fuel return line...how?

[Gerrelt]

Once again I am resurrecting this old thread... But I wanted to report my results with the above modelled fuel line system.

It worked fine!

With a sidenote...

I do hear the fuel pump whine when I am standing still (like for a traffic light).
Now, these pumps are prone to making a whining/buzzing sound, so I may just be all normal.

But I am thinking about replacing my home made "merge pipe" (the 22 mm pipe with the inlet, return and outlet on it) , with this factory VW "cachetank":



It's meant for some VW Golf convertibles that were equiped with a fuel injection system.

See:


It's actually a small swirl pot. In the Golf a small in-tank pump delivers fuel into it. One hose attached to
it will be the return fuel line that comes from the engine. The fuel hose on top will provide a fuel return
hose to the tank, for the small fuel pump. And there is this larger outlet that goes to the main fuel
injection pump.

I think this is an ideal and cheap alternative for a swirl tank. They sell for about 20 euros (listed
wrongly as "fuel filter", btw). The VW part number is: 533201511A .

Once I got my other projects done, I am going to use one of these for my beetle.
This is how I would connect it:



The great thing is, that this thing offers a way to convert your beetle/bus to fuel injection without
having to modify the fuel tank!

And you don't have to worry about running out of fuel in a corner.
The only drawback I can think of is the fuel heating up, but as my fuel lines run under the car all the way
to the back and back to the front again, I think the fuel will get enough cooling. It never was an issue with my
current setup.

Apparently, the black hose is 6 mm (would be perfect for a VW beetle tank outlet), the blue hoses are 8 mm,
and the fuel pump outlet is 10.22 mm.

I found this thing in this german thread: LINK

So, anybody ever tried to use this thing?

[MarioVelotta]

That is Saaaweet!! I may have to get one and try it out in my FI kits. That is great that you wouldn't even need to mod the fuel tank!

So no I haven't tried one but I'm going to

[Chris V]

I've got a brand new one right here in front of me...As you see there on the list they were used on CIS VW fox's too (my donor parts for my CIS stuff came from one) - (3) 8mm inlets and (1) 10mm

[Gerrelt]

I see that "CIS" in the Golf/Rabbit forums too.

What does it stand for, CIS?

edit: found it in another thread.

-Constant injection system(CIS), a Bosch developed mechanical injection system that was popular on many european cars from the early 1970s to the early 1990s. A central fuel distributor controls the flow of fuel to the each injector by a swing arm attached to a piston in the middle of the fuel distributor drawn up and down by the air pulled into the engine.

[raggdout63]

I ordered through AutohausAZ for $23 each. If you spend over $50 its free shipping. Nice and easy transaction took only a couple days to get. Shipped out of Phoenix. Thanks for posting up that part # Gerrelt.

[Wentzel]

Hi, I know this is a very old topic but would like to ask some advice from the guys with more expierience. I installed a Y piece and filter for the accumilator but now my fuel pressure is up by about 7-8 psi and I can hear the pump taking strain. Does this mean I need a bigger filter / accumilator? Or where should I start looking? What volume should I look for in thd filter?

Thanks

[raygreenwood]

What filter did you use and how is it plumbed? Ray

[Wentzel]

Hi Ray, I installed the Y with the tank feed and return on the top legs and the bottom leg to the filter and then to the pump. I tried to get the filter mentioned on the thread but it seems the part numbers are different or non existent on my side of the world. VW also didnt have the models mentioned for the filter to use locally. The filter I used the biggest low pressure filter they had and I would estimate it around 2" diameter by 2" long.

[Piledriver]

I'm surprised they didn't sell Mk2 Golfs/Jettas where you are...
The Cabriolet (Mk1) takes the same part.

Did you Google for the part#?

[Wentzel]

Thanks no I didn't get around to google it yet. Are we talking about the filter or the CIS fuel return? They did sell the Mk2 Golfs/Jettas and I will look into that.

[raygreenwood]

Yes...that filter is small. The filter they used for Mk-1 cabrio that Piledriver noted....is a large low pressure filter. It should be similar for any digifant II engined car. Ray

[Wentzel]

Thanks Ray and Piledriver, I couldn't find anything on the part number mentioned but found the large filter used on the Jetta etc from different manufacturer.

Will a small accumulator cause the pressure to go up by "force feeding" the pump? I was just trying to understand the logic behind it Anyways I will install the new large filter and see what it does now.

[raygreenwood]

The accumulator allows the pump some volume to feed from. Many fuel pumps do not "suck" well. A great many pumps are fed by a moderate volume/very low pressure feeder pump. Others are put at the lowest point below the tank so that gravity wil force feed at a very low pressure. It keeps the pump from cavitating.
The problem with jsut gravity is feed is that on fuel tanks that do not have surge rings built in for fuel injection, teh naturalsloshing f rom driving, having a half tank ro less or from cornering can cause interuptions in gravity feed. The accumulator helps prevent this. Ray

[Wentzel]

Ok I see it is basically used as a 'surge tank' it I can call it that.

Thanks for the help. I am still learning a lot and appreciate the advice.

[Tom Notch]

I have found something that is quite easy to install, in some/many situations, that greatly reduces any problem caused by fuel slosh. I added fuel cell foam to an old oval window tank. Admitted, the 100mm gas cap helped immensely, but it's a very viable option to a "slosh ring". I ordered the foam from Summit and it was a convenient size at 3"x3"x 16". It could be easily hacked to smaller chunks. It completely eliminated even any fuel slosh out of the gas cap on my 11 sec. split window.

(Ray, I did some minor clean up to what I quoted)

The problem with just gravity feed is that on fuel tanks that do not have built-in rings for fuel injection, the natural sloshing from driving, having a half tank or less, and/or from cornering, can cause interuptions in gravity feed. The accumulator helps prevent this.
Ray