Home » Public Forums » GMCnet » [GMCnet] Air suspension and leveling system
| [GMCnet] Air suspension and leveling system [message #319284] |
Mon, 19 June 2017 09:58  |
glwgmc
Messages: 1014
Registered: June 2004
Karma: 10
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Senior Member |
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Hi Rob,
Tongue firmly planted in cheek I would suggest your logic ignores the obvious.
The GMC engineers did what they did based on technology available to them at the time. At that time they had no option for a far simpler, more reliable, less expensive and flexible Air control system such as we do today with things like the wireless air controller. Who knows how they might have elected to design this system if they did, but I really doubt they would have elected to fill the coach with air lines, fittings and numerous leak points as they had to do given the options available to them at the time. They likely also would not have had to try three times in six years to come up with the semi-satisfactory compromise.
Tongue still firmly planted in cheek, if they had the same redesign rate over the ensuing 40 plus years if GMC continued to be produced we could now be dealing with auto air control system version 23. Hmmmmmm.
Me thinks this is one case where newer technology trumps old school.
Jerry
Jerry Work
The Dovetail Joint
Fine furniture designed & hand crafted
in the 1907 former Masonic Temple building
in historic Kerby, OR
http://jerrywork.com
................
Message: 13
Date: Mon, 19 Jun 2017 14:15:21 +1000
From: "Rob Mueller"
To:
Subject: Re: [GMCnet] Air suspension and leveling system
Message-ID:
Content-Type: text/plain; charset="us-ascii"
Rich, Matt,
I agree with both of you!
If the GMC suspension engineers didn't think the automatic leveling system
was necessary why did they install it?
AND why did the accountants approve it?
Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808
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Jerry & Sharon Work
78 Royale
Kerby, OR
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| Re: [GMCnet] Air suspension and leveling system [message #319288 is a reply to message #319284] |
Mon, 19 June 2017 11:26  |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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That sounds nice - and if it leveled en route, it would in fact be a more modern version of the OEM setups. As a 'set and it stays there' system, it trumps a shutoff valve only in that you don't have to find a gas station and walk around back to set the height statically. Surely the inventor is in the process of doing this.
--johnny
Foolish Carriage, 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
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| Re: [GMCnet] Air suspension and leveling system [message #319290 is a reply to message #319284] |
Mon, 19 June 2017 11:26 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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Let's see, they could have coil over airbags filled with a slurry of
magnetically sensitive material that could be surrounded by a strong
electromagnetic coil, the field strength of which could be influenced by
forward looking sensors. That way when a pothole or truck groove were
detected, the suspension could react before obstacles were encountered.
Many times a second.
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Jun 19, 2017 7:59 AM, "Gerald Work" wrote:
> Hi Rob,
>
> Tongue firmly planted in cheek I would suggest your logic ignores the
> obvious.
>
> The GMC engineers did what they did based on technology available to them
> at the time. At that time they had no option for a far simpler, more
> reliable, less expensive and flexible Air control system such as we do
> today with things like the wireless air controller. Who knows how they
> might have elected to design this system if they did, but I really doubt
> they would have elected to fill the coach with air lines, fittings and
> numerous leak points as they had to do given the options available to them
> at the time. They likely also would not have had to try three times in six
> years to come up with the semi-satisfactory compromise.
>
> Tongue still firmly planted in cheek, if they had the same redesign rate
> over the ensuing 40 plus years if GMC continued to be produced we could now
> be dealing with auto air control system version 23. Hmmmmmm.
>
> Me thinks this is one case where newer technology trumps old school.
>
> Jerry
> Jerry Work
> The Dovetail Joint
> Fine furniture designed & hand crafted
> in the 1907 former Masonic Temple building
> in historic Kerby, OR
> http://jerrywork.com
> ................
> Message: 13
> Date: Mon, 19 Jun 2017 14:15:21 +1000
> From: "Rob Mueller"
> To:
> Subject: Re: [GMCnet] Air suspension and leveling system
> Message-ID:
> Content-Type: text/plain; charset="us-ascii"
>
> Rich, Matt,
>
> I agree with both of you!
>
> If the GMC suspension engineers didn't think the automatic leveling system
> was necessary why did they install it?
>
> AND why did the accountants approve it?
>
> Regards,
> Rob M.
