Home » Public Forums » GMCnet » air pressure for Quadra Bag Rear Suspension System
| air pressure for Quadra Bag Rear Suspension System [message #238953] |
Thu, 06 February 2014 08:43  |
rjw
Messages: 697
Registered: September 2005
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I installed a Quadra Bag Rear Suspension System a while ago. Last year I installed a new air compressor and air tank. The install included a 90-120 PSI Pressure Switch to control the compressor. Has anyone gone with a higher switch setting, say 120-150PSI? It seems that I am not able to get the coach up as high as the single bag system did when camping and wonder if the higher pressure would help.
Richard
76 Palm Beach
SE Michigan
www.PalmBeachGMC.com
Roller Cam 455, TBI+EBL, 3.42 FD, 4 Bag, Macerator, Lenzi (brakes, vacuum system, front end stuff), Manny Tranny, vacuum step, Tankless + OEM water heaters.
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| Re: air pressure for Quadra Bag Rear Suspension System [message #238964 is a reply to message #238953] |
Thu, 06 February 2014 10:17  |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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| rjw wrote on Thu, 06 February 2014 07:43 |
I installed a Quadra Bag Rear Suspension System a while ago. Last year I installed a new air compressor and air tank. The install included a 90-120 PSI Pressure Switch to control the compressor. Has anyone gone with a higher switch setting, say 120-150PSI? It seems that I am not able to get the coach up as high as the single bag system did when camping and wonder if the higher pressure would help.
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Shortly after I got my coach, I was tracking down air system leaks and one of the leaks was from the air pressure switch. I talked to Jim Bounds about it and ordered an electric switch from him. IIRC, the pressures are 110 on, and 140 off. It has worked well with my Viair compressor and stock air bags. It should work even better with Quadrabags
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member
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| Re: air pressure for Quadra Bag Rear Suspension System [message #238965 is a reply to message #238953] |
Thu, 06 February 2014 10:30 |
zhagrieb
Messages: 676
Registered: August 2009
Location: Portland Oregon
Karma: 0
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Mike Foster,
At a recent convention I asked the same question of several who'd had a quad system for some time, including guru Dave Lenzi, and they'd had no issue and didn't expect any.
Glenn
Glenn Giere, Portland OR, K7GAG
'73 "Moby the Motorhome" 26'
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| Re: air pressure for Quadra Bag Rear Suspension System [message #238968 is a reply to message #238953] |
Thu, 06 February 2014 10:43 |
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SeanKidd
Messages: 747
Registered: June 2012
Location: Northern Neck Virginia
Karma: 4
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I have the Viair model number 90111...110 on 150 off, I regulate the the discharge from the reservoir at 120 psi. I use the Viair 350C, cockpit pressure gauge, and new 1 gallon tank, recovery is fast but a little loud, could use better vibration mounting pads...huge improvement over PO installed Campbell Hausfield 12v compressor with a clamp on Schrader valve taped to the air line with the switch behind the glove box.
What is the maximum air pressure for a quad bag?
Sean and Stephanie
73 Ex-CanyonLands 26' #317 "Oliver"
Hubler 1-Ton, Quad-Bags, Rear Disc, Reaction Arms, P.Huber TBs, 3.70:1 LSD Honda 6500 inverter gen.
Colonial Travelers
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| Re: air pressure for Quadra Bag Rear Suspension System [message #238972 is a reply to message #238968] |
Thu, 06 February 2014 10:59 |
rjw
Messages: 697
Registered: September 2005
Karma: 4
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| SeanKidd wrote on Thu, 06 February 2014 11:43 |
I have the Viair model number 90111...110 on 150 off, I regulate the the discharge from the reservoir at 120 psi. I use the Viair 350C, cockpit pressure gauge, and new 1 gallon tank, recovery is fast but a little loud, could use better vibration mounting pads...huge improvement over PO installed Campbell Hausfield 12v compressor with a clamp on Schrader valve taped to the air line with the switch behind the glove box.
What is the maximum air pressure for a quad bag?
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How do you regulate the discharge from the reservoir to 120 psi? I have a 120 on and 150 PSI off switch that I might install. I have a new stainless steel tank I installed (had been in my attic for over 10 years waiting on me).
By the way, the info I have from HOTROCKS (Firestone) seems to indicate the "Recommended Design Position Static Pressure 0-100 psi" for the air spring used by the Quadra Bag.
Some truck spring places I've seen also spec the WO1-358-7375 air springs as 100 psi max, so are we are going over the spec even at 120 psi?
Richard
76 Palm Beach
SE Michigan
www.PalmBeachGMC.com
Roller Cam 455, TBI+EBL, 3.42 FD, 4 Bag, Macerator, Lenzi (brakes, vacuum system, front end stuff), Manny Tranny, vacuum step, Tankless + OEM water heaters.
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| Re: [GMCnet] air pressure for Quadra Bag Rear Suspension System [message #238974 is a reply to message #238968] |
Thu, 06 February 2014 10:55 |
James Hupy
Messages: 6806
Registered: May 2010
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I have installed a bunch of QUADRA BAG systems. Some with reaction arms and
disc brakes with sway bars. I have only encountered one system, that I did
not install, that required more than 100 pounds air pressure. At that
point, the shocks are fully extended and additional air pressure is
unnecessary. That would lead me to think about incorrect FRONT ride height.
