Alternate,air pump

[Rdenney]

Rob, probably. If the crown is sufficient to cause a weight transfer, the
factory system will correct it. I think that will take more than the usual
2% crown. The leveling valves sense bogie position with respect to the
frame, not the road. A little tilt from a crown on a straight highway isn’t
body roll and doesn’t change bogie position with respect to the frame.

On a sweeping curve, where there is body roll caused by weight transfer,
the factory system will correct for it, if the curve is long enough to get
past the damping delay. On my Power Level coach, that’s more like five
seconds. I’ve watched the air pressure gauge go down in those situations.

Rick “whose dead zone is about 1/2” total” Denney

> Jim,
>
> Was I incorrect when I stated "works like the OEM system and controls ride
> height through sensors that adjust the attitude of the coach as you go down
> the road. If you are on a road that is highly crowned it will raise the
> curb side automatically with no input from the driver?"
>
> --
Rick Denney
73 x-Glacier 230 "Jaws"
Off-list email to rick at rickdenney dot com

 

[Ken B]

ROB, Rear wheel leveling switch will not make up for the crown but it does make up for any additional shift in weight that caaued the body to ground
clearance to change.

The strangest example I have experienced of this was heading eastbound on the interstate in a very heavy cross wind out of he north. I stopped at a
Flying J and the first thing I noticed was the leveling switches had aired up the right air bag to the point that the right was running about 2 "
higher when not being blown sideways. I was facing north direct into the wind when I saw this.

I also notice that the air compressor kicks in sometimes when I get off of the Interstate and run on higher crowned 2 lane local roads.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

 

[Keith V]

Remember also that pressure based control systems invert the height control. In other words if you are on said crowned road, or as you use fuel, passenger changes etc. the control system will do the exact wrong thing.

For example, if you get heavier, the coach will squat, the bag pressure will go up, the controller will then lower the bag pressure back to the setpoint lowering the coach even more.

Microlevels analog ( OEM hall effect non contact ) sensors measure true height. it has enough resolution to sense me leaning side to side while sitting on the cab step. Having a microcontroller allows a fast adjustment that gets the coach within height tolerance, +- 1/4", as fast as the air supply allows, then switches to height maintenance to keep height to within +- 1/8". The maintenance algorithm also keeps adjustments to a minimum, no less than 30 seconds between adjusting, meaning no adjusting on cloverleafs or wind gusts.

Campground leveling is a single button press.

Keith Vasilakes
Mound sview Minnesota
1976 ex-Royale

________________________________
From: Gmclist on behalf of Rob Mueller
Sent: Wednesday, July 18, 2018 9:43 PM
To: gmclist
Subject: Re: [GMCnet] Alternate,air pump

Jim,

Was I incorrect when I stated "works like the OEM system and controls ride height through sensors that adjust the attitude of the coach as you go down the road. If you are on a road that is highly crowned it will raise the curb side automatically with no input from the driver?"

Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808

-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of James Hupy
Sent: Wednesday, July 18, 2018 7:34 PM
To: gmclist
Subject: Re: [GMCnet] Alternate,air pump

Rob, the OEM systems ride height is ( are) controlled in two ways.
1. The original early system was entirely operated by air pressure
and left and right hydraulic/pneumatic height control valves that sensed
movement of the frame height when the load in the coach either increased or
decreased. That moved the linkage attached to the height control valves.
Built into the valves was a time delay of up to 18 seconds before any air
was let into the air bag or out of it. In addition, there was a null space
of + or- 3/8" where the frame could move up or down without anything
happening. That is a dead space of 3/4" in the center of the travel. Small
road shocks of a duration of less than 18 seconds never activate this
system.
2. The second generation of height control used the same height
control valves, and had the same operating parameters as the one I
described above. Differences in these two systems were that rocker switches
replaced the original round knob air valves in the dash, and added
solenoids with valves to control the inlet and exhaust of air to the height
control valves. Same null space and time delay as the original system.
3. Finally, the Electro Level II system came out. Totally electric in
control of ride height. Used LED light sources aligned with photo
transistors to open and close electrical circuits that either opened
exhaust valves or started smaller compressors to raise or lower the coach.
Manual controls in the form of rocker switches allows the operator to raise
or lower the coach as required. The null point is narrowed to 5° of travel,
and the time delay is lengthened to a max of 28 seconds before anything
happens. Shutter wheels attached to linkage either block the led's or
expose them to the photo transistors.
Small road shocks, swales of short duration (less than 28 seconds) do
nothing to activate the system. All this information is from GMC manuals,
not from my foggy brain. What does change ride height is inputs from the
driver through the rocker switches, or changes in loads in the coach.
Jim Hupy
Salem, Or