> The Pedantic Mechanic
> USAussie - Downunder
> AUS '75 Avion - The Blue Streak TZE365V100428
> USA '75 Avion - Double Trouble TZE365V100426
> USA '77 Kingsley - TZE 267V100808
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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| Re: [GMCnet] Air suspension and leveling system [message #319297 is a reply to message #319284] |
Mon, 19 June 2017 14:19 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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Or they could just use one of the newer optical height sensors. Add a little hysteresis (that reads so much cooler than 'delay')and it would mimic the OEM.
--johnny
Foolish Carriage, 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
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| Re: [GMCnet] Air suspension and leveling system [message #319312 is a reply to message #319290] |
Mon, 19 June 2017 19:33 |
 |
USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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G'day,
I apologize for my original email as it was not clear.
It should have read:
If the GMC suspension engineers didn't think the automatic leveling system WITH HEIGHT CONTROL TO COMPENSATE FOR VARYING ROAD
CONDITIONS . . . . . . . .
The road that leads to the storage facility where I keep Double Trouble in Huffman is highly crowned. Just before the facility is a
decreasing radius left hand turn. The speed limit on that road is 30mph. One time when I went around that turn in Double Trouble I
was going a bit too quick and I scared the s#!t out of myself! The crown in the road had the coach leaning to the right, going
around the left hand turn made it lean further yet and the decreasing radius was the icing on the cake, I almost lost it!
When I got back to the shop I noticed that the PowerLevel valves were in HOLD not TRAVEL. Subsequent to this incident I ALWAYS check
to make sure they are in TRAVEL when I drive Double Trouble.
My theory is that when a GMC is going down a crowned road it will lean to the right, the system will sense this and after the built
in time delay it will add pressure to the air bags on the right side to decrease the lean.
Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
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@list.gmcnet.org] On Behalf Of James Hupy
Sent: Tuesday, June 20, 2017 2:26 AM
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Air suspension and leveling system
Let's see, they could have coil over airbags filled with a slurry of
magnetically sensitive material that could be surrounded by a strong
electromagnetic coil, the field strength of which could be influenced by
forward looking sensors. That way when a pothole or truck groove were
detected, the suspension could react before obstacles were encountered.
Many times a second.
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Jun 19, 2017 7:59 AM, "Gerald Work" wrote:
> Hi Rob,
>
> Tongue firmly planted in cheek I would suggest your logic ignores the
> obvious.
>
> The GMC engineers did what they did based on technology available to them
> at the time. At that time they had no option for a far simpler, more
> reliable, less expensive and flexible Air control system such as we do
> today with things like the wireless air controller. Who knows how they
> might have elected to design this system if they did, but I really doubt
> they would have elected to fill the coach with air lines, fittings and
> numerous leak points as they had to do given the options available to them
> at the time. They likely also would not have had to try three times in six
> years to come up with the semi-satisfactory compromise.
>
> Tongue still firmly planted in cheek, if they had the same redesign rate
> over the ensuing 40 plus years if GMC continued to be produced we could now
> be dealing with auto air control system version 23. Hmmmmmm.
>
> Me thinks this is one case where newer technology trumps old school.
>
> Jerry
> Jerry Work
> The Dovetail Joint
> Fine furniture designed & hand crafted
> in the 1907 former Masonic Temple building
> in historic Kerby, OR
> http://jerrywork.com
> ................
> Message: 13
> Date: Mon, 19 Jun 2017 14:15:21 +1000
> From: "Rob Mueller"
> To:
> Subject: Re: [GMCnet] Air suspension and leveling system
> Message-ID:
> Content-Type: text/plain; charset="us-ascii"
>
> Rich, Matt,
>
> I agree with both of you!
>
> If the GMC suspension engineers didn't think the automatic leveling system
> was necessary why did they install it?
>
> AND why did the accountants approve it?
>
> Regards,
> Rob M.
> The Pedantic Mechanic
> USAussie - Downunder
> AUS '75 Avion - The Blue Streak TZE365V100428
> USA '75 Avion - Double Trouble TZE365V100426
> USA '77 Kingsley - TZE 267V100808
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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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 suspension and leveling system [message #319325 is a reply to message #319312] |
Tue, 20 June 2017 08:59 |
Keith V
Messages: 2337
Registered: March 2008
Location: Mounds View,MN
Karma: 0
|
Senior Member |
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Thats interesting Rob
The problem is what is the 'right' time delay?
