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Helpful ReplyFuel System Design Advice

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stuka
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2013/06/16 20:32:09 (permalink)
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Fuel System Design Advice

looking for some advice or pointers for how to design a fuel system as I have never done anything like this before and its not an area I want to make mistakes with. I have decided on E85, have the right walbro in tank pump, have the spare car to model things up, with fuel tank already removed. the car will be used for circuit and rally, was thinking a surge tank would be wise too so another pump would be needed. I already have the racerx fuel rail and ID2000s. any advice, good websites or guides would be appreciated.
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    WIDEMR
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    Re: Fuel System Design Advice 2013/06/16 21:03:24 (permalink) ☄ Helpfulby Dudeman 2013/06/16 21:45:46
    +4 (4)
    The factory MR2 tank isnt bad for fuel surge, it has some baffles and that small pot at the bottom the pump sits in, but for heavy track i would still use a surge tank.
     
    If youre using a surge tank then the intank pump will only be to fill up the surge tank, which will just overflow back to the tank, most high pressure pumps, ie the walbro, dont flow that much fuel when not pumping up to a restriction (reg and injectors) so filling a surge tank which just overflows back it wont build up much pressure at all, flow rate is alot less, while still drawing alot of current and heating the fuel.
     
    Most good in tank low pressure 'lift pumps' will out flow a bosch 044 and draw much less current (around 1 Amp when running compared to around 8 - 12Amps)
     
    Below is a typical setup. 
    Its showing 3 fittings on the top of the surge tank, if you got one that had 1 on the very top and 2 on the side near the top, the very top will be the overflow to the tank, the 2nd highest typically return from reg and 3rd highest the feed from the in tank pump.
     

     
    For E85 you prob know all about what it can do to normal rubber hoses, you can get some rubber hose thats suppose to be ok with E85 but the best would be Teflon hose.
     
    You can get cheap 'smooth bore' teflon hose with stainless steel braid which has a high min. bend radius and if bent to hard can kink, or depending on your budget the best would be 'convoluted bore' with a material outer braid with crimped on hose ends (such as BMRS - Brown & Miller) which is highly flexible and light.
     
    Teflon hose requires different hose ends then normal rubber, usually using an olive. Teflon hose also has a much smaller OD as the teflon is very thin, compared to thick walled rubber hoses.
    Teflon hose will also not stink up the cabin with fuel smell if you run them in the cabin.
    post edited by WIDEMR - 2013/06/16 21:52:50
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    WIDEMR
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    Re: Fuel System Design Advice 2013/06/16 21:10:11 (permalink)
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    Surge tank locations would either be under the front bonnet, keeps weight low and foward, i know B24 wants to go this way, in the PS pump location, or the boot which seems to be the most common, this is were mine is due to i have other tricks under the front bonnet and wanted to keep the main fuel pump close to the rail. 
     
    My setup is also, at the moment, is a 'dead headed' setup, i only have 1 hose on the fuel rail, my reg has several ports so the fuel in and out are joined, with then the return to the surge tank. 
     
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    stuka
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    Re: Fuel System Design Advice 2013/06/17 09:57:32 (permalink)
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    thanks for the info mate
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    B24
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    Re: Fuel System Design Advice 2013/06/19 22:15:14 (permalink)
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    Excellent write up WideMR.
     
     
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