> Keith,
>
> To me the MOST important thing about the MicroLevel system is that it
> works like the OEM system and controls ride height through
> sensors that adjust the attitude of the coach as you go down the road. If
> you are on a road that is highly crowned it will raise the
> curb side automatically with no input from the driver just like the OEM
> system.
>
> Regards,
> Rob M.
> The Pedantic Mechanic
> Sydney, Australia
> AUS '75 Avion - The Blue Streak TZE365V100428
> USA '75 Avion - Double Trouble TZE365V100426
> USA '77 Kingsley - TZE 267V100808
>
> -----Original Message-----
> From: Gmclist [mailto:gmclist-bounces] On Behalf Of Keith
> V
> Sent: Wednesday, July 18, 2018 8:52 AM
> To: gmclist
> Subject: Re: [GMCnet] Alternate,air pump
>
> Why would you EVER run ANY air compressor without a pressure switch??
> Thats just asking for trouble, don't do it. The over pressure valve is not
> designed for multiple cycles!
> Even manual mode should just enable the pressure switch, not over ride it.
>
> Better than wire less air, MicroLevels RF remote allows individual height
> control of both sides, so you can tilt the coach for
> dumping. This even works with the ignition off as MicroLevel wakesup on a
> button press, enables the compressor and opens the
> valve(s).
> Not to mention true height control and campground leveling.
>
> Keith Vasilakes
> 75 ex Roylae
> MicroLevel<
> http://www.gmcmotorhomemarketplace.com/vasilakes/microlevel_intro.pdf>
>
>
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
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[Will Albers]

Is there a way to monitor the voltage output of the ELII ride height
sensors? To simply turn on a light if need be? I'm simply curious of the
output in different conditions, and when the delay kicks in. Would be fun
to study while im a passenger.

> Remember also that pressure based control systems invert the height
> control. In other words if you are on said crowned road, or as you use
> fuel, passenger changes etc. the control system will do the exact wrong
> thing.
>
> For example, if you get heavier, the coach will squat, the bag pressure
> will go up, the controller will then lower the bag pressure back to the
> setpoint lowering the coach even more.
>
> Microlevels analog ( OEM hall effect non contact ) sensors measure true
> height. it has enough resolution to sense me leaning side to side while
> sitting on the cab step. Having a microcontroller allows a fast adjustment
> that gets the coach within height tolerance, +- 1/4", as fast as the air
> supply allows, then switches to height maintenance to keep height to within
> +- 1/8". The maintenance algorithm also keeps adjustments to a minimum, no
> less than 30 seconds between adjusting, meaning no adjusting on cloverleafs
> or wind gusts.
>
> Campground leveling is a single button press.
>
> Keith Vasilakes
> Mound sview Minnesota
> 1976 ex-Royale
>
> ________________________________
> From: Gmclist on behalf of Rob Mueller <
> robmueller>
> Sent: Wednesday, July 18, 2018 9:43 PM
> To: gmclist
> Subject: Re: [GMCnet] Alternate,air pump
>
> Jim,
>
> Was I incorrect when I stated "works like the OEM system and controls ride
> height through sensors that adjust the attitude of the coach as you go down
> the road. If you are on a road that is highly crowned it will raise the
> curb side automatically with no input from the driver?"
>
> Regards,
> Rob M.
> The Pedantic Mechanic
> Sydney, Australia
> AUS '75 Avion - The Blue Streak TZE365V100428
> USA '75 Avion - Double Trouble TZE365V100426
> USA '77 Kingsley - TZE 267V100808
>
> -----Original Message-----
> From: Gmclist [mailto:gmclist-bounces] On Behalf Of James
> Hupy
> Sent: Wednesday, July 18, 2018 7:34 PM
> To: gmclist
> Subject: Re: [GMCnet] Alternate,air pump
>
> Rob, the OEM systems ride height is ( are) controlled in two ways.
> 1. The original early system was entirely operated by air pressure
> and left and right hydraulic/pneumatic height control valves that sensed
> movement of the frame height when the load in the coach either increased or
> decreased. That moved the linkage attached to the height control valves.
> Built into the valves was a time delay of up to 18 seconds before any air
> was let into the air bag or out of it. In addition, there was a null space
> of + or- 3/8" where the frame could move up or down without anything
> happening. That is a dead space of 3/4" in the center of the travel. Small
> road shocks of a duration of less than 18 seconds never activate this
> system.
> 2. The second generation of height control used the same height
> control valves, and had the same operating parameters as the one I
> described above. Differences in these two systems were that rocker switches
> replaced the original round knob air valves in the dash, and added
> solenoids with valves to control the inlet and exhaust of air to the height
> control valves. Same null space and time delay as the original system.
> 3. Finally, the Electro Level II system came out. Totally electric in
> control of ride height. Used LED light sources aligned with photo
> transistors to open and close electrical circuits that either opened
> exhaust valves or started smaller compressors to raise or lower the coach.
> Manual controls in the form of rocker switches allows the operator to raise
> or lower the coach as required. The null point is narrowed to 5° of travel,
> and the time delay is lengthened to a max of 28 seconds before anything
> happens. Shutter wheels attached to linkage either block the led's or
> expose them to the photo transistors.
> Small road shocks, swales of short duration (less than 28 seconds) do
> nothing to activate the system. All this information is from GMC manuals,
> not from my foggy brain. What does change ride height is inputs from the
> driver through the rocker switches, or changes in loads in the coach.
> Jim Hupy
> Salem, Or
>
>
>

