so good with frothy oil. And they are not a cheap date even without coilovers.

I think you're right, heat and frothing is probably their weakness. But for $70 a pair, it might be worth trying them to see how much abuse they could handle.

fubar · Post by **fubar** » Sun Dec 23, 2007 10:26 pm

If you have an on board air system you could adjust your ride height on the fly too..

5150bossman · Post by **5150bossman** » Wed Dec 26, 2007 6:30 pm

Let's remember what a shock is suppose to be for. Shocks dampen the motion of the springs that are already on the car to keep the car from bouncing down the road after hitting a bump or a dip. If one is to go off-road, these bumps and dips can be substantial. To remove the springs and go with some sort of air suspension to increase travel means that you are combining two different systems. If you think about it, if you hit a good size bump, the mechanical leverage of the suspension will compress the gas in the shock substantially as the wheel moves up. When it reaches the top of it's movement, the gas will be at it's highest pressure and want to return to it's nuetral state. This will then force the suspension back down with a force equal to the force that moved it up in the first place. So instead of dampening the motion, it's accentuating it. The suspension acts like a giant spring, and the car goes bouncing uncontrollably down the road. I can possibly see an air suspension on a lowered car as the bumps on the street are usually small and controllable. Off-road though I do not think it to be a wise choice. :2cents: :driving:

CairoManx · Post by **CairoManx** » Wed Dec 26, 2007 7:59 pm

I really don't know if it would work. However, I did see a Top Gear episode recently where they used a stock Citroen steet sedan with an air suspension as a TV camera platform to film a steeplechase horse race. It was driven alongside the horses on a heavily rutted dirt track. They also used a new Range Rover with all the off road bells and whistles. It wasn't even close, the Citroen's air suspension soaked up all the bumps and dips and the picture was rock steady. The Range Rover's picture wasn't even recognisable enough to tell which horse you were looking at. They also said all the horse tracks in the UK exclusively use Citroen sedans as their camera platforms. The advice Bruce gives is to remove about 50% of your front torsion leaves and find the most clapped out pair of cheap hydraulic shocks you can. He even suggests reducing their damping fluid viscocity with something like BBQ starter fluid. He really advocates a soft supple suspension with minimum damping. I'm not sure a Monroe Max-Air will provide the same kind of soft progressive compression a regular airbag will but it appears worth checking out. It definitely looks like the mounting point on the lower trailing arms would need to be relocated. However, the Monroe MA768 which has 12mm I.D. bushing type upper and lower mounting with 6.5" of travel, is on Amazon for $57.31 a pair, including shipping. http://shopping.msn.com/results/stock-parts/bcatid10519/monroe/2-4561108/forsale?text=category:stock-parts+Brand:Monroe&page=4