Fuel Tank design
Discussion
Here's a pump out of a WRC rally car. Two lift pumps on the outside filling up the inside which is a pair of 044's.
http://mez.co.uk/graphics/liftpump2.jpg
http://mez.co.uk/graphics/liftpump1.jpg
http://mez.co.uk/graphics/liftpump2.jpg
http://mez.co.uk/graphics/liftpump1.jpg
andygtt said:
... but it will have the effect of cooling the pump and deadening the noise.
You don't need to worry about cooling the outside of the pump,because it's cooled by the fuel flowing through it!regarding the "self priming head" which is the issue of the maximum dry height of priming, becuase these pumps use roller cell systems, when they are dry (no, or little, fuel in them) they do not seal very well (they rely on the fuel to form a wet dynamic seal on the pumping parts) hence they are poor to self prime. With the pump in the tank, generally if you have actually run out of fuel and got air into the pump, you have refilled the tank full before restarting, so they get primed by the full tank. Outside of the tank, things like U bends in the plumbing etc tend to make self priming more difficult. Once the pump has primed, the lifting capacity of the system (on the suction side) is then purely set by the current vapour pressure of the fuel (i.e. if you try to suck too hard, the fuel just vapourises and you cannot lift liquid fuel any higher) but this value is easily high enough to keep the pump primed up to several M of height.
andygtt said:
stevieturbo said:
andygtt said:
What I mean is if the pump is hung in the tank then at some stage the fuel will be well below the pump....
That is called "running out of petrol" lolTime to refuel.
All in tank systems place the pump inlet at the bottom of the tank. So there is never a situation where the pump doesnt see fuel, until you have run out of fuel.
Anyone with the notion of mounting the pump high inside the tank...... ?????????
I really cant understand why anyone would even contemplate that
Max_Torque said:
andygtt said:
... but it will have the effect of cooling the pump and deadening the noise.
You don't need to worry about cooling the outside of the pump,because it's cooled by the fuel flowing through it!regarding the "self priming head" which is the issue of the maximum dry height of priming, becuase these pumps use roller cell systems, when they are dry (no, or little, fuel in them) they do not seal very well (they rely on the fuel to form a wet dynamic seal on the pumping parts) hence they are poor to self prime. With the pump in the tank, generally if you have actually run out of fuel and got air into the pump, you have refilled the tank full before restarting, so they get primed by the full tank. Outside of the tank, things like U bends in the plumbing etc tend to make self priming more difficult. Once the pump has primed, the lifting capacity of the system (on the suction side) is then purely set by the current vapour pressure of the fuel (i.e. if you try to suck too hard, the fuel just vapourises and you cannot lift liquid fuel any higher) but this value is easily high enough to keep the pump primed up to several M of height.
The tank is off being made now... still not sure how gona fit it all in, the filter is the hardest thing to fit in.
will post pics when i get em
Right... well after an issue with finding large enough submersible fuel line to feed the A1000 I have discovered a source only to decided to completely rethink the design.
WHY?
I have now heard from more than one person with experience of the A1000's that they are not the most reliable of pumps and are know to have issues... this worries me as Im trying to design a belt and braces system and fitting a potential problem into the tank thats hard to remove and thus get at the pump is a bad move.
Ive also found out that having large pumps in tank usually makes them louder, again the only real reason for mounting in tank is to quiten a loud pump.
So I have decided to fit 2 lifter pumps in tank, that feed and external swirl pot fitted inside the tank.... I will then have 2 brand new bosch 044s external which I will feed the fuel rail.
Genuine 044's have a non return valve so I will be able to have one of them switchable on under load using Max's revolutionary pump controler which reduces the issue of massive overfueling on idle and large volts being drawn to power them.
bit of a nightmare actually as the tank was already mostly made but its got to be right lol
WHY?
I have now heard from more than one person with experience of the A1000's that they are not the most reliable of pumps and are know to have issues... this worries me as Im trying to design a belt and braces system and fitting a potential problem into the tank thats hard to remove and thus get at the pump is a bad move.
Ive also found out that having large pumps in tank usually makes them louder, again the only real reason for mounting in tank is to quiten a loud pump.
So I have decided to fit 2 lifter pumps in tank, that feed and external swirl pot fitted inside the tank.... I will then have 2 brand new bosch 044s external which I will feed the fuel rail.
Genuine 044's have a non return valve so I will be able to have one of them switchable on under load using Max's revolutionary pump controler which reduces the issue of massive overfueling on idle and large volts being drawn to power them.
bit of a nightmare actually as the tank was already mostly made but its got to be right lol
andygtt said:
Right... well after an issue with finding large enough submersible fuel line to feed the A1000 I have discovered a source only to decided to completely rethink the design.