>
> > Keith,
> >
> > To me the MOST important thing about the MicroLevel system is that it
> > works like the OEM system and controls ride height through
> > sensors that adjust the attitude of the coach as you go down the road. If
> > you are on a road that is highly crowned it will raise the
> > curb side automatically with no input from the driver just like the OEM
> > system.
> >
> > Regards,
> > Rob M.
> > The Pedantic Mechanic
> > Sydney, Australia
> > AUS '75 Avion - The Blue Streak TZE365V100428
> > USA '75 Avion - Double Trouble TZE365V100426
> > USA '77 Kingsley - TZE 267V100808
> >
> > -----Original Message-----
> > From: Gmclist [mailto:gmclist-bounces] On Behalf Of
> Keith
> > V
> > Sent: Wednesday, July 18, 2018 8:52 AM
> > To: gmclist
> > Subject: Re: [GMCnet] Alternate,air pump
> >
> > Why would you EVER run ANY air compressor without a pressure switch??
> > Thats just asking for trouble, don't do it. The over pressure valve is
> not
> > designed for multiple cycles!
> > Even manual mode should just enable the pressure switch, not over ride
> it.
> >
> > Better than wire less air, MicroLevels RF remote allows individual
> height
> > control of both sides, so you can tilt the coach for
> > dumping. This even works with the ignition off as MicroLevel wakesup on a
> > button press, enables the compressor and opens the
> > valve(s).
> > Not to mention true height control and campground leveling.
> >
> > Keith Vasilakes
> > 75 ex Roylae
> > MicroLevel<
> > http://www.gmcmotorhomemarketplace.com/vasilakes/microlevel_intro.pdf>
> >
> >
> >
> >
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[Will Albers]

(you can delete one of those "simply" from my statement. Your choice =) )

> Is there a way to monitor the voltage output of the ELII ride height
> sensors? To simply turn on a light if need be? I'm simply curious of the
> output in different conditions, and when the delay kicks in. Would be fun
> to study while im a passenger.
>