Jim Hupy
Salem, Or
78 GMC Royale 403
On Feb 6, 2014 8:43 AM, "Sean Kidd" <fiatkidd@yahoo.com> wrote:
>
>
> I have the Viair model number 90111...110 on 150 off, I regulate the the
> discharge from the reservoir at 120 psi. I use the Viair 350C, cockpit
> pressure gauge, and new 1 gallon tank, recovery is fast but a little loud,
> could use better vibration mounting pads...huge improvement over PO
> installed Campbell Hausfield 12v compressor with a clamp on Schrader valve
> taped to the air line with the switch behind the glove box.
>
> What is the maximum air pressure for a quad bag?
> --
> Sean and Stephanie
> 73 Ex-CanyonLands 26' #317 "Oliver"
> Hubler 1-Ton, Quad-Bags, Rear Disc, Reaction Arms,
> Fluorescent Mineral Capital of the World, New Jersey
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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| Re: air pressure for Quadra Bag Rear Suspension System [message #238980 is a reply to message #238953] |
Thu, 06 February 2014 12:25 |
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SeanKidd
Messages: 747
Registered: June 2012
Location: Northern Neck Virginia
Karma: 4
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Isn't pressure relative to volume, temperature, and vehicle weight. In travel mode an average motorhome may have quad bags at 50% volume to maintain that height, wether this is attainable with 60 psi or 70 psi will vary, if I supply 100 psi during travel, there is a constant volume change...over a big bump I'm sure those bags see a lot more pressure. It doesn't mean there is 100 psi in the bag... I guess the only max pressure would be when maximum height is achieved despite your controls in "raise" and supplying more than 100 psi...Considering this, I will lower my output to whatever pressure is required to raise the rear to max height, then back off a few psi for thermal expansion.
Sean and Stephanie
73 Ex-CanyonLands 26' #317 "Oliver"
Hubler 1-Ton, Quad-Bags, Rear Disc, Reaction Arms, P.Huber TBs, 3.70:1 LSD Honda 6500 inverter gen.
Colonial Travelers
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| Re: air pressure for Quadra Bag Rear Suspension System [message #238981 is a reply to message #238979] |
Thu, 06 February 2014 12:34 |
rjw
Messages: 697
Registered: September 2005
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| WD0AFQ wrote on Thu, 06 February 2014 12:56 |
I don't think I would ever travel with 100 pounds in a bag, no need for that. Mine normally are running 65-75 pounds for proper ride hight. Only air them higher for leveling the coach.
I need to get under my refer and drain the tank. Thanks for the reminder.
Dan
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What I find annoying with my current setup (90PSI ON 120 PSI OFF) is when I try to raise the coach above ride height. If the system goes down to slightly more than 90 PSI (tank and bags) I can't get maximum up because the pump won't start. To get it to start I have to bleed air pressure off by lowering and then raising the coach in order to get below the 90PSI ON point. Once it starts then I can get maximum up.
Maybe if I install the 120PSI ON and 150 PSI OFF switch I have and also install a regulator set to 110 PSI or so to the bags I won't have to bleed off pressure to get the pump to start because tank pressure will always be over 120 PSI.
Richard
76 Palm Beach
SE Michigan
www.PalmBeachGMC.com
Roller Cam 455, TBI+EBL, 3.42 FD, 4 Bag, Macerator, Lenzi (brakes, vacuum system, front end stuff), Manny Tranny, vacuum step, Tankless + OEM water heaters.
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| Re: [GMCnet] air pressure for Quadra Bag Rear Suspension System [message #238994 is a reply to message #238965] |
Thu, 06 February 2014 15:32 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Glenn,
For the record Dave Lenzi runs the Harrison system on his coach and has replaced one of the bags it comes with (Firestone P/N
W01-358-3400 with Firestone P/N W01-358-7350) The 7350 is the bag used on the Q-Bag system. The 7350 is a larger OD bellows (7.44")
vs the 3400 bellows (7.25"). He did that to reduce the amount of pressure required to get his Coachman Royale to ride height.
Anticipating the next question; according to Dave you cannot run two 7350's on the Harrison system.
Regards,
Rob M.
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: Glenn Giere
Mike Foster,
At a recent convention I asked the same question of several who'd had a quad system for some time, including guru Dave Lenzi, and
they'd had no issue and didn't expect any.
Glenn
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] air pressure for Quadra Bag Rear Suspension System [message #238996 is a reply to message #238974] |
Thu, 06 February 2014 15:40 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Jim,
I'm confused!
When I look at the photo of the Q-Bag system it looks like the shocks get compressed when the bags expand?
Have I got that backwards?
http://www.appliedgmc.com/products/full/684.jpg
Regards,
Rob M.
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: James Hupy
I have installed a bunch of QUADRA BAG systems. Some with reaction arms and
disc brakes with sway bars. I have only encountered one system, that I did
not install, that required more than 100 pounds air pressure. At that
point, the shocks are fully extended and additional air pressure is
unnecessary. That would lead me to think about incorrect FRONT ride height.
Jim Hupy
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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