mk2 16V lift pump flow rates, to suit rally car on twin 45's

Discussion in 'Carburettor' started by Jon Olds, May 2, 2023.

  1. Jon Olds Forum Junkie

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    My tarmac rally car is a self build combination of all sorts.

    I run a 1L swirl pot under the bonnet and a facet pump to move the fuel from the pot to the twin 45's

    I use the original mk2 16V fuel lines to fill the swirl pot and return excess back to the tank (keep the swirl pot full, in theory)

    The original in tank lift pump pumps the juice to the swirl pot.

    I am concerned that I am nearing the limits of the in tank pump, flow wise.

    Is there an upgraded one available? Or is there a one from say, a G60 that flows more?

    I have measured 1L/minute being returned to the tank (engine off) , ideally I would like a minimum of 2L/minute

    TIA
    Jon
     
  2. rubjonny

    rubjonny Administrator Staff Member Admin

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    theyre all the same spec but you should be able to find some facet or similar submersible pump to do the job its nowt fancy
     
  3. Jon Olds Forum Junkie

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    thanks Jonny, think its the easiest option.
    Jon
     
  4. KeithMac Forum Junkie

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    I fitted a Mitsubishi GTO pump in mine, used the return as the feed though as it made plumbing easier (I run 4 bar pressure through it).

    Just make sure you use Submersible fuel line in tank, I use Cohline pipe.

    A Walbro 255 would fit but completely overkill!.

    A good 2nd Hand Denso or Bosch will be better than a new Chinese fantastic pump, I've had trouble with new pumps costing £80+ on the Motorcycles.
     
  5. Jon Olds Forum Junkie

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    Thanks keith. With it being just to fill the swirl pot a low pressure pump seems a more obvious choice
    Jon
     
  6. Jon Olds Forum Junkie

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    More research on this. The OE part number is 191906092. Research on autodoc lists the flow as 75L/hr, roughly what I have measured.
    Out of the many many listed, one is apparently rated at 130L/hr (JOHNS KSP 23-002) This is given as a direct equivalent to the Quinton Hazel QFP624.
    Going to splash some cash and see where this takes me..
    Jon
     
  7. Jon Olds Forum Junkie

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    Only one available today is a Lucas FDB733, so I'm going to give this a bash first
     
  8. rubjonny

    rubjonny Administrator Staff Member Admin

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    the bentley says it should deliver 300cc in 10 seconds, so if my maths is right around 100l/hr
     
  9. Jon Olds Forum Junkie

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    There is a definite difference between pumps. Physically, from what I have in stock, the VW one is shorter and fatter than a typical aftermarket
    one. I have 'borrowed' a genuine one and the flow rate seems about 50% more. Still waiting for the Lucas one to arrive, so after testing that one may well end up in the 'rally spares' box.
    Also, tried it at nominal battery 12V and elevated voltage typical of a running car (nominal 14V : added a battery charger..) Not really a measurable flow difference, but in reality there must be
     
  10. KeithMac Forum Junkie

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    Worth noting it's not the pump that produces the pressure but the restriction caused by the Fuel Pressure Regulator.

    May open up your options a bit as you can't over run a swil pot.
     
  11. Jon Olds Forum Junkie

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    Thanks Keith, I'm not running an FPR, its piped to the swirl pot and directly back. The pipework is the only restriction (that I know about..)
    Jon
     

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