Changing From Carb To Injection

[Les Welsher]

I am changing my 2L DOHC 8V carb engine to an RS 2000 DOHC 16V injection engine to get a few extra horses.

To save me some time looking around for bits for the fuel system I thought I would ask on here for some advice as to components to use.

Parts I think I need are a fuel pump (extra pressure), fuel filter, swirl pot.

I was thinking of using my original fuel pump to get the fuel to the swirl pot then using another pump to get the fuel to the fuel rail, excess fuel from the pressure regulator back to the swirl pot to keep it full and an overflow from the swirl pot back to tank.

 

any suggestions welcome.

 

Les

[Longboarder]

That sounds OK Les. Low pressure lifter pump to keep the swirl pot full. Doesn't need to pump lots of fuel. Pre filter so the fuel in the swirl pot is fairly clean. If it feeds into the swirl pot about half way up it will have the effect of keeping the fuel in the pot cool as warm returning fuel from the rail should go in close to the top and a proportion will be returned to the tank by the overflow, along with any air or vapour. High pressure fuel injection pump sucks from just above the base of the pot and pushes the fuel at 3bar+ through a high pressure micro filter to the rail. (Change the LP prefilter more often than you changed the last one!) If you want the swirlpot under the bonnet it will need to be insulated against heat. Use big pipes for the HP feed (15mm is good) and HP circuit (8mm or better 10mm)

 

Nigel

[Guest salty_monk]

Les I read on Locost that the Golf GTI fuel pump & "accumulator" (read filter & Swirl pot) is a good cheap compact way of achieving everything for about 20-30 notes secondhand...

 

They say it's good up to about 180BHP. No personal experience of them.

 

Dan

[Guest chris brown]

What a fancy picture Nigel you can even do them standing on your head Very clever

 

Les, the swirl pot needs to be fairly big if you are going to return the "hot" petrol into it as I have heard of air lock (fuel vapor) problems due to the fuel getting to hot in the pot. Remember that a large proportion of the fuel pumped forward returns, especially at low loading like in heavy traffic where heat is already a problem.

[Les Welsher]

Nigel,

as ever, a nice diagram of the layout

Any idea of make of pump and filter to use

 

Dan,

do you know if it was an in tank pump or seperate from the tank as there seem to be a few types on ebay

 

Thanks

Les

 

Chris,

the swirl pot is about 1 litre and would be sited next to the fuel tank

 

I was looking at THIS

 

Les

[Longboarder]

I used the basic electronic solid state facet (the one with the irritating ticking noise) with its filter for the LP side and a Bosch HP pump from an scrap Astra along with a new Astra HP filter.

 

Nigel

[Guest chris brown]

I was looking at THIS

 

Les

That is a nice looking tank Les and should do the job well and is big enough not to get too hot I think the temptation is because the return is being fed back into the swirl pot people tend to make them rather small

As for a low pressure pump I would use one of those little square blocks with the annoying tick. Don’t worry you don’t hear it when the engine is running I had one in my last kit and it was alongside the seat and I never heard it when on the move. Virtually any high pressure pump will do the job as most if not all will supply 70+lb pressure which is then dropped to whatever the ECU or in the case of the pinto the plenum vacuum decides is required.

[steve in stockport]

Les

i am running injection with only a 250ml swirl pot and had to re-jig the plumbing after i started to get vapour locking at tick over in hot weather - most embarrassing when you go to set off from the lights and the engine coughs farts and dies on you till you gun it stupid to pump the fuel round and cool it down.

have since fed the return from the fuel rail back to the bottom of the fuel tank into the nice cool fuel and had no probs since

 

Steve

[Guest turbo]

les another option is to fit the sierra dohc sender unit to your tank,this has the hp pump fitted to it.

the benefit of this is its a tidy install.

disadvantage if you have the sierra tank already.

disadvantage with the r.hood tank as you will have to fit a baffle around the pump.

[Les Welsher]

Jamie,

I'm using the sierra DOHC sender and pump at the moment (LP one for carb engine) I was thinking of using the one from an injection engine to make life easy as you suggest. I have a kind of swirl pot thing I made around my pick up at the moment, not a problem with normal driving even with an emptyish tank, but it was useless on a trackday at Llandow where I had to have at least 1/2 a tank to stop it spluttering on long right hand bends.

 

Cheers

 

Les

[Graham B]

Les

 

I have a high pressure external pump and large filter mounted on the back of the tank. No swirl pot at all, and my 8 valve DOHC Efi has no problems. I have not run the tank below 1/4 full, so I suppose the tank itself is the pot. I dont mollycoddle it around bends either so there is plenty of splosh..

The pickup pipes were home made into the RH fuel guage sender. -- pipes straight down, original T sghape gauze filter at tank floor level, return about 1" up.

 

 

Graham B

[Guest salty_monk]

Sorry Les, should have been more specific. It's the Mk2 8v GTI pump.

 

You can see one here http://cgi.ebay.co.uk/VW-MK2-GOLF-GTI-K-JE...1QQcmdZViewItem

 

The box is the swirl pot, big cylinder the filter & small one the pump.

 

Dan

[Les Welsher]

Got a vw gti fuel pump as Dan suggested

On inspection there a quite a few inlet/outlets

Does anyone know which pipes go where ?

The one from the pump goes to the fuel filter then on to the fuel rail but there is one on the bottom and two on the top.

The ones on the top has arrows, right hand in. left hand out.

 

 

Les

[Guest salty_monk]

Les,

 

My friend is a VW nut, he's on all the Forums & has owned a couple of these. I can get him to ask the questions for you if you get really stuck.

 

I think you can work it out from here http://www.engr.uconn.edu/~lianjian/jetta/...ms/1081-04b.pdf around page 10.

 

Here's the full manual http://www.engr.uconn.edu/~lianjian/jetta/manual.html it's all divided into sections.

 

Dan

[steve in stockport]

Les

 

i had to double check because the one in this thread is a bit muckier than yours, but its all in there.

 

according to the reply one of the lines is from a low pressure pump which the golfs have in the tank

 

Steve