45 replies to this topic

[Toranamat69]

I use a very similar setup in my LX and I didn't clean out the tank until I managed to burn out 2 VL pumps in the first 3 weeks - Then I cleaned the tank and it hasn't re-occurred for the last 3 1/2 years - at $250 a pump I would clean the tank.
I am using, and always have been using a 10 micron filter straight out of the tank before the first pump but the really fine shite that got through took down my pumps and I found it when I pulled them apart.

Holley blues are the noiseyest POS in the world and they should stop selling them, you will kick yourself from now till the end of time if you install one.

I have a 2.1L surge tank and if my tank is under 1/3 full, I get fuel surge and engine missing on hard corners on the track - Never notice it on the street though so after all that farting around, I would advise a custom baffled tank with an in tank High pressure pump - no external pumps, no external surge tank, just the feed line, the return and a 10 micron filter hidden away somewhere.

Simpler, lighter, cleaner, quiter and will work better and with what I have spent, I could now have that sytem.
As it is, I now have all that $$ and work still to spend.

I'm not bitter am I

One of those hard lessons in life.

M@

[ls2lxhatch]

The purpose of the surge tank is to guarantee a constant fuel flow without air to the EFI pump which in turn guarantee's a constant fuel pressure to the engine. If the fuel pressure drops then the engine will run lean. If the fuel pressure drops at full throttle it could be terminal for the engine.

The only way you can guarantee fuel pressure at all fuel levels and G-Force loads is to have a surge tank system with sufficient capacity to provide fuel when the lift pump is sucking air.

A swirl pot is not suitable for the EFI pump but would help keep the lift pump from running dry.

[Toranamat69]

There are plenty of factory high performance cars out there with in-tank high pressure pumps which draw from an internal baffled section of their tank and suffer no fuel surge (kind of like an intank - surge tank anyway) so I am going to follow their lead.

I am also a very strong believer of the less is more method of building cars now - the fewer parts, the less there are to fail, the lighter it is (not many parts weigh less than air) and the easier it is to package.

M@

[ls2lxhatch]

I agree simpler is best. I wanted to fit a VZ Commodore fuel pump $250 which has a built in surge tank inside the swirl pot in my drop tank. You can buy weld in mount rings for the VZ pump from Castle Auto Electric. The problem is that they require a minimum depth of 240mm and 40mm clearance above the pump. My Brown Davis 120lt drop tank is only 210mm deep and has 5mm clearance above.

A point to note is that the Torana fuel tank is the worst possible design when it comes to fuel surge. The ideal tank is as deep, thin and narrow as possible with the pickup at the rear. The Torana tank is shallow, wide and long.

I am still looking for a fuel system for my drop tank. My current plan is to open up the tank and fit a swirl pot inside and modify the recess in the tank for the spare tyre to house a Bosch 044 pump. I will probably use a VL style pump to supply the surge tank. This will cost around $1000 so if you can come up with a simpler or cheaper option I would like to hear about it.

Edited by ls2lxhatch, 13 March 2007 - 10:25 PM.

[ls2lxhatch]

The tank is a 120lt aluminium drop tank so is does stand out a bit.

The lift pump will bolt into the front of the tank in a similar maner to a VL Commodore. The EFI pump will be mounted on the outside of the tank in the modified spare tyre recess. The surge tank will have hard lines welded to the outside of the tank so there should not be anything inside that tank that requires servicing.

You could check whether mounting the surge tank in the engine bar is legal or not in your state. I think Litre8 has the surge tank and EFI pump in the engine bay.

http://www.litre8.com/neweng9.JPG

[Toranamat69]

wouldn't you (toranamatt) still have the same gear just located in a tank instead of spread out? how is it you are saving weight then?

Using the system on a 300ZX as an example (I like stealing some of their ideas) the surge tank built into the tank is plastic and would be lucky to weight 100g's.

If I used the same system, I would save the weight of 1xholley blue pump, 1xsurge tank (mine is stainless and approx 5kg), 1 fuel filter, approx 2m of stainless braided hose, the fuel to fill all of these items (approx 3litres) and about 5 or 6 fuel fittings to hook them all up.

I'd say I would have nearly 10kg saving there - maybe 7-8kg if the surge tank you were ditching was alloy. I also use 2 VL pumps so if I get 1 large one which can handle the flow of both then I will most likely save a bit more too.

The fuel pump is mounted under a bolted flnge in one unit with fuel level float so you can undo the flange and take it all out - this is standard on almost all EFI cars these days.

M@

Edited by Toranamat69, 15 March 2007 - 06:20 PM.