>
>> Remember also that pressure based control systems invert the height
>> control. In other words if you are on said crowned road, or as you use
>> fuel, passenger changes etc. the control system will do the exact wrong
>> thing.
>>
>> For example, if you get heavier, the coach will squat, the bag pressure
>> will go up, the controller will then lower the bag pressure back to the
>> setpoint lowering the coach even more.
>>
>> Microlevels analog ( OEM hall effect non contact ) sensors measure true
>> height. it has enough resolution to sense me leaning side to side while
>> sitting on the cab step. Having a microcontroller allows a fast adjustment
>> that gets the coach within height tolerance, +- 1/4", as fast as the air
>> supply allows, then switches to height maintenance to keep height to within
>> +- 1/8". The maintenance algorithm also keeps adjustments to a minimum, no
>> less than 30 seconds between adjusting, meaning no adjusting on cloverleafs
>> or wind gusts.
>>
>> Campground leveling is a single button press.
>>
>> Keith Vasilakes
>> Mound sview Minnesota
>> 1976 ex-Royale
>>
>> ________________________________
>> From: Gmclist on behalf of Rob Mueller
>>
>> Sent: Wednesday, July 18, 2018 9:43 PM
>> To: gmclist
>> Subject: Re: [GMCnet] Alternate,air pump
>>
>> Jim,
>>
>> Was I incorrect when I stated "works like the OEM system and controls
>> ride height through sensors that adjust the attitude of the coach as you go
>> down the road. If you are on a road that is highly crowned it will raise
>> the curb side automatically with no input from the driver?"
>>
>> Regards,
>> Rob M.
>> The Pedantic Mechanic
>> Sydney, Australia
>> AUS '75 Avion - The Blue Streak TZE365V100428
>> USA '75 Avion - Double Trouble TZE365V100426
>> USA '77 Kingsley - TZE 267V100808
>>
>> -----Original Message-----
>> From: Gmclist [mailto:gmclist-bounces] On Behalf Of
>> James Hupy
>> Sent: Wednesday, July 18, 2018 7:34 PM
>> To: gmclist
>> Subject: Re: [GMCnet] Alternate,air pump
>>
>> Rob, the OEM systems ride height is ( are) controlled in two ways.
>> 1. The original early system was entirely operated by air pressure
>> and left and right hydraulic/pneumatic height control valves that sensed
>> movement of the frame height when the load in the coach either increased
>> or
>> decreased. That moved the linkage attached to the height control valves.
>> Built into the valves was a time delay of up to 18 seconds before any air
>> was let into the air bag or out of it. In addition, there was a null space
>> of + or- 3/8" where the frame could move up or down without anything
>> happening. That is a dead space of 3/4" in the center of the travel. Small
>> road shocks of a duration of less than 18 seconds never activate this
>> system.
>> 2. The second generation of height control used the same height
>> control valves, and had the same operating parameters as the one I
>> described above. Differences in these two systems were that rocker
>> switches
>> replaced the original round knob air valves in the dash, and added
>> solenoids with valves to control the inlet and exhaust of air to the
>> height
>> control valves. Same null space and time delay as the original system.
>> 3. Finally, the Electro Level II system came out. Totally electric in
>> control of ride height. Used LED light sources aligned with photo
>> transistors to open and close electrical circuits that either opened
>> exhaust valves or started smaller compressors to raise or lower the coach.
>> Manual controls in the form of rocker switches allows the operator to
>> raise
>> or lower the coach as required. The null point is narrowed to 5° of
>> travel,
>> and the time delay is lengthened to a max of 28 seconds before anything
>> happens. Shutter wheels attached to linkage either block the led's or
>> expose them to the photo transistors.
>> Small road shocks, swales of short duration (less than 28 seconds) do
>> nothing to activate the system. All this information is from GMC manuals,
>> not from my foggy brain. What does change ride height is inputs from the
>> driver through the rocker switches, or changes in loads in the coach.
>> Jim Hupy
>> Salem, Or
>>
>>
>>
>> On Wed, Jul 18, 2018, 1:59 PM Rob Mueller

>>
>> > Keith,
>> >
>> > To me the MOST important thing about the MicroLevel system is that it
>> > works like the OEM system and controls ride height through
>> > sensors that adjust the attitude of the coach as you go down the road.
>> If
>> > you are on a road that is highly crowned it will raise the
>> > curb side automatically with no input from the driver just like the OEM
>> > system.
>> >
>> > Regards,
>> > Rob M.
>> > The Pedantic Mechanic
>> > Sydney, Australia
>> > AUS '75 Avion - The Blue Streak TZE365V100428
>> > USA '75 Avion - Double Trouble TZE365V100426
>> > USA '77 Kingsley - TZE 267V100808
>> >
>> > -----Original Message-----
>> > From: Gmclist [mailto:gmclist-bounces] On Behalf Of
>> Keith
>> > V
>> > Sent: Wednesday, July 18, 2018 8:52 AM
>> > To: gmclist
>> > Subject: Re: [GMCnet] Alternate,air pump
>> >
>> > Why would you EVER run ANY air compressor without a pressure switch??
>> > Thats just asking for trouble, don't do it. The over pressure valve is
>> not
>> > designed for multiple cycles!
>> > Even manual mode should just enable the pressure switch, not over ride
>> it.
>> >
>> > Better than wire less air, MicroLevels RF remote allows individual
>> height
>> > control of both sides, so you can tilt the coach for
>> > dumping. This even works with the ignition off as MicroLevel wakesup on
>> a
>> > button press, enables the compressor and opens the
>> > valve(s).
>> > Not to mention true height control and campground leveling.
>> >
>> > Keith Vasilakes
>> > 75 ex Roylae
>> > MicroLevel<
>> > http://www.gmcmotorhomemarketplace.com/vasilakes/microlevel_intro.pdf>
>> >
>> >
>> >
>> >
>> >
>> > _______________________________________________
>> > GMCnet mailing list
>> > Unsubscribe or Change List Options:
>> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>> >
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>