Do you want the coach to adjust while taking a turn, like a cloverleaf or roundabout?
I say no, thats a bad idea
What about cross winds?
Yes
crowned roads?
Definitly
Ideally the system would sense steering angle and then it would be able to do the right thing.
Maybe using an accelerometer could determine if the coach is turning...
________________________________
From: Gmclist on behalf of Rob Mueller
Sent: Monday, June 19, 2017 7:33:40 PM
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Air suspension and leveling system
G'day,
I apologize for my original email as it was not clear.
It should have read:
If the GMC suspension engineers didn't think the automatic leveling system WITH HEIGHT CONTROL TO COMPENSATE FOR VARYING ROAD
CONDITIONS . . . . . . . .
The road that leads to the storage facility where I keep Double Trouble in Huffman is highly crowned. Just before the facility is a
decreasing radius left hand turn. The speed limit on that road is 30mph. One time when I went around that turn in Double Trouble I
was going a bit too quick and I scared the s#!t out of myself! The crown in the road had the coach leaning to the right, going
around the left hand turn made it lean further yet and the decreasing radius was the icing on the cake, I almost lost it!
When I got back to the shop I noticed that the PowerLevel valves were in HOLD not TRAVEL. Subsequent to this incident I ALWAYS check
to make sure they are in TRAVEL when I drive Double Trouble.
My theory is that when a GMC is going down a crowned road it will lean to the right, the system will sense this and after the built
in time delay it will add pressure to the air bags on the right side to decrease the lean.
Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
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@list.gmcnet.org] On Behalf Of James Hupy
Sent: Tuesday, June 20, 2017 2:26 AM
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Air suspension and leveling system
Let's see, they could have coil over airbags filled with a slurry of
magnetically sensitive material that could be surrounded by a strong
electromagnetic coil, the field strength of which could be influenced by
forward looking sensors. That way when a pothole or truck groove were
detected, the suspension could react before obstacles were encountered.
Many times a second.
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Jun 19, 2017 7:59 AM, "Gerald Work" wrote:
> Hi Rob,
>
> Tongue firmly planted in cheek I would suggest your logic ignores the
> obvious.
>
> The GMC engineers did what they did based on technology available to them
> at the time. At that time they had no option for a far simpler, more
> reliable, less expensive and flexible Air control system such as we do
> today with things like the wireless air controller. Who knows how they
> might have elected to design this system if they did, but I really doubt
> they would have elected to fill the coach with air lines, fittings and
> numerous leak points as they had to do given the options available to them
> at the time. They likely also would not have had to try three times in six
> years to come up with the semi-satisfactory compromise.
>
> Tongue still firmly planted in cheek, if they had the same redesign rate
> over the ensuing 40 plus years if GMC continued to be produced we could now
> be dealing with auto air control system version 23. Hmmmmmm.
>
> Me thinks this is one case where newer technology trumps old school.
>
> Jerry
> Jerry Work
> The Dovetail Joint
> Fine furniture designed & hand crafted
> in the 1907 former Masonic Temple building
> in historic Kerby, OR
> http://jerrywork.com
> ................
> Message: 13
> Date: Mon, 19 Jun 2017 14:15:21 +1000
> From: "Rob Mueller"
> To:
> Subject: Re: [GMCnet] Air suspension and leveling system
> Message-ID:
> Content-Type: text/plain; charset="us-ascii"
>
> Rich, Matt,
>
> I agree with both of you!
>
> If the GMC suspension engineers didn't think the automatic leveling system
> was necessary why did they install it?
>
> AND why did the accountants approve it?
>
> Regards,
> Rob M.
> The Pedantic Mechanic
> USAussie - Downunder
> AUS '75 Avion - The Blue Streak TZE365V100428
> USA '75 Avion - Double Trouble TZE365V100426
> USA '77 Kingsley - TZE 267V100808
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
_______________________________________________
GMCnet mailing list
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Keith Vasilakes
Mounds View. MN
75 ex Royale GMC
ask me about MicroLevel
Cell, 763-732-3419
My427v8@hotmail.com
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| Re: [GMCnet] Air suspension and leveling system [message #319327 is a reply to message #319284] |
Tue, 20 June 2017 09:44 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
|
Senior Member |
|
|
I'd rather it compensate for leaning over a period of time than worry with what the steering angle is. You'd either have to add delay to it or you'd be riding in a rocking chair. Once you add the delay, why not just mimic the OEM? Or simply repair it and ;et it do its thing? The last third of the trip bringing home my current coach had to be run with the Schrader valves closed due to mis-routing of the air lines. Substantially worse ride that way.
