Fuel system modifications while engine is out
Discussion
Engine is coming out the car to upgrade to 6 speed, but im thinking about modding the fuel tank while im there.
On brief inspection, it seems the fuel line to the pump comes out the side nearest the engine and then loops around towards the side pod. Can i simply put a new hole on the other side and have a short run of pipe into the filter/pump? I have seen that some people have cut the bottom of the tank away as per the picture below.What is the benefit of this?
Is there anything else i should do to the tank whilst i can get easy access? Should i drill out the connection holes, Im sure i heard that they could be restrictive.
Thanks for any help!
Julian
On brief inspection, it seems the fuel line to the pump comes out the side nearest the engine and then loops around towards the side pod. Can i simply put a new hole on the other side and have a short run of pipe into the filter/pump? I have seen that some people have cut the bottom of the tank away as per the picture below.What is the benefit of this?
Is there anything else i should do to the tank whilst i can get easy access? Should i drill out the connection holes, Im sure i heard that they could be restrictive.
Thanks for any help!
Julian
The cutout is to allow the fuel outlet to fgace backwards whilst avoiding the chassis bar and also to create a sump for the tank.
I truly believe this is a good idea although it i also believe it is better to have a sloping face to create/achieve the same, a diagonal face nturally can transfer loads from vertical and horizontal faces, whilst reducing fuel capacity at sump level..
Here is a pic of the schematic and the actual tank, the tank pic is old and before the swirl pot was installed, but you will see the sump design also allows for the fuel pump to live undernerath the tank, just ignore the swirl pot on the schmatic and the principle remains the same, but a baffled sump tank with dual pickups and swirl pot is no doubt overkill..
but please also take into accountthat normally you have 20 litres left in the tank at empty, and its jnot safe for spirited driving on empty, you have to have a "minimum"of 35 litres to be safe...the sloping.sump tank design means you can drive safely with only 5 litres, which the sump level is cunningly the same level where the tank shows empty, thats a 20kg weight saving of unuseable fuel,,,
Alternatively Andy has a simple sytem to install a swirl pot in the tank, it eliminates the need for cutout, for sump and it does not matter if the outlet is higher than the chassis due to the Bosch 044 being pressure fed..it also keeps everything neat and tidy..plus the )44 really needs to be pressure fed, they dio not like to suck. which prwetty much solves all the other feed issues at the same time as long as you have replaced the ARV..
I truly believe this is a good idea although it i also believe it is better to have a sloping face to create/achieve the same, a diagonal face nturally can transfer loads from vertical and horizontal faces, whilst reducing fuel capacity at sump level..
Here is a pic of the schematic and the actual tank, the tank pic is old and before the swirl pot was installed, but you will see the sump design also allows for the fuel pump to live undernerath the tank, just ignore the swirl pot on the schmatic and the principle remains the same, but a baffled sump tank with dual pickups and swirl pot is no doubt overkill..
but please also take into accountthat normally you have 20 litres left in the tank at empty, and its jnot safe for spirited driving on empty, you have to have a "minimum"of 35 litres to be safe...the sloping.sump tank design means you can drive safely with only 5 litres, which the sump level is cunningly the same level where the tank shows empty, thats a 20kg weight saving of unuseable fuel,,,
Alternatively Andy has a simple sytem to install a swirl pot in the tank, it eliminates the need for cutout, for sump and it does not matter if the outlet is higher than the chassis due to the Bosch 044 being pressure fed..it also keeps everything neat and tidy..plus the )44 really needs to be pressure fed, they dio not like to suck. which prwetty much solves all the other feed issues at the same time as long as you have replaced the ARV..
just in case you are interested, here is a pic the the side pod mounted Swirl pot in conjunction, both lifter and 044 are on same fuse/relay so its a pretty much bullet proof system which also helps keep the fuel cool and pump quiet...also when you have a sorted fuel delivery system is offers peace of mind and combats performance drops due to overheated fuel..although its overkill i think that with the baffled sump tank feeding the swirl pot, you are ensured the lifter pump is also consistently fed at low fuel levels..whicjh in turns ensures the swirl pot is kept topped up, i have run this sytem hard to test it, i did an additional 5 laps of heavy cornering and braking when fuel gauge was showing empty, which on this sytem is 7 litres...
What you need to take into consideration is that the conventional fuel tank design even with foam, still needs a significant ammount of fuel to keep fuel levels above the outlet level, thats 4" minumum, due to the large surface area of the bottom of the tank, thats 12 to 15 litres and the fuel sender will not be reading anything under 20 litre so under this its all guess work how much is left in., nobody takes the risk even on tank foam so again it unuseable fuel and dead weight..thats a 15 litre difference even with pro alloy design..
What you need to take into consideration is that the conventional fuel tank design even with foam, still needs a significant ammount of fuel to keep fuel levels above the outlet level, thats 4" minumum, due to the large surface area of the bottom of the tank, thats 12 to 15 litres and the fuel sender will not be reading anything under 20 litre so under this its all guess work how much is left in., nobody takes the risk even on tank foam so again it unuseable fuel and dead weight..thats a 15 litre difference even with pro alloy design..
