Swirl Pot or Not
Discussion
The consensus from when I asked was no it's not needed, several members stated that their cars hadn't got swirlpots when they acquired them just a T-piece.
I was considering going the T-piece route but decided to go with a swirlpot so it seemed like less of a bodge, RT racing quoted me £105 + vat which seemed pretty reasonable.
I was considering going the T-piece route but decided to go with a swirlpot so it seemed like less of a bodge, RT racing quoted me £105 + vat which seemed pretty reasonable.
Seperate swirl pots de air the returning excess fuel to the tank, prevents starvation under surge conditions AND in doing so cools the fuel pump. Many (all?) injection fuel pumps are cooled by the fuel they pump. Cooling is not an issue with in tank pumps but it is for external pumps. If you have no swirl pot and you're frequently surging, the pump will run dry and eventually burn out, sometimes quickly. Some tanks are designed with the pot built in but for those that are not it is HIGHLY recommended a swirl pot is used for injected engines. New pumps aren't expensive but swirl pots can be cheaper. You could do without so long as you have plenty of fuel.
Semantics perhaps - but this thing isn't a swirl pot, it's just a small reservoir with a tee piece on the top and an outlet to the pump at the bottom. Rumour has it that it has a mesh filter inside too. there is a vent pipe on the top but there's no 'swirl' involved!
Interesting that Mr Zig said his Tee-piece equiped car hesitated on turning left - that makes sense to me. the fuel rail return goes to the left hand tank so the fuel level is potentially lower in the right hand tank. I wonder if on turning left, the fuel sloshes to the right and uncovers the right hand tank connection to the tee piece - the pump will then pull in air.
My take would be that this 'swirl pot' thingy doesn't look cheap and TVR were not ones for spending money on the cars unnecessarily, ergo it's essential!
Interesting that Mr Zig said his Tee-piece equiped car hesitated on turning left - that makes sense to me. the fuel rail return goes to the left hand tank so the fuel level is potentially lower in the right hand tank. I wonder if on turning left, the fuel sloshes to the right and uncovers the right hand tank connection to the tee piece - the pump will then pull in air.
My take would be that this 'swirl pot' thingy doesn't look cheap and TVR were not ones for spending money on the cars unnecessarily, ergo it's essential!
nice and shiny but pricey http://www.ebay.co.uk/itm/TVR-TASMIN-280-350-400SE...
Thanks for the responses. Since finding a source on fleebay who will make them to order, suppling drawings etc and priced £40/£60.So guess I'll fit one. Pumps certainly don't like air so it seems a reasonable course of action to fit one. Does anyone know if these pumps will only function when primed with fuel please? My removed one, does nothing when power is applied to it. Is there a safety device inside to prevent damage, overheating or a fire risk? Thanks J C.
The Hatter said:
Interesting that Mr Zig said his Tee-piece equiped car hesitated on turning left - that makes sense to me. the fuel rail return goes to the left hand tank so the fuel level is potentially lower in the right hand tank.
Couple of one-way valves in the supply pipes from the tanks - or plumb the return pipe into the 'swirl pot'?The swirl is the motion of the fuel as it is fed in back from the injection system. In true external swirl pots the return pipe usually enters at an angle so the the fuel runs round the wall and downwards just like filling a bucket with a garden hose at an angle. As it does this much of the air comes out before the fuel gathers in the bottom. There is no standard design for a swirl pot, the one I have in my kitcar has 4 ports but I believe 5 port are available. On mine here are 2 output ports and 2 input ports. One is at the bottom and GRAVITY feeds the electric pump (therefore the output of the swirl pot should be above the electric pump otherwise the pump has to suck) the other output is a return the the tank proper for overflow control. One input is from the injection return and the other is from the tank itself as the primary source. These ports will be at different heights with the top one being the return and the bottom one being the output to the pump. If the electric pump is higher than the tank output you will need a second low pressure pump to feed the swirl pot because the electric pump is not good at sucking/pulling, they are designed to push. Again in my Kit I have a RedTop pump feeding the the swirl pot from the tank. Bench testing the pump is not necessarily a good idea because it may over heat very quickly only 'pulse' the power. A working pump may or may not make any noise and you may feel it vibrate. One of my fully working pumps failed after I bench tested without knowing what I now know. (A baffled tank on it's own without swirl pots or seperate reservoirs will not prevent an electric pump from running dry if there is too little fuel, ie when the fuel level is below the baffle openings and it is therefore free to slosh and surge.
Not a lot else in there, two pipes in at the top, small baffle plate at the bottom outlet. Now to weld it up. I'll try and upload some pics. Cheers J C. Automax said:
GRAVITY feeds the electric pump (therefore the output of the swirl pot should be above the electric pump otherwise the pump has to suck)... If the electric pump is higher than the tank output you will need a second low pressure pump to feed the swirl pot because the electric pump is not good at sucking/pulling, they are designed to push.... (A baffled tank on it's own without swirl pots or seperate reservoirs will not prevent an electric pump from running dry if there is too little fuel, ie when the fuel level is below the baffle openings and it is therefore free to slosh and surge.
On the Wedge the swirl pot and fuel pump are below the bottom of the tanks so as long as there's appreciable fuel in the tanks it's all gravity-fed.If there's 'too little fuel' then arguably it makes no odds whether the tank is baffled or there's a switl pot or not: you're about to run out of fuel so should you be driving hard enough to use the last of it quickly...?
The Hatter said:
Interesting that Mr Zig said his Tee-piece equiped car hesitated on turning left - that makes sense to me. the fuel rail return goes to the left hand tank so the fuel level is potentially lower in the right hand tank.
Aren't you overlooking the balance pipe between the tanks? If fitted properly it should form a U-bend below the tanks but I did see a 280i some years ago where the balance pipe formed a massive inverted U going up over the propshaft. So it drained the left-hand tank and then started sucking air through the T-piece causing rough running, that may be a variant of what was happening to Mark's car.
On my set up I run the return fuel back the to the left tank and into the top of the swirl pot and to make sure I don't over pressure the system the pip that links the swirl pot to the right hand tank is linked into the same set of pipes, I put a brass X connector in and linked the lot, I was getting fed up of the fuel only been returned to the left tank and not getting to use it all but now I can
Cambelt
Cambelt
Hi Campbell are you saying you can run the fuel lower before it runs out? In that case it sounds like a useful mod.
I have noticed after running out (or it spluttering) I have got anything between 51 and 56 litres in when brimming the tank after. But I know the tanks should take 61l. So I think there's a gallon or so at the bottom, that isn't being collected.
I have noticed after running out (or it spluttering) I have got anything between 51 and 56 litres in when brimming the tank after. But I know the tanks should take 61l. So I think there's a gallon or so at the bottom, that isn't being collected.
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