--johnny
Foolish Carriage, 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
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| Re: [GMCnet] Air suspension and leveling system [message #319329 is a reply to message #319325] |
Tue, 20 June 2017 09:56 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
|
Senior Member |
|
|
When I was in high school, I worked for farmers during the summer for money
to by school clothes. One of the jobs I did was sewing sacks on a combine.
The swather bar on that combine was about 10 feet wide. It occasionally
would dip into the earth on the ends due to irregularities in the fields.
Not good.
A couple of years ago I was looking at a spanking brand new John Deere
combine and it had a 36 foot swather bar. I asked the guy "how do you keep
the bar from digging into the ground?" He said Radar equipped, fully
articulated hydraulic equipped, it adjusts the suspension of the combine
and the header bar at the same time. The cab was sound insulated and air
conditioned and had a killer stereo. Pneumatic seat that adjusted to the
drivers weight.
That is the state of technology in ag equipment today. If they can make a
combine handle sidehills, a motor home should be within the realm of
possibility, I would think.
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Jun 20, 2017 7:10 AM, "Keith V" wrote:
>
> Thats interesting Rob
>
> The problem is what is the 'right' time delay?
>
> Do you want the coach to adjust while taking a turn, like a cloverleaf or
> roundabout?
>
> I say no, thats a bad idea
>
>
> What about cross winds?
>
> Yes
>
>
> crowned roads?
>
> Definitly
>
>
> Ideally the system would sense steering angle and then it would be able to
> do the right thing.
>
> Maybe using an accelerometer could determine if the coach is turning...
>
>
> ________________________________
> From: Gmclist on behalf of Rob Mueller robmueller@iinet.net.au>
> Sent: Monday, June 19, 2017 7:33:40 PM
> To: gmclist@list.gmcnet.org
> Subject: Re: [GMCnet] Air suspension and leveling system
>
> G'day,
>
> I apologize for my original email as it was not clear.
>
> It should have read:
>
> If the GMC suspension engineers didn't think the automatic leveling system
> WITH HEIGHT CONTROL TO COMPENSATE FOR VARYING ROAD
> CONDITIONS . . . . . . . .
>
> The road that leads to the storage facility where I keep Double Trouble in
> Huffman is highly crowned. Just before the facility is a
> decreasing radius left hand turn. The speed limit on that road is 30mph.
> One time when I went around that turn in Double Trouble I
> was going a bit too quick and I scared the s#!t out of myself! The crown
> in the road had the coach leaning to the right, going
> around the left hand turn made it lean further yet and the decreasing
> radius was the icing on the cake, I almost lost it!
>
> When I got back to the shop I noticed that the PowerLevel valves were in
> HOLD not TRAVEL. Subsequent to this incident I ALWAYS check
> to make sure they are in TRAVEL when I drive Double Trouble.
>
> My theory is that when a GMC is going down a crowned road it will lean to
> the right, the system will sense this and after the built
> in time delay it will add pressure to the air bags on the right side to
> decrease the lean.
>
> Regards,
> Rob M.
> The Pedantic Mechanic
> USAussie - Downunder
> 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@list.gmcnet.org] On Behalf Of James
> Hupy
> Sent: Tuesday, June 20, 2017 2:26 AM
> To: gmclist@list.gmcnet.org
> Subject: Re: [GMCnet] Air suspension and leveling system
>
> Let's see, they could have coil over airbags filled with a slurry of
> magnetically sensitive material that could be surrounded by a strong
> electromagnetic coil, the field strength of which could be influenced by
> forward looking sensors. That way when a pothole or truck groove were
> detected, the suspension could react before obstacles were encountered.
> Many times a second.
> Jim Hupy
> Salem, Or
> 78 GMC ROYALE 403
>
> On Jun 19, 2017 7:59 AM, "Gerald Work" wrote:
>
>> Hi Rob,
>>
>> Tongue firmly planted in cheek I would suggest your logic ignores the
>> obvious.
