Most of whe watercooled have 2 pumps.
in the gas tank and the other in the frame
My fuel rails are done and so is my FPR billet adapter.
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raygreenwood
- Posts: 11907
- Joined: Wed Jan 22, 2003 12:01 am
Hey papg! Long time no hear from! Yes...you are correct. Mostwater cooled do have two pumps.
I also forgot to mention...that digifant on most (not all) golfs, Jettas etc....have the filter on the suction side.
Its worth it to make note...that the "feeder" pump in the gas tank....is a vane type pump. In and of itself...it is NOT afuel injection pump. They are generally capable of less than 10 psi and about .5 to 1.0 liters per minute. It simply charge the rear of the main roller type pump with a suitable volume to allow the deletion of the accumulator. Thats not because this is a good thing...its because it simplifys and cheapens construction of the vehicle.
The vane type feeder pumps are generally identical to thelate 70's electric in tank carburettor pumps found on american cars. In fact the one in my golf...is a delco brand pump...from the fcatory.
I guess instead of making a long rant...i should explain exactly where I am coming from.
The document taht tells you that a 1/2" feedertube will support 500 HP...is a steaming pile of worthless crap. Why? did it happen to mention at what pressure, what type of pump , what injector size, what volume of flow per minute and what type of engine configuration you were needding to generate that 500 HP?...if not....then its crap.
Bear this in mind. Lets just do some cheap fer-instances. We all know that high performance cars gulp fuel...right? So do street cars when pushed. So lets take something in the middle. Lets say you have an engine...wether just due to heavy foot...or high HPconfiguration....that gets 10 mpg. Again ...in the middle here...lets say you are going 60 mph. Thats 1 mile per minute. In ten minutes you will do ten miles...and use 1 gallon...or about 3.5+ liters?. Ok so far? Well...during that 10 minutes...a decent injection pump...even on a "low hp" measley 7mm line...will cycle 20 liters through your fuel system at anaverage of 35+ psi. And you used what....at best 1/5th of that? At 20 mpg...you use about 1/10th of the total fuel volume circulated. So unless you are actually starving the pump...what in gods name difference will a 1/2" feed line do. As you can tell...its a huge pain in the backside to add one. Why not just do like the factories did...(cause its dirt cheap and works)...either add a fuel accumulator in line.....or greatly increase the volume of the fuel filter.
How does that work? Well...for instance...the original D-jet filter...had between 12 and 15 pleats..depending on the make. At about 30mm in length and about15mm in depth ...two walls each facing the fuel....Thats around 9000 sq/mm of filter surface. There is a whoile lot of room for fuel to flow through at its own rate and still not evere be a blcokage. Thats also roughly 20 times the size of that crappy little inline carb filter we see on the pict-3. It also presents less of a hindrance to the pump downsteam....because the holes in the media are rather large. thats because there is a packed "lint" media filter inside of the filter body that does the heavy filtration first...and has even larger surface area. Now...move to the water cooled cannister filter...with roughly 20 times what the D and L-filters have...for surfacearea. There is a whole huge amount of area that the fuel can flow through at a rather liesurely rate...and not impede the pump.
But...filters are cheap...pumps...good pumps...are quite expensive. Itwas easier to put cheaper lower tolerance pumps in...move the filter upstream...and add an $8 feeder pump (thatswhat mine cost on both the golf and my Saab). It saved the factory about $200 and made mainetnace easier....but pump lidespans shorter. Because....you see.....the main damage by grit is done to teh pump motor itself...even before it wears out the roller cells. Thats because all of the pumps are brushless...liquid cooled bythe incoming gas.
My whole point to this rambling is this. The factory started putting the filters after the pump...for very stupid...and cheap reasons. We...meaning you as well....are able ...while building our own vehicles...to not have to make poor compromises on the fuel system for the sake of money. Why not improve uponwhat the factory did?
