| [GMCnet] New thread on vapor lock, carbs and EFI [message #282081] |
Tue, 14 July 2015 09:12  |
glwgmc
Messages: 1014
Registered: June 2004
Karma: 10
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Senior Member |
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In all this talk about various ways to address vapor lock or related issues, I have yet to hear anyone discuss a front mounted surge tank like many aftermarket, high performance EFI units employ. Seems to me a gallon or so fuel canister mounted in the air stream up forward would overcome most fuel starvation and fuel heat issues. Plumb whatever fuel pump you use to supply that canister with a return to the fuel filler. Plumb whatever you use for a fuel pump supplying the carb or EFI to draw from and return to that canister and I think one would always have cool, liquid fuel going into the carb or EFI no matter what was going on aft of that canister. I see these things advertised all the time in the usual hot rod sources but have yet to hear much about them on this forum for our GMCs.
On a related note, for those of you who regularly drive in high altitudes, have you found any of the EFI systems to be demonstratively better than the carb? I know the carb will lack power at altitude as it will run way to rich if tuned for lower altitudes. We live at 1200 feet and regularly go down to zero or up to 4000 feet and occasionally to 6000 feet and in that range the carb seems fine. Above 6000 it struggles. As we occasionally cross the Rockies and run in the 8000 to even 10000 foot range I am considering EFI for one or both of our coaches. But, we don’t do that often enough to really justify EFI for that application alone. Both coaches run well with stock carbs and HEI ignition but what other gains might I see from EFI and which EFI have you found to offer the best combination of benefits?
Not looking to start a tire or oil war here, but I am perfectly happy to make the investment if there is a real payoff. We drive both our coaches a lot each year and I much prefer going than fiddling so simple and reliable are beneficial traits from my POV. The last thing I want is a laptop sitting on the floor connected to the EFI with me fiddling around with mixture settings while going down the road! Thanks for your comments and suggestions.
Jerry
Jerry Work
The Dovetail Joint
Fine furniture designed and hand crafted in the 1907 former Masonic Temple building in historic Kerby, OR
glwork@mac.com
http://jerrywork.com
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Jerry & Sharon Work
78 Royale
Kerby, OR
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| Re: [GMCnet] New thread on vapor lock, carbs and EFI [message #282083 is a reply to message #282081] |
Tue, 14 July 2015 10:04  |
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wally
Messages: 643
Registered: August 2004
Location: Omaha Nebraska
Karma: 5
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Senior Member |
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glwgmc wrote on Tue, 14 July 2015 09:12In all this talk about various ways to address vapor lock or related issues, I have yet to hear anyone discuss a front mounted surge tank like many aftermarket, high performance EFI units employ. Seems to me a gallon or so fuel canister mounted in the air stream up forward would overcome most fuel starvation and fuel heat issues. Plumb whatever fuel pump you use to supply that canister with a return to the fuel filler. Plumb whatever you use for a fuel pump supplying the carb or EFI to draw from and return to that canister and I think one would always have cool, liquid fuel going into the carb or EFI no matter what was going on aft of that canister. I see these things advertised all the time in the usual hot rod sources but have yet to hear much about them on this forum for our GMCs.
On a related note, for those of you who regularly drive in high altitudes, have you found any of the EFI systems to be demonstratively better than the carb? I know the carb will lack power at altitude as it will run way to rich if tuned for lower altitudes. We live at 1200 feet and regularly go down to zero or up to 4000 feet and occasionally to 6000 feet and in that range the carb seems fine. Above 6000 it struggles. As we occasionally cross the Rockies and run in the 8000 to even 10000 foot range I am considering EFI for one or both of our coaches. But, we don't do that often enough to really justify EFI for that application alone. Both coaches run well with stock carbs and HEI ignition but what other gains might I see from EFI and which EFI have you found to offer the best combination of benefits?
Not looking to start a tire or oil war here, but I am perfectly happy to make the investment if there is a real payoff. We drive both our coaches a lot each year and I much prefer going than fiddling so simple and reliable are beneficial traits from my POV. The last thing I want is a laptop sitting on the floor connected to the EFI with me fiddling around with mixture settings while going down the road! Thanks for your comments and suggestions.
Jerry
Jerry Work
The Dovetail Joint
Fine furniture designed and hand crafted in the 1907 former Masonic Temple building in historic Kerby, OR
glwork@mac.com
http://jerrywork.com
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Russ Harms, Ken Henderson and I run surge tanks.Kinsler Fuel Injection describes this scheme on page 154-155 in their handbook. Link
http://www.kinsler.com/Kinsler-Handbook/HTML/#154
I'm running the low pressure loop at 10 psi to hopefully keep fuel liquid, so far so good.
HTH
Wally Anderson
Omaha NE
75 Glenbrook
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| Re: [GMCnet] New thread on vapor lock, carbs and EFI [message #282126 is a reply to message #282081] |
Tue, 14 July 2015 20:09 |
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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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Jerry,
Steve Southwood uses a surge tank fed by two in-tank electric pumps. Even though the JimB fix (Facet electric pump plumbed in
between the AUX tank and the selector valve) works fine I am going to copy his system on Double Trouble and The Blue Streak cause I
reckon it's MO BETTA!
Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: Gerald Work
In all this talk about various ways to address vapor lock or related issues, I have yet to hear anyone discuss a front mounted surge
tank like many aftermarket, high performance EFI units employ. Seems to me a gallon or so fuel canister mounted in the air stream
up forward would overcome most fuel starvation and fuel heat issues. Plumb whatever fuel pump you use to supply that canister with
a return to the fuel filler. Plumb whatever you use for a fuel pump supplying the carb or EFI to draw from and return to that
canister and I think one would always have cool, liquid fuel going into the carb or EFI no matter what was going on aft of that
canister. I see these things advertised all the time in the usual hot rod sources but have yet to hear much about them on this
forum for our GMCs.
On a related note, for those of you who regularly drive in high altitudes, have you found any of the EFI systems to be
demonstratively better than the carb? I know the carb will lack power at altitude as it will run way to rich if tuned for lower
altitudes. We live at 1200 feet and regularly go down to zero or up to 4000 feet and occasionally to 6000 feet and in that range
the carb seems fine. Above 6000 it struggles. As we occasionally cross the Rockies and run in the 8000 to even 10000 foot range I
am considering EFI for one or both of our coaches. But, we don't do that often enough to really justify EFI for that application
alone. Both coaches run well with stock carbs and HEI ignition but what other gains might I see from EFI and which EFI have you
found to offer the best combination of benefits?
Not looking to start a tire or oil war here, but I am perfectly happy to make the investment if there is a real payoff. We drive
both our coaches a lot each year and I much prefer going than fiddling so simple and reliable are beneficial traits from my POV.
The last thing I want is a laptop sitting on the floor connected to the EFI with me fiddling around with mixture settings while
going down the road! Thanks for your comments and suggestions.
Jerry
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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] New thread on vapor lock, carbs and EFI [message #282131 is a reply to message #282081] |
Tue, 14 July 2015 20:38 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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After reading 'Timing 101', I've skipped the ported vacuum and hooked the advance to the manifold. If I understood the dissertation correctly, this should result in cooler operation at idle, which is where the last thing I need is the engine throwing off more heat at a traffic light. I hope this, along with the new electric pumps will alleviate my problem. Next is to block opff the crossover, but I'm trying to stay away from surgery on it for the rest of the year.
--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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