Air bags guys need your expertise

Got a 49 plymouth with air bags. I am running bias ply tires and the car seems to ride really bouncy (sorry or all the techical terms ) Has new stock shocks in the front and stock toyota pickup shocks in the back. The rear has a c notch and 2 link setup. Running 2500 firestone bags.

Will air shocks help with the ride?? Do alot of guys use air shocks with air bags??

Thanks
matt

 

How much pressure are you running in the bags?

 

Not for sure. I really need to get some gauges hooked up. I have to run alot more in the front because of the weight.

 

I run pretty low pressures in my car and the ride is great, but will get bouncy with high pressures. Try letting some pressure out and see what happens.

 

Yea i have tried high pressure, low pressure, and everything in between. It doesn't ride terrible but doesn't ride as nice as i think it should. I'm guessing that a heavyer shock or air shocks would work. just a guess though.

 

air shocks will make it stiffer and ride worse. the cups could be to short on the front bags in which you would need more psi to lift the car and make it stiffer and ride bouncy. how much travle do you have on the shocks? when the care is up are the shocks all the way extended? it will make the ride bouncy it could be a 1000 things but i would start there

 

The cups are good and the front shocks are long and short enough. The car rides like a modern car with bad shocks.

 

You may be using too small of a bag. I'm using Slam Specialties front and rear and was told before hand that too small of a bag will give you a ****py ride but like OCFAB says it could be a bunch of issues going on. Guages would help you dial in your ride for sure.

 

I am using the firestone 2500. Too small???

 

what shocks? and are you running a sway bar? and are the right and left on the same line or are they split

 

There is so much more to a nice riding suspension than simply adding bags. It is the sum total of all the parts. Sway bars, shocks, tires, bag length, air pressure, etc. If it is not all working together, you will never get the ride you are looking for...

 

Could the suspension be binding anywhere?

 

Here is a good check list for you to go over and then you will see what is causing your problems.

1) Do you have each wheel on seperate valves? Do you have the front on seperate valves and the rear together one one set. If all you are looking for is lift and lower and not FBSS then you need to use one of those 2 setups. If you have only 4 valves on the whole car then it will ride "wierd".

2) How close to the bags are the valves? The farther away from the bags the valves are the more room the air has to expand and contract in the lines giving you a more swoopy ride where as the closer to the bags the vlaves are the stiffer the ride will be.

3) What PSI is needed to lift the car 1 inch off the ground? For an ideal setup with the right sized bags it should be no more then 40lbs. Well atleast thats what I shoot for on installs. BB cars and big boats are different but even on a BB 70 Newport it should be no more then 60. If you need more then that to lift the car 1 inch then you need bigger bags.

4) What size air line do you have? The smaller the air line the stiffer the ride will be because it has less room for expansion and contraction during the drive and it will lift and lower a lot slower.

5) What size/stiffness shocks are you using? If the ride is too stiff then try taking the shocks off the FRONT ONLY!!!! The weight of the front of the car and air bags makes for a nice ride without shocks, but the back end is much lighter and should always have shocks on it.

6) Do you have sway bars? Sway bars limit the side to side deflection of the suspension and can make for a much stiffer ride with Air Bags.

7) What size tires do you have and what PSI do you run in those tires? I ran 215/70/15 On my car before and had to run them at 27-29 PSI to get it to ride smoother but now I have 175/75/14 and I can run those at 32-34 PSI and still get the same ride. That sounds wierd but the suspension amplifies the "bounce" of a tire.

Well that should get you in the right direction even though there are about 20 other things to look into. Those are the top candidates for your issues.

 

Yikes!

As an mechanical engineer and professional suspension builder, I have to say do not EVER operate any car without functional shock absorbers or all four corners.

Not having them can result in uncontrolled suspension oscillation, causing you to lose control of your vehicle, resulting in serious injury or death. If you want to shoulder the risk of killing yourself, that is fine, but the risk of killing some innocent bystander is just too great.

If you are a shop doing this you are risking a wrongful death lawsuit. You will have no defense.

If you have been doing this without problems, you are one lucky mo-fo. Sooner or later this will catch up with you. Don't find out the hard way.

 

those 2500 might be too small depending on how much your car weights, i would look into getting some slam re7's they have a thicker side wall and should take a lot less psi to lift,

not only that but could we get some more specifics on your setup like are you running a 8 valve setup? like said before if you have a 4 or 6 valve setup it might be riding weird becuase of air transfer between the bags, but with out knowing more its hard to say

 

air transfer wouldn't necessarily make it ride bouncier. I think the problem lies in your bags. trying switching them out to a bigger bag. i suggest slam specialties re-7s or try the new airlift dominator 2600 bags. you might be running too high PSI in the bags causing the ride to be really bouncy.

 

Thanks, I totally agree...

 

Back to the topic at hand.