Also by the way...you should study the factory systems in the junkyards. Even though they have made mistakes...there is a vast array of fabulous engineering laid out before you....with the solutions to most all of the problems that are being rehashed here on aftermarket systems. By my observation...most of the after market manufacturers have done very poor research into a lot of FI problems...like connectivity, heat and vibration damping...and fuel supply stability. Just some thoughts. Ray
I also forgot to mention...that digifant on most (not all) golfs, Jettas etc....have the filter on the suction side.
Its worth it to make note...that the "feeder" pump in the gas tank....is a vane type pump. In and of itself...it is NOT afuel injection pump. They are generally capable of less than 10 psi and about .5 to 1.0 liters per minute. It simply charge the rear of the main roller type pump with a suitable volume to allow the deletion of the accumulator. Thats not because this is a good thing...its because it simplifys and cheapens construction of the vehicle.
The vane type feeder pumps are generally identical to thelate 70's electric in tank carburettor pumps found on american cars. In fact the one in my golf...is a delco brand pump...from the fcatory.
I guess instead of making a long rant...i should explain exactly where I am coming from.
The document taht tells you that a 1/2" feedertube will support 500 HP...is a steaming pile of worthless crap. Why? did it happen to mention at what pressure, what type of pump , what injector size, what volume of flow per minute and what type of engine configuration you were needding to generate that 500 HP?...if not....then its crap.
Bear this in mind. Lets just do some cheap fer-instances. We all know that high performance cars gulp fuel...right? So do street cars when pushed. So lets take something in the middle. Lets say you have an engine...wether just due to heavy foot...or high HPconfiguration....that gets 10 mpg. Again ...in the middle here...lets say you are going 60 mph. Thats 1 mile per minute. In ten minutes you will do ten miles...and use 1 gallon...or about 3.5+ liters?. Ok so far? Well...during that 10 minutes...a decent injection pump...even on a "low hp" measley 7mm line...will cycle 20 liters through your fuel system at anaverage of 35+ psi. And you used what....at best 1/5th of that? At 20 mpg...you use about 1/10th of the total fuel volume circulated. So unless you are actually starving the pump...what in gods name difference will a 1/2" feed line do. As you can tell...its a huge pain in the backside to add one. Why not just do like the factories did...(cause its dirt cheap and works)...either add a fuel accumulator in line.....or greatly increase the volume of the fuel filter.
How does that work? Well...for instance...the original D-jet filter...had between 12 and 15 pleats..depending on the make. At about 30mm in length and about15mm in depth ...two walls each facing the fuel....Thats around 9000 sq/mm of filter surface. There is a whoile lot of room for fuel to flow through at its own rate and still not evere be a blcokage. Thats also roughly 20 times the size of that crappy little inline carb filter we see on the pict-3. It also presents less of a hindrance to the pump downsteam....because the holes in the media are rather large. thats because there is a packed "lint" media filter inside of the filter body that does the heavy filtration first...and has even larger surface area. Now...move to the water cooled cannister filter...with roughly 20 times what the D and L-filters have...for surfacearea. There is a whole huge amount of area that the fuel can flow through at a rather liesurely rate...and not impede the pump.
But...filters are cheap...pumps...good pumps...are quite expensive. Itwas easier to put cheaper lower tolerance pumps in...move the filter upstream...and add an $8 feeder pump (thatswhat mine cost on both the golf and my Saab). It saved the factory about $200 and made mainetnace easier....but pump lidespans shorter. Because....you see.....the main damage by grit is done to teh pump motor itself...even before it wears out the roller cells. Thats because all of the pumps are brushless...liquid cooled bythe incoming gas.
My whole point to this rambling is this. The factory started putting the filters after the pump...for very stupid...and cheap reasons. We...meaning you as well....are able ...while building our own vehicles...to not have to make poor compromises on the fuel system for the sake of money. Why not improve uponwhat the factory did?
