EFI fuel line routing
11-01-2015, 08:55 PM
#21
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St. Jude Donor '07
Bill
11-01-2015, 09:04 PM
#22
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Seems like the safest route is to go with a loop and make fuel rails that look like separate nozzle blocks, but aren't. I could alleviate any heat concerns by insulating the lines like I did on this car when it ran the original Rochester system...
That worked fine...come to think of it, why am I changing?
The injectors are LS2, I think, they were recommended by FAST. I don't know the pressure for the eight injector, port injection system, yet, although it was to be 43 when there were only four injectors on a throttle body... I'll get with FAST this week on that.
That worked fine...come to think of it, why am I changing?
The injectors are LS2, I think, they were recommended by FAST. I don't know the pressure for the eight injector, port injection system, yet, although it was to be 43 when there were only four injectors on a throttle body... I'll get with FAST this week on that.
Last edited by Vettrocious; 11-01-2015 at 09:17 PM.
11-01-2015, 09:10 PM
#23
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Seems like the safest route is to go with a loop and make fuel rails that look like separate nozzle blocks, but aren't. I could alleviate any heat concerns by insulating the lines like I did on this car when it ran the original Rochester system...
That worked fine...come to think of it, why am I changing?
That worked fine...come to think of it, why am I changing?
but, necessity is the mother of invention; and I have no drivability problems anymore (I do think I did lose a mpg or so tho..., although I averaged about 25mpg with the a/c on on a trip to Clermont today)
Last edited by wmf62; 11-01-2015 at 09:13 PM.
11-01-2015, 09:30 PM
#24
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if it wasn't for the C1 perc problem I'd still be running the Rochester... or, if I'd have had access to a C2 fuel meter and spider with the return line that I could have installed in the C1 plenum, I might still be running Rochester...
but, necessity is the mother of invention; and I have no drivability problems anymore (I do think I did lose a mpg or so tho..., although I averaged about 25mpg with the a/c on on a trip to Clermont today)
but, necessity is the mother of invention; and I have no drivability problems anymore (I do think I did lose a mpg or so tho..., although I averaged about 25mpg with the a/c on on a trip to Clermont today)
I sorta figured that by adding AC to the silver car in the rebuild, I was pushing my luck with the Rochester, especially on a car that will be driven a lot in the heat.
11-01-2015, 09:43 PM
#25
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The blue car in my avatar still has its Rochester, and really, it runs great now that its fuel lines have insulation all over them.
I sorta figured that by adding AC to the silver car in the rebuild, I was pushing my luck with the Rochester, especially on a car that will be driven a lot in the heat.
I sorta figured that by adding AC to the silver car in the rebuild, I was pushing my luck with the Rochester, especially on a car that will be driven a lot in the heat.
BUT, EFI will/should solve all those problems... good luck, I think your line routing is clever; if I can help, let me know.
oh well....
Bill
Last edited by wmf62; 11-01-2015 at 09:46 PM.
11-01-2015, 09:49 PM
#26
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I've always had Rochester (for over 30 years), and a/c since 2006, and I NEVER had a problem until we got ethanol in our gas; and then, only in the summer around town. and never had a problem with ethanol when the ambient temp was about 75 or below.
BUT, EFI will/should solve all those problems... good luck, I think your line routing is clever; if I can help, let me know.
oh well....
Bill
BUT, EFI will/should solve all those problems... good luck, I think your line routing is clever; if I can help, let me know.
oh well....
Bill
11-02-2015, 03:26 AM
#27
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giving it some thought... it's going to be a bit crowded trying to fit all that 'stuff' under the plenum... I can't think of any reason why the pressure regular can't be located in the return line in some other convenient place.
BUT, if Doug is correct, and 'modern' EFI systems use a return directly from the regulator to the tank, then maybe that is worth considering; if for no other reason than not having to run an additional line.... I just think having a return line, and the regulator within that line, is a way to provide a more stable pressure to the injectors.
Bill
BUT, if Doug is correct, and 'modern' EFI systems use a return directly from the regulator to the tank, then maybe that is worth considering; if for no other reason than not having to run an additional line.... I just think having a return line, and the regulator within that line, is a way to provide a more stable pressure to the injectors.
