| [GMCnet] 4.8 MPG [message #324111] |
Thu, 21 September 2017 10:16  |
glwgmc
Messages: 1014
Registered: June 2004
Karma: 10
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Senior Member |
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Today's smaller gas class As get around 8 MPG, larger gas jobs around 6. Smaller diesel rigs around 14, larger diesel coaches around 8. Our Prevost Country Coach has a GVW of just under 50,000 pounds. At an open scale in Oregon with full water, half fuel, empty black and gray tanks and loaded for a month long trip we weighed 43,000 pounds with both of us in the coach. We get between 7 and 8 in normal freeway driving at a legal 60 MPH towing a Mini Cooper S Clubman. The lowest I have seen over the last ten or so fuelings (usually done at around 50%) was 6.8 and the highest just under 8. The engine is a 12.7 Detroit Diesel Series 60 DECC 3 with an Allison auto trans that predates the use of DEF.
Our former 1998 Beaver Patroit had a GVW of 32,000 and got 7-8 pulling a Subaru Outback for four years all over North America with a 330 hp Cat.
Both of our GMCs got 8-9 depending on speed, headwinds, altitude and average grade without a tow car and 1 MPG less towing a Fiat Abarth on a tow dolly. One GMC was carbureted the other had FiTech EFI. The EFI rig was a bit better MPG overall but not by much, maybe 0.5 to no more than 1 MPG. Average speed made more difference than anything else. I always estimated about 0.5 +\- MPG for every 5 MPH change.
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
.......
Date: Wed, 20 Sep 2017 16:04:24 -0700
From: John Phillips
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] 4.8 MPG
Message-ID:
Content-Type: text/plain; charset="UTF-8"
what do the new class A gas MHs get?
On Wed, Sep 20, 2017 at 2:48 PM, Chris Tyler
wrote:
> Just to make you feel better, contemporary [to GMC MH] SOB class As
> usually only got 4-5 mpg routinely
> --
> 76 Glenbrook
>
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Jerry & Sharon Work
78 Royale
Kerby, OR
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| Re: [GMCnet] 4.8 MPG [message #324114 is a reply to message #324111] |
Thu, 21 September 2017 10:33  |
Keith V
Messages: 2337
Registered: March 2008
Location: Mounds View,MN
Karma: 0
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Senior Member |
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So I got the 4.8 in an area with a lot of hills and I wasn't being nice to the coach, I was going up them at 60, same as on the flats.
On the way home I left the cruise off and let the speed sag on hills keeping the vacuum above 10, that got me above 8.
I have a wide band O2 that tells me I'm running 15.5-16.0 to 1 AFR, so it's not overly rich.
as I put the throttle down it richens up till it gets into the 13's at WOT
What do you do on hills to get an average of 8-9?
________________________________
From: Gmclist on behalf of Gerald Work
Sent: Thursday, September 21, 2017 10:16:08 AM
To: gmclist@list.gmcnet.org
Subject: [GMCnet] 4.8 MPG
Today's smaller gas class As get around 8 MPG, larger gas jobs around 6. Smaller diesel rigs around 14, larger diesel coaches around 8. Our Prevost Country Coach has a GVW of just under 50,000 pounds. At an open scale in Oregon with full water, half fuel, empty black and gray tanks and loaded for a month long trip we weighed 43,000 pounds with both of us in the coach. We get between 7 and 8 in normal freeway driving at a legal 60 MPH towing a Mini Cooper S Clubman. The lowest I have seen over the last ten or so fuelings (usually done at around 50%) was 6.8 and the highest just under 8. The engine is a 12.7 Detroit Diesel Series 60 DECC 3 with an Allison auto trans that predates the use of DEF.
Our former 1998 Beaver Patroit had a GVW of 32,000 and got 7-8 pulling a Subaru Outback for four years all over North America with a 330 hp Cat.
Both of our GMCs got 8-9 depending on speed, headwinds, altitude and average grade without a tow car and 1 MPG less towing a Fiat Abarth on a tow dolly. One GMC was carbureted the other had FiTech EFI. The EFI rig was a bit better MPG overall but not by much, maybe 0.5 to no more than 1 MPG. Average speed made more difference than anything else. I always estimated about 0.5 +\- MPG for every 5 MPH change.
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
.......
Date: Wed, 20 Sep 2017 16:04:24 -0700
From: John Phillips
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] 4.8 MPG
Message-ID:
Content-Type: text/plain; charset="UTF-8"
what do the new class A gas MHs get?
On Wed, Sep 20, 2017 at 2:48 PM, Chris Tyler
wrote:
> Just to make you feel better, contemporary [to GMC MH] SOB class As
> usually only got 4-5 mpg routinely
> --
> 76 Glenbrook
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
_______________________________________________
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
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] 4.8 MPG [message #328359 is a reply to message #324114] |
Wed, 17 January 2018 16:41 |
NextGenGMC
Messages: 146
Registered: December 2017
Location: Washington State
Karma: -1
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Senior Member |
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Keith V wrote on Thu, 21 September 2017 08:33
...What do you do on hills to get an average of 8-9?
Looking back at some older discussions, I noticed that this one did not generate any replies. I have the same question as Keith V - what is the best way to drive our GMC in the areas with lots of hills?
Vadim Jitkov
'76 Glenbrook 26'
Pullman, WA
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