Discussion
I have run both tanks down to zero on each tank via the dashboard switch but one tank took 40 litres and the other 10 litres.
The last 10 litres in tank 1 took forever to fill.
Is there a way of calibrating the senders or gauges as it would appear they are showing empty but aren't.
Also when filling does one tank partly fill from the other?
The last 10 litres in tank 1 took forever to fill.
Is there a way of calibrating the senders or gauges as it would appear they are showing empty but aren't.
Also when filling does one tank partly fill from the other?
When you fill the first tank the transfer pipe is slowly filling tank two.
If you take your time going round to fill tank two then tank one has drained down.
At the last stage of topping off tank two you are also slowly topping off tank one.
With the standard gauges there is no way to calibrate them. Check if they are equal by having the car on level ground and switch from one tank to the other and wait for the gauge to settle (they are damped so they don't react to fuel sloshing about).
Steve
If you take your time going round to fill tank two then tank one has drained down.
At the last stage of topping off tank two you are also slowly topping off tank one.
With the standard gauges there is no way to calibrate them. Check if they are equal by having the car on level ground and switch from one tank to the other and wait for the gauge to settle (they are damped so they don't react to fuel sloshing about).
Steve
Alex93 said:
I'm sure I remember reading somewhere that the tanks hold 40L each?
I thought it was a total of 44 litres each. However, you cannot use all of it as the outlet pipe is not at the bottom of each tank. Also, you will be sucking air with your low pressure pumps.The estimate of 35 litres each is not far out IMO.
Paul
Storer said:
...... However, you cannot use all of it as the outlet pipe is not at the bottom of each tank....
Not quite true.There are two outlets on the tank both on the same level but not quite at the bottom of the tank side.
The forward most fitting is for the low level transfer pipe (if fitted) and is a straight fitting into the tank.
The rearward fitting however has a pipe running off the back of the fitting and bending down to suck right from the bottom of the tank.
Steve
Well I had less fuel than I thought at the weekend as I still find my standard gauges both show zero when around or even just over half full. Therefore guesswork is my only way of telling what I have left when below half full.
Saw a Shell station so pulled in.
One tank took 38.8 litres, the other 38.2 litres! 77 in total....
So they can't be less than 40 litres each, but don't think they are much more.
Mark
Saw a Shell station so pulled in.
One tank took 38.8 litres, the other 38.2 litres! 77 in total....
So they can't be less than 40 litres each, but don't think they are much more.
Mark
The tanks are 40 litres each, it's surprising how much volume the foam takes up, then there's the about 4-5 litres spread thinly on the bottom that the pick up pipe doesn't get. If you get yourself a 'proper' fuel gauge, one that can actually read what's in there such as SPA or Stack when you come to calibrate it it will not register any fuel until you get over 5 litres (per tank) I'm guessing that's why people see low 30's when filling.
When I was at the Donington show there was a stand selling a box of tricks that would read fuel levels in odd shape tanks if you wanted to keep your std gauge, but can't for the life of me remember who they were, maybe the answer.......
When I was at the Donington show there was a stand selling a box of tricks that would read fuel levels in odd shape tanks if you wanted to keep your std gauge, but can't for the life of me remember who they were, maybe the answer.......
Even with a calibratable gauge to linearise fuel level to quantity, you still will struggle to read the contents accurately at low fill levels due to the sender hitting the bottom of the tank and due to fuel slosh etc. Most production cars now use a Kalman filter (google it!) type strategy running in the driver display/dash embedded controller to blend an known minimum fuel quantity minus actual fuel consumption to calculate an estimated true fuel quantity.
Max_Torque said:
Even with a calibratable gauge to linearise fuel level to quantity, you still will struggle to read the contents accurately at low fill levels due to the sender hitting the bottom of the tank and due to fuel slosh etc. Most production cars now use a Kalman filter (google it!) type strategy running in the driver display/dash embedded controller to blend an known minimum fuel quantity minus actual fuel consumption to calculate an estimated true fuel quantity.
This is how modern cars are able to display an estimated mileage until re-fill, right?I've not been montoring my fill ups that closely but will now! I have a standard twin pump set up, and i was thinking is there any need for a swirl pot set up? or are the pick ups from the std tanks ok? I alway wondered why the twin pump? surly 2 lift pumps and swirl pot would be a better idea?
confusionhunter said:
I've not been montoring my fill ups that closely but will now! I have a standard twin pump set up, and i was thinking is there any need for a swirl pot set up? or are the pick ups from the std tanks ok? I alway wondered why the twin pump? surly 2 lift pumps and swirl pot would be a better idea?
Depends on Carb or Fi.confusionhunter said:
fair point, however Im weighup options in the future for an EFI solution so was just wondering if a swirl pot is a must or to the tanks do a good enough job?
If you go EFI then yes a surge is your best bet. You could go for HP pump in the tank but that is a major mod.Take the existing LP pump outputs that tee into the supply to the carb. Connect these to the surge. Bring the return from the EFI pressure regulator back to the surge. Take a bleed from the top of the surge back to one of the tanks but make it restricted so it barely passes anything but it will bleed off any air. This will keep the surge under about 5psi pressure which will help eliminate cavitation at the entry to the HP pump.
Steve
Prob a bit off topic.
I am about to take out my swirl pot and give it a try without whilst keeping a close eye on AFR in hard cornering. My idea is to take the -6 out puts from each tank and connect to a block with -8 out into the suction of a speed controlled HP pump only mounted at low level on the bulkhead where my current HP pump is. It means that two tanks become one but does away with lp pumps swirl pots and loads of pipework. If it doesn't work I will go back to swirl pot. Obvoiusly a problem If one tank becomes empty but running that low is stupid anyway. Balance pipe can also be capped off. I guess filling will be a pain but maybe an ign controlled solenoid in the fuel pipe would solve that and be even better than the current balance pipe fill problems. Just can't see it being a prob unless fuel gets v low.
I am about to take out my swirl pot and give it a try without whilst keeping a close eye on AFR in hard cornering. My idea is to take the -6 out puts from each tank and connect to a block with -8 out into the suction of a speed controlled HP pump only mounted at low level on the bulkhead where my current HP pump is. It means that two tanks become one but does away with lp pumps swirl pots and loads of pipework. If it doesn't work I will go back to swirl pot. Obvoiusly a problem If one tank becomes empty but running that low is stupid anyway. Balance pipe can also be capped off. I guess filling will be a pain but maybe an ign controlled solenoid in the fuel pipe would solve that and be even better than the current balance pipe fill problems. Just can't see it being a prob unless fuel gets v low.
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