fuel pumps

mk5 luva · Forum Junkie

fuel pumps

Wolf · Rehab Dropout...

Hey mate,

Attached is the setup for our fuel system.

The lift pumps are cheap arse ??? pumps - we're gonna change them to carter high volume, low pressure pumps. The main pumps are VL Turbo jobbies, but again, we're gonna change them to bosch motorsport ones.

We're using the standard 1uz reg - no dramas with it at Finke. Whether it was at idle or flat out it stayed very steady at 40psi.

All electricals are duplicated. A 3 way switch on the dash powers seperate relays for fuel system 1 and fuel system 2. They run seperate fuses and even the pumps are earthed in different spots.

We had no probs with it, but Chris Western has told us that with the VL turbo pumps on the 1uz's he's had probs keeping fuel pressure up on long flat out runs which could result in the engine leaning out, getting hot, going bang etc.

mk5 luva · Forum Junkie

Thanks, i new you would have the answer very promptly and with excellent diagram biggrin

. Sounds like the double pump set up is the way to go. How much are the Bosch Motorsport pumps? What sort of fuel consumption are you getting. I have to buy axles for it, have been told to go to Albins but havent priced them yet.

In rehab

Hey Wolf; Don't mean to be picky but if your fuel flow diagram is accurate I can see a possible flaw in that if you are unlucky enough to have one pump shag itself, it may not be able to hold line pressure (one of the first tests done on EFI pumps when diagnosing) & according to your diagram could allow bleed back to the low pressure side therefore reducing pressure & flow. I'm sure the system works great but it may not be a problem until theres a problem. Maybe worth a look or tell me to eat my lunch & keep my ideas to myself. Car looks good BTW.

Wolf · Rehab Dropout...

260 - By all means be picky mate! Definately worth a look, anyone got a suggestion? I also forgot to put in the vent line out of the main tank in the diagram.

MK5 - Re the pumps, not sure how much, pretty much any speed shop should have them, or be able to get them though. Even try ebay.

Re the axles, we got ours made by Cliff Alderton, an ex offroader here in sydney. I think they're 36.5" and cost a grand odd if memory serves, which it doesnt always. I'll pm you his mobile no if you want it.

*edit* ebay has a few listed from 200 to 250, plus some cheaper alternatives if you're interested. search on bosch fuel pump.

I'll recreate the diagram a bit more accurately too as the swirl pot has 2 inlets from the lift pumps and 2 outlets for the high pressure pumps, so theres another possible problem same as the one that 260 pointed out.... *edit ends*

-- Edited by Wolf on Friday 24th of July 2009 02:36:12 PM

-- Edited by Wolf on Friday 24th of July 2009 02:39:27 PM

In rehab

Wolf, I would consider an electromagnetic fuel shut-off for each pump between pump & filter (the same as the ones used in LPG conversions, when open offer no restriction & seem to be quite reliable) powered by the same circuit as each fuel pump respectively. This will also stop the healthy pump feeding shagged pump parts back into it's own supply line. The trouble is to counter any possible failure gives more parts to rely on. Sorry while thinking more I would change that to putting the shutoffs between the rail & the filters as the healthy pump would also backflush the other filter first.

-- Edited by 260 on Friday 24th of July 2009 02:57:26 PM

bert5 · Powerhouse Poster

Does your fuel system use any one way check valves or do the pumps have them built in.

Wolf · Rehab Dropout...

nope and dont know! But as I only paid $80 for each pump Im guessing they're not built in!

One way check valve huh. any fuel flow restrictions from these items?

In rehab

Most EFI pumps are designed to maintain a certain line pressure when switched off, ie; built in valve. Your VL ones would have but they can fail.

Wolf · Rehab Dropout...

Cheers 260. That makes sense considering that the fuel system holds pressure for a while after the car is switched off. Der.

What about lift pumps? Any idea?

*edit* btw, long lunch today mate? :p

-- Edited by Wolf on Friday 24th of July 2009 03:20:57 PM

Wolf · Rehab Dropout...

hey mk5 - check out the pics of the micklefab TT in dirtcomp - very tidy fuel system that! and similar to what you'll be after.

Wolf · Rehab Dropout...

http://www.mscn.com.au/scripts/prodView.asp?idproduct=471

$63. Cheap insurance for a dual system I guess!

In rehab

Those little do-dahs look the goods. Not a long lunch, just frequent visits to the office. Sorry Wolf, you thought you were just answering a question & then it all became about you.

Stingray 2212 · Rehab Dropout...

I find it hard to believe that a VL turbo pump can't keep up. A Bosch 070 VL turbo pump flows at 270 litres per hour at 3 bar pressure.

dessert-people · Rehab Dropout...

mk 5

we just run a bosch in tank pump we mounted it in little box drilled some holes in it and run the return line into the box it works a treat on our 1uz , its out of a merc and not that dear we also run a cooler in the return line
furious

mk5 luva · Forum Junkie

The in tank pump set up has its benefits, runs cooler and dust free. We have already had the tank made so external will be the simplest. The single pump obviously keeps up with the 1uz, Whats the flow rate of the Benz pump DP? The little do-dahs are worth having at 60 bucks!! Had a look at the Micklefab TT, sweet looking truck and the fuel system looks like what i need. . When are we going to see the Wolf in Dirt Comp????? wink

Thanks for all the advice, every little bit helps.

mk5 luva · Forum Junkie

Got off track a bit fitting the front suspension, now its time to sort out the fuel system. Had a look at the bosch pumps on ebay. Theres one model 044 which sounds the goods. Flows 300lph at 72psi? according to the ebay speil confuse

. I guess one of these would be enough for my 1uz. There only about $250ish so not too bad on whats left of my buggy fund(non existent).