Also by the way...you should study the factory systems in the junkyards. Even though they have made mistakes...there is a vast array of fabulous engineering laid out before you....with the solutions to most all of the problems that are being rehashed here on aftermarket systems. By my observation...most of the after market manufacturers have done very poor research into a lot of FI problems...like connectivity, heat and vibration damping...and fuel supply stability. Just some thoughts. Ray
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raygreenwood
- Posts: 11907
- Joined: Wed Jan 22, 2003 12:01 am
Hey papg! Long time no hear from! Yes...you are correct. Mostwater cooled do have two pumps.
I also forgot to mention...that digifant on most (not all) golfs, Jettas etc....have the filter on the suction side.
Its worth it to make note...that the "feeder" pump in the gas tank....is a vane type pump. In and of itself...it is NOT afuel injection pump. They are generally capable of less than 10 psi and about .5 to 1.0 liters per minute. It simply charge the rear of the main roller type pump with a suitable volume to allow the deletion of the accumulator. Thats not because this is a good thing...its because it simplifys and cheapens construction of the vehicle.
The vane type feeder pumps are generally identical to thelate 70's electric in tank carburettor pumps found on american cars. In fact the one in my golf...is a delco brand pump...from the fcatory.
I guess instead of making a long rant...i should explain exactly where I am coming from.
The document taht tells you that a 1/2" feedertube will support 500 HP...is a steaming pile of worthless crap. Why? did it happen to mention at what pressure, what type of pump , what injector size, what volume of flow per minute and what type of engine configuration you were needding to generate that 500 HP?...if not....then its crap.
Bear this in mind. Lets just do some cheap fer-instances. We all know that high performance cars gulp fuel...right? So do street cars when pushed. So lets take something in the middle. Lets say you have an engine...wether just due to heavy foot...or high HPconfiguration....that gets 10 mpg. Again ...in the middle here...lets say you are going 60 mph. Thats 1 mile per minute. In ten minutes you will do ten miles...and use 1 gallon...or about 3.5+ liters?. Ok so far? Well...during that 10 minutes...a decent injection pump...even on a "low hp" measley 7mm line...will cycle 20 liters through your fuel system at anaverage of 35+ psi. And you used what....at best 1/5th of that? At 20 mpg...you use about 1/10th of the total fuel volume circulated. So unless you are actually starving the pump...what in gods name difference will a 1/2" feed line do. As you can tell...its a huge pain in the backside to add one. Why not just do like the factories did...(cause its dirt cheap and works)...either add a fuel accumulator in line.....or greatly increase the volume of the fuel filter.
How does that work? Well...for instance...the original D-jet filter...had between 12 and 15 pleats..depending on the make. At about 30mm in length and about15mm in depth ...two walls each facing the fuel....Thats around 9000 sq/mm of filter surface. There is a whoile lot of room for fuel to flow through at its own rate and still not evere be a blcokage. Thats also roughly 20 times the size of that crappy little inline carb filter we see on the pict-3. It also presents less of a hindrance to the pump downsteam....because the holes in the media are rather large. thats because there is a packed "lint" media filter inside of the filter body that does the heavy filtration first...and has even larger surface area. Now...move to the water cooled cannister filter...with roughly 20 times what the D and L-filters have...for surfacearea. There is a whole huge amount of area that the fuel can flow through at a rather liesurely rate...and not impede the pump.
But...filters are cheap...pumps...good pumps...are quite expensive. Itwas easier to put cheaper lower tolerance pumps in...move the filter upstream...and add an $8 feeder pump (thatswhat mine cost on both the golf and my Saab). It saved the factory about $200 and made mainetnace easier....but pump lidespans shorter. Because....you see.....the main damage by grit is done to teh pump motor itself...even before it wears out the roller cells. Thats because all of the pumps are brushless...liquid cooled bythe incoming gas.
My whole point to this rambling is this. The factory started putting the filters after the pump...for very stupid...and cheap reasons. We...meaning you as well....are able ...while building our own vehicles...to not have to make poor compromises on the fuel system for the sake of money. Why not improve uponwhat the factory did?
