Home » Public Forums » GMCnet » short trip report, new carb averaging 7 MPG (What size are the jets in a stock Q-jet?)
| short trip report, new carb averaging 7 MPG [message #63570] |
Mon, 09 November 2009 11:19  |
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Well took the coach out for a run this weekend, and drove about 120 miles. approximaely 30% of those were city miles, and 70% freeway miles at 55-65 mph.
The new holley carb performed just fine, though im averaging only about 7 mpg, i'm guessing I have slightly larger jets then I need so I have ordered 2 sets of smaller primaries, and I will adjust the vac secondary. the power valve should be the stock 6.5 hg one which I onl see that kind of vac if I floor it, so I dont think I need to swap the PV.
the only real problem I had was when the coach adbruptly stalled out several times, turned out to be the PO had riged the batt wire on the coil with a quick splice when the coach as converted to HEI, therefore it had become corroded, and required on-site replacement, but I always pack a DVM and a set of electrical connectors as well as fairly compleate set of tools, so once the problem was identified it took 5 minutes to fix.
I have had no problems with her since, so just waiting for my tuning parts from summit for the carb....
stay tuned...
73 Canyon Lands, (a.k.a. The Yellow Submarine) West Los Angeles CA
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| Re: [GMCnet] short trip report, new carb averaging 7 MPG [message #63572 is a reply to message #63570] |
Mon, 09 November 2009 11:23  |
powerjon
Messages: 2446
Registered: January 2004
Karma: 5
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Senior Member |
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Shan,
Do you have a Fuel/Air gauge installed on the coach?
J.R. Wright
On Nov 9, 2009, at 12:19 PM, Shan Rose wrote:
>
>
> Well took the coach out for a run this weekend, and drove about 120
> miles. approximately 30% of those were city miles, and 70% freeway
> miles at 55-65 mph.
>
> The new holley carb performed just fine, though Imo averaging only
> about 7 mpg, i'm guessing I have slightly larger jets then I need so
> I have ordered 2 sets of smaller primaries, and I will adjust the
> vac secondary. the power valve should be the stock 6.5 hg one which
> I onl see that kind of vac if I floor it, so I dont think I need to
> swap the PV.
>
> the only real problem I had was when the coach adbruptly stalled out
> several times, turned out to be the PO had riged the batt wire on
> the coil with a quick splice when the coach as converted to HEI,
> therefore it had become corroded, and required on-site replacement,
> but I always pack a DVM and a set of electrical connectors as well
> as fairly compleate set of tools, so once the problem was identified
> it took 5 minutes to fix.
>
> I have had no problems with her since, so just waiting for my tuning
> parts from summit for the carb....
>
> stay tuned...
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
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| Re: [GMCnet] short trip report, new carb averaging 7 MPG [message #63635 is a reply to message #63572] |
Mon, 09 November 2009 20:59 |
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Unfortunately I dont have this yet, I really need to get a wideband for the coach, I could use the one I have on my mustang but I wired it in as a permenant installation so now it simulates the narrow band stock sensor. I need another WB but dont have the $300 to sink on another innovate at the moment...
I will just pop in the slightly smaller jets and see how she drives, if its crap, not problem! the beauty of a holley is jets are easy to change 
| powerjon wrote on Mon, 09 November 2009 11:23 |
Shan,
Do you have a Fuel/Air gauge installed on the coach?
J.R. Wright
On Nov 9, 2009, at 12:19 PM, Shan Rose wrote:
>
>
> Well took the coach out for a run this weekend, and drove about 120
> miles. approximately 30% of those were city miles, and 70% freeway
> miles at 55-65 mph.
>
> The new holley carb performed just fine, though Imo averaging only
> about 7 mpg, i'm guessing I have slightly larger jets then I need so
> I have ordered 2 sets of smaller primaries, and I will adjust the
> vac secondary. the power valve should be the stock 6.5 hg one which
> I onl see that kind of vac if I floor it, so I dont think I need to
> swap the PV.
>
> the only real problem I had was when the coach adbruptly stalled out
> several times, turned out to be the PO had riged the batt wire on
> the coil with a quick splice when the coach as converted to HEI,
> therefore it had become corroded, and required on-site replacement,
> but I always pack a DVM and a set of electrical connectors as well
> as fairly compleate set of tools, so once the problem was identified
> it took 5 minutes to fix.
>
> I have had no problems with her since, so just waiting for my tuning
> parts from summit for the carb....
>
> stay tuned...
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
|
73 Canyon Lands, (a.k.a. The Yellow Submarine) West Los Angeles CA
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