Air shocks will do nothing but harm the ride quality.

You say you are running stock shocks, are they 'good' shocks to begin with?

You should always run the largest bag that the space will allow, with prudent t******* to accommodate.

In addition to all of the other things to look at, the spacer on top of the front bags may simply be too short, requiring that the bags be pumped up to a really high pressure to achieve proper ride height. I have seen this quite a few times.

When the suspension is cycled to full compression, there should be almost no travel left in the bag. You don't want the end caps of the bag to strike each other, unless you are running a bag with an integral bump stop, like Slam Specialties bags.

If you still have a lot of travel left in the bag at full suspension compression, then the spacers are too short.

If there is little travel left in the bag at full compression, and the car still does not reach proper ride height without excess pressure (harsh ride) then the bags are too short.

If they prove too short/small and you simply cannot cram a larger bag in there, you can run an ac***ulator. This is a small tank that goes in-between each bag and the valve servicing that bag, which give more air expansion volume. Import car guys frequently have to run these to get a decent ride quality, when stuck with tiny bags inside tiny wheel houses.

 

I might be a little late to the party but let me throw my two cents in. I have seen any mention of how the front shocks are mounted. I don't remember how the shocks on a 49 plymouth are mounted but I ***ume that they run inside the coil spring meaning they would have to be relocated when an air spring is added. If the shocks were mounted in a fashion that made thier opperation ineffective that could cause the problem you described. If you could provide a picture of your suspension we could better figure out your problem.

Brick

 

Let me ask you what is a shock? Typically it is a cylinder filled with air, gas, or fluid. What is an Air Bag? A cylinder filled with air to a certain air pressure. I do not see what you see wrong here. I have cars/Trucks running around for the last 10 years with no shocks on the front. As I wrote in my other post I do not suggest running no shocks on all 4 corners but only in front. My 55 has been baged in front for the last 3 years without shocks and I have customer cars that I did 10 years ago with no shocks in front. All a shock does is "slow the rebound of the suspension" therefore eleminating any chance for bounce or float.

What is an Air Shock on the rear end of a car with weak leafs? Well hell the leafs aint holding anything up because the person inflated the shock up to get the car back to a level ride. The Air Bags do the same thing. By adding air pressure to the bag you are eliminating the potentiaql bounce/float of the suspension.

I dont care how much of a "Suspension Engineer" you think you are you need to do more research before you start making acusations about suspensions capabilities.


It was a suggestion about how he can figure out what his problem was and since nobody else seems to offer solutions I figured I would. If you dont like my solutions then offer your own solutions and dont tell me how I do or dont know how to do what I have done for 10+ years without 1 single failure or complaint because I know how to ask the customer questions and build what they want.

 

I have seen some of your work and you got no room to throw stones in this gl*** house. Out of respect I will not go into details but lets just say I had to fix some of your work.

 

I don't see how any of the bickering is gonna help this guy. Just stick to the facts. Everyone has their own opinion on how things should be done and what may work for some may not work for others. Taking shots at each won't accomplish ****.

 

You are welcome to ignore my opinions if you don't like them. The laws of physics, on the other hand, you ignore at your own peril.

So long as your guardian angel is up to the task at hand, carry on.

 

Have you driven a car on air ride with no front shocks? Over 20 mph? its very scary..
I would listen to gimpyshotrods and run shocks And a sway bar

 

I have.. Not saying its the right or wrong way but I had a truck in highschool with airbags. rode very nice with no shocks in front. Only had shocks in the back. was my daily driver and seen 70 and 80 mph on the freeway often. The truck I'm having air ride installed in right now will have shocks on all 4 corners though..

http://www.jalopyjournal.com/forum/showthread.php?t=373539

 

X2 for me too. I can't say I would recommend it but I have run no front shocks for a while on my '54 with great results. That being said, I just redid my front end and have front shocks now.

 

********. The only car that has left the shop that anyone would have had to deal with was this. 68 Mercury.



Had the guy actually paid his bill it would have gotten finished and not left the shop half done. I also know that he had some hacks mess with it after it left as well.

So what of mine did you have to fix? Fess up. I'm curious.

 

Lol, he PM'd e back, wasn't a car I worked on. I'm not worried about the quality of my work, what I'm worried about is people running their mouth about my shop. We value our reputation. I do not put out ****. And I won't.

 

Tank - have you relocated the front upper shock mount to the frame? The ****py Plymouth shock mount design for the front might be what you're running into.

I've also heard that with bias plys you should run more air pressure in the tires than what you would in a radial, is that right? Some guys also talk about the tires bouncing as they drive with bias plys, does this seem like the cause? I think the fix from those posts has been to shave the tires round.

 

I was thinking the same thing, it may be something as simple as tires...did you run these tires before you bagged it? do you have another set of tires you can try?