Ben Hutchings Posted January 26, 2009 Posted January 26, 2009 Hi, I'm looking to replace my mechanical fuel pump with a Facet jobby. Can anyone advise on the sort of PSI Strombergs need to be fed at? Cheers!
rotoflex Posted January 26, 2009 Posted January 26, 2009 http://www.geocities.com/rotoflex/gt6-mod.htm#_Electric_fuel_pump3.3.1 Electric fuel pump A low-pressure electric fuel pump is required for the GT6 if one is used. A typical replacement is manufactured by Facet, model 40105. It should be fitted as near the tank as possible, lower than the fuel outlet, the mechanical fuel pump should be removed, & the opening in the engine block covered with a plate & gasket. It is essential that the fuel pressure of any replacement fuel pump be only 1.5 to 2.5 psi if used with the Stromberg carburettors.
Ben Hutchings Posted January 26, 2009 Author Posted January 26, 2009 Brilliant! thanks. I was looking at this: http://www.merlinmotorsport.co.uk/p10861/SOLID-STATE-FUEL-PUMP-1.5-2.5-PSI/product_info.htmlLooks like it'll be perfect. However... how would I know if my engine is pulling /needing more? It's not very heavily modified at all, so its probably standard fuel requirements. If the pump did underperform, I guess I'd see lean conditions? Any advice on this?btw, did you write all that info on the site? It's like an e-book, very very useful.Thanks again...
Ben Hutchings Posted January 27, 2009 Author Posted January 27, 2009 On the 10CR and LMC last year I had quite a few fuelling issues always when climbing long hills or mountain roads. Turning the car around and sitting it level or facing down for a while sorted the problem and then I was able to drive on upwards for a few more minutes. Each time, the pressure seemed very low or non existent from the pump while facing up-hill. Plus the fuel was constantly boiling in the bowl on the mech pump.I just thought that the Facet might give me a few advantages: It'll be nearer the tank, it won't be close to the block and boil the petrol, I can use the wiring of it as a small security feature, plus the mech pump hole could be used for breathing the case in the future.. maybe. Also, if the pump fails anywhere around the world I can get a replacement, probably not so with the mechanical one.Of course I'm open to suggestions :)
Royboy66 Posted January 27, 2009 Posted January 27, 2009 ah, yep, remember the early morning in Austria! :)Worth a try from what you say, cant think of any negatives! :)
Ben Hutchings Posted January 27, 2009 Author Posted January 27, 2009 Yea, you probably also remember waiting for us half-way up Via Stelvio after we 'broke down' before the bridge...It MUST be fixed before 10CR09 :)
rotoflex Posted January 27, 2009 Posted January 27, 2009 The 1.5 to 2.5 psi fuel pressure is from the factory shop manual; it's the pressure for which to test the mechanical pump.As has been mentioned here, there is a problem going with fuel pumps with higher pressures as they overcome the carb design.However, Facet's page athttp://facet-purolator.com/index.php?option=com_content&task=category§ionid=7&id=16&Itemid=31lists the output of the 40105 pump as 3.0 to 4.5 psi.The one you linked to must be the 40163, with 1.5 to 2.5 psi.When I originally started sticking info in there, I didn't include references for the data, & I'm not sure now where the 40105 model comes from. It's likely from something like the US Victoria British aftermarket parts catalog or some other comapny that's been selling Facet replacement pumps for years for Stromberg/SU/Weber equipped cars. It may be that the carbs will accommodate 4.5 psi & it gives you extra GPH if needed, but now I'm wondering. You'll probably be fine & safest with the 40163.The typical caution when fitting an electric fuel pump is to wire it through the oil pressure switch so that if the engine dies it won't keep pumping gas. Probably the best way is to put a piggyback spade connector on the spade connector on the oil pressure switch, one side running off to the dash light as usual, the other side going to activate a relay & the fuel pump power wired through the relay.
BarryH Posted January 27, 2009 Posted January 27, 2009 I have also had it strongly recommended to put a filter between the tank and the pump. This was 2 or 3 years ago when Facets had a history of failing and the filter solved it. I think they have changed them since to solve the problem but for the price of a filter why take a risk. The information came from some ex Cambridge Motorsport guys who now have their own business and weren't trying to flog me a pump or a filter or anything else.PS if you want a FilterKing to regulate the carb side pressure from the pump let me know, I have one that only saw 12-18 months use before I reverted to a mechanical pump. I didn't have a filter from the tank and the pump failed after 12-18 months.
Clive Posted January 27, 2009 Posted January 27, 2009 Thats a great offer, and well worth taking up. Also the advice about a pre-pump filter. I would also carry a spare pump, just in case. They are pretty small and cheap, and if you have a spare it will never go wrong :)
Ben Hutchings Posted January 27, 2009 Author Posted January 27, 2009 Brilliant, thanks for the extra info gents. So for flexibility, it might be good to run a Facet that's slightly over spec'd (3-4.5) and the FilterKing? That way I can (I'm guessing) dial down the pressure with the FK, and up it to 4.5 odd of needed in the future.Regarding the wiring with the oil pressure switch, excellent idea, but how will this work during the first few seconds of start-up? Would you suggest a momentary by-pass switch to pump some fuel before I turn the engine over?(PM sent Barry!)
Clive Posted January 28, 2009 Posted January 28, 2009 I wouldn't bother. At worse it means the car wont start until the oil pressure is over 10psi or whatever the switches are set at. And there is usually plenty of fuel in the float chamber to start the car anyway. Regarding the pumps, the red top interrupter type are supposedly much better (also pricier :() than the solid state type. Gues you pays the money etc. And I would avoid the "facet style" ones and get the real thing! Also those filterkings are the DB's
Ben Hutchings Posted January 28, 2009 Author Posted January 28, 2009 Ok cheers, whats the differences, practically, between the two types of pump?I've had 'noise' and 'longevity' suggested... any experiences?
Ben Hutchings Posted February 1, 2009 Author Posted February 1, 2009 Hi, I think I'm decided on the Cylindrical type with solid state internals. One last question: Does anyone know if it's ok to limit a pump with a regulator below it's opperating range? i.e., if I have a 4-5.5 psi pump, can I regulate it to 2psi with a FilterKing or will this damage/strain the pump? I might call Facet or their distributor, but thought I'd ask the 'CT FORUM BRAIN Construct' first...
willcolumbine Posted February 2, 2009 Posted February 2, 2009 Hutch wrote:Does anyone know if it's ok to limit a pump with a regulator below it's opperating range? i.e., if I have a 4-5.5 psi pump, can I regulate it to 2psi with a FilterKing or will this damage/strain the pump? I might call Facet or their distributor, but thought I'd ask the 'CT FORUM BRAIN Construct' first...Nah, it's fine. They're designed to be used like that!
Clive Posted February 3, 2009 Posted February 3, 2009 indeed, i ran my twin dhla carbs at 2psi, using a pressure regulator. No problems. The cylindrical ones have a built in filter, but DO use one of those cheapo filters before as well. Clive
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