Also by the way...you should study the factory systems in the junkyards. Even though they have made mistakes...there is a vast array of fabulous engineering laid out before you....with the solutions to most all of the problems that are being rehashed here on aftermarket systems. By my observation...most of the after market manufacturers have done very poor research into a lot of FI problems...like connectivity, heat and vibration damping...and fuel supply stability. Just some thoughts. Ray
I also forgot to mention...that digifant on most (not all) golfs, Jettas etc....have the filter on the suction side.
Its worth it to make note...that the "feeder" pump in the gas tank....is a vane type pump. In and of itself...it is NOT afuel injection pump. They are generally capable of less than 10 psi and about .5 to 1.0 liters per minute. It simply charge the rear of the main roller type pump with a suitable volume to allow the deletion of the accumulator. Thats not because this is a good thing...its because it simplifys and cheapens construction of the vehicle.
The vane type feeder pumps are generally identical to thelate 70's electric in tank carburettor pumps found on american cars. In fact the one in my golf...is a delco brand pump...from the fcatory.
I guess instead of making a long rant...i should explain exactly where I am coming from.
The document taht tells you that a 1/2" feedertube will support 500 HP...is a steaming pile of worthless crap. Why? did it happen to mention at what pressure, what type of pump , what injector size, what volume of flow per minute and what type of engine configuration you were needding to generate that 500 HP?...if not....then its crap.
Bear this in mind. Lets just do some cheap fer-instances. We all know that high performance cars gulp fuel...right? So do street cars when pushed. So lets take something in the middle. Lets say you have an engine...wether just due to heavy foot...or high HPconfiguration....that gets 10 mpg. Again ...in the middle here...lets say you are going 60 mph. Thats 1 mile per minute. In ten minutes you will do ten miles...and use 1 gallon...or about 3.5+ liters?. Ok so far? Well...during that 10 minutes...a decent injection pump...even on a "low hp" measley 7mm line...will cycle 20 liters through your fuel system at anaverage of 35+ psi. And you used what....at best 1/5th of that? At 20 mpg...you use about 1/10th of the total fuel volume circulated. So unless you are actually starving the pump...what in gods name difference will a 1/2" feed line do. As you can tell...its a huge pain in the backside to add one. Why not just do like the factories did...(cause its dirt cheap and works)...either add a fuel accumulator in line.....or greatly increase the volume of the fuel filter.
How does that work? Well...for instance...the original D-jet filter...had between 12 and 15 pleats..depending on the make. At about 30mm in length and about15mm in depth ...two walls each facing the fuel....Thats around 9000 sq/mm of filter surface. There is a whoile lot of room for fuel to flow through at its own rate and still not evere be a blcokage. Thats also roughly 20 times the size of that crappy little inline carb filter we see on the pict-3. It also presents less of a hindrance to the pump downsteam....because the holes in the media are rather large. thats because there is a packed "lint" media filter inside of the filter body that does the heavy filtration first...and has even larger surface area. Now...move to the water cooled cannister filter...with roughly 20 times what the D and L-filters have...for surfacearea. There is a whole huge amount of area that the fuel can flow through at a rather liesurely rate...and not impede the pump.
But...filters are cheap...pumps...good pumps...are quite expensive. Itwas easier to put cheaper lower tolerance pumps in...move the filter upstream...and add an $8 feeder pump (thatswhat mine cost on both the golf and my Saab). It saved the factory about $200 and made mainetnace easier....but pump lidespans shorter. Because....you see.....the main damage by grit is done to teh pump motor itself...even before it wears out the roller cells. Thats because all of the pumps are brushless...liquid cooled bythe incoming gas.
My whole point to this rambling is this. The factory started putting the filters after the pump...for very stupid...and cheap reasons. We...meaning you as well....are able ...while building our own vehicles...to not have to make poor compromises on the fuel system for the sake of money. Why not improve uponwhat the factory did?