>>
>> The GMC engineers did what they did based on technology available to them
>> at the time. At that time they had no option for a far simpler, more
>> reliable, less expensive and flexible Air control system such as we do
>> today with things like the wireless air controller. Who knows how they
>> might have elected to design this system if they did, but I really doubt
>> they would have elected to fill the coach with air lines, fittings and
>> numerous leak points as they had to do given the options available to
> them
>> at the time. They likely also would not have had to try three times in
> six
>> years to come up with the semi-satisfactory compromise.
>>
>> Tongue still firmly planted in cheek, if they had the same redesign rate
>> over the ensuing 40 plus years if GMC continued to be produced we could
> now
>> be dealing with auto air control system version 23. Hmmmmmm.
>>
>> Me thinks this is one case where newer technology trumps old school.
>>
>> Jerry
>> Jerry Work
>> The Dovetail Joint
>> Fine furniture designed & hand crafted
>> in the 1907 former Masonic Temple building
>> in historic Kerby, OR
>> http://jerrywork.com
>> ................
>> Message: 13
>> Date: Mon, 19 Jun 2017 14:15:21 +1000
>> From: "Rob Mueller"
>> To:
>> Subject: Re: [GMCnet] Air suspension and leveling system
>> Message-ID:
>> Content-Type: text/plain; charset="us-ascii"
>>
>> Rich, Matt,
>>
>> I agree with both of you!
>>
>> If the GMC suspension engineers didn't think the automatic leveling
> system
>> was necessary why did they install it?
>>
>> AND why did the accountants approve it?
>>
>> Regards,
>> Rob M.
>> The Pedantic Mechanic
>> USAussie - Downunder
>> AUS '75 Avion - The Blue Streak TZE365V100428
>> USA '75 Avion - Double Trouble TZE365V100426
>> USA '77 Kingsley - TZE 267V100808
>>
>> _______________________________________________
>> 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:
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| Re: [GMCnet] Air suspension and leveling system [message #319330 is a reply to message #319325] |
Tue, 20 June 2017 10:09 |
Richard Denney
Messages: 920
Registered: April 2010
Karma: 9
|
Senior Member |
|
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Keith, I don't agree that leveling on curves is a bad idea. My coach will
fill the outside bag on long, sweep turns, which provides a bit of roll
stiffness just the same as a roll bar. It levels back out pretty quickly
after the turn. It would take a pretty long cloverleaf ramp ("loop ramp" in
the biz) to get past the damping of the leveling valves, but when driving
in our Eastern mountains, we have a lot of sweeping turns that extent for a
mile or more. We have to realize that most curves are superelevated
(banked) and that doesn't look much different than a crown except for the
lateral forces on the coach. I cannot imagine why the leveling system
controlling roll would be something to overcome rather than enjoy.
Leveling valves won't level a coach on a crowned road, except to correct
any tendency for the coach body to roll to the downhill side, which will be
pretty minor.
Crosswinds are usually gusty and the damping of the leveling valves filters
them out.
Rick "who has a dash air pressure gauge and knows when the leveling valves
open up" Denney
On Tue, Jun 20, 2017 at 9:59 AM, Keith V wrote:
>
> Thats interesting Rob
>
> The problem is what is the 'right' time delay?
>
> Do you want the coach to adjust while taking a turn, like a cloverleaf or
> roundabout?
>
> I say no, thats a bad idea
>
>
> What about cross winds?
>
> Yes
>
>
> crowned roads?
>
> Definitly
>
>
> Ideally the system would sense steering angle and then it would be able to
> do the right thing.
>
> Maybe using an accelerometer could determine if the coach is turning...
>
>
>
--
'73 X-Glacier 230 "Jaws"
Northern Virginia
Offlist email: rick at rickdenney dot com
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| Re: [GMCnet] Air suspension and leveling system [message #319331 is a reply to message #319330] |
Tue, 20 June 2017 10:46 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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Senior Member |
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Sorry but my choice would be power level with JR valves and an isolator valve at each bag. No electronics too worry about and simple to fix . High tech is just another headache to worry about in this old guys opinion.
Roy Keen
Minden,NV
76 X Glenbrook
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| Re: [GMCnet] Air suspension and leveling system [message #319334 is a reply to message #319330] |
Tue, 20 June 2017 10:46 |
Keith V
Messages: 2337
Registered: March 2008
Location: Mounds View,MN
Karma: 0
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Jim,
Radar is a little extreme for my world I think!
Rick,
I'm pretty sure the OEM system adjusts on a cloverleaf, I remember seeing it.
