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Fuel injecting with a non injection fuel tank?
snapper - 18/7/19 at 05:31 PM

I have a 7 replica I built, when I built it I ran 2 hard lines to the tank.
So can I run an injection pump from the 1 litre swirl pot to the injection rail or is this to small?

I’m also considering changing the Crossflow in the Fury I bought a while back with a Duratec and the same issue applies although I think the Fury will get more money thrown at it in the long run.

big_wasa - 18/7/19 at 06:08 PM

My understanding is the swirl pot still needs to return to the tank to take the air out but it only needs to be tiny.
I was looking at drilling and tapping the fuel sender as I don't want to change my tank this year.

I think motor sport regs say a min of 2L. 1L should be fine unless your running serious hp or serious track use.

bi22le - 18/7/19 at 10:09 PM

I run FI quad throttle bodies with no swirl pot. My tank has a little sump at the bottom. I have not had any issues with fuelling

snapper - 19/7/19 at 10:58 AM

Thanks, my thoughts now are to use the silver top to fill the swirl pot as that has more flow than the cube and use a bike injection fuel pump for the bike throttle bodies.

scudderfish - 19/7/19 at 12:44 PM

I did exactly this when I changed my Fury from carbs to efi. The old pump feeds a 1 litre swirl pot in the engine bay, which then feeds the HP pump to the filters. I ran a return from the swirl pot back to my MG Midget tank and plumbed it into the top of the sender so that if I got it wrong, leaks would be unlikely and easier to source a replacement. As the LP pump normally pumps against a dead end at the carbs, I put a restriction in the return pipe (a welding tip) to give it something to work against and not spend it's shortened life at full chat.

ianhurley20 - 19/7/19 at 03:25 PM

If you have to make a new feed from the fuel tank at all these are very useful

https://www.parts4aircraft.com/fuel-tank-fitting-c2x9383165

snapper - 22/7/19 at 05:37 AM

Scudderfish please explain restriction in return pipe a little more, my swirl pot has 4 ports in from LP, out to HP, return to tank and air vent with tip over cutoff

“As the LP pump normally pumps against a dead end at the carbs, I put a restriction in the return pipe (a welding tip) to give it something to work against and not spend it's shortened life at full chat.”

Ianhurley20 please give me some info on fitting the connector in your link

kingster996 - 22/7/19 at 06:26 AM

Here’s a diagram I drew to explain a basic swirl pot setup - hope it helps.



The restriction mentioned goes in between the Pot overflow and tank to give the pump something to pump against so that it’s not running at full chat constantly.

In reality, the return on mine is into the bottom of the tank btw

[Edited on 22/7/19 by kingster996]

[Edited on 22/7/19 by kingster996]

ianhurley20 - 22/7/19 at 10:29 AM

quote:
Originally posted by snapper
Scudderfish please explain restriction in return pipe a little more, my swirl pot has 4 ports in from LP, out to HP, return to tank and air vent with tip over cutoff

Ianhurley20 please give me some info on fitting the connector in your link


I used to be involved in the aircraft industry about 40 years ago and these were used to make feeds from fuel tanks. They were very easy to fit and only required access from one side. The instructions an the link - Drill a 1/2" hole in the tank. Push in the rubber bush and insert the metal fitting for a leak free seal. 1/4" barbed pipe fitting. Ideal for plastic and metal tanks. - are exactly what you need to do. I wouldn't want to use this fitting on a high pressure line but as a feed or a vent would be fine. Used one on a Tiger fuel tank recently but then revised it and made a small boxed sump as a pick up area where the baffle is in the middle of the tank and welded in a PCL airline fitting as an outlet.

40inches - 22/7/19 at 12:00 PM

quote:
Originally posted by ianhurley20
quote:
Originally posted by snapper
Scudderfish please explain restriction in return pipe a little more, my swirl pot has 4 ports in from LP, out to HP, return to tank and air vent with tip over cutoff

Ianhurley20 please give me some info on fitting the connector in your link


I used to be involved in the aircraft industry about 40 years ago and these were used to make feeds from fuel tanks. They were very easy to fit and only required access from one side. The instructions an the link - Drill a 1/2" hole in the tank. Push in the rubber bush and insert the metal fitting for a leak free seal. 1/4" barbed pipe fitting. Ideal for plastic and metal tanks. - are exactly what you need to do. I wouldn't want to use this fitting on a high pressure line but as a feed or a vent would be fine. Used one on a Tiger fuel tank recently but then revised it and made a small boxed sump as a pick up area where the baffle is in the middle of the tank and welded in a PCL airline fitting as an outlet.


I used an Aircraft fitting as above, used the vent on the tank for the return from the pot, and used the aircraft fitting for the vent.
I did exactly as scudderfish, fitted a 0.8mm mig tip in the return hose to create some back pressure in the pot, otherwise the lift pump was running at full speed all the time, the restriction slows the lift pump down

scudderfish - 22/7/19 at 01:01 PM

quote:
Originally posted by kingster996
Here’s a diagram I drew to explain a basic swirl pot setup - hope it helps.



The restriction mentioned goes in between the Pot overflow and tank to give the pump something to pump against so that it’s not running at full chat constantly.

In reality, the return on mine is into the bottom of the tank btw

[Edited on 22/7/19 by kingster996]

[Edited on 22/7/19 by kingster996]


This is exactly my set up. I mentally think of it as there being two loops, one low one high pressure that overlap at the swirl tank.

kingster996 - 22/7/19 at 02:30 PM

Here's a full diagram of my setup (uses dead-head fuel rail)