Fuel injection: hose & pumps system layout

Road-race engines and ancillaries - general discussion
chrislandy
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Fuel injection: hose & pumps system layout

Post by chrislandy » Thu Feb 12, 2009 4:02 pm

Hello Guy et al,
From looking through some previous posts I can see that you (and others) use and highly recommend the Aeroquip push on hose for oil systems. Due to the nature of this construction method it is obviously well suited to home construction and hence my interest in using it. Have you or would you use this hose for fuel delivery too? I am currently planning my fuel system for the T16 turbo. I would expect the maximum fuel pressure to be around 5bar at full boost (1.5bar boost + 3.5bar base fuel pressure).

The spec. sheet would suggest that is suitable for petrol delivery and the working & burst pressures are well within my requirements. I have spoken to an Aeroquip supplier/dealer about this and they feel it would be ok to use but having never used this type of hose before any thoughts from others experiences would be very appreciative.

Thanks
Chris

Guy Croft
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Re: Hose for fuel delivery

Post by Guy Croft » Thu Feb 12, 2009 4:40 pm

Aeroquip 'furry' textile braided push-on hose: It is indeed suitable for oil or gasoline.

I just checked with Think Automotive to be sure.

GC

chrislandy
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Re: Hose for fuel delivery

Post by chrislandy » Thu Feb 12, 2009 5:02 pm

I thought it should be ok (it was Think Automotive that i'd spoken to but I was not sure if I could post their name!)

This is my proposed fuel system layout, any comments would be welcome. The engine will be going into my Shelsley T2 which is mid-engined, I know from the racing versions and a number of high power Elises that fuel starvation can be a problem during cornering hence the swirl pot.

Chris
Attachments
ShelsleyFuel.JPG
Proposed fuel system layout - red is high pressure and blue is low pressure / return
ShelsleyFuel.JPG (93.06 KiB) Viewed 4428 times

smckeown
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Re: Hose for fuel delivery

Post by smckeown » Fri Feb 13, 2009 12:46 am

That's going to cost a small fortune in fittings. Why do you have so many filters and fuel tanks ? Also are you planning on using adjustable or fixed pressure regulator ?

Sean
205 8v Track car

chrislandy
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Re: Hose for fuel delivery

Post by chrislandy » Fri Feb 13, 2009 8:44 am

The Shelsley has two small fuel tanks, one on either side of the engine bay with 32mm outlets (see attachment), I have already got the link Tee from a few years ago with a 1/2" oulet and a baffle (haven't got a picture of that at the moment).

I am going to use an adjustable 1:1 pressure regulator (most likely an FSE or Sytec) and have a new fuel rail fabricated. With regard to the filters, I was using good practice and filtering before any major components as I don't want my fuel pumps getting clogged or my injectors - I already have the parts shaded from my stock of random bits - could the one between the tank and the low pressure pump be omitted? The low pressure pump is an FSE "bluetop" pump and I am using a DTA E48 ecu
Attachments
P1010014.JPG
Fuel tank positons, just infront of the engine and behind the main bulkhead to control the weight distribution
P1010014.JPG (46.83 KiB) Viewed 4394 times

Guy Croft
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Re: Hose for fuel delivery

Post by Guy Croft » Fri Feb 13, 2009 9:17 am

CAD dwg?

Can u post on white background so I can print it off please?

GC

chrislandy
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Re: Hose for fuel delivery

Post by chrislandy » Fri Feb 13, 2009 9:40 am

See attached.

Chris.
Attachments
ShelsleyFuel2.JPG
Proposed Shelsley fuel system (white background)
ShelsleyFuel2.JPG (109.17 KiB) Viewed 4381 times

Guy Croft
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Re: Hose for fuel delivery

Post by Guy Croft » Fri Feb 13, 2009 12:38 pm

See below.

Looks broadly OK to me in general terms except I'd increase the hose size at one place as shown and the mid filter is not really needed. Using -8 (equiv to 1/2BSP) will minimsie pressure drop over a long run.

You maybe need to consider bulkhead fittings - you don't want to run fuel hose thru grommets and from memory I think RAC MSA regs forbid that anyway. By the same token any internal fuel lines (ie: thru driver compartment) - and you need to check this - might well need to be aerospcae style stainless steel braided type - not push-on. The hose designation from Think Automotive is Aeroquip FC333 and it's FIA approved for fuel lines. However it reuires screw-on compression fittings and you have to lay out the hose line very carefully before assembly or the hose will twist. I think internal oil or fuel lines may require coloring red too. Can't remember if it's in the RAC Blue or Yellow book, sorry. You can run fuel lines under the car but they'd have to be metal pipe not rubber tubing. This is also true of oil lines on cars with dry sump system (tank in boot).

