Lift pump upgrade

[Poodle]

I'm thinking an upgrade here will lessen the strain on the HP pump (been flamed for this idea before, but i've yet to see an argument against it based on actual scientific principles), which has got to be a bonus. At the very least it'll allow for higher flow before the system is at it's limit, although if i understand how the pump works it should also bring the rpm threshold for max pressure down a bit and make it possible to up the pressure across the whole range.

So yeah, has anyone looked into any upgrade possibilities at all? It's looking more and more likely that i should be replacing mine in the near future, and what's the point of paying out for something that's no bigger/faster/stronger than the original, right?

[Midnightclub]

Are the 2.2 16v HDi or newer 2.0 16v HDi lift pumps any different mate? or perhaps one from the 330/335d's?

[Dum-Dum]

Sytec do upgraded pumps that fit to lift pumps I'm pretty sure they list one for the GTi6 and its the same pump (probably)

I assume its the same pump as I'm running a petrol lift pump with no issues and they both feed at about the same pressure. If anything id expect the petrol to pump better thinking about it.

---

Merlin Motorsport advertise one but it doesn't say if its an upgrade, whats the GPH of the OEM pump.

This is the bit inside the lift pump that needs upgrading





From this guide on the 6 forum
http://www.306gti6.com/forum/showthread.php?id=44703

[Jonny81191]

Yeah, need to look into this, mine cut out again this morning

[Dum-Dum]

Just a thought has anyone put a gauge on the line to the HP pump to see if the pressure is dropping off. Supposed to feed at 3.5Bar IIRC

Also are you sure its the pump not coping. I'm sure Darren made reference to the 306 fuel lines being tiny. Wouldn't cost too much to have a 10mm feed an 12mm return made up. Also 12mm is a nice diameter to then get connectors made to a Mocal cooler o you could relocate the fuel cooler to the front of the car.

[Ruan]

The lift pump is quite high pressure for it's size, but not very high flow, you can pick up proper diesel lift pumps from the US with proper filter systems which enable you to sack off the shitty stock filter...

Repeatedly causing the HP pump to starve of fuel will wreck it, it uses the fuel for it's own lubrication.

Also the HDi stock fuel cooler looks seriously restrictive to me!!!

[darrenjlobb]

Ive got no idea if the stock lift pump is becoming a restriction on the hdi's but given I used a HDI lift pump once, it wouldnt suprise me if it is, as they flow very little really, a HDI needs alot less total flow than VE pumped engine, but still, could be an issue, the drag on the fuel lines is also very high. As Ruan said, my plan of action has always been to run 12mm lines front to rear, including into the tank, and then a big pump / spin on filter assay under the boot floor, job done!

[Poodle]

Thats what I was hoping Danny, but i'd rather have something concrete to go on

My pump is on 120k and was starved repeatedly back when I didn't know better lol. Everything else in my fuel system is either brand new, genuine parts, or recently refurbished, yet p0230 made another appearance recently. Either my lift pump is dying or i'm missing something fundamental lol.

Another possibility i'm considering is pump starvation thanks to a combination of low fuel and high g's, think I want to try putting a baffle around the pump before giving up on it completely.

Maybe an upgrade from across the pond is necessary then, along with larger lines to match...

I've found some information on lift pumps, but nothing listing flow specs, only pressure. Depending on which information you rely on, the standard item provids 3-3.2bar of pressure. I haven't yet found info on any oem diesel pumps that provide more than 4bar, that said I haven't found any useful information that is less than ten years out of date either, so there may still be alternatives to find...

[Dum-Dum]

Walbrough in tank pump here is £70 and flows 255lph. Says it would do 500bhp on a normal car http://www.ebay.co.uk/itm/WALBRO-255-FUE...2567798862



Actually f*ck me this looks awesome, cant work out what the catch is. 300lph at 94psi (over 6bar) working pressure, M10 outlet and only £25 http://www.ebay.co.uk/itm/12V-UNIVERSAL-...3a81c8faf3

[Poodle]

That is a hell of a lot cheaper than I expected it to be, petrol pump be alright with diesel will it?

[Dum-Dum]

Course it will, most of them say they are fine for petrol diesel alcohol etc

In my head £25 is too cheap, something HAS to be wrong (not right) with it. Although at that price I suppose its cheap enough to find out. I might have to take my spare lift pump apart and see what I can play with.


IMO for me fitting big fuel lines and a decent fuel cooler is the more exciting part of this whole proposition.

If the £25 pump is good then £150 should sort you the whole set up with a mocal cooler.

[Jonny81191]

IMO, more gauges are needed before this sort of thing is done. Is it a restriction? Find out, THEN upgrade as necessary. I certainly don;t have the money to just upgrade everything (although gauges are hardly cheap )

[Dum-Dum]

IMO, more gauges are needed before this sort of thing is done. Is it a restriction? Find out, THEN upgrade as necessary. I certainly don;t have the money to just upgrade everything (although gauges are hardly cheap )

Your not wrong there, a stack fuel pressure gauge is £147 on ebay. I suppose youd want to test fuel temp too to accurately size a cooler, that would need another gauge.

[Jonny81191]

Yeah, but if we're talking about big power, the gauges are a must..

[Dum-Dum]

Just on the subject of fuel density vs temperature it is very hard to find any information specifically relating to petrol (far less diesel) but there is some smart arse pilots talking alot about it and as jet fuel is only a few fractions above diesel it could be relevant

http://www.pprune.org/tech-log/348739-te...nsity.html

Probably one for only people like Poodle to read cos they start going into coefficients of thermal expansion at the relative specific gravity or some shit like that so its a little bit of a head f*ck after a few beers.