Bill
Last edited by wmf62; 11-02-2015 at 04:06 AM.
11-02-2015, 07:08 AM
#28
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giving it some thought... it's going to be a bit crowded trying to fit all that 'stuff' under the plenum... I can't think of any reason why the pressure regular can't be located in the return line in some other convenient place.
BUT, if Doug is correct, and 'modern' EFI systems use a return directly from the regulator to the tank, then maybe that is worth considering; if for no other reason than not having to run an additional line.... I just think having a return line, and the regulator within that line, is a way to provide a more stable pressure to the injectors.
Bill
BUT, if Doug is correct, and 'modern' EFI systems use a return directly from the regulator to the tank, then maybe that is worth considering; if for no other reason than not having to run an additional line.... I just think having a return line, and the regulator within that line, is a way to provide a more stable pressure to the injectors.
Bill
The body is off the frame and the new fuel tank has a port for a return, so a return line is no big deal. I'll deal with the heat by shielding the lines within the air filter. The regulator is pretty small, once I get the filter canister modified (or more likely, make a new one), it might fit in there with the lines. The canister has a 55 sq in cross section, the air inlet is only 12 sq in, so there's lots of room for stuff in there without restricting air flow...I'm thinking of milling it in two pieces of aluminum that hinge and open like a clam shell to expose the stuff I put in there.
Mike
11-02-2015, 07:27 AM
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I agree, I think both the loop and the return line with the regulator are the best way. I'd rather not deal with problems later that I can prevent now, so I'll plan on that.
The body is off the frame and the new fuel tank has a port for a return, so a return line is no big deal. I'll deal with the heat by shielding the lines within the air filter. The regulator is pretty small, once I get the filter canister modified (or more likely, make a new one), it might fit in there with the lines. The canister has a 55 sq in cross section, the air inlet is only 12 sq in, so there's lots of room for stuff in there without restricting air flow...I'm thinking of milling it in two pieces of aluminum that hinge and open like a clam shell to expose the stuff I put in there.
Mike
The body is off the frame and the new fuel tank has a port for a return, so a return line is no big deal. I'll deal with the heat by shielding the lines within the air filter. The regulator is pretty small, once I get the filter canister modified (or more likely, make a new one), it might fit in there with the lines. The canister has a 55 sq in cross section, the air inlet is only 12 sq in, so there's lots of room for stuff in there without restricting air flow...I'm thinking of milling it in two pieces of aluminum that hinge and open like a clam shell to expose the stuff I put in there.
Mike
Bill
11-02-2015, 10:39 AM
#30
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No fuel perc, when motor is off, injectors are closed, and the injectors at idle are only open for the smallest fraction of second, plus the pressure...
All modern EFI systems are dead headed, since the last 15 years or so, maybe earlier.
Doug
All modern EFI systems are dead headed, since the last 15 years or so, maybe earlier.
Doug
I forsee one potential BIG problem if you have the distribution blocks & lines run between the adapter manifold and the plenum AND you deadhead the nozzles'; fuel percolation, just like the C1s experience.
if you have the regulator at the end of the fuel loop, although Doug says heated fuel returns to the tank, you at least have continuous flow of 'cooler' fuel in the neighborhood of the injectors and less chance of perc.
Bill
but, then, EFI injector fuel line pressure is higher than the Rochester at engine idle, so maybe perc wouldn't be a problem... dunno... food for thought...
if you have the regulator at the end of the fuel loop, although Doug says heated fuel returns to the tank, you at least have continuous flow of 'cooler' fuel in the neighborhood of the injectors and less chance of perc.
Bill
but, then, EFI injector fuel line pressure is higher than the Rochester at engine idle, so maybe perc wouldn't be a problem... dunno... food for thought...
11-02-2015, 11:40 AM
#31
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I realize I'm mixing fruit... apples & oranges; but as you know the Rochester has low nozzle pressure at idle and low speed, hence the 'perc'... due to engine heat; whereas EFI has a relative constant nozzle pressure, open or closed.
I have no clue what is sufficient line pressure to prevent perc...
it was just a thought..
