How Many Valves Do I Need?
 

I'm setting up a simple bag set-up for my '67, and in reseraching saw that some run an 8 valve and some run a a 6 valve set-up. With the 6 valve, the front gets 1 fill and 1 dump valve for the two bags, leaving 1 fill /1 dump for each bag in the back(4 valves in back). Is there a reason why the back couldn't be set up like the front for a total 4 valve set-up?

Re: How Many Valves Do I Need?
 

you can have a 4 valve setup but you will get body roll. use 8. and if you use 6, have the front wheels independent of each other by having 4 valves in front.

Re: How Many Valves Do I Need?
 

yeah i tryed to go the cheap route and that didnt last very long... felt like i was going to tip over around corners.. the pressure will push out of one side around corners and fill the other bag..

Re: How Many Valves Do I Need?
 

This and adding a front anti-sawy bar will get you by on a budget. Go with 8 and fo-get-about-it.

Re: How Many Valves Do I Need?
 

Thanks - Simple stuff like that which makes a ton of sense, that i just didn't think of. Thanks again!

Re: How Many Valves Do I Need?
 

[IMG]http://www.*****************/how_to/wire-diagrams/8valve.gif[/IMG]
[IMG]http://www.*****************/how_to/wire-diagrams/6valve.gif[/IMG]

Re: How Many Valves Do I Need?
 

Technically you can do it with 4 valves and 8 check valves BUT you have to have dual port bags. With this you have the front as a pair and the rear as a pair. Each pair gets the same pressure and with the check valves, no cross air flow.

Basically one pair would be plummed like this,

Air source in>Inlet Valve>Tee>Check Valve to each bag>Into Bag (port 1)>Out of Bag (port 2)>Check Valve from each bag>Tee>Dump Valve>Vent to outside.

This keeps all the airflow in one direction and the check valves keeps any pressure from backing up the system to the other bag.

Might not be the best system but would work. YMMV

Edit: After thinking more, you could do it with single port bags, just Tee at the bag with the check vavles on each side of the Tee.

Re: How Many Valves Do I Need?
 

Check valves would be a little less expensive than valves but the valves are a better option in my opinion.

Re: How Many Valves Do I Need?
 

True, valves would be better but doing a very simple setup, the check valve method could work. If you were just doing the rear, mega cheap and would only need one switch, a center off, DPDT momentary switch to control. I think I am going this route on my '64 since I want to be able to adjust for load weight to keep the ride height the same no matter what load or trailer I might have on it.

Re: How Many Valves Do I Need?
 

There is a way to run the system with 6 valves and still have the lift and ride quality of a F/B/S/S system. Let me explain how it can be done, and with simple plumbing and wiring.

The truck will have 4 fill valves and 2 dump valves:

Run a line from the tank to the fill valves. The run an airline from the fill valves towards the airbag. Near the bag install a tube "T" inline. Run an airline from the middle of the "T" into the bagd, and the other lines forward. You can now run the open lines forward and into a check valve on each side. Out of the check valve you will run the line forward into another "Branch T" that has thread in the center. Screw that "Branch T" into the dump valve.

http://www.kplinks.com/media/GMFS/6v01.jpg

http://www.kplinks.com/media/GMFS/6v02.jpg

The truck will now have 4 fill valves and 2 dump valves. The air can not transfer between the two bags because of the check valves inline. So now you can get a responsive fill speed with 4 valves, just like F/B/S/S, however you get the comfort and controlled drop speed of a F/B system.

Hope the images help show how the 6 valve system works. I've installed that same system on several custom rides for customer in the past.

Good luck with the project. Let me know if we can help you out in any other way.

Re: How Many Valves Do I Need?
 

If you want to run a gauge you can still do so and install the fitting right off the pump valves no problem. Best of all you can still have independant control of each bag on the fill side to help level the truck out if need be.

Good luck with the project.

:cool:

Re: How Many Valves Do I Need?
 