[Ruan]

Remember P0230 will be shown if request pressure is lower than actual - this could be to do with the high pressure side, it's just that it so commonly comes up when caused by lift pump issues...

But it's SO common to happen when driving normally...

I need to take a GOOD look at how the HDi low pressure side is supplied to see any potential issues...

IMO you need to be looking at much bigger pumps, you'd be surprised at how much fuel the HP pumps move, remember they move near enough their full quantity 24/7 - since the regulator is placed AFTER the pump... They use the fuel as their lubrication - that's the main difference, and notice they even have a fuel COOLER circuit, they bypass that much fuel!

Look into the Airdog FRRPs, they're 100gph pumps and adjustable pressure... If you're wanting decent power levels, I wouldn't be looking at much else.

Though I also think people should be getting Rail Pressure gauges, also inlet pressure gauges, even if you start to just log them on a laptop or something for diagnostic purposes... That would be enough to see whether you're getting problems...

[Dum-Dum]

Ruan those Airdog pumps look like serious pieces of kit. 100gph is massive fuel but I'd start to worry about battery drain/alternator draw at that level. I'm guessing you'd certainly need to run bigger wires to the pump and they look like they are external so you still need somewhere to mount it and do they lift the fuel themselves or do you still need a separate lift pump.


Id never thought of it but do they make High pressure rail gauges? Im guessing a 2000bar gauge aint cheap. That said i dont see why we cant read it straight out the ECU. wonder if the SG can read it.

[Ruan]

What's the point in reading from the ECU... K-Line update is too slow to notice quick variations and if something is a-miss with the ECU, you're in the same situation as the ECU - reading false information!

They won't draw that much power tbh, they're not high pressure pumps, just high flow... You're not going to draw more than a few amps, I mean, they're STOCK replacement pumps, you don't want to see the BIG LP pumps they do!!! They will of course lift the fuel, then you can basically use/modify a DT style lifter with the massive hoover snout thingy at the bottom with the gauze removed for a good amount of fuel out the tank... Or go about making something else... Get some big bore hose or something and attach a weight to the bottom of it or something, it'll pick up the fuel properly then... I'd also run a twin pipe setup, so that if one starts air'ing up whilst giving it some titty round a roundabout, it's not going to starve.

Or you can possibly modify a - or maybe a 5 pot rail which I've spoken about a thousand times feed another FRPS and just get something that reads 0-5v... We have the calibration data for them, so easy to linerize...

[Dum-Dum]

^^^ I suppose my issue is I don't want to be messing about with the HP side of things. Could tap a fitting for a HP hose and then run a hydraulic pressure gauge inside the cab (there's a 2000bar one on ebay at about £90) but if the hose splits or anything goes wrong especially at full chat that'll cause serious damage, if it goes pop inside the cockpit there's enough pressure there to remove limbs/kill


I think it might be easier to use a swirl pot than twin lines to stop aring of the fuel. Forget who it was but someone on the 6 forum from the surey area had his mounted under the boot floor.

[Ruan]

Well, yeah, that's another idea I had - why not swirl pot it up to the engine bay using the stock lift pump, then take apart a GTi6 pump and then pressurize it to the pump - that way you near enough negate any problems with air'ing and you've got a damned good supply - if you then realize that the GTi6 pump isn't man enough, you can then just replace it with whatever pump you like...

ISSPro do a 30,000psi gauge - but that comes with a proper sender which sits in the bay, then electrics to the gauge.

[Poodle]

I did think about a swirl pot, but then you can't rely on the standard pump to keep up the flow to match something like that Airdog. I suppose you could rig the return line back to the swirlpot and control the level with a float arm controlling a switched feed to the lift pump, but then it's getting over-complex, too much to go wrong.

I agree about the gauges and more data, but when you can do so much more with the money they cost... The amounts of readouts i want/would need would require at least a grand to be spent on sensors and gauges, if not more, money i haven't got. £100 for an upgraded pump i could stretch to though lol.

[Jonny81191]

I had a good look earlier while making my exhaust, and I gotta agree that the fuel lines do look a bit small..

[Dum-Dum]

Did you measure them by any chance dude?

[Jonny81191]

er, no. but i'd guess 10mm

[Dum-Dum]

Thats pretty big considering its only thin wall pvc, are you sure. Id of thought at best a 6mm feed and 8mm return

[Ruan]

Remember, flow increases with a drop in pressure... Hence stock lift will probably be fine to swirl pot...

[Ricky]

If for example I fitted a seperate uprated lift pump, and unplugged the old pump, would it throw up a fault code? If the answer is yes would it still show a fault if I used the original wiring?

[Dum-Dum]

I dont believe it does as long as the pump and rail are getting enough pressure.

[Ruan]

Yeah doesn't matter, ECU isn't sensing power usage - just that rail pressure is up when cranking and running,

[Arron]

Walbrough in tank pump here is £70 and flows 255lph. Says it would do 500bhp on a normal car http://www.ebay.co.uk/itm/WALBRO-255-FUE...2567798862



Actually f*ck me this looks awesome, cant work out what the catch is. 300lph at 94psi (over 6bar) working pressure, M10 outlet and only £25 http://www.ebay.co.uk/itm/12V-UNIVERSAL-...3a81c8faf3

I emailed walbro. They said that top pump would be unsuitable for the hdi.

But I hear your running a gti 6 lift pump in a hdi?

Also the bottom link the price is now £125!! Did anyone ever fit/try this?