Anthony Posted December 20, 2002 Share Posted December 20, 2002 I have a 1990 ali petrol tank for carbs and would like to run injection. Is it a simple case of having a breather and return boss fitted ? What fuel pumps are used please for tuned VX's on injection Many thanks Anthony VX the real way sideways Link to comment Share on other sites More sharing options...
AMMO Posted December 20, 2002 Share Posted December 20, 2002 I have to do this mod myself to convert my Zetec to fuel injection. You can either buy the Caterham fuel injection tank or get a swirl pot. I'm getting the latter as it is generally accepted to be the best solution. You feed the swirl pot with a low pressure pump from the original pickup in the tank. The swirl pot then feeds a high pressure pump which goes to the injectors and regulator. The regulator then feeds back to the swirl pot and finally the swirl pot has a return to the fuel tank. I plan to have one made and fit it to the rear bulkhead near the diff. I'm using a Bosch pump which will run to 4 bar if required. The only mod you need to do to the tank is to fit a return pipe. If you do a search you will probably find more information about this. It will be explained a lot better too! AMMO Link to comment Share on other sites More sharing options...
oilyhands Posted December 20, 2002 Share Posted December 20, 2002 The trick is to avoid fuel surge with injected systems, with carburettors there is a reservoir of fuel in the carb so if the fuel supply is momentarily interrupted the engine will continue to run, with injection systems there is no such reservoir so a momentary interuption of fuel supply such as tht caused by fuel surge in the tank will cause instantaneous cut-out of the engine, or worse still a weakening of the fuelling. The ideal solution is a tall and relatively narrow surge pot which is all but immune to the affects of centripedal force, the injection pump is fed from this pot and the pot is kept full by a regular low pressure pump fed from the tank, the return from the fuel rail is plumbed back into the surge pot which also has an overflow back into the original tank. An alternative might be careful baffling of the tank or a separate compartment in the tank with one-way valves to inhibit fuel surge. The fuel mis then drawn from this compartment. An injection system requires much higher fuel pressure than a conventional carb setup (up to 4 -5 bar) and the pump must be gravity fed. Since most pumps are roller vane you will also need to pre-filter the fuel or the pump will fail. Bosch fuel pumps are fitted to many injected vehicles, I have used an Xr4x4 fuel pump on a number of cars and it has proved to have the capacity required for up to 300BHP. Oily There is some more info here Link to comment Share on other sites More sharing options...
Tight fart Posted December 20, 2002 Share Posted December 20, 2002 Hi Anthony, I had lots of problems last year going this route. I finally got it sorted by the above means, if you want to have a look and see how we cured the problems I am at home over xmas / new year, you are welcome to come and have a look. Richard p.s. the m/cylinder is still here if you need it Link to comment Share on other sites More sharing options...
Anthony Posted December 20, 2002 Author Share Posted December 20, 2002 Thanks Guys, looks like a swirl pot for me. Richard I have mailed you off line Best regards Anthony VX the real way sideways Link to comment Share on other sites More sharing options...
DohNut Posted December 20, 2002 Share Posted December 20, 2002 I am not sure of the internals of my swirl pot but it works with only one pump mounted on the bulkhead next to the swirl pot, so it is possible, it has the advantage that there is only one pump and the tank remains untouched, but weather the orriginal cost of the swirl pot which must increase with the extra complication out weighs that ...... I dont know. Nick ps the original install was done by Whiting using a Weber injection - but it was 10 years ago so I dont know what Link to comment Share on other sites More sharing options...
Trevor Phillips Posted December 20, 2002 Share Posted December 20, 2002 Anthony, I might part with a tank, new pump, filter and piping for suitable readies! Racing pics and items for sale here Link to comment Share on other sites More sharing options...
eric Posted December 20, 2002 Share Posted December 20, 2002 Hi Antony I have transformed a vauxhall injection tank to use in my 1600 Kent with carbs. Welded the hole where was the fuel pump and closed all the returns. The big difference is the hole on the side for the pump... Maybe it is better to buy the right one and sale yours.... regards Eric Link to comment Share on other sites More sharing options...
Anthony Posted December 20, 2002 Author Share Posted December 20, 2002 Thanks Eric, actually I regret sellin g the bag tank earlier this year, but hindsight is a wonderful thing ! Speak to you soon my Friend Anthony VX the real way sideways Link to comment Share on other sites More sharing options...
Graham Perry Posted December 20, 2002 Share Posted December 20, 2002 Be very careful, if your are going to fit a swirlpot. Have a look in the archive as we have discussed it before as nausium. I think Arnie found it was a false economy to fit one and ended up buying a Caterham ready made job with the proper pump after lots of grief. Link to comment Share on other sites More sharing options...
AMMO Posted December 20, 2002 Share Posted December 20, 2002 Graham Arnie probably fitted a Southern Hemisphere swirl pot in a Northern Hemisphere environment. I think Perfect Peter runs a swirl pot. Who's right? Dunno. I didn't know anything about them until fairly recently. We don't run them on bikes. Either gravity fed or pump in tank. No problems with surge although Ducatis run a de-gasser in the tank to avoid vapour lock. Oilyhands explains fairly well what the requirements are. Even road cars like V-dubs run a form of swirl pot apparently. A box around the size of a biscuit sits tin under one of the rear passenger seats. Fed by a low pressure pump with a high pressure pump immersed. Don't know 100% if this is true. Something that was told to me. AMMO Link to comment Share on other sites More sharing options...
captain chaos Posted December 20, 2002 Share Posted December 20, 2002 I am just converting my Vx from carbs to TB's with the help of DaveK and Daves' advise was similar to that of Graham Perry's posting. I've fitted a K series tank with pump etc. The swirl pot, which obviously seems to work OK, just seemed to be alot of extra plumbing and extra tank with no advantages over a cleaner, simpler installation. We actually had the debate the other night after I'd had a good look at Marius's site which has some photo's of his swirl pot installed. Link to comment Share on other sites More sharing options...
AMMO Posted December 21, 2002 Share Posted December 21, 2002 Captain Chaos Thanks for mentioning Marius's site. Had a good look. Some interesting pictures. WWW.MOSPEED.DE AMMO Link to comment Share on other sites More sharing options...
EFA Posted December 21, 2002 Share Posted December 21, 2002 If you use the K series injection tank with an uprated pump there is no need for any swirl pot. The internal baffling resolves all surge issues untill you get down to the last couple of litres, at which point its actually quite useful to know you are about to run out. (Unless you are racing of course) Bag tanks however, including the baffled SLR type DO require a swirl pot to work properly at below around 1/3 full. Arnie Webb The Fat Bloke 😳 in a not so Slow Vauxhall Link to comment Share on other sites More sharing options...
AMMO Posted December 21, 2002 Share Posted December 21, 2002 Arnie Thanks for that clarification. What are you currently running? Bag tank and swirl pot or pump in tank? Now not sure which way to go. Pump in tank would be neater / less hoses. More of a nightmare to change the pump if it fails. Haven't had the swirl pot made yet so still in time to change my mind. Internal / external? Hmmmm. AMMO Link to comment Share on other sites More sharing options...
Trevor Phillips Posted December 21, 2002 Share Posted December 21, 2002 On a similar vein, can you use the Caterham 55 litre bag tank on carbs with a Red Top external pump? Will you need a swirl pot? I don't want the expense of moving to TB's but do want the long range tank for next season. Racing pics and items for sale here Link to comment Share on other sites More sharing options...
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