Also by the way...you should study the factory systems in the junkyards. Even though they have made mistakes...there is a vast array of fabulous engineering laid out before you....with the solutions to most all of the problems that are being rehashed here on aftermarket systems. By my observation...most of the after market manufacturers have done very poor research into a lot of FI problems...like connectivity, heat and vibration damping...and fuel supply stability. Just some thoughts. Ray
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Kaferlago
- Posts: 193
- Joined: Thu Feb 28, 2002 12:01 am
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panel
- Posts: 4227
- Joined: Sun Sep 24, 2000 12:01 am
I did the drill and tap for a 3/8 pipe thread. Only because the pump itself has a 1/2" intake on it. Not to be cool or to say I have a huge 1/2" fuel line but ONLY 'cause of the pumps intake size hole. The output size is what I'm running for the rest of the system.
Ray what do you mean nice welding? Me or?
Ray what do you mean nice welding? Me or?
'65 Bus with a JDM Subaru EJ20 Turbo
Built by Germans powered by Japanese and brought together by Canadians
Built by Germans powered by Japanese and brought together by Canadians
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raygreenwood
- Posts: 11907
- Joined: Wed Jan 22, 2003 12:01 am
I was looking at the exhaust on kafers photos. I know they are as yet unfinished...but thats a lot of work. I am really just learning to weld right now. You all do much better work than me with moten metal 
I understand the 1/2" entrance port issue. What pump are you running? It may be easier to actually install an accumulator onto that end...instead of changing the tank port itself. It should accomplish the same thing. Most pumps that have a port that big...are simply using the line as an accumlator. Its ususally done when the tank is in the rear and the pump is down low up front. That way the fat line gives it something to draw from...so the whole long line is not dragging on the pump. Its much less of a problem when the pump is very near the tank. Ray
I understand the 1/2" entrance port issue. What pump are you running? It may be easier to actually install an accumulator onto that end...instead of changing the tank port itself. It should accomplish the same thing. Most pumps that have a port that big...are simply using the line as an accumlator. Its ususally done when the tank is in the rear and the pump is down low up front. That way the fat line gives it something to draw from...so the whole long line is not dragging on the pump. Its much less of a problem when the pump is very near the tank. Ray
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Guest
fuel stability
raygreenwood wrote:All of that is totally unnecessary. This is not a carb..where the wimpy assed pump will create a restriction/drag on the pump if it pulls through too small of a line. If you get a restriction on a 7-8mm line..that a larger line SEEMS to solve...then thats not the problem. It never is. The pump needs an accumulator period. From that accumulator, to the pump, a simple 7-8mm line will do. The REAL problem is undersizing of pumps. The volume a pump is capable of is FAR FAR more important than the "on the box" pressure rating.
ALL FI pumps create little or no UNFRESTRICTED pressure. That means that without a line and regulator attached....the pump simply pushes a stream ...maybe a foot at best...of "no pressure" fuel out of the outlet. The pressure is created by trying to push a large volume of fuel, through a restricted space.
For instace....the 1.5 liter per minute of the lowly and ancient D-jet pump....is more than enough to feed a 300 ci v8 at 34 psi. thats for basic running. For best fuel stability....I have found that about 2.9 liters per minute allows the best pressure with the least lag. Speaking of....adding higher fuel line volume IS where the pressure lag comes from. Considering that a standard D or L jet pump alone feed about 20 times more fuel than a standard 2.0 liter engine uses, but is still a little low in volume to prevent dips in pressure,.....all having larger lines does...is create a larger volume for an already slightly under volume pump to replenish. It also creates mass ahead of the pump....further adding drag. The huge useless surge pots do the same thing. A surge pot of no more than a pint is needed for anything. Check into it carefully...I have. No matter what you are doing....a relatively standard line will do. The pump feed line...does not need to be any larger than the pressure line. But...you should have a volume to draw from...such as an accumulator...if you have a high volume pump. Ray