With push-on layouts it is customary to use a fir-tree type swivel on the hose end with female fitting and fit this to a male union on the accessory. Having a swivel allows you to orient the hose without twisting. There is a bewildering array of steel and alloy push-on fittings aval, in JIC, metric and BSP so I anticipate a fair bit of mix-and-match.


I'd advise you request a catalog from Think Automotive (BTW - since you were kind enough to remark upon it they are certainly a GC approved supplier and there is no problem mentioning their name on this site) and carefully survey the available fittings for the filters and pumps. Some will have male, some female connections and some may be set up for banjo unions. They could be any thread so unless you're sure (ie: have it on the bench in front of you..) don't assume JIC will fit everything.


GC
Attachments
ShelsleyFuel.JPG
Your layout with hose ID included for reference (for those unfamilar with dash codes)
ShelsleyFuel.JPG (57.39 KiB) Viewed 4364 times

chrislandy
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Re: Hose for fuel delivery

Post by chrislandy » Fri Feb 13, 2009 1:53 pm

Thank you Guy for taking the time to explain and advise. I will have to check my bluebook, although with the engine and fuel tank configuration everything is housed in the (rear) engine bay and only water pipes and brake lines go through the cockpit.

The longest run will be the return from the regulator or the return from the swirl pot at around 1.5m, I suspect that it is going to be a very tight fit for everything else! It is a bit concerning when the FIA say to use oetiker clamps with the push on fittings when Aeroquip state on their website that using a clamp in addition to the push on fitting has been known to cause premature failure!

Chris.

Guy Croft
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Re: Hose for fuel delivery

Post by Guy Croft » Fri Feb 13, 2009 4:30 pm

Aeroquip of course are absolutely right.

Hose of all kinds is subject to fatigue over time due to pulsations in pressure. This is why hydraulic hoses fail on excavators et alia.

Clamping the hose onto a fir-tree type swivel (ribbed) creates a dangerous local stress concentration that can cause rapid premature failure of hose polymer (rubber..) and its textile or steel reinforcement.

GC

Rich Ellingham
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Re: Hose for fuel delivery

Post by Rich Ellingham » Sat Feb 14, 2009 9:55 am

Hi Chris I only have some trivial points to mention. Go for sweept bends and not the cheaper forged bends if you use JIC connectors, the swept bends are also swivel type. You'll need a nice set of AF spanners for assembly of Alloy JIC fittings. The steel fittings are much cheaper but have larger radii, take more space and have a notable weight if you use a lot of them. Even the lightest contact between steel braided hose and anything is touches will cause significan abrasion if movement is available. Be careful with steel braid near anything electrical is makes an excellent short circuit and fire risk. Assembling steel hoses was not a fun task, you must follow the instructions in the back of the think auto catalogue exactly. It may not be applicable in your case but if your engine is not rigidly mounted then consider any movement between the engine and the fixed side of the line; on my pressure regulator return I had to arrange a set up to angle the return hose correctly, this male-female section failed at Mallory park and glad I stopped to investigate the 'petrol' smell to see fuel all over the place. Replacment with a fixed non swivel forged fitting solved the issue, but that was lucky; an angle forged -6 -6 connector ends up with its bend facing in which ever direction its stops turning when screwed into the the female thread on the pressure regulator, its was not possible in my case but a male-male adaptor and swivel on the return hose would have solved this nicer.

Rich
book 38

Cousin Cleotis
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Re: Hose for fuel delivery

Post by Cousin Cleotis » Sat Feb 14, 2009 2:04 pm

I know this question hasnt been asked but something that alot of people dont realise is that JIC an AN fittings are not compatable, the threads are the same and both are measured in 'dash' sizes, but the sealing surfaces are at different angles. JIC fittings are 45 degrees and AN fittings are 37 degrees.

If you are interested in saving money, Aircraft AN fittings are often alot cheaper than "motorsport" fittings

Paul

Guy Croft
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Re: Hose for fuel delivery

Post by Guy Croft » Sat Feb 14, 2009 3:06 pm


smckeown
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Re: Hose for fuel delivery

Post by smckeown » Sat Feb 14, 2009 3:57 pm

I wouldn't use an adjustable regulator. I'd go for a fixed one, say 3 or 4 bar, depending of course on what pressure is needed based on the injectors you have. The problem with adjustable ones, is once adjusted, they apparently do not stay fixed at that level.
205 8v Track car

chrislandy
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Re: Hose for fuel delivery

Post by chrislandy » Mon Feb 16, 2009 9:59 am

Thanks for all your advice guys, following this could anyone recommend a suitable fixed fuel pressure regulator to run at somewhere between 3 and 3.5 bar, the injectors I am using are Siemens deka 60lb (4off).

Chris.

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