That looks like what I need, for rear only. what size tank is that KP ? thanks

Re: How Many Valves Do I Need?
 

i think the cost of the check valves and additional fittings would cost more than just buying 8 valves. that, and you get 4 corner dump control with 8. with 6 you only have f/b dump control.

cool idea with 6 valves. I had never thought of that.

Re: How Many Valves Do I Need?
 

Cost isn't going to be that much more, and it's a clean and simple setup to run for those not looking for an 8 valve system. I've personally installed that type of a system on several customers cars before.

The tank in that picture is one of our 3 gallon tanks that has (2) 1/2" ports on each end, and (1) 1/4" port on top and bottom for drains depending on mounting position.


Good luck with the projects guys.

Re: How Many Valves Do I Need?
 

I think the main advantage of the six valve KP 4L2D style is the quick lift speed with a slower more controllable dump. On my shop dually with the BB it would SLAM the x-member on the ground. I had some old push button bleed valves from a firestone kit that I installed in the dash next to the switches so I could dump it most of the way then use the bleed to gently come to earth. It added a ton of additional plumbing and potential for leaks. I'm testing KP's design on two other trucks now and if it pans out the way I think it will I'll be using on all of my personal rides and reccomending it to any I build.

Re: How Many Valves Do I Need?
 

Copy Cat.

Actually the 6 valve system performs really good. There's not a huge difference on price when you build the system, and it's perfect for someone who wants to have a smooth drop speed, but still have the ride quality of a FBSS kit. :gi:

Let me know how you like the 6 valve once you get it installed. And remember all the pieces shown in my image are availble @ kplinks.com :bling2:

Re: How Many Valves Do I Need?
 

What do I do when the bags are "out of synch" with one another-- as in... left side is fed 80# and right side is fed 50#? I've got to dump the thing all the way to the ground and start coming up all over again. Not worth the hassle, and as others have stated... check valves and fittings quickly out-cost (and out-complicate) 8 valves.

Re: How Many Valves Do I Need?
 

a quick bump down will equalize it and since I have a lift for each wheel I can bump 50PSI bag to 80psi if that is what I want but to each his own.
I've been riding on air since 1992 and installed my fair share of systems in that time and IMHO ( and yes the "O" stands for my opinion) this system is a good one. I've now used it in a vehicle, you know, at least tried it and it goes down so smooth and even and will still hit sides.
Everyone can think what they want, buy whatever parts they want but from now on I'll at least be saving the money on two valves ($130pr 3/8th GC extreems 450's) and spending $50 on fittings(I buy Parker Prestolok) . woo hoo an extra $80 bucks for gas.
Josh

Re: How Many Valves Do I Need?
 

Hey I referenced your thread and gave you credit multiple times. BTW the Nissan loves the set-up and I should at least have the front in the blazer before long.

Now if only Santa could put something in MY stocking;)

Josh

Re: How Many Valves Do I Need?
 

wired correctly can you get fbss with 6 valves? well at least as far as pump goes?

Re: How Many Valves Do I Need?
 

it's more about how it's plumbed rather than wired. KP's pic is pretty clear in how it works. It lift's each wheel, dumps front or back pairs, and limits the body roll caused by air transfer in most tee'd FB set-ups. feel free to PM for a more detailed set-up if you need.
Josh

Re: How Many Valves Do I Need?
 

If you run a 6 or 8 bag system, will it ride decent enough to not run shocks? I have 8 valves for FB/SS. thanks

Re: How Many Valves Do I Need?
 

Absolutely not. Shocks and springs (including air springs) do different things. You can't get by without either.

Re: How Many Valves Do I Need?
 

I meant I have 8 valve system, not 8 bag system........thanks for the info XL, I just had not noticed shocks on alot of the bag setups I have seen on the internet. My nephew's bagged truck runs shocks, but he is only running 4 valves.

Re: How Many Valves Do I Need?
 

the shock absorber (aka compression and rebound Dampner) serves to stop the "bouncys" from your springs. You NEED to have something or it'll feel like a pogo stick. In my minitruck days guys would run with out shocks all the time (since an outboard shock would rub tire and limit steering) and I could never understand how. For me it has to ride better than a stock set-up or else why bother spending money.


Josh