The question is should it?
The OEM system had 1 delay time, I have more control, so I contest that on short turns no leveling should be done as that would change the handling of the coach and runs the compressor more than necessary
Long sweeping turns yes, that should be fine and is pretty much unavoidable.
Keith, who has height data and knows how it rolls, vasilakes
________________________________
From: Gmclist on behalf of Richard Denney
Sent: Tuesday, June 20, 2017 10:09:08 AM
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Air suspension and leveling system
Keith, I don't agree that leveling on curves is a bad idea. My coach will
fill the outside bag on long, sweep turns, which provides a bit of roll
stiffness just the same as a roll bar. It levels back out pretty quickly
after the turn. It would take a pretty long cloverleaf ramp ("loop ramp" in
the biz) to get past the damping of the leveling valves, but when driving
in our Eastern mountains, we have a lot of sweeping turns that extent for a
mile or more. We have to realize that most curves are superelevated
(banked) and that doesn't look much different than a crown except for the
lateral forces on the coach. I cannot imagine why the leveling system
controlling roll would be something to overcome rather than enjoy.
Leveling valves won't level a coach on a crowned road, except to correct
any tendency for the coach body to roll to the downhill side, which will be
pretty minor.
Crosswinds are usually gusty and the damping of the leveling valves filters
them out.
Rick "who has a dash air pressure gauge and knows when the leveling valves
open up" Denney
On Tue, Jun 20, 2017 at 9:59 AM, Keith V wrote:
>
> Thats interesting Rob
>
> The problem is what is the 'right' time delay?
>
> Do you want the coach to adjust while taking a turn, like a cloverleaf or
> roundabout?
>
> I say no, thats a bad idea
>
>
> What about cross winds?
>
> Yes
>
>
> crowned roads?
>
> Definitly
>
>
> Ideally the system would sense steering angle and then it would be able to
> do the right thing.
>
> Maybe using an accelerometer could determine if the coach is turning...
>
>
>
--
'73 X-Glacier 230 "Jaws"
Northern Virginia
Offlist email: rick at rickdenney dot com
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Keith Vasilakes
Mounds View. MN
75 ex Royale GMC
ask me about MicroLevel
Cell, 763-732-3419
My427v8@hotmail.com
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| Re: [GMCnet] Air suspension and leveling system [message #319366 is a reply to message #319325] |
Tue, 20 June 2017 23:49 |
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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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Keith,
Regarding the time delay for the Power-Level system see:
MM X-7525 / Section 4 - Rear Suspension / Pages 4-25 & 4-26 - TIME DELAY CHECK
The Electro-Level system uses the same height control valves therefore the delay is the same.
For Electro-Level II see:
MM X-77725 / Section 4 - Rear Suspension / Pages 4B-3, 4B-4 & 4B-5 ELECTRONIC HEIGHT SENSOR
Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
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@list.gmcnet.org] On Behalf Of Keith V
Sent: Wednesday, June 21, 2017 12:00 AM
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Air suspension and leveling system
Thats interesting Rob
The problem is what is the 'right' time delay?
Do you want the coach to adjust while taking a turn, like a cloverleaf or roundabout?
I say no, thats a bad idea
What about cross winds?
Yes
crowned roads?
Definitly
Ideally the system would sense steering angle and then it would be able to do the right thing.
Maybe using an accelerometer could determine if the coach is turning...
________________________________
From: Gmclist on behalf of Rob Mueller
Sent: Monday, June 19, 2017 7:33:40 PM
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Air suspension and leveling system
G'day,
I apologize for my original email as it was not clear.
It should have read:
If the GMC suspension engineers didn't think the automatic leveling system WITH HEIGHT CONTROL TO COMPENSATE FOR VARYING ROAD
CONDITIONS . . . . . . . .
The road that leads to the storage facility where I keep Double Trouble in Huffman is highly crowned. Just before the facility is a
decreasing radius left hand turn. The speed limit on that road is 30mph. One time when I went around that turn in Double Trouble I
was going a bit too quick and I scared the s#!t out of myself! The crown in the road had the coach leaning to the right, going
around the left hand turn made it lean further yet and the decreasing radius was the icing on the cake, I almost lost it!
When I got back to the shop I noticed that the PowerLevel valves were in HOLD not TRAVEL. Subsequent to this incident I ALWAYS check
to make sure they are in TRAVEL when I drive Double Trouble.