Thanks for that! Lots of info to take in!
At the moment im only planning on doing small mods to the tank rather than a whole re-think. Budget is already being pushed!
Will moving the outlet for the pump to the opposite side to make the distance between pump and tank be worthwhile? or should i just leave it as it is?
At the moment im only planning on doing small mods to the tank rather than a whole re-think. Budget is already being pushed!
Will moving the outlet for the pump to the opposite side to make the distance between pump and tank be worthwhile? or should i just leave it as it is?
Moving the outlet will eliminate the tight bends in the feed pipe, so it is a step forward, the next step forward is to modify the tank to allow rear facing outlet which can be much lower due to avoiding chassis bar and cretaes a sump which helps low fuel delivery, next step on is to modify the tank to add internal baffles..
A new tank will cost approx £500,, i would talk to Andy or Simon to see who can modify it for you, even welding a new outlet is classed as modifying as it requires welding and blocking up existing hole, the tank is not baffled sufficiently as stock..so it really is worth doing properly the fuel delivery system is one of the most important areas and worth paying attention to, you can have blowing manifolds, smoking turbos. all we would class as something that needs attention, the fuel system needs serious attention its just not so visible...
A new tank will cost approx £500,, i would talk to Andy or Simon to see who can modify it for you, even welding a new outlet is classed as modifying as it requires welding and blocking up existing hole, the tank is not baffled sufficiently as stock..so it really is worth doing properly the fuel delivery system is one of the most important areas and worth paying attention to, you can have blowing manifolds, smoking turbos. all we would class as something that needs attention, the fuel system needs serious attention its just not so visible...
JBliss said:
Thanks for that! Lots of info to take in!
At the moment im only planning on doing small mods to the tank rather than a whole re-think. Budget is already being pushed!
Will moving the outlet for the pump to the opposite side to make the distance between pump and tank be worthwhile? or should i just leave it as it is?
That pic is mine. the cut out about half way up is a mod I would recommend, helps with the clearance of the starter( without it the live from the starter is a few mm away from the tank!!) also if you are changing to the six speed it will make getting water and gear cables through the gap a LOT easier.At the moment im only planning on doing small mods to the tank rather than a whole re-think. Budget is already being pushed!
Will moving the outlet for the pump to the opposite side to make the distance between pump and tank be worthwhile? or should i just leave it as it is?
Bottom cut out is so a proper goodridge dash fitting could be welded in with no clearance issues for the fuel line with the chassis.
Lots of threads on here, do the tank right once as it's def cheaper in long run.
Swirl pot in tank is what I'd recommend... Similar money to cut out above and means you shouldn't have a buzzy pump again!
Of cause there is more to it as you need some pumps and lines etc, but you need this anyhow if your upgrading.
Swirl pot in tank is what I'd recommend... Similar money to cut out above and means you shouldn't have a buzzy pump again!
Of cause there is more to it as you need some pumps and lines etc, but you need this anyhow if your upgrading.
Right, So if i use a swirl pot set up i will not have to cut away the fuel tank?
What is the benefit of running a swirl pot inside the fuel tank in comparison to outside. What fittings and lines must you use for an internal swirl pot set up?
Maybe a silly question, But how do i make sure there is no fuel or vapour left in the tank before i go at it with a welder? i was going to drain it and then leave for a week or two open before starting. Will that be good enough?
What is the benefit of running a swirl pot inside the fuel tank in comparison to outside. What fittings and lines must you use for an internal swirl pot set up?
Maybe a silly question, But how do i make sure there is no fuel or vapour left in the tank before i go at it with a welder? i was going to drain it and then leave for a week or two open before starting. Will that be good enough?
Edited by JBliss on Friday 15th June 22:30
JBliss said:
Right, So if i use a swirl pot set up i will not have to cut away the fuel tank?
What is the benefit of running a swirl pot inside the fuel tank in comparison to outside. What fittings and lines must you use for an internal swirl pot set up?
Maybe a silly question, But how do i make sure there is no fuel or vapour left in the tank before i go at it with a welder? i was going to drain it and then leave for a week or two open before starting. Will that be good enough?
Fill it with water with a hose, let it run for a bit and then empty it. Job done.What is the benefit of running a swirl pot inside the fuel tank in comparison to outside. What fittings and lines must you use for an internal swirl pot set up?
Maybe a silly question, But how do i make sure there is no fuel or vapour left in the tank before i go at it with a welder? i was going to drain it and then leave for a week or two open before starting. Will that be good enough?
Edited by JBliss on Friday 15th June 22:30
Packaging, there is realistically not enough room for a proper size swirl pot... Its best to be thin and tall.
Also safer having it inside the chassis... Lot of people call me paranoid but I did a lot of work to get all the fuel system within the chasis, including pumps. To be fair I can be funny about some things lol
Also safer having it inside the chassis... Lot of people call me paranoid but I did a lot of work to get all the fuel system within the chasis, including pumps. To be fair I can be funny about some things lol
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