WHY?
I have now heard from more than one person with experience of the A1000's that they are not the most reliable of pumps and are know to have issues... this worries me as Im trying to design a belt and braces system and fitting a potential problem into the tank thats hard to remove and thus get at the pump is a bad move.
Ive also found out that having large pumps in tank usually makes them louder, again the only real reason for mounting in tank is to quiten a loud pump.
So I have decided to fit 2 lifter pumps in tank, that feed and external swirl pot fitted inside the tank.... I will then have 2 brand new bosch 044s external which I will feed the fuel rail.
Genuine 044's have a non return valve so I will be able to have one of them switchable on under load using Max's revolutionary pump controler which reduces the issue of massive overfueling on idle and large volts being drawn to power them.
bit of a nightmare actually as the tank was already mostly made but its got to be right lol
why 2 lift pumps ?WHY?
I have now heard from more than one person with experience of the A1000's that they are not the most reliable of pumps and are know to have issues... this worries me as Im trying to design a belt and braces system and fitting a potential problem into the tank thats hard to remove and thus get at the pump is a bad move.
Ive also found out that having large pumps in tank usually makes them louder, again the only real reason for mounting in tank is to quiten a loud pump.
So I have decided to fit 2 lifter pumps in tank, that feed and external swirl pot fitted inside the tank.... I will then have 2 brand new bosch 044s external which I will feed the fuel rail.
Genuine 044's have a non return valve so I will be able to have one of them switchable on under load using Max's revolutionary pump controler which reduces the issue of massive overfueling on idle and large volts being drawn to power them.
bit of a nightmare actually as the tank was already mostly made but its got to be right lol
And I cant see any reason why you would have massive overfuelling on idle, unless it's very badly tuned or designed.
I'm not knocking the controller BTW...as I think I'm going to have a go at one myself when Max gets them built and ready.
But there isnt any problem running 2 x 044's all the time. Ive been doing it for about 5 years.
And TBH, I still think that with the controller. I'd run both pumps all the time at equal flow levels. And not staged as you suggest.
If the controller can keep both ticking over at a low level, then it will simplify things and no need for any check valves.
andygtt said:
1 lift pump wont provide enough fuel and the swirl pot may run dry... by overfueling I was meaning it would be massivelly flowing too much fuel on idle, this was an issue with my single 044 I was running.
Generally most people return fuel to the swirl tank from the engine. I'm sure Max can correct me, but running a controller will only assist ensuring the swirl tank remains full.What size of swirl tank are you going to use ? and what capacity does the lift pump have ?
Unless the lift pump is very small or poorly sized ( or a very small swirl tank, you'd need to be driving flat out for extended periods to drain a swirl tank dry.
And there must have been something badly wrong with your previous design, if it couldnt cope with a single 044.
What symptoms made you think this ? Ive fitted 044's to plenty of cars, retaining standard FPR's and fuel lines, and never had any issues
Doing some very basic maths. Say 5-600bhp requires around 3.5 litres of fuel per minute. That's only 210 lph.
That isnt a huge volume by any means. A single 255lph Walbro as a lift pump will cope with that all day long with no concerns whatsoever.
So regardless of swirl tank size, you could hold the car flat out forever and it would never run dry.
The only time fuel would start to run dry in the swirl tank is when actual consumption exceeds lift pump supply, which could only be for very brief periods of time and very slowly too.
Every time you lift off the throttle, it would very quickly restore itself to full capacity again.
I'm mystified by this entire thread. Baffled fuel tank, single external lifter pump under that feeding a big swirl pot, high pressure EFI pump from that feeding the fuel rail with a return to the swirl pot and a return out of that back to the tank for any overflow. Job done.
The wheel seems to be being reinvented here with a determination bordering on the perverse.
The wheel seems to be being reinvented here with a determination bordering on the perverse.
thats all great except there isnt room... the petrol tank is actually in the engine bay around 2 inches from the engine and its very tight in there.... a single 044 isnt adequate hence I either need 2 or I need a larger pump.
yes there is a return to the tank from the rail, yes most nobles upgraded to an 044 have the issue were the pump starts to gets excessivelly noisy when pootling around. This is why I want to eliminate the problem.
yes there is a return to the tank from the rail, yes most nobles upgraded to an 044 have the issue were the pump starts to gets excessivelly noisy when pootling around. This is why I want to eliminate the problem.
andygtt said:
thats all great except there isnt room... the petrol tank is actually in the engine bay around 2 inches from the engine and its very tight in there.... a single 044 isnt adequate hence I either need 2 or I need a larger pump.
yes there is a return to the tank from the rail, yes most nobles upgraded to an 044 have the issue were the pump starts to gets excessivelly noisy when pootling around. This is why I want to eliminate the problem.