Bill
11-02-2015, 02:05 PM
#32
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, its sorta half baked...Actually, its my preliminary intent to try to get the fuel lines and air flow path sealed in the lower half, with a flat horizontal divider at the midpoint of the cylinder. The upper portion would house the wiring and modules for the EFI. Obviously, I need to devise a way to insure the two are separate, insulated, and sealed that way, so I don't create a nice bomb...
Last edited by Vettrocious; 11-02-2015 at 02:15 PM.
11-02-2015, 04:22 PM
#33
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Well, me too, its sorta half baked...
Actually, its my preliminary intent to try to get the fuel lines and air flow path sealed in the lower half, with a flat horizontal divider at the midpoint of the cylinder. The upper portion would house the wiring and modules for the EFI. Obviously, I need to devise a way to insure the two are separate, insulated, and sealed that way, so I don't create a nice bomb...
, its sorta half baked...Actually, its my preliminary intent to try to get the fuel lines and air flow path sealed in the lower half, with a flat horizontal divider at the midpoint of the cylinder. The upper portion would house the wiring and modules for the EFI. Obviously, I need to devise a way to insure the two are separate, insulated, and sealed that way, so I don't create a nice bomb...
11-02-2015, 10:07 PM
#34
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I believe the injectors are CAR-1 type which have been used in many applications for many years.
Mine are 32 pounds per hour at 43 psi fuel pressure. With the bypass regulator system the delivered pressure can be varied to change the effective fuel delivery of the injectors.
The current FAST systems can use a return (what I use) or a returnless system if you use a fuel pump which can be pulsed to control fuel pressure.
With the return system a bypass regular is used and the excess fuel is returned to the fuel tank.
Mine are 32 pounds per hour at 43 psi fuel pressure. With the bypass regulator system the delivered pressure can be varied to change the effective fuel delivery of the injectors.
The current FAST systems can use a return (what I use) or a returnless system if you use a fuel pump which can be pulsed to control fuel pressure.
With the return system a bypass regular is used and the excess fuel is returned to the fuel tank.
Last edited by ohiovet; 11-02-2015 at 10:21 PM.
11-02-2015, 10:35 PM
#35
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Thanks Bruce, good info on the injectors and pressure. FAST gives instructions for both set-ups, but recommends using a return. With the body off and a new tank already set up for a return, a return is easy to do...
I'm probably going to use a bypass regulator that I can adjust down to 6-10 lbs by (changing its spring), in case I want to go back to the mechanical FI some day...
Mike
I'm probably going to use a bypass regulator that I can adjust down to 6-10 lbs by (changing its spring), in case I want to go back to the mechanical FI some day...
Mike
11-02-2015, 11:19 PM
#36
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Thanks Bruce, good info on the injectors and pressure. FAST gives instructions for both set-ups, but recommends using a return. With the body off and a new tank already set up for a return, a return is easy to do...
I'm probably going to use a bypass regulator that I can adjust down to 6-10 lbs by (changing its spring), in case I want to go back to the mechanical FI some day...
Mike
I'm probably going to use a bypass regulator that I can adjust down to 6-10 lbs by (changing its spring), in case I want to go back to the mechanical FI some day...
Mike
Mike ,
My fuel system is simple but functional and mounted on a aluminum plate which is mounted on the frame rail of my 57 Corvette.
It consists of a filter , the fuel pump then a bypass regulator most lines are 6AN socket less hose and fittings. I take the fuel out of the drain hole in the stock tank and return it through the stock fuel pickup line on the fuel level sender in the tank.
I have a heat shield to keep exhaust heat away from the fuel system.
It has worked for 3 years without a problem.
Bruce B
I have attached a picture.
11-03-2015, 07:56 AM
#38
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Bill,
Nice clean tank setup.
I used a Rock Vally tank with a in tank pump on my Ramjet 62.
What brand is the pump?
I love your setup, no doubt lots of thought went into it.
Very nice.
Bruce B
Nice clean tank setup.
I used a Rock Vally tank with a in tank pump on my Ramjet 62.
What brand is the pump?
I love your setup, no doubt lots of thought went into it.
Very nice.
Bruce B