 

[Matt Colie]

> Is there a way to monitor the voltage output of the ELII ride height
> sensors? To simply turn on a light if need be? I'm simply curious of the
> output in different conditions, and when the delay kicks in. Would be fun
> to study while im a passenger.

Will,

Somewhere in the documentation is a very good and complete description of the operation of the ELII system.
I thought I remembered where it was. Really I did. It isn't in the regular manuals, but I know it is someplace.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit

 

[johnny]

Take a look in the supplement if it's a new enough supplement.

--johnny
--
76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

 

[amansfield1104]

Did you use the ½ or ¾ Hp motor. 30 or 50 amp. I need to do something for mine.

Art

>
> Just as another example of what one CAN do:
>
> My 12 VDC air system runs a Puma compressor (apparently NLA - similar to
> Viair 480C). It performs very nicely for normal operations.
>
> Since I always lower the rear suspension when dumping the holding tanks, to
> expedite the process, I wanted faster return to ride height. I had an old
> Craftsman 120 vac "bowling bag" compressor. When I disassembled what I'd
> always figured was a diaphragm compressor, I found a nice little piston
> compressor. To make it fit available space behind the refrigerator (my 23'
> requires careful space planning), I repackaged it in a custom Lexan box.
> It's equipped with a quick disconnect and toggle switch for tires, etc.
> Its main control, however, is a "Raise" push button beside the controls for
> my two macerators (black & grey water). Also located there are independent
> momentary "Lower" switches for the left and right air bags, so I can tilt
> the coach to fit the terrain. After dumping, pushing the "Raise" button
> routes the compressor output, through check valves, directly into both air
> bags. Full down to full up takes about 30 seconds. I do have to have
> either the 1500W inverter or the generator running, of course.
>
> Ken H.
> Americus, GA
> '76 X-Birchaven w/Cad500/Howell EFI & EBL,
> Manny Brakes & 1-Ton, Troy-Bilt APU, etc., etc., etc.
> www.gmcwipersetc.com
>
>>
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[Ken H.]

Art,

I don't know which compressor you're interested in. As far as the Puma, I
can't be any help: When I bought it 10+ years ago, it was similar in
design to a current Viair 480C, but less expensive. Now, Puma seems to
have nothing in that class.

That 120 vac Craftsman compressor had been around so long that I have no
firm idea of its HP rating, though I'd say, off the top of my head, 1-1/2
HP.

I'm not sure what your 30A or 50A question means unless it's shore cable.
In that case, it's 30A, since I have a Birchaven. The 120 vac compressor
doesn't stress that at all -- in fact, even the inverter carries it well --
for a FEW minutes.

Ken H.

On Fri, Jul 20, 2018 at 8:53 PM amansfield1104 <

> Did you use the ½ or ¾ Hp motor. 30 or 50 amp. I need to do something
> for mine.
>
> Art
> > On Jul 17, 2018, at 8:38 AM, Ken Henderson

> >
> > Just as another example of what one CAN do:
> >
> > My 12 VDC air system runs a Puma compressor (apparently NLA - similar to
> > Viair 480C). It performs very nicely for normal operations.
> >
> > Since I always lower the rear suspension when dumping the holding tanks,
> to
> > expedite the process, I wanted faster return to ride height. I had an
> old
> > Craftsman 120 vac "bowling bag" compressor.

​,,,