Using the controller, there will be no issues with pump noise or flow problems.yes there is a return to the tank from the rail, yes most nobles upgraded to an 044 have the issue were the pump starts to gets excessivelly noisy when pootling around. This is why I want to eliminate the problem.
Although Ive driven my car sometimes for 4+ hours non stop, and never had any real concerns with both 044 pumps at full speed. Yes they do make a little noise, but it has never affected their ability to pump fuel.
And with the controllers ability to bump the voltage to 16v on demand, there should be no problems with fuel supply even around 600bhp on a single 044.
As I said, I tested my pair, via a single -6 line at only 13.1v and 60psi test pressure and they flowed approx 486 litres per hour. That's enough fuel for a considerable amount of power. At 14v it would easily exceed 500lph
A single should perform slightly better.
At a guess, at 16v a pair could easily be pushing 525lph
If people making less than 550-600bhp per 044 are having issues. It isnt the pump itself. It's something else with their fuel system.
andygtt said:
I have now heard from more than one person with experience of the A1000's that they are not the most reliable of pumps and are know to have issues...
We ran three of them on RV2 without issue.. (as in, all 3 were on the car at the same time.. 3 for strip duty, 1 for street)stevieturbo said:
If people making less than 550-600bhp per 044 are having issues. It isnt the pump itself. It's something else with their fuel system.
ok let me put it another way, the noble runs the fuel rail etc from a NA 4x4 in the states..... its not even a performace car so its designed for 200bhp.... when you put an 044 in the car they buzz like crazy when sitting in traffic or cruising as the pump cavitates or whatever.I have run 044's on other cars without the same issue, hence I am redesigning my Noble fuel system to eliminate the issue.
andygtt said:
ok let me put it another way, the noble runs the fuel rail etc from a NA 4x4 in the states..... its not even a performace car so its designed for 200bhp.... when you put an 044 in the car they buzz like crazy when sitting in traffic or cruising as the pump cavitates or whatever.
I have run 044's on other cars without the same issue, hence I am redesigning my Noble fuel system to eliminate the issue.
So the biggest design flaw is in the fuel rail ? And as you mentioned before, tank design ?I have run 044's on other cars without the same issue, hence I am redesigning my Noble fuel system to eliminate the issue.
The fuel pump itself is actually fine ? and capable of doing the job ?
The only reason I originally went across to the A1000 was that a single 044 wont flow enough and I didnt what to run 2 pumps... I'm sure the issue would have been worse with the A1000 as its so much bigger.... this is the entire reason for me redesigning the fuel system.
Im going back to using two 044's as I have heard the A1000's can be unreliable, Im not prepared to take the chance and would rather change now during build stage than later and now I know we will be able to control the 044's using Max's controllers it completely removes all concerns I had about using two pumps over a single large one.
Im going back to using two 044's as I have heard the A1000's can be unreliable, Im not prepared to take the chance and would rather change now during build stage than later and now I know we will be able to control the 044's using Max's controllers it completely removes all concerns I had about using two pumps over a single large one.
andygtt said:
The only reason I originally went across to the A1000 was that a single 044 wont flow enough and I didnt what to run 2 pumps... I'm sure the issue would have been worse with the A1000 as its so much bigger.... this is the entire reason for me redesigning the fuel system.
Im going back to using two 044's as I have heard the A1000's can be unreliable, Im not prepared to take the chance and would rather change now during build stage than later and now I know we will be able to control the 044's using Max's controllers it completely removes all concerns I had about using two pumps over a single large one.
I would agree on using 044's over an A1000. I ditched my A1000 in favour of a pair of 044's.Im going back to using two 044's as I have heard the A1000's can be unreliable, Im not prepared to take the chance and would rather change now during build stage than later and now I know we will be able to control the 044's using Max's controllers it completely removes all concerns I had about using two pumps over a single large one.
I never had any problems with the A1000 though. It was just too big to mount where I would like, and certainly on paper, it's performance wasnt fantastic and again on paper if needing to use higher fuel pressures....it seemed it would not handle this at all.
As to whether that was actually how it would perform in reality, Ive no idea.
But I know the Bosch pumps are ultra reliable, they are compact, and they will keep blasting fuel out even beyond 100psi where many pumps are struggling.
But unless pushing over 550-600, a single 044 is fine. A pair of Walbros would be a cheap option ( although again, once beyond 75psi, they start to struggle ).
Or a pair of 044's will give you headroom for beyond 1000bhp.
But your previous post seems to suggest the crux of the fuel flow problem is now the fuel rails. Not the tank or pump ?
How bad are they ?
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