My theory is that when a GMC is going down a crowned road it will lean to the right, the system will sense this and after the built
in time delay it will add pressure to the air bags on the right side to decrease the lean.
Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
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@list.gmcnet.org] On Behalf Of James Hupy
Sent: Tuesday, June 20, 2017 2:26 AM
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Air suspension and leveling system
Let's see, they could have coil over airbags filled with a slurry of
magnetically sensitive material that could be surrounded by a strong
electromagnetic coil, the field strength of which could be influenced by
forward looking sensors. That way when a pothole or truck groove were
detected, the suspension could react before obstacles were encountered.
Many times a second.
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Jun 19, 2017 7:59 AM, "Gerald Work" wrote:
> Hi Rob,
>
> Tongue firmly planted in cheek I would suggest your logic ignores the
> obvious.
>
> The GMC engineers did what they did based on technology available to them
> at the time. At that time they had no option for a far simpler, more
> reliable, less expensive and flexible Air control system such as we do
> today with things like the wireless air controller. Who knows how they
> might have elected to design this system if they did, but I really doubt
> they would have elected to fill the coach with air lines, fittings and
> numerous leak points as they had to do given the options available to them
> at the time. They likely also would not have had to try three times in six
> years to come up with the semi-satisfactory compromise.
>
> Tongue still firmly planted in cheek, if they had the same redesign rate
> over the ensuing 40 plus years if GMC continued to be produced we could now
> be dealing with auto air control system version 23. Hmmmmmm.
>
> Me thinks this is one case where newer technology trumps old school.
>
> Jerry
> Jerry Work
> The Dovetail Joint
> Fine furniture designed & hand crafted
> in the 1907 former Masonic Temple building
> in historic Kerby, OR
> http://jerrywork.com
> ................
> Message: 13
> Date: Mon, 19 Jun 2017 14:15:21 +1000
> From: "Rob Mueller"
> To:
> Subject: Re: [GMCnet] Air suspension and leveling system
> Message-ID:
> Content-Type: text/plain; charset="us-ascii"
>
> Rich, Matt,
>
> I agree with both of you!
>
> If the GMC suspension engineers didn't think the automatic leveling system
> was necessary why did they install it?
>
> AND why did the accountants approve it?
>
> Regards,
> Rob M.
> The Pedantic Mechanic
> USAussie - Downunder
> AUS '75 Avion - The Blue Streak TZE365V100428
> USA '75 Avion - Double Trouble TZE365V100426
> USA '77 Kingsley - TZE 267V100808
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
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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 suspension and leveling system [message #319485 is a reply to message #319330] |
Thu, 22 June 2017 23:24 |
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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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G'day,
Tune back into this channel in September as I intend to do some testing to find out what the PowerLevel and ElectroLevel system will
do vis-a-vis the "verticality" of Double Trouble and the Kingsley on the crowned road leading to where I store them!
Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
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@list.gmcnet.org] On Behalf Of Richard Denney
Sent: Wednesday, June 21, 2017 1:09 AM
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Air suspension and leveling system
Keith, I don't agree that leveling on curves is a bad idea. My coach will
fill the outside bag on long, sweep turns, which provides a bit of roll
stiffness just the same as a roll bar. It levels back out pretty quickly
after the turn. It would take a pretty long cloverleaf ramp ("loop ramp" in
the biz) to get past the damping of the leveling valves, but when driving
in our Eastern mountains, we have a lot of sweeping turns that extent for a
mile or more. We have to realize that most curves are superelevated
(banked) and that doesn't look much different than a crown except for the
lateral forces on the coach. I cannot imagine why the leveling system
controlling roll would be something to overcome rather than enjoy.
Leveling valves won't level a coach on a crowned road, except to correct
any tendency for the coach body to roll to the downhill side, which will be
pretty minor.
Crosswinds are usually gusty and the damping of the leveling valves filters
them out.
Rick "who has a dash air pressure gauge and knows when the leveling valves
open up" Denney
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
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 suspension and leveling system [message #319516 is a reply to message #319485] |
Fri, 23 June 2017 20:40 |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
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Senior Member |
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You could easily use the same type sensors that are being used for backup sensors to sense the height of the frame from the roadbed.
Ardunio, etc.to the rescue.
Tom, MS II
2012 Phoenix Cruiser model 2552
KA4CSG
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