Swirl pot for fuel injection.
Discussion
Morning all,
I'm toying with the idea of converting my1.6 Xflow from carbs to ITBs but would obviously need to upgrade the fuel system for starts. Is it possible to leave the old low pressure fuel pump in place and have that feed a 1.5L swirl pot, and then have that feed the high pressure fuel pump?
Then I could plumb in a new line for the return into the filler neck. I know in an ideal world I should remove the current tank and fit it out for a high pressure pump but that looks like it could be a costly and time consuming affair!
Cheers,
Kev
I'm toying with the idea of converting my1.6 Xflow from carbs to ITBs but would obviously need to upgrade the fuel system for starts. Is it possible to leave the old low pressure fuel pump in place and have that feed a 1.5L swirl pot, and then have that feed the high pressure fuel pump?
Then I could plumb in a new line for the return into the filler neck. I know in an ideal world I should remove the current tank and fit it out for a high pressure pump but that looks like it could be a costly and time consuming affair!
Cheers,
Kev
You might be surprised!
I did exactly this back in ~2010, and assumed the same thing, so I reused the existing carb fuel pump to feed a swirl pot and then the HP pump. The result was frankly a mess, a real hornets nest of pipe work that I was not happy with. It survived for a year, before I removed it all the following year.
I had the tank modified to incorporate a swirl pot, and because it was an early Westfield tank, they also fitted a breather/vent to make refueling quicker and easier. The swirl pot I bought was £72, plus fittings, pipe work, etc.
The tank was modified by, if I remember correctly, Pro Alloy in Haverhill for something like £100. I phoned them before with my requirements, booked a day, drove down with the tank and they modified it while I waited. The end result was much more professional.
I did exactly this back in ~2010, and assumed the same thing, so I reused the existing carb fuel pump to feed a swirl pot and then the HP pump. The result was frankly a mess, a real hornets nest of pipe work that I was not happy with. It survived for a year, before I removed it all the following year.
I had the tank modified to incorporate a swirl pot, and because it was an early Westfield tank, they also fitted a breather/vent to make refueling quicker and easier. The swirl pot I bought was £72, plus fittings, pipe work, etc.
The tank was modified by, if I remember correctly, Pro Alloy in Haverhill for something like £100. I phoned them before with my requirements, booked a day, drove down with the tank and they modified it while I waited. The end result was much more professional.
Cheers chaps,
I must admit I have had a look at the swirls pots and there is going to be a lot of plumbing involved! The things I'm most reserved about it trying to get the fuel tank out of my Fury, I've heard it's a real pain in the arse job to do hence trying to go down the "easy" route!
On another point, does anyone know of any throttle bodies that would fit under the bonnet? I've twin Webers at the moment and it looks like they just about fit with the bonnet down. My budget on this project is very limited to say the least, which I know does not sit hand in hand well with this sort of upgrade!
Thanks,
Kev
I must admit I have had a look at the swirls pots and there is going to be a lot of plumbing involved! The things I'm most reserved about it trying to get the fuel tank out of my Fury, I've heard it's a real pain in the arse job to do hence trying to go down the "easy" route!
On another point, does anyone know of any throttle bodies that would fit under the bonnet? I've twin Webers at the moment and it looks like they just about fit with the bonnet down. My budget on this project is very limited to say the least, which I know does not sit hand in hand well with this sort of upgrade!
Thanks,
Kev
Difficult to say for certain. But, if you can get Weber's in, the likely hood of Jenvey's not fitting is vanishingly small. They bolt to the same manifold, I believe they are the same length, the fuel rail is in a similar position to the bowl of a Weber, and you can even get an underslung throttle linkage. Granted, they are cheap, but you pay for the knowledge they will fit.
Anything else will be a suck and see exercise.
Anything else will be a suck and see exercise.
ChimaeraKev said:
Cheers chaps,
I must admit I have had a look at the swirls pots and there is going to be a lot of plumbing involved! The things I'm most reserved about it trying to get the fuel tank out of my Fury, I've heard it's a real pain in the arse job to do hence trying to go down the "easy" route!
On another point, does anyone know of any throttle bodies that would fit under the bonnet? I've twin Webers at the moment and it looks like they just about fit with the bonnet down. My budget on this project is very limited to say the least, which I know does not sit hand in hand well with this sort of upgrade!
Thanks,
Kev
I can confirm that it is indeed a total bI must admit I have had a look at the swirls pots and there is going to be a lot of plumbing involved! The things I'm most reserved about it trying to get the fuel tank out of my Fury, I've heard it's a real pain in the arse job to do hence trying to go down the "easy" route!
On another point, does anyone know of any throttle bodies that would fit under the bonnet? I've twin Webers at the moment and it looks like they just about fit with the bonnet down. My budget on this project is very limited to say the least, which I know does not sit hand in hand well with this sort of upgrade!
