Fuel Pumps

**jimnielsen** · 02-04-09, 10:35

I have been considering getting a higher performance fuel pump for the Q4 and a swirl pot (surge tank). Has anybody already tried this using the existing 'in tank' pump as a 'lift pump'?

cheers, jim~

**arjunior45** · 02-04-09, 10:58

not me.
I only replaced the oem one with the walbro 255lt. So far, a year later, had no problems at all. The oem one, lasted less than a year from new.

Nick

**jimnielsen** · 02-04-09, 11:16

Are you using it inside the tank, or external?

**arjunior45** · 02-04-09, 11:32

inside the tank.

Nick

**jimnielsen** · 10-05-09, 01:19

Nick - hi can you please tell me the model number of this pump? would a Bosch 040 fit just as well?

cheers, jim.

**axaQ42** · 10-05-09, 07:38

Jimnie order this one:

http://www.flat4online.co.uk/catalog...elta-integrale

**jimnielsen** · 10-05-09, 07:51

Thanks for the advice, I appreciate it. but I have decided to go for the external walbro pump and a surge take as well. But I can get that at the site you have pointed out.

cheers, jim.

**arjunior45** · 10-05-09, 10:21

it's the Walbro 255 liter per hour Hi Pressure In Tank fuel pump, I believe 'GSS 34x' {x = 1 or 2}. It should be the one on the above link, used on Mitsubishi Evo as well.
I'll check it in the next few days.
Nick

**arjunior45** · 11-05-09, 15:34

It's the GSS342.

**jimnielsen** · 12-05-09, 06:44

I decided to go with the Siemens Deka IV 107961 (630cc) injectors and the Walbro GSL392 inline (external) pump. Pics attached. Also is a picture comparing the Weber IW058 injector with the Siemens one.

Tomorrow I'll see if these injectors actually fit the standard manifold and rail!

jimn~

**jimnielsen** · 14-05-09, 01:49

Well the siemens Deka IV injectors do fit just fine into the standard manifold...

cheers, jimn~

**jimnielsen** · 16-05-09, 07:14

I have now obtained a swirl pot that fits nicely underneath the Q4. Its located in the spot where the fuel filter normally goes. I am using the fuel filters mounting to hold the new Walbro pump and will move the filter elsewhere.....

**arjunior45** · 16-05-09, 09:35

use the filter before the pump, I think it will be better.

**AlfaJack** · 16-05-09, 09:36

What is it that swirl pots actually do and why 4 connections?

**jimnielsen** · 16-05-09, 12:50

The 'typical' way of setting these things up is:

http://www.skylinesaustralia.com/forums/post-a150001-

The purpose of the surge tank (swirl pot) is to make it more difficult for G forces from cornering, braking and acceleration preventing the fuel from getting pumped by the fuel pump. They are really only useful on racecars. You can see what the four connections are used for in the pic in the link above, but basically its..

1. lower - fuel out to main pump (and on the the injectors)
2. upper 1. - fuel from the intank (original) pump to the surge tank.
3. upper 2. - fuel from the return line of the injectors to the surge tank.
4. upper 3. - overflow from the surge tank back to the main tank.

the main tank also needs a vent to the outside with a one way valve.

thanks about it.

cheers, ~

**wrinx** · 17-05-09, 10:00

I've had an email from a chap who needs a Walbro pump and wants to know if he should go for the gs341 or gs342

Quick search reveals they both flow 255lph, so what's the difference?

The gs341 looks man enough...

wrinx

**arjunior45** · 17-05-09, 10:42

do not know the difference between gss341 and gss342, but it's the gss342 mounted in my car.

**jimnielsen** · 17-05-09, 11:47

Both the GSS 341 and GSS 342 are 'in tank' pumps - there is a difference between the positioning of the inlet and outlets. As ARJunior already has a GSS342 in his car it must be the correct version if you are going to replace the existing 'in-tank' pump.

**wrinx** · 17-05-09, 13:17

Thanks guys, message has been passed on

wrinx

**juamin** · 18-05-09, 13:19

I have a walbro gs-342 installed and it works fine, fits Ok in the original pump place.

**wrinx** · 18-05-09, 16:43

Another vote for the 342....conclusive then

wrinx

**jimnielsen** · 21-05-09, 02:23

Well thats about it.....I am using the original fuel pump as a lift pump and the Walbro GSL392 as the main pump to the injectors. The main fuel line is 3/8" the return line is 5/16". There are two filters - a main one after the lift pump and a secondary one on the line to the injectors. Just a bit of wiring to come

jimn~

**arjunior45** · 21-05-09, 05:43

Originally Posted by jimnielsen

Well thats about it.....I am using the original fuel pump as a lift pump and the Walbro GSL392 as the main pump to the injectors. The main fuel line is 3/8" the return line is 5/16". There are two filters - a main one after the lift pump and a secondary one on the line to the injectors. Just a bit of wiring to come

jimn~

good job.
Do not like that much this spot!
You could make smoother the 'angle' of the metal part that 'touch' the fuel line or make a hole and pass through?

**jimnielsen** · 21-05-09, 07:17

Yes, I know I can't leave it like that at that particular point. I will probably use a 'sleeve' of some description - but thanks for reminding me! Maybe there is enough room for the 'hole' where you have suggested it. I will have a look tomorrow.

Wiring: I have not made any changes to the wiring of the original pump. For the 2nd pump I will simply wire it direct to the battery with a switch and fuse. Then when Its working properly I'd like to tap into the existing fuel pump wiring and use its 12v feed to power a relay to switch on the 2nd pump so that both will in effect be controlled via the ECU (so if the engine stops running the both pumps will be switched off.)

jimn~

**AlfaJack** · 21-05-09, 08:43

Originally Posted by jimnielsen

The 'typical' way of setting these things up is:

http://www.skylinesaustralia.com/forums/post-a150001-

The purpose of the surge tank (swirl pot) is to make it more difficult for G forces from cornering, braking and acceleration preventing the fuel from getting pumped by the fuel pump. They are really only useful on racecars. You can see what the four connections are used for in the pic in the link above, but basically its..

1. lower - fuel out to main pump (and on the the injectors)
2. upper 1. - fuel from the intank (original) pump to the surge tank.
3. upper 2. - fuel from the return line of the injectors to the surge tank.
4. upper 3. - overflow from the surge tank back to the main tank.

the main tank also needs a vent to the outside with a one way valve.

thanks about it.

cheers, ~

Cheers Jim, appreciated