Fuel injection: Pre instal advice appreciated .

[Peter +2]

Hello all,

The engine and gearbox of my Plus two is going to be removed in a months time. I would like to carry out some fuel injection prep work without disturbing the current setup. At this point I just plan to install the high-pressure fuel line within the chassis and leave for later, when I’m able to continue with the project.

I am considering using , “Classic injection “8 mm fuel line see https://www.classicfuelinjection.co.uk/fuelhose-8mmx10m for the Fuel supply line.

My questions are:

- Would it be okay to use the current fuel supply line as a return line to the tank when I get to the next stage?

- I hope everything else can be addressed with the engine and gearbox in situ at a later date, but Is there anything else I should consider doing whilst the engine and gearbox are out?

As I mentioned above, once the engine and gearbox are back in, I intend to be using the car, as normal while I plan for the next stage.

I would be very grateful for any comments on the questions above thanks in advance

Peter.

[HCA]

My advice (that I wish I followed on my EFI five years ago..) forget the return line and opt for a single line feed. And an in-tank pump and swirl pot ( that I did implement!) Much neater and cleaner. Do these now and the rest is easy bolt on.

[h20hamelan]

Not gospel, but also not the standard street meat found around the globe from dogs and cats in 3rd world places.

https://www.msextra.com/forums/viewtopic.php?t=65757

Hal, why do you figure a return line is not important. Every car has one since the first fuel injection?

[HCA]

Technology stands still for no man.

Google returnless EFI

[Peter +2]

Many thanks all for the quick replies, I had read Peter's post advocating return-less installs see:

viewtopic.php?f=31&t=39853

... and definitely open minded to either approach.

Reverting back to my questions, if deciding on a "Return" system, is there any technical reason as to why I should not use the current fuel pipe for the return?


I would love to here an update from Peter and I will certainly google Returnless EFI. and research further

Look forward to views.

Cheers

Peter

[HCA]

You can use the existing line, but the return should enter the tank from above to be effective.
Have a tank made with top feed, internal swirl pot and pump/ filter/ regulator.

[Peter +2]

Thanks that’s good to know I just need to install one high pressure fuel line and options are left open as to which type of system I go for.

Cheers

Peter

[ill_will]

Hi Peter,

I'm going through this at the moment.

Last time I looked, Jenvey have some advice on their website on minimum pipe IDs for both 'returned" and returnless systems, for both the supply and return lines.

I don't know off the top of my head the size of the low pressure carb supply line but it could be a bit on the small side. I think (and I don't have my notes in front of me) that maybe -06 line is Jenveys recommendation? But if smaller it may be fine. (Edit: lots of conflicting info on the ID, some references to 8.7ish mm and others to 3/8", tbc.)

Personally I am opting to use nylon lines (as used in most OEM fuel injection systems.) They can be fitted to barb style connectors (plenty of YouTube videos showing how to) as they are compact and durable. The downside is the bend radii is bigger than rubber hose. I will also use a returned system, but each to their own on that.

As HCA mentioned, integrating the pump and other gubbins in the tank gives a cleaner install with fewer connections to leak, and likely quieter too. Also cools the pump. I posted a pic of the adapter I made for using an Elise pump in this thread viewtopic.php?f=39&t=49709&start=135 on page 9, which has a built in reservoir and swirl pot.

Cheers

Will

[berni29]

Hi

I am just doing the EFI for my Zetec conversion. I am using 3/8 Kunifer (I think thats the size) for the fuel line and return and a swirl pot with the fuel pump in that. (see link below). It sits in the boot floor just under the tank and is gravity fed.

https://www.ebay.co.uk/itm/204356015333 ... AZA&edge=0

All the best

Berni

[HCA]

I’d urge you to re-think the Kunifer bit if you plan to use pump fuel. Copper does not like bio fuels.

[elanman999]

I hope kunifer is not an issue as I've been using it for seven years now. But then again some alloys are also not good with E10 fuel when it gets water in it.

Do not use the rubber-ish pipe through the cockpit, most of it is permeable so will stink the car out.

The return or no-return. There are issues either way. With a return it is said the the fuel can get too warm, without a return IF you get any vapour in the feed line it takes some time to come out. I have only had one problem and that was in Italy after leaving the car in the sun (40c) for a couple of hours it developed vapour in the fuel feed but the engine still started and because I have a return it fed through very quickly, 30 secs.

I run a LP and HP out of tank pumps with a swirl pot.
The system was installed over ten years ago now and things have moved on. IF I did it again I might well think about an in tank pump, but I would need to have a new tank made for a good installation.
Edit:- most of the pipe work Is PTFE braided with -6 AN fittings there is a small amount of kunifer.
YMMV.
Cheers
John.

[gav]

I use Goodridge/Krontek flow and returns. It is light weight malleable ally that can be gently bent into position. The connections aren't cheap but careful planning meant that I needed 4 connections (flow and return) and the rest are traditional Goodridge fittings.
I use 10mm bore flow and return because on a two pipe system, the return is still pressurised (albeit controlled by the pressure regulator ahead of the fuel rail)
Because they are solid fuel lines, they can be run through the cabin if desired but if you do this, I strongly recommend that there are no joints at all in the cabin area.
Personally I wouldn't reuse the existing line - but I've always been a little extravagant
Hope this helps.
Gavin

[Peter +2]

First of all, thank you for everybody’s input. I will certainly do some more digging about which type of pipe to use as well as the correct fittings. I can foresee cutting pipes to final length and connecting the fittings in the car will be a little more challenging than first thought due to access and tools required.

I’ve been doing more research and an “in tank” systems seem to be gaining momentum so will continue to research that. Thanks also for the suggestion of the Jenvey site.

Many thanks, Peter.

[elanman999]

One add on I would like to put to my previous post is that the minimum bend radius of PTFE braided pipe is not small and so tight bends will require fittings.
Cheers
John.

[Donels]

Interesting comment on E10 compatibility with copper and Kunifer. I have used Kunifer for the fuel line and could find no hard evidence of it being unsuitable for E10. Some well recognised suppliers also sell copper pipe for fuel lines with no comments about E10 unsuitability. Has anyone seen any evidence or is it just urban myth?