intank surge tank setup...

[ed]

so which commonwhore model am i looking at for this intank lift pump? and do they run an intank surge pot also? worth pilfering?

[thechuckster]

hmmm, they run a submersible intank lift pump?

yup - i foolishly tried to use one as an EFI pump once ... for my sins i had to waste nearly twenty litres emptying the MA61 tank a second time.

[ed]

so which commonwhore model am i looking at for this intank lift pump? and do they run an intank surge pot also? worth pilfering?

as above

?

cheers
ed

[thechuckster]

early EFI commode - the ones with nissan motors apparently

i know little of these shitbox cars - only that they have external EFI pumps, 70mm throttle bodies and the aforementioned intank pump.

[Forcefed6]

That would be a VL commodore you are refering too.

I have seen a few different pumps used at time with good results. These include the VT intank pump, and walbros. Walbro pumps pump heaps when not under pressure.

[Norbie]

Yup VL and EFI VK Commodores have an in-tank low-pressure pump. I was looking at one the other day (a friend has a spare I'm planning to pilfer for use in my RA23) and it's absolutely tiny, significantly smaller than a Walbro even, but apparently it's fine for big HP setups if used with a surge tank. If on the other hand you want to use it to directly feed a high-pressure pump, I'd suggest going for something a bit better (eg low-pressure Walbro pump).

As for the VL's in-tank surge pot, if it has one it doesn't work very well. The aforementioned friend installed an external surge tank for this very reason.

[ed]

thinking of running 2 on opposite sides of the tank feeing a pot for the efi pump

[Norbie]

That might work OK then. Depending on the capacity and drain time of this pot it may not be necessary to have two lift pumps though? Remember you'll only be utilising the full flow of the EFI pump for relatively short periods.

[ed]

only considering 2 because of placement in opposite sides of the main tank

[JustenGT8]

Ed, i can't categorically answer your questions but i can add weight to your concerns

Running an EFI pump to no pressure will quite likely wear the pump out quickly as it's basically running at it's full rpm full time. You'll also quite likely have a spa bath in the surge pot as the flow rate from the 'open' EFI pump will be HUGE, literally blasting the fuel in there....suspect the aeration created will no be a good thing.

As you know EFI pumps hate running dry.....if you surge in the current surge tank then HEAPS more in the main tank....EFI lift pump won't last long.

Now having said all that, i run the stock GrpA in-tank pump as my lift pump to my surge tank (x2 bosch motorsport pumps from there). No probs to date and supports a shitload of hp. I suspect that the surge tank does pressurise to some extent, plus the 1.5m of line to get it there so the intank pump is actually having to do some work and isn't spinning at full rpm. The GrpA fuel tank has always been excellent in terms of surge so that's never been an issue.

My vote is for external surge with external Bosch pump, use your current intank arrangement as the lift pump. Don't skimp on the fuel side, only a bee's dick less important than the oiling and look at the effort you have gone to there.

[YLD-16L]

Just to add some info regarding the HP pump as a feed to the surge tank.

I run a HP pump feeding my surge tank and it has been like that for 7 (nearly 8) years now.

Never had any issues or had to replace it so far *touches nearest wooden item*. So it may not be an ideal situation for a HP fuel pump (for the reasons Justen mentioned) but 7 years of trouble free use isn't a bad lifespan (it was a second hand pump too).

[thechuckster]

Justen & YLD: both cars are daily drivers or track-only? not challenging your experiences, just curious as to whether i'm treating that kind of use as a high instead of low risk of pump failure. Yours would suggest it's a low risk.

[YLD-16L]

both cars are daily drivers or track-only?

My car is used for everything that I do with a car - commuting, track days, motorkhanas, drags, 1000km+ trips interstate etc.

So it sees everything from a cruise to the shops to driving it as hard as it'll let me on the track

As yet the fuel system setup (Tank>Feed Pump>Surge Tank>HP Pump) has not had an issue under any form of use.

[WDE_BDY]

I can confirm that the VN Commodore V8 wagons run the twin pump setup too, I would presume other VN models are similar. Mate transfered the setup to his EH Holden wagon tank when he did the V8 conversion. He figured replicating the factory fuel system was the best way to go for a conversion into a cruiser.

Callum

[JustenGT8]

Justen & YLD: both cars are daily drivers or track-only? .

The GT8 is a regular streeter but not what you'd call high annual kms. It did the run from Canberra-Dubbo-Brissie-Canberra in the stinking heat last year with some long days which would kill a suss pump.

As a lift pump as described i think OK.... as a lift pump as Ed orig described i think not