Thanks,
Kev
d of a job. I ended up cutting the rear fibreglass a bit so I could bend it enough to drop the tank out, then I covered it with a home-made aluminium diffuser-type thing.My Fury has a swirl-tank with a high pressure pump in the engine bay, whoever plumbed it in was evidently a complete moron as one of the rubber hoses was just pushed 3-threads deep onto a threaded fitting and had a jubilee clip over it. I redid it all with proper fittings etc..., quite a few pipes going back and forth but not too bad.
Mine has Jenvey throttle bodies on a Zetec, whether my bonnet is the same as yours I've no idea - mine is the style with the smaller bulge and the unfaired headlights.
Did this exact job in 2005 to our then Xflow powered Westfield. Fitted some GSXR600 ITBs into the stripped out/butchered remains of a pair of dead DHLA 40s so they bolted straight onto the same manifold and into the same space, put a Mk2 Golf GTi swirl pot/pump/filter assembly on the firewall by the drivers feet, ran a new larger fuel line in CuNiFer 10 alongside the original steel line for the feed, used the old feed line as the return and plumbed it into the filler neck of the tank. The original Facet rattle pump acts as the lift pump. You will want to put a restrictor in the return line too - 1mm hole or so. A MIG tip works well. This setup has worked perfectly, without a glitch, since it went in. Car now has a Zetec on the same ITBs & feel system. It's a stock 2l and made a gnats under 170bhp on the rollers, which is bang-on.
FWIW, the GSXR600 ITBs are, IMO, the perfect size for a Xflow of almost any spec. Many folk love to go big and opt for GSXR1000 bits but I honestly don't think it adds anything expect bragging rights. The stock K1 GSXR600 injectors are good for 220cc/min @ 3BAR gauge pressure.
Alternatively, you can always opt for a dead-head solution and put all the plumbing at the back and simply use the existing hard line to feed 3 BAR fuel to the front. I'd probably do that if I was doing it again. Fashions change and at the time, dead-heading seemed exotic!
Keep us posted.
FWIW, the GSXR600 ITBs are, IMO, the perfect size for a Xflow of almost any spec. Many folk love to go big and opt for GSXR1000 bits but I honestly don't think it adds anything expect bragging rights. The stock K1 GSXR600 injectors are good for 220cc/min @ 3BAR gauge pressure.
Alternatively, you can always opt for a dead-head solution and put all the plumbing at the back and simply use the existing hard line to feed 3 BAR fuel to the front. I'd probably do that if I was doing it again. Fashions change and at the time, dead-heading seemed exotic!
Keep us posted.
Edited by Chris-S on Wednesday 11th September 10:20
I converted the Beetle engine in my UVA from twin carbs to EFI using a swirl pot fed by the original fuel pump. The plumbing is not difficult if you plan it properly. The only thing that might give you a problem is the return fuel line from the swirl pot back to the fuel tank. I knew that the conversion was planned when I built the car so I plumbed the return line in during the build. I modified Beetle inlet manifolds to accept injectors and I mounted the high pressure fuel system on one module and the electronics on a second module.
Excellent info chaps thank you!
Looks like I may make a start on this then over the coming winter months. One other question
I have is would the mechanical fuel pump on my 1.6 Xflow be sufficient or would I need to replace that with an electric one?
I've had a browse on eBay and I'm surprised at how cheap those throttle bodies are! Looks like you can get some low mileage, with injectors and the TPS for about £100. Looks like the ECU will be the most expensive part!
Kev
Looks like I may make a start on this then over the coming winter months. One other question
I have is would the mechanical fuel pump on my 1.6 Xflow be sufficient or would I need to replace that with an electric one?
I've had a browse on eBay and I'm surprised at how cheap those throttle bodies are! Looks like you can get some low mileage, with injectors and the TPS for about £100. Looks like the ECU will be the most expensive part!
Kev
Low pressure pumps, typically designed for carburettors, are self regulating and designed to work all day long like that so there is no need for float valves etc. Use a small restriction in the return line will help eliminate cavitation of the HP pump by keeping pressure in the swirl pot and will also stop fuel going round and round the fuel system heating up all the time.
Steve
Steve
Time to get a shopping list put together then!
The only item I can see which may cause some difficulty is finding some sort of adaptor to connect the ITBs to my inlet manifold. I am presuming this won't be an off the shelf item. Would it be a good idea to get friendly with someone who is good with welding?
Kev
The only item I can see which may cause some difficulty is finding some sort of adaptor to connect the ITBs to my inlet manifold. I am presuming this won't be an off the shelf item. Would it be a good idea to get friendly with someone who is good with welding?
Kev
gtmdriver said:
I' haven't come across that idea before, consequently I didn't do it in my system, and it worked fine with no return flow restrictor.
As the LP pump is self regulating there would, in theory, be no need for a return to the tank...but there is the chance that air or vapour can build up in the top of the swirl pot so a return will clear that but as it is air/vapour it only needs a tiny hole to escape through.HP pumps pump nicely but don't like the sucking bit so increasing the pressure at the pump inlet will help eliminate cavitation in the inlet.
Another good practice is mounting the HP pump vertically directly below the swirl with as short a hose as is practical.
The likelihood of cavitation issues increases with the size